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Saxena K, Kitzmiller KJ, Wu YL, Zhou B, Esack N, Hiremath L, Chung EK, Yang Y, Yu CY. Great genotypic and phenotypic diversities associated with copy-number variations of complement C4 and RP-C4-CYP21-TNX (RCCX) modules: a comparison of Asian-Indian and European American populations. Mol Immunol 2009; 46:1289-303. [PMID: 19135723 PMCID: PMC2716727 DOI: 10.1016/j.molimm.2008.11.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 11/22/2008] [Indexed: 01/26/2023]
Abstract
Inter-individual gene copy-number variations (CNVs) probably afford human populations the flexibility to respond to a variety of environmental challenges, but also lead to differential disease predispositions. We investigated gene CNVs for complement component C4 and steroid 21-hydroxylase from the RP-C4-CYP21-TNX (RCCX) modules located in the major histocompatibility complex among healthy Asian-Indian Americans (AIA) and compared them to European Americans. A combination of definitive techniques that yielded cross-confirmatory results was used. The medium gene copy-numbers for C4 and its isotypes, acidic C4A and basic C4B, were 4, 2 and 2, respectively, but their frequencies were only 53-56%. The distribution patterns for total C4 and C4A are skewed towards the high copy-number side. For example, the frequency of AIA-subjects with three copies of C4A (30.7%) was 3.92-fold of those with a single copy (7.83%). The monomodular-short haplotype with a single C4B gene and the absence of C4A, which is in linkage-disequilibrium with HLA DRB1*0301 in Europeans and a strong risk factor for autoimmune diseases, has a frequency of 0.012 in AIA but 0.106 among healthy European Americans (p=6.6x10(-8)). The copy-number and the size of C4 genes strongly determine the plasma C4 protein concentrations. Parallel variations in copy-numbers of CYP21A (CYP21A1P) and TNXA with total C4 were also observed. Notably, 13.1% of AIA-subjects had three copies of the functional CYP21B, which were likely generated by recombinations between monomodular and bimodular RCCX haplotypes. The high copy-numbers of C4 and the high frequency of RCCX recombinants offer important insights to the prevalence of autoimmune and genetic diseases.
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Affiliation(s)
- Kapil Saxena
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
| | - Kathryn J. Kitzmiller
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
- Department of Pediatrics, The Ohio State University, Columbus, Ohio
| | - Yee Ling Wu
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
- Department of Pediatrics, The Ohio State University, Columbus, Ohio
| | - Bi Zhou
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
| | - Nazreen Esack
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
| | - Leena Hiremath
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Erwin K. Chung
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio
| | - Yan Yang
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio
| | - C. Yung Yu
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus Ohio 43205
- Department of Pediatrics, The Ohio State University, Columbus, Ohio
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio
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Mustafa A, Nityanand S, Berglund L, Lithell H, Lefvert AK. Circulating immune complexes in 50-year-old men as a strong and independent risk factor for myocardial infarction. Circulation 2000; 102:2576-81. [PMID: 11085959 DOI: 10.1161/01.cir.102.21.2576] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Circulating immune complexes (CICs) and autoantibodies against oxidatively modified LDLs (oxLDLs) and cardiolipin occur in patients with atherosclerosis and myocardial infarction (MI). The ability of such CICs and antibodies to predict myocardial infarction (MI) was investigated in a prospective nested case-control study in which healthy 50-year-old men were followed for 20 years. METHODS AND RESULTS Two hundred fifty-seven men were included in the study, and 119 developed MI (39 died) between 50 and 70 years of age. One hundred thirty-eight randomly chosen men who did not develop MI up to 70 years of age served as controls. The prevalence of elevated levels of CICs and the concentration of CICs in men who developed MI were higher than in those who remained healthy. The concentration of CICs at age 50 was associated with a marked increased risk for MI, and this risk was independent of other conventionally recognized risk factors. There was a positive correlation between the levels of CIC and IgG antibodies to cardiolipin in men who developed MI. The level of IgG antibodies and the prevalence of elevated IgG and IgM antibodies to cardiolipin were higher in those who developed MI and had CICs than in those without CICs. Among men homozygous for C4 null alleles, those who developed MI had higher concentrations of CICs than did those who remained healthy. CONCLUSIONS This prospective study shows that CICs alone or in combination with autoantibodies against cardiolipin in healthy males at 50 years of age predict subsequent MI between the age of and 70 years.
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Affiliation(s)
- A Mustafa
- Immunological Research Unit, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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Grant SF, Kristjánsdóttir H, Steinsson K, Blöndal T, Yuryev A, Stefansson K, Gulcher JR. Long PCR detection of the C4A null allele in B8-C4AQ0-C4B1-DR3. J Immunol Methods 2000; 244:41-7. [PMID: 11033017 DOI: 10.1016/s0022-1759(00)00251-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The genes coding for the two components of complement 4 (C4), C4A and C4B, are located within the major histocompatibility complex (MHC) on the short arm of chromosome 6. Several studies have shown that deficiency of C4A is associated with systemic lupus erythematosus (SLE), rheumatoid arthritis and scleroderma. A large deletion covering most of the C4A gene and the 21-hydroxylase-A (21-OHA) pseudogene found on the extended haplotype B8-C4AQ0-C4B1-DR3 is estimated to account for approximately two-thirds of C4A deficiency in Caucasian SLE patients. Detection of this C4A null allele has been technically difficult due to the high degree of homology between C4A and C4B, with protein analysis and restriction fragment length polymorphism (RFLP) analysis using Southern blotting being the only approaches available. In this study, a long PCR strategy was used to rapidly genotype for the C4A deletion through specific primer design. The methodology makes use of the unique sequence of the G11 gene upstream of C4A and the sequence of a 6.4 kb retrotransposon, the human endogenous retrovirus HERV-K(C4), which is present in intron 9 of C4A but absent in the case of the deletion.
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Kozlov LV, Lakhtin VM, Skorokhodova TG, Batalova TN, Shoibonov BB, D’yakov VL, Guzova VA, Matveevskaya NS. Isotyping of component C4 of human complement using differences in the functional activity of isotypes C4A and C4B. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2000. [DOI: 10.1007/bf02758619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nityanand S, Truedsson L, Mustafa A, Bergmark C, Lefvert AK. Circulating immune complexes and complement C4 null alleles in patients in patients operated on for premature atherosclerotic peripheral vascular disease. J Clin Immunol 1999; 19:406-13. [PMID: 10634214 DOI: 10.1023/a:1020506901117] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Circulating immune complexes can lead to vascular inflammation and premature atherosclerosis and the fourth component of complement, C4, plays an important role in the removal of immune complexes. The objective of this study was to analyze the relation between circulating immune complexes and C4 null alleles in patients operated on for peripheral vascular disease before the age of 50. The prevalence of circulating immune complexes and null alleles of C4 (C4Q0) was determined in 62 patients with peripheral atherosclerosis requiring surgery before 50 years of age and in a matched control group. C4A and C4B null alleles (C4A*Q0, C4B*Q0) were determined by electrophoresis of plasma, followed by immunofixation. C4A and C4B concentrations were measured by ELISA. Circulating immune complexes were determined by sucrose density gradient centrifugation and gel filtration. There was no difference in the distribution of C4Q0 between patients and controls. The patients had higher prevalences and levels of circulating immune complexes. This was correlated with the presence of C4Q0, especially C4A*Q0. There was an inverse correlation of concentration of circulating immune complexes with C4A levels and with ratio of C4A/B levels. Thus, a significant proportion of patients with premature peripheral atherosclerosis had circulating immune complexes and C4A*Q0 enhanced the propensity to immune complex formation. This might represent one mechanism for vascular damage in this patient group.
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Affiliation(s)
- S Nityanand
- Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
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Abstract
The classical risk factors, hypercholesterolemia, smoking, hypertension and diabetes, explain only a part of the epidemiological features of atherosclerotic coronary heart disease. Investigations in the past few years have shown involvement of immunological mechanisms in atherosclerosis. Circulating immune complexes accelerate atherosclerosis both in experimental animal models and in humans. The fourth component of complement (C4) plays an important role in the solubilisation and elimination of immune complexes. C4 consists of two allotypes, C4A and C4B. An earlier report showed an association between C4B null alleles (C4B*Q0) and myocardial infarction and to infarction related mortality. In the present investigation, C4A*Q0 and C4B*Q0 were studied in two population samples. The first (Group I) was a cross sectional study of 100 consecutive males with myocardial infarction before the age of 45 years and 164 population based healthy controls, age and sex matched. The second (Group II) was a nested case control study in which a cohort of 50 year-old males were followed for 20 years for development of myocardial infarction between 50-60 and 60-70 years, and the results compared with those who did not develop MI. We observed no association of homozygous and/or heterozygous C4A*Q0 or C4B*Q0 with myocardial infarction occurring in the age groups < 45, 50-60 and 60-70 years or with the infarction related mortality (P > 0.05). The prevalence/frequency of C4A*Q0 and C4B*Q0 was not related to the age at which MI occurred. The prevalence of C4A*Q0 was not affected by age. We thus conclude that partial deficiency of C4 does not appear to be a major risk factor for myocardial infarction.
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Affiliation(s)
- S Nityanand
- Immunological Research Unit, Center for Molecular Medicine Karolinska Hospital, Stockholm, Sweden
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Schneider PM, Stradmann-Bellinghausen B, Rittner C. Genetic polymorphism of the fourth component of human complement: population study and proposal for a revised nomenclature based on genomic PCR typing of Rodgers and Chido determinants. EUROPEAN JOURNAL OF IMMUNOGENETICS : OFFICIAL JOURNAL OF THE BRITISH SOCIETY FOR HISTOCOMPATIBILITY AND IMMUNOGENETICS 1996; 23:335-44. [PMID: 8909940 DOI: 10.1111/j.1744-313x.1996.tb00006.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The fourth component of human complement (C4) is coded for by two homologous genes, C4A and C4B, located in the class III region of the major histocompatibility complex (MHC). Genetic typing of C4A and B alleles is routinely carried out by high-voltage agarose gel electrophoresis. The electrophoretic C4 polymorphism can be further subdivided by the Rodgers (Rg) and Chido (Ch) blood groups, which are antigenic determinants of the C4A and B alpha-chains, respectively. We have used a recently described direct PCR typing method using sequence-specific primers (PCR-SSP) in combination with electrophoretic C4 typing as well as genomic RFLP analysis to determine the frequency of C4 allotypes, Rg/Ch subtypes and C4A-B haplotypes in a family study of the German population. As the current C4 allele designation does not provide any information about the presence or absence of Rodgers and Chido antigens, we have developed an extension to the existing C4 nomenclature. This revised allele designation combines the existing numerical allotypes defined by electrophoretic mobility with eight subtypes (01-08) based on Rg/Ch PCR genotyping results. Using this approach, most electrophoretic allotypes could be subdivided. Among the C4A allotypes, the most common allele was A*0301 (59.9%), and the most common subtype among all electrophoretic allotypes was 01 (85.1%; = Rg1,2-positive, Ch-negative). For C4B, the most common allele was B*0101 (64.3%), and the most common subtype was 01 (79.6%; = Ch1,2,3,4,5,6-positive, Rg-negative). The subtypes 03, 04, 07 and 08 of the C4A allotypes, and the subtypes 03, 07 and 08 of the C4B allotypes, were not detected in this study. The analysis of duplicated C4 alleles revealed considerable heterogeneity of their subtypes. The results demonstrate that all known C4 allotypes can now be assigned unambiguously, which facilitates the identification of MHC haplotypes relevant for transplantation and disease association studies.
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Affiliation(s)
- P M Schneider
- Institute of Forensic Medicine, Johannes Gutenberg University, Mainz, Germany
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Park KS, Park MH, Juji T, Tokunaga K. Complement C4A, C4B and BF haplotypes in Koreans. TISSUE ANTIGENS 1996; 47:200-5. [PMID: 8740769 DOI: 10.1111/j.1399-0039.1996.tb02541.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Specific alleles at C4A, C4B and BF loci occur in populations and are inherited in complotypes, which are linked with particular HLA haplotypes. Considerable differences in complement allele and complotype frequencies have been observed among various ethnic groups. In the present study, 109 Korean families were analyzed for complement and complotype polymorphism. Thirty-four different complotypes were detected: the most common was BF*S-C4A*3-C4B*1 (S31) with a frequency of 42.2%, followed by S42 (14.3%) and F31 (13.8%). Three complotypes, S42, F31, and FQ01, showed positive linkage disequilibrium. Some of the complotypes were linked with characteristic HLA haplotypes. Two complotypes carrying duplicated C4A genes, S3+31(BF*S-C4A*3-C4A*3-C4B*1) and S3+2Q0(BF*S-C4A*3-C4A*2-C4B*Q0), were exclusively associated with HLA-A24-Cw7-B7-DR1-DQ1 and A24-CBL-B52-DR15-DQ1 haplotypes, respectively. Twelve families showed recombinant haplotypes, nine in the class I region, three between the HLA-B and HLA-DR loci, and none in the class III region. Maternal recombination occurred twice as frequently as paternal. The results obtained in this study represent the frequencies of complotypes and extended HLA haplotypes of well-defined Koreans, based on a family study.
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Affiliation(s)
- K S Park
- Department of Biology, Sung Shin Women's University, Seoul, Republic of Korea
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Nityanand S, Dawkins RL, Lithell H, Holm G, Lefvert AK. C4 null alleles in a Swedish population. EUROPEAN JOURNAL OF IMMUNOGENETICS : OFFICIAL JOURNAL OF THE BRITISH SOCIETY FOR HISTOCOMPATIBILITY AND IMMUNOGENETICS 1995; 22:435-41. [PMID: 8597560 DOI: 10.1111/j.1744-313x.1995.tb00281.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The distribution of C4 null alleles (C4Q0) was studied in a Swedish population comprising 410 male individuals from Stockholm County and Uppsala City. The prevalances of homozygous C4A*Q0 and C4B*Q0 determined by analysing the gene products in serum were 5.0 and 5.6%, respectively, in the Stockholm population and 4.0% each in the Uppsala population. These values are higher than those previously reported from other Caucasian populations. The finding reflects a different genetic composition of the Swedish population and may have relevance to the disease spectrum in this population as compared to other Caucasian populations.
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Affiliation(s)
- S Nityanand
- Department of Medicine, Karolinska Hospital, Stockholm, Sweden
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10
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Tanaka H, Bannai M, Tokunaga K, Itoh Y, Moriyama S, Itoh K, Siga J, Hirakawa K. Two rare MHC haplotypes carrying DR2 in the Japanese population. TISSUE ANTIGENS 1994; 43:120-3. [PMID: 8016839 DOI: 10.1111/j.1399-0039.1994.tb02311.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- H Tanaka
- Japanese Red Cross Yamaguchi Blood Center
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11
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Shornick JK, Artlett CM, Jenkins RE, Briggs DC, Welsh KI, Garvey MP, Kelly SE, Black MM. Complement polymorphism in herpes gestationis: association with C4 null allele. J Am Acad Dermatol 1993; 29:545-9. [PMID: 8408788 DOI: 10.1016/0190-9622(93)70219-j] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Herpes gestationis (HG) is a rare, pregnancy-related skin disease characterized by the production of an autoantibody to a component of the hemidesmosome. It is associated with the class II antigens HLA-DR3 and HLA-DR4, but its potential association with the "class III antigens" C2, C4, and factor B has not previously been studied. OBJECTIVE Our purpose was to study complement polymorphism in HG. METHODS Using electrophoresis and immunofixation techniques, we determined the allele frequencies of C4A, C4B, C3, and factor B in 42 patients with a history of HG. RESULTS Ninety percent of patients carried a C4 null allele (C4*QO). No statistically significant association with C3 or factor B alleles was seen. CONCLUSION HG is associated with the presence of a C4*QO. Whether the C4*QO is the primary genetic association, or whether the C4*QO is related to its linkage disequilibrium with DR3 and DR4 has yet to be determined.
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Affiliation(s)
- J K Shornick
- St. John's Institute of Dermatology, St. Thomas' Hospital, London, UK
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13
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Revised nomenclature for human complement component C4. WHO-IUIS Nomenclature Sub-Committee. J Immunol Methods 1993; 163:3-7. [PMID: 8335957 DOI: 10.1016/0022-1759(93)90232-v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Regueiro JR, Arnaiz-Villena A, Vicario JL, Martinez-Laso J, Pacheco A, Rivera-Guzman JM. A decrease in the estimated frequency of the extended HLA haplotype B18 CF130 DR3 DQw2 is common to non-insulin-dependent diabetes, juvenile rheumatoid arthritis, and Berger's disease. EXPERIENTIA 1993; 49:553-6. [PMID: 8335082 DOI: 10.1007/bf01955162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Extended HLA haplotypes frequencies were estimated from the HLA, C2, Bf and C4 phenotypes of 74 patients with non-insulin-dependent diabetes (NIDD), 92 with juvenile rheumatoid arthritis (JRA), 44 with Berger's disease (BD), 83 with insulin-dependent diabetes (IDD), and 140 healthy controls. The extended HLA haplotype B18 CF130 DR3 DQw2, which is common (around 10% phenotype frequency) in healthy Spaniards and in other populations of paleo-North African origin, was found to be significantly less frequent in NIDD, JRA and BD, whereas its frequency was normal in IDD (although DR3 DQw2 haplotypes were increased in the latter disease). These data support the existence of a common HLA-linked pathogeneic mechanism in NIDD, JRA and BD, and point to a genetic difference between IDD and NIDD at the HLA level. This effect is readily detectable in our population because the uncommon BfF1 allele marks that haplotype instead of the more common BfS, which marks B8 CS01 DR3 DQw2 in other Caucasians. Our results support the hypothesis of strong selective pressures operating at the HLA level to preserve extended HLA haplotypes with advantageous gene sets from dilution by crossing-over. Imbalanced incomplete haplotypes may give rise to inappropriate T-cell repertoire selection in the thymus and/or antigen handling in the periphery, and be partly responsible for the pathogenesis of certain HLA-linked diseases (i.e. NIDD, JRA, and BD).
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Affiliation(s)
- J R Regueiro
- Hospital 12 de Octubre, Facultad de Medicina, Universidad Complutense, Madrid, Spain
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May KP, West SG, Moulds J, Kotzin BL. Different manifestations of the antiphospholipid antibody syndrome in a family with systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 1993; 36:528-33. [PMID: 8457227 DOI: 10.1002/art.1780360413] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Familial associations of the antiphospholipid antibody syndrome (APS) offer the opportunity to study genetic mechanisms of autoantibody production and disease, but are unusual. We identified a family, including identical twins and their mother, in which all members had systemic lupus erythematosus (SLE) and presented with different manifestations of the APS. METHODS Review of case histories and clinical laboratory results, antiphospholipid antibody (aPL) studies, complement C4 protein and gene analysis, and HLA typing of family members were performed. RESULTS Each of the 3 family members presented with a different clinical association of the APS. These various clinical presentations were closely temporally related. No particular aPL activity could be separated out that would account for the different manifestations, although the twin with thrombocytopenia and livedo reticularis had a strikingly high IgM anticardiolipin antibody level. C4A or C4B deficiencies could not be implicated in the autoimmune process. However, the mother and the twins shared the HLA haplotype that included the class II antigens DR4, DRw53, and DQw7, which has previously been associated with aPL production. CONCLUSION This family study emphasizes the different clinical associations of aPL production in SLE. In addition to genetic influences that appear to include HLA class II antigens, the clinical presentations also suggest an environmental trigger.
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Affiliation(s)
- K P May
- Division of Rheumatology, Fitzsimons Army Medical Center, Aurora, CO 80045-5001
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Ratanachaiyavong S, Lloyd L, Darke C, McGregor AM. MHC-extended haplotypes in families of patients with Graves' disease. Hum Immunol 1993; 36:99-111. [PMID: 8096501 DOI: 10.1016/0198-8859(93)90112-e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
MHC-extended haplotypes were investigated in multiplex families of patients with hyperthyroid GD. Using a combination of both phenotypic (serology and protein electrophoresis) and genotypic (DNA-RFLP) markers, 159 MHC-extended haplotypes extending from HLA-A across the MHC class III (C2, Bf, C4A, and C4B) toward the HLA-DR/DQ complex were deduced from 217 (51 and 166 affected and unaffected) members of 21 families of patients with GD. Thyroid autoantibodies were measured and found positive in 27.1% of 166 clinically euthyroid unaffected members. Extended haplotypes were classified into four categories--affected (n = 40), Aff/Ab + ve (shared haplotype between affected and Ab + ve members, n = 31), Ab + ve (n = 29), and Ab - ve (n = 59)--based on the presence and absence of these haplotypes in 51 affected members with GD and 45 and 121 unaffected members who were respectively positive and negative for thyroid autoantibodies. Five recombinations were detected: three were found between HLA-A and B and two between HLA-B and the MHC class III. No recombination was found between or within the MHC class III and class II complex. Though the HLA-DR17 (DR beta 17(1) and DR beta 17(2)) allele was found to be significantly increased in both the affected and the Aff/Ab + ve when compared with the Ab - ve haplotypes (p < 0.042 and p < 0.018), the frequency of the HLA-B8, 2.7-kb SstI-4.5-kb TaqI/C2 Bf*S, 6.4-kb TaqI/C4A*Q0C4B*1, HLA-DR beta 17(1)/DQ alpha 2-DQ beta 2a extended haplotype was found to be significantly increased only in the affected haplotype (p < 0.05). These results suggest that while HLA-DR17 is a susceptibility allele shared between GD and individuals with positive thyroid autoantibodies, the HLA-B8, 2.7-kb SstI-4.5-kb TaqI/5'-3'C2 Bf*S, 6.4-kb TaqI/C4A*Q0B*1, DR beta 17(1)/DQ alpha 2-DQ beta 2a is a disease susceptibility-extended haplotype for Graves' disease.
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Park KS, Choi SY, Park MH, Tokunaga K. Allotypes of the fourth component of complement in Koreans. THE JAPANESE JOURNAL OF HUMAN GENETICS 1992; 37:285-92. [PMID: 1297448 DOI: 10.1007/bf01883319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The analysis of genetic polymorphism in C4 was performed on EDTA-plasma from 169 healthy unrelated Koreans. Plasma samples were subjected to high-voltage agarose gel electrophoresis followed by immunofixation. C4B allotypes were further detected by a hemolytic overlay method. The allele frequencies of C4A and C4B were as follows; for C4A, C4A*3 = 0.6099, C4A*4 = 0.1702, C4A*Q0 = 0.1525, C4A*2 = 0.0461, and C4A*R = 0.0213; for C4B, C4B*1 = 0.6406, C4B*2 = 0.2740, C4B*5 = 0.0569, C4B*Q0 = 0.0178, and C4B*R = 0.0107. C4A*3 and C4B*1 were among the most common alleles at each locus. C4A*6 was not detected in this study, but this allele is relatively common in both Caucasoid and Negroid populations. C4B*5 is a common allele in Asian, which is rare in Caucasoids and Negroids. C4B*5 appeared to be a characteristic allele of Oriental. In the C4A locus, five individuals with duplicated allotypes (three C4A 3,3 + 2, one C4A 4,3 + 2, and one C4A 3,3 + 3) were observed, and in the C4B locus, one individual with duplicated allotype (C4B 1,1 + 1) was detected.
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Affiliation(s)
- K S Park
- Department of Biology, Sung Shin Women's University, Seoul, Korea
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Venneker GT, Westerhof W, de Vries IJ, Drayer NM, Wolthers BG, de Waal LP, Bos JD, Asghar SS. Molecular heterogeneity of the fourth component of complement (C4) and its genes in vitiligo. J Invest Dermatol 1992; 99:853-8. [PMID: 1469300 DOI: 10.1111/1523-1747.ep12614826] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In view of evidence suggesting vitiligo is an autoimmune disease, we investigated whether vitiligo is associated with inherited deficiencies of the fourth (C4) and second (C2) component of complement and with certain human leukocyte antigens (HLA). Analysis of functional activities of C4 and C2 in sera of patients with vitiligo (n = 42) showed that 17% of them had a heterozygous C4 deficiency and 5% had a heterozygous C2 deficiency. In the normal control group (n = 30), 3% had a heterozygous C4 deficiency and none had a C2 deficiency. C4 typing by Western blot analysis showed the frequency of the C4A*Q0 allele in the vitiligo patient group to be close to normal. However, the frequency of one C4B*Q0 allele was three times higher, and that of two C4B*Q0 alleles five times higher in the vitiligo patient group than the reported frequencies in normal control groups. Southern blot analysis of Taq1 digests of DNA using C4 and 21-hydroxylase probes showed that two patients with two C4B*Q0 alleles had a deletion of a 21-OHA-C4B segment. In the other patients, having one or two C4B*Q0 alleles, these null alleles probably occurred due to a loss of C4 gene expression. HLA analysis did not show any allelic association of C4A*Q0 or C4B*Q0 with any HLA antigen in vitiligo, but confirmed the previous findings of a negative association with HLA-DR3 and a positive association with HLA-DR4. These results suggest that abnormalities of the C4B gene and the above-mentioned associations with HLA antigens may be some of the risk factors in vitiligo.
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Affiliation(s)
- G T Venneker
- Department of Dermatology, University of Amsterdam, The Netherlands
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19
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Holme ER, Veitch J, Johnston A, McKay IC, Whaley K. The relative roles of C4A and C4B in prevention of immune precipitation, solubilisation and immune adherence. Rheumatol Int 1992; 12:187-90. [PMID: 1290020 DOI: 10.1007/bf00302150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
C4A and C4B levels were measured in serum from 246 normal individuals. Complement-mediated solubilisation, assayed using alkaline phosphatase anti-alkaline phosphatase immune complexes (IC), correlated with both C4A and C4B levels. However, C4A and C4B levels showed no correlation with solubilisation of bovine serum albumin (BSA) ICs, or with the prevention of immune precipitation of BSA or alkaline phosphatase ICs, nor with immune adherence assayed using thyroglobulin and BSA ICs.
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Affiliation(s)
- E R Holme
- Department of Pathology, University of Glasgow, Western Infirmary, UK
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20
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Torii H, Nakagawa H, Ishibashi Y, Tokunaga K, Juji T. Genetic polymorphisms in the fourth component of complement (C4) and in properdin factor B (BF) in Japanese patients with palmoplantar pustulosis. J Dermatol 1992; 19:353-5. [PMID: 1401488 DOI: 10.1111/j.1346-8138.1992.tb03238.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Genetic polymorphisms in the fourth component of complement (C4) and in properdin factor B (BF) were investigated in 49 and 32 Japanese patients with palmoplantar pustulosis (PPP), respectively. C4B2 was significantly increased in frequency, whereas no significant deviations were detected in BF compared with the controls. These results may indicate that complement polymorphisms are involved in the pathogenesis of PPP.
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Affiliation(s)
- H Torii
- Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan
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21
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Shoenfeld Y, Slor H, Shafrir S, Krause I, Granados J, Villarreal GM, Alarcón-Segovia D. Diversity and pattern of inheritance of autoantibodies in families with multiple cases of systemic lupus erythematosus. Ann Rheum Dis 1992; 51:611-8. [PMID: 1616325 PMCID: PMC1005692 DOI: 10.1136/ard.51.5.611] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The pattern of inheritance of autoantibodies in eight families chosen from a pool of 110 families of patients with systemic lupus erythematosus (SLE) is described. In all the eight families at least two members were already affected by SLE. In total, 19 patients and 43 first degree relatives were examined. The inheritance of a large set of antinuclear antibodies (for example, DNA, Sm, RNP, Ro, La, histones) and 16/6 idiotype seemed to be related to some unknown genetic factors but not related to HLA. The presence of numerous antinuclear autoantibodies in the serum of a subject was not necessarily associated with overt disease. The incidence of the 16/6 idiotype among patients and their relatives was low. It is not yet clear whether the 'autoantibody burden' is greater in families with multiple cases of SLE than in families with single cases.
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Affiliation(s)
- Y Shoenfeld
- Department of Medicine B, Sheba Medical Center, Tel-Hashomer, Israel
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22
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Finco O, Li S, Cuccia M, Rosen FS, Carroll MC. Structural differences between the two human complement C4 isotypes affect the humoral immune response. J Exp Med 1992; 175:537-43. [PMID: 1732415 PMCID: PMC2119129 DOI: 10.1084/jem.175.2.537] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
An animal model has been used to address the question of the biological importance of the known structural difference between the two isotypes of human C4, i.e., C4A and C4B. Guinea pigs deficient in C4 were reconstituted transiently with either human C4A or C4B protein and immunized with the bacteriophage phi X174. Results from this study showed that C4A-reconstituted animals made a secondary response, i.e., switch from IgM to IgG; whereas the C4B-reconstituted animals did not.
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Affiliation(s)
- O Finco
- Department of Pathology Harvard Medical School, Boston, Massachusetts 02115
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23
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Hartung K, Ehrfeld H, Lakomek HJ, Coldewey R, Lang B, Krapf F, Müller R, Schendel D, Deicher H, Seelig HP. The genetic basis of Ro and La antibody formation in systemic lupus erythematosus. Results of a multicenter study. The SLE Study Group. Rheumatol Int 1992; 11:243-9. [PMID: 1579805 DOI: 10.1007/bf00301501] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Antibodies against Ro and La, including recombinant La and recombinant 60 kD-Ro, were determined by counter immunoelectrophoresis and ELISA in over 300 central European systemic lupus erythematosus (SLE) patients. The presence of both Ro and La antibodies was strongly associated with the MHC haplotype B8-C4AQ0-DR3-DQ2, the association being strongest for DR3. After exclusion of all B8-DR3 positive patients only DR3 positive patients still showed an increased incidence of Ro and La antibodies, suggesting DR3 as the primary association factor. High titers of La antibody, but not of 60 kD-Ro antibody, were also significantly associated with the presence of DR3. Other DR and DQ antigens or heterozygous DQ combinations were not significantly associated with Ro and La antibodies.
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Affiliation(s)
- K Hartung
- Department of Medicine and Immunology, University of Hannover, Federal Republic of Germany
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24
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Abstract
Many human diseases are associated with HLA class I, class II and class III antigens. It appears that the class III antigen disease associations can be explained by a direct defect operating at the level of either the class III gene or its gene product. The mechanism underlying class I and class II antigen disease associations is at present unknown. In this review we have considered thirty diseases which have been ranked according to their relative risk as defined by the frequency of a given HLA antigen in patient and control populations. The chronic inflammatory disorder, ankylosing spondylitis and its association with HLA B27 has been used as a model to study the HLA linked diseases. We have suggested that the disease may be caused by the Gram-negative microorganism Klebsiella which has antigenic similarity to HLA B27. It is proposed that some antibodies made against Klebsiella bind to HLA B27, thereby acting as autoantibodies leading to the pathological sequelae of chronic inflammatory arthritis. This is the crosstolerance hypothesis or molecular mimicry model and it has been compared to the receptor model. It is further suggested that the crosstolerance hypothesis can be utilised as a general theory to explain the association of other diseases with the class I and class II antigens, and offer a possible explanation for the polymorphism of HLA.
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Affiliation(s)
- M Baines
- Immunology Unit, King's College, Kensington, London, U.K
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25
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Hartung K, Coldewey R, Corvetta A, Deicher H, Kalden JR, Krapf F, Lang B, Lakomek HJ, Liedvogel B, Peter HH. MHC gene products and anticardiolipin antibodies in systemic lupus erythematosus results of a multicenter study. SLE Study Group. Autoimmunity 1992; 13:95-9. [PMID: 1467439 DOI: 10.3109/08916939209001909] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Anticardiolipin antibodies (aCL) and HLA-DR antigens were determined in 314 central European patients with systemic lupus erythematosus (SLE). Both HLA-DR4 and DR7 were increased in aCL-positive patients, and aCL were significantly associated with DRw53. The association between DRw53 and aCL was also apparent in those 17 patients with SLE and the anticardiolipin syndrome. There was no association between aCL and HLA-DQ or C4 alleles in SLE.
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Affiliation(s)
- K Hartung
- Department of Medicine, University of Hannover, FRG
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26
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Simon S, Awdeh Z, Campbell RD, Ronco P, Brink SJ, Eisenbarth GS, Yunis EJ, Alper CA. A restriction fragment of the C2 gene is a unique marker for C2 deficiency and the uncommon C2 allele C2*B (a marker for type 1 diabetes). J Clin Invest 1991; 88:2142-5. [PMID: 1684365 PMCID: PMC295824 DOI: 10.1172/jci115545] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
There are three common C2 protein alleles in caucasians, C2*C, C2*B, and C2*Q0, with allele frequencies of 0.96, 0.03, and 0.01, as well as Sst I RFLP variants of 2.75, 2.7, 2.65, 2.55, and 2.4 kb, with frequencies of 0.017, 0.533, 0.358, 0.017, and 0.075. Thus, C2*C is informatively split by the RFLP. Of 94 nonrandomly ascertained caucasian complotypes, 77 contained C2*C, four contained C2*Q0, and 13 had C2*B. None of the C2*C-containing complotypes carried the 2.75 kb Sst I fragment and all of the complotypes with C2*B or C2*Q0 carried it. All of the C2*Q0 alleles were associated with C4A*4, C4B*2 in the complotype S042 as previously reported. C2*B was usually (9/13) in the complotype SB42, occasionally (1/13 each) in SB45, SB41, SB(4,3)0, and SB31. Thus, the association of the C2 2.75-kb fragment was with C2*B and C2*Q0, not with C4A*4, C4B*2, or even C4A*4 alone. The complotype SC42 was associated with the 2.65-kb Sst I fragment in four of five instances and in a single example with the 2.7-kb fragment. C2*B and C2*Q0 possibly had a common evolutionary ancestor complotype which carried the 2.75-kb Sst I fragment, and BF*S, C4A*4, and C4B*2. C2*B (particularly as the haplotype HLA-Bw62, SB42, DR4) is associated with type 1 diabetes but C2*Q0 is protective.
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Affiliation(s)
- S Simon
- Center for Blood Research, Boston, Massachusetts 02115
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27
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Lokki ML, Koskimies SA. Allelic differences in hemolytic activity and protein concentration of BF molecules are found in association with particular HLA haplotypes. Immunogenetics 1991; 34:242-6. [PMID: 1916952 DOI: 10.1007/bf00215259] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
After separating the *F and *S alleles by electrophoresis the allele-specific hemolytic activity was detected by agarose overlay method using the programmable densitometer for scanning. The hemolytic activity of BF allotypes was analyzed from 81 individuals. In thirteen FS heterozygous serum samples BF F had lower hemolysis than BF S. Four FF homozygous samples also exhibited lower hemolysis than a homozygous control sample. The low hemolytic activity of F in FS heterozygotes was not due to decreased protein concentrations relative to S. On the contrary, BF F was associated with higher protein concentration than BF S. The relative quantitation of the allele specific BF protein was done by crossed immunoelectrophoresis. BF F with low hemolytic activity but with high protein concentration associated strongly with HLA B35 phenotype and the family material confirmed the association with the haplotypes A3, Cw4, B35, DR1, BFFB, C4A3BQO (or A2BQO, A3,2BQO). The results suggest that particular MHC haplotypes contain a factor B allele with encoding for poor hemolytic activity or that MHC haplotype specific regulatory elements affect pre- or post-translational activity levels.
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Affiliation(s)
- M L Lokki
- FRC Blood Transfusion Service, Helsinki, Finland
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28
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Tokunaga K, Zhang WJ, Christiansen FT, Dawkins RL. The genomic structure of two ancestral haplotypes carrying C4A duplications. Immunogenetics 1991; 34:247-51. [PMID: 1680806 DOI: 10.1007/bf00215260] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two major histocompatibility complex (MHC) ancestral haplotypes (AH) HLA A24, Bw52, C2C, BfS, C4A3+2, C4BQO, DRw15, DQw6 (52.1) and HLA A24, Cw7, B7, C2C, BfS, C4A3+3, C4B1, DR1, DQw5 (7.2), which occur with the haplotype frequencies of approximately 10% and 4% respectively in the Japanese population, carry duplicated C4A alleles by C4 allotyping. Southern blot analysis with Taq I indicated that the 52.1 AH has two C4 genes defined by 7.0 kilobase (kb) and 6.0 kb C4 hybridizing fragments but both encode C4A allotypes, being C4A3 and C4A2 respectively. The 7.2 AH carries two C4A3 and one C4B1 alleles and restriction length polymorphism (RFLP) analysis with Taq I showed that 6.0 kb and 7.0 kb fragments are in the proportion of 2:1. By pulsed field gel electrophoresis (PFGE) analysis, the lengths of the Pvul fragments carrying C4 and Cyp21 genes were approximately 390 kb for 52.1 and 440 kb to 7.2. The results indicate that the RFLP markers do not correlate with C4 isotype (A or B) or allotype and that the C4 gene copy number is a function of the number of genomic blocks containing C4 and Cyp21.
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Affiliation(s)
- K Tokunaga
- Department of Clinical Immunology, Royal Perth Hospital, Western Australia
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29
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Hessing M. The interaction between complement component C4b-binding protein and the vitamin K-dependent protein S forms a link between blood coagulation and the complement system. Biochem J 1991; 277 ( Pt 3):581-92. [PMID: 1831349 PMCID: PMC1151280 DOI: 10.1042/bj2770581] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M Hessing
- Department of Haematology, University Hospital Utrecht, The Netherlands
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30
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Kumar A, Kumar P, Schur PH. DR3 and nonDR3 associated complement component C4A deficiency in systemic lupus erythematosus. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1991; 60:55-64. [PMID: 2044237 DOI: 10.1016/0090-1229(91)90111-m] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The molecular basis of complement component C4A deficiency in white U.S. and Mexican patients with systemic lupus erythematosus (SLE) was studied. Genomic DNA from SLE patients and non-SLE controls was analyzed for restriction fragments using HindIII and a 5' C4 cDNA probe. C4A gene deletion was recognized by the loss of a 15-kb restriction fragment and the appearance of a 8.5-kb fragment. Thirty-two selected U.S. SLE patients, 7 nonSLE controls, and 11 Mexican SLE patients and 9 relatives were studied. The deletion was recognized in all of the 14 HLA-B8;DR3 SLE patients with a C4A protein deficiency. Two SLE patients with DR3 but without B8 also had this gene deletion. None of the 3 U.S. SLE nonDR3, C4A protein deficient patients nor 20 C4A protein deficient Mexican individuals (11 SLE patients and 9 relatives; none had B8 and/or DR3) showed this deletion. Thus the C4A gene deletion failed to account for the C4A protein deficiency in all the nonDR3 Mexicans and in some U.S. SLE patients. To determine whether gene conversion at the C4A locus would encode a C4B-like protein and be responsible for the C4A protein deficiency (in nonDR3 patients), the C4d region of the gene was amplified by polymerase chain reaction and subjected to Nla IV digestion, and restriction fragment analysis was performed using a C4d region-specific probe. The resulting restriction fragment length polymorphism pattern revealed no changes in the isotype-specific region of the gene as characterized by C4A-specific 276- and 191-bp fragments in Dr3 or nonDR3 individuals. Thus, homoexpression of C4B at both loci was not responsible for C4A deficiency in nonDR3 SLE patients without C4A gene deletion.
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Affiliation(s)
- A Kumar
- Department of Rheumatology/Immunology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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31
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Nakagawa H, Akazaki S, Asahina A, Tokunaga K, Matsuki K, Kuwata S, Ishibashi Y, Juji T. Study of HLA class I, class II and complement genes (C2, C4A, C4B and BF) in Japanese psoriatics and analysis of a newly-found high-risk haplotype by pulsed field gel electrophoresis. Arch Dermatol Res 1991; 283:281-4. [PMID: 1929549 DOI: 10.1007/bf00376613] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Genetic polymorphisms of HLA antigens and HLA-linked serum complement components (C2, C4A, C4B and BF) were investigated in 79 Japanese patients suffering from psoriasis. HLA typing revealed increased frequencies of HLA-A1, A2, B39, Bw46, Cw6, Cw7 and Cw11. Among complement components, positive associations were obtained with C4A4 and C4B2 and a negative association with BFF. The major histocompatibility complex haplotype (supratype), HLA-A2-Cw11-Bw46-C2C-BFS-C4A4-C4B2-DRw8 is purported to be a new high-risk haplotype in Japanese patients with psoriasis. Analysis of patients with this supratype via pulsed field gel electrophoresis showed the existence of specific, extensive DNA deletions near HLA-DR genes, but no disease-specific patterns could be observed by means of this technique. The newly-found high-risk haplotype indicates racial and ethnic differences among psoriatic patients.
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Affiliation(s)
- H Nakagawa
- Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan
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32
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Varga L, Alper CA, Zam Z, Füst G. Decreased inhibition of immune precipitation by sera with the C2 B allotype. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1991; 59:65-71. [PMID: 2019011 DOI: 10.1016/0090-1229(91)90082-l] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Complement-mediated precipitation inhibiting (CMPI) activity of sera of 5 individuals homozygous for C2 B was compared to that of sera of 20 individuals carrying the common C2 C allotype. Sera with the rare C2 B allotype had a depressed CMPI capacity in both the early (5 min) and the late (60 min) stages of the reaction. We have also compared the CMPI activity of seven homozygous C4A deficient (C4A*Q0) and eight C4B deficient (C4B*Q0) serum samples and did not find significant differences from the controls (no C4 null alleles) in any stage of the reaction. These results indicate that C2 is the critical component in the CMPI reaction of the two constituents of the classical pathway C3 convertase and that C2 B is less active than C2 C.
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Affiliation(s)
- L Varga
- National Institute of Haematology and Blood Transfusion, Budapest, Hungary
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33
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Briggs DC, Senaldi G, Isenberg DA, Welsh KI, Vergani D. Influence of C4 null alleles on C4 activation in systemic lupus erythematosus. Ann Rheum Dis 1991; 50:251-4. [PMID: 2029208 PMCID: PMC1004396 DOI: 10.1136/ard.50.4.251] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Deficiencies of early components of the classical complement pathway are known to be associated with systemic lupus erythematosus (SLE). C4 null alleles, C4A Q0 and C4B Q0, are prime candidates for the major histocompatibility complex associated factor which determines susceptibility to SLE. There is poor correlation, however, between the presence of low concentrations of C4 and possession of C4 null alleles, and thus the basis of the association between C4A Q0, C4B Q0 and SLE remains obscure. The possibility that activation of C4 may be related to the possession of C4 null alleles was examined. C4 phenotypes were investigated, and C4 concentration and activation were estimated in patients with SLE. C4 activation was determined by measuring the concentration of C4d--a split product of C4. Twenty five of 35 patients had C4 phenotypes which include null alleles. No association between low C4 concentrations and C4 null alleles was found, but a significant association between low C4d concentrations and C4 phenotypes including null alleles, particularly those with C4A Q0, was noted. No correlation between concentrations of C4 and C4d was found. These results show an influence of C4 null alleles on the activation of the C4 molecule, which is independent of the concentration of C4. The possession of silent genes coding for C4 null alleles might predispose to SLE by conditioning poor C4 activation, a critical event for the clearance of immune complexes mediated by the classical complement pathway.
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Affiliation(s)
- D C Briggs
- Tissue Typing Laboratory, Guy's Hospital, London
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34
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Bontrop RE, Broos LA, Otting N, Jonker MJ. Polymorphism of C4 and CYP21 genes in various primate species. TISSUE ANTIGENS 1991; 37:145-51. [PMID: 1681597 DOI: 10.1111/j.1399-0039.1991.tb01862.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To study the genetic heterogeneity of the C4 and CYP21 genes in selected primate species we used the technique of restriction fragment length polymorphism (RFLP). Genomic DNA was digested using several restriction endonucleases and filters were hybridized with a 500 bp BamHI/KpnI fragment derived from the 5' section of a human C4-cDNA and with a 1700 bp BamHI obtained from a human CYP21 gene. Abundant RFLP heterogeneity was observed for the C4 genes within a rhesus monkey population but not for the chimpanzee colony analyzed. Duplicated C4-CYP21 clusters can be traced back in humans, but also in chimpanzees, orang-utans and rhesus monkeys. Thus, duplication of the basic C4-CYP21 cluster in primates may have happened more than 30 million years ago. Non-duplicated C4-CYP21 regions were found for the gorilla and orang-utan. Apart from this, shortened C4A and C4B genes were observed in chimpanzees, orang-utans and rhesus monkeys, whereas the so-called long variety of the C4A gene appears to be present in humans and orang-utans. This ancestral modification, resulting from an insertion of a 6.5 kb intron in the C4A gene, therefore predates at least speciation of human and orang-utan which is estimated to have taken place more than 12 million years ago.
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35
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Arellano J, Granados J, Pérez E, Félix C, Kretschmer RR. Increased frequency of HLA-DR3 and complotype SC01 in Mexican mestizo patients with amoebic abscess of the liver. Parasite Immunol 1991; 13:23-9. [PMID: 2014135 DOI: 10.1111/j.1365-3024.1991.tb00260.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Our preliminary study (31 patients) of HLA frequencies and amoebic abscess of the liver (AAL) in Mexican mestizos was extended to include 110 patients with this condition. The previously found increase in HLA-B16 was not confirmed, but the frequency of HLA-DR3 was again found significantly increased in patients with AAL when compared to the normal, ethnically matched control population, both in its isolated (35.5% vs 12.7%) and in the HLA-A2, DR3 haplotypic version (20.9% vs 4.5%). Moreover, seven of the 17 HLA specificities that were found to be individually different at P (yet not at PC) level in patients with AAL when compared to the control population, were actually HLA-DR3 containing haplotypes. HLA-DR3 may thus encode a risk factor(s) for AAL, at least in the Mexican mestizo population. Furthermore a significant increase in the complotype SC01 and its haplotypic version SC01, DR4 were identified in 45 non selected patients with AAL when compared to normal controls (31.1% vs 6.7% and 17.8% vs 0% respectively). Even though a relationship between allelic forms of complement components and their function has not been fully established, this complotype could represent a risk factor as well, since complement appears to play a role in host defence against amoebic invasion. Finally, no extended haplotype preference was found in these AAL patients.
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Affiliation(s)
- J Arellano
- Division of Immunology, Facultad de Medicina, UNAM, México, DF
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36
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Substitution of a single amino acid (aspartic acid for histidine) converts the functional activity of human complement C4B to C4A. Proc Natl Acad Sci U S A 1990; 87:6868-72. [PMID: 2395880 PMCID: PMC54639 DOI: 10.1073/pnas.87.17.6868] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The C4B isotype of the fourth component of human complement (C4) displays 3- to 4-fold greater hemolytic activity than does its other isotype C4A. This correlates with differences in their covalent binding efficiencies to erythrocytes coated with antibody and complement C1. C4A binds to a greater extent when C1 is on IgG immune aggregates. The differences in covalent binding properties correlate only with amino acid changes between residues 1101 and 1106 (pro-C4 numbering)--namely, Pro-1101, Cys-1102, Leu-1105, and Asp-1106 in C4A and Leu-1101, Ser-1102, Ile-1105, and His-1106 in C4B, which are located in the C4d region of the alpha chain. To more precisely identify the residues that are important for the functional differences, C4A-C4B hybrid proteins were constructed by using recombinant DNA techniques. Comparison of these by hemolytic assay and binding to IgG aggregates showed that the single substitution of aspartic acid for histidine at position 1106 largely accounted for the change in functional activity and nature of the chemical bond formed (ester vs. amide). Surprisingly, substitution of a neutral residue, alanine, for histidine at position 1106 resulted in an increase in binding to immune aggregates without subsequent reduction in the hemolytic activity. This result strongly suggests that position 1106 is not "catalytic" as previously proposed but interacts sterically/electrostatically with potential acceptor sites and serves to "select" binding sites on potential acceptor molecules.
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37
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Berg ES, Markussen G, Teisberg P, Olaisen B. Use of DNA amplification (PCR) and direct DNA sequencing in the characterization of C4 alleles. Ann Hum Genet 1990; 54:183-9. [PMID: 2221823 DOI: 10.1111/j.1469-1809.1990.tb00376.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A procedure for detailed characterization of individual C4 alleles has been developed. DNA containing the two polymorphic clusters of C4 was amplified in the polymerase chain reaction (PCR). Direct DNA sequencing of amplified DNA was then performed by a modification of previously described techniques. The results were confirmed by M13 sequencing. Single C4A3 and C4B1 allele sequences were in accordance with previous reports. An individual typed C4A3B1 revealed double bands in the autoradiogram in the positions corresponding to the polymorphic nucleotides. We did not find the reported thymine in position 3641 specific for the C4A4 allele in an individual typed C4A4B2.
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Affiliation(s)
- E S Berg
- Institute of Forensic Medicine, Rikshospitalet, University of Oslo, Norway
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38
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Plum G, Siebel E, Bendick C, Rasokat H, Braun M, Krickeberg H, Mauff G. Major histocompatibility complex class I to III allotypes in patients with AIDS-related complex/Walter-Reed 5, disseminated Kaposi's sarcoma and in normal controls. The ARC-IVIG Study Group. Vox Sang 1990; 59 Suppl 1:15-20. [PMID: 2238573 DOI: 10.1111/j.1423-0410.1990.tb01638.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In HIV-infected patients major histocompatibility complex (MHC) class I and II (= HLA-A, B, C, DR) association has been controversial. Of the MHC class III coded complement components C2, BF, C4A/C4B especially C4 allotypes appear of major immunogenetic relevance for their potential differences in virus neutralizing potency and immune complex formation. In the present study 29 patients with AIDS-related complex and Walter-Reed 5 ARC/WR5), 35 patients with disseminated Kaposi's sarcoma (KS), and 160 HIV-negative control individuals were compared for MHC class I to III allotypes. Diagnosis of ARC and KS (WR criteria) was done by clinical and laboratory parameters, MHC testing, by standard procedures. An increase in frequency (p less than or equal to 0.05) was observed between ARC/WR5 patients and controls for HLA-B35/CW4, DRW14, a decrease for B16, CW6/DR7. However, values were not significant if corrected for the number of tested antigens. No significant differences were seen between KS and ARC patients or controls for class III allotypes, nor for previously reported associations, e.g. for B8, DR2, DR3, and especially DR5, including the DR5 splits DRW11, 12. The results indicate the lack of a strong MHC association with the investigated antigens in West German Caucasoids, and support the hypothesis of ethnic dependence of HIV-related diseases. The HLA-B35/CW4 increase, also associated with the duplicated C4 A*3 A*2 and the silent C4B*Q0, was more pronounced in ARC patients with progression to AIDS-OI. The increased frequency of C4B*Q0 alleles in these patients was thought to be secondary to a hypothetical increase in 'converted' and dysregulated C4 genes not seen to be associated in this study.
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Affiliation(s)
- G Plum
- Institut für Medizinische Mikrobiologie und Hygiene, Universität Köln, BRD
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39
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Abstract
The importance of complement in the potentiation of the immune response is now firmly established. More recently, however, evidence has accumulated which suggests that complement may influence biological events following non-immunologically mediated tissue damage. Several of the many different genetically controlled structural forms of complement components, which are now recognised, have been shown to influence immunoregulation and disease susceptibility. Furthermore, molecular and genetic analyses have revealed that some of the regulatory elements such as S-protein may have multiple biological functions. As a consequence, it is likely that reference to detailed functional and molecular properties of various complement components, with special reference to regulatory elements will provide new insights into mechanisms of pathogenesis of disease.
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Affiliation(s)
- P H Kay
- Department of Pathology, University of Western Australia, Nedlands, Australia, Australia
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40
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Gorgi Y, Arnold D, Uring-Lambert B, Bardi R, Ayed K, Hauptmann G. A new duplication C4B*1,12 at the C4B locus associated with BF*S07 in a Tunisian population. TISSUE ANTIGENS 1990; 35:217-9. [PMID: 2402756 DOI: 10.1111/j.1399-0039.1990.tb01786.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Twenty-five Tunisian families were analyzed for their complement alleles in order to detect duplications at the C4 loci. In this population, the most characteristic duplications are C4A2, B1.12 or C4A1, B1,12 always associated with BFS07 and C2C. This previously undescribed C4B1,12 duplication was found in seven families, five times in association with HLA-A2, B50.
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Affiliation(s)
- Y Gorgi
- Immunology Laboratory, Tunis, Tunisia
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41
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Mimori A, Takeuchi F, Tokunaga K, Maeda H, Matsuki K, Matsuta K, Nakano K, Kosuge E, Yukiyama Y, Omoto K, Miyamoto T. Restriction fragment length polymorphism of complement C4 in Japanese patients with rheumatoid arthritis and normal Japanese. TISSUE ANTIGENS 1990; 35:197-202. [PMID: 1976276 DOI: 10.1111/j.1399-0039.1990.tb01782.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Restriction fragment length polymorphism (RFLP) of the two genes for complement C4A and C4B was studied in 56 Japanese patients with rheumatoid arthritis (RA) and 161 normal individuals. HindIII digestion revealed six common patterns, from which the segregation of three common RFLP-types were deduced; 32-15 kb, 32-25 kb, and 32-20-13-6.5 kb. The last type showed positive associations with C4B5 and HLA-DR4. In the RA patients, an increase of this type was found as well as a decrease of the 32-15 kb/32-25-15 kb heterozygotes.
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Affiliation(s)
- A Mimori
- Department of Medicine and Physical Therapy, Faculty of Medicine, Tokyo University, Japan
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42
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C4 null alleles in childhood onset systemic lupus erythematosus. Is there any relationship with renal disease? Pediatr Nephrol 1990; 4:207-12. [PMID: 2400645 DOI: 10.1007/bf00857655] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
C4 genotyping was performed in 38 unrelated patients with systemic lupus erythematosus (SLE) aged 2-16 years at onset. Null alleles were found in 68% of patients. Ten patients had one null allele at the C4A locus and 11 others had one null allele at the C4B locus. One patient was homozygous for C4A*Q0, 2 homozygous for C4B*Q0 and 1 heterozygous C4A*Q0/B*Q0. The last patient was C4A*Q0B*Q0/B*Q0. Three patients, being heterozygous C2 deficient, had thus a combined C2 and C4 deficiency. A significant increase in C4 null alleles in SLE patients has been reported by different authors who have suggested that the C4 null alleles confer susceptibility to SLE. However, when considering only the 20 patients of French descent, no differences in gene frequencies were found between this group and the French population. Disease patterns were compared in patients with or without null C4. Renal involvement was more frequent in the C4A*Q0 or C4A*Q0/C4A*Q0 patients than in the patients without null C4 (9/11 vs 3/12). These data suggest that differences between these results and those of others might be due to clinical heterogeneity of the disease, as exemplified by the frequency of renal involvement in the different groups. In susceptible individuals the absence of one C4A gene product may predispose the patient to renal involvement.
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43
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Ahmed AR, Yunis EJ, Alper CA. Complotypes in pemphigus vulgaris: differences between Jewish and non-Jewish patients. Hum Immunol 1990; 27:298-304. [PMID: 2318675 DOI: 10.1016/0198-8859(90)90081-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Haplotypes of alleles of the major histocompatibility complex (MHC) complement genes BF, C2, C4A, and C4B are inherited as single highly polymorphic genetic units called complotypes. There are about a dozen complotypes with frequencies above about 0.01 in Caucasians. In the blistering disease pemphigus vulgaris, the complotypes SC21 and SB45 were found to be markedly elevated in patients compared with general Caucasian controls. The SC21 increase was in Ashkenazi Jewish patients exclusively (relative risk = 17 in that population), whereas SB45 was found solely in non-Jewish Caucasians (specific population relative risk = 57). Although these are unusually high relative risks, it is most unlikely that these complotypes represent susceptibility genes for pemphigus vulgaris. Rather, it is probable that they mark extended major histocompatibility complex haplotypes with fixed DNA so that independent examples in the population have the same alleles. It is likely that it is the class II genes on these haplotypes that confer susceptibility.
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Affiliation(s)
- A R Ahmed
- Center for Blood Research, Boston, Massachusetts 02115
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44
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Dawkins RL, Martin E, Saueracker G, Kay PH, Leaver A, Christiansen FT. Supratypes and ancestral haplotypes in IDDM: potential importance of central non-HLA MHC genes. J Autoimmun 1990; 3 Suppl 1:63-8. [PMID: 2187461 DOI: 10.1016/s0896-8411(09)90011-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Juvenile insulin-dependent diabetes mellitus develops in susceptible children exposed to unknown environmental factors. If the genes responsible for susceptibility could be identified, it should be possible to understand the method of injury to beta cells as well as identify the infectious or other agents involved. For a decade it has been known that one or more of the susceptibility genes must be within the major histocompatibility complex (MHC). Unfortunately, there are at least 20 different genes in the complex and it has not been possible to determine which are actually responsible. Therefore, we undertook to apply a new concept and new technology to the problem. Over several years we have shown that the diabetogenic gene(s) are contained within conserved ancestral haplotypes which can then be used as markers of the DNA which must contain the gene(s), whether present in a patient or an asymptomatic carrier such as a parent. This approach avoids the confusion which has resulted from using DR3 or DR4 which are only sometimes associated with the relevant genes. The new technology involves pulsed field gel electrophoresis which allows examination of large fragments of DNA containing all of the MHC, and makes it possible to identify deletions and duplications which were otherwise undetectable. In the first instance we compared two ancestral haplotypes [1,8,3 (8.1) and 18,F1,3 (18.2)] known to contain the relevant genes, and contrasted the DNA with that of another ancestral haplotype [3,7,2(7.1)] which is known to lack these genes. We have shown that there are three major deletions common to the two carrier haplotypes but absent in the protective haplotypes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R L Dawkins
- Department of Clinical Immunology, Royal Perth Hospital, Western Australia
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45
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McLean RH, Bias WB, Giles C, Yu CY, Campbell RD. Characterization of two hybrid C4 allotypes (C4A*12 and C4B*3) by electrophoretic, serological and restriction fragment length polymorphism analyses. TISSUE ANTIGENS 1990; 35:75-81. [PMID: 1693017 DOI: 10.1111/j.1399-0039.1990.tb01760.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Informative pedigree analysis of two rare C4 allotypes is reported. One proband was C4A deficient as a consequence of having one haplotype with a deleted C4A gene, and the second haplotype with two C4B genes--one encoding the common C4B*1 and one encoding a unique hybrid gene product C4B*3. C4B*3 had approximately normal C4B hemolytic activity, a single alpha-chain of MR 94,000 by SDS-PAGE but was positive for Rg:1,2 by hemagglutination inhibition (HAI) and for Rg:1 by Western blotting. The hybrid nature was confirmed by RFLP analysis with a Rg:1-associated fragment by Eco0109 digestion but no C4A-associated fragments by N1aIV digestion were identified. A gene conversion at Locus I which included just the C4 isotype region could explain the structure of C4B*3. The second pedigree had a Rodgers negative C4A*12 allotype. This C4A gene, which segregated with a single 7.0 kb TaqI fragment, encoded a C4A alpha-chain, which was negative for Rg:1 epitope. The affected haplotype lacked the Rg:1-associated fragment by Eco0109 digestion yet had the C4A specific N1aIV digestion fragment. These studies successfully employed RFLP analyses to confirm serologic and electrophoretic observations.
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Affiliation(s)
- R H McLean
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
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46
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47
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Fraser PA, Moore B, Stein R, Alosco S, Johnson AH, Marcus-Bagley D, Awdeh Z, Yunis EJ, Alper CA. Complotypes in individuals of African origin: frequencies and possible extended MHC haplotypes. Immunogenetics 1990; 31:89-93. [PMID: 2303279 DOI: 10.1007/bf00661218] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We analyzed the frequency distribution of 106 complotypes [four allele sets of the major histocompatibility complex (MHC) genes for the complement proteins factor B, C2, C4A, and C4B] from 32 Black families residing in Boston and Washington, DC. Twenty-five different complotypes were identified, among which there were four complotypes that had not been previously observed in our large database of complotypes compiled from family studies of Boston Caucasians and that are, presumably, unique to individuals of African origin. These four African-derived complotypes are FC(1,90)0, FC63, S1C2, 17, and SC(3,2,90)0. The frequencies of two of these four unique Black complotypes, FC(1,90)0 and FC63, were increased significantly when compared to Caucasians (pcorr less than 0.00042, pcorr = 0.00294, respectively). The complotype FC(1,90)0 was in positive linkage disequilibrium with HLA-DR3 haplotypes containing the B locus antigens Bw42, Bw52, Bw53, and Bw58, while FC63 was associated with HLA-Bw70, -DR5. These findings demonstrate the extensive polymorphism of complotypes in Blacks, and also suggest that it may be possible to define unique extended haplotypes of African origin.
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Affiliation(s)
- P A Fraser
- Center for Blood Research, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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48
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Braun L, Schneider PM, Giles CM, Bertrams J, Rittner C. Null alleles of human complement C4. Evidence for pseudogenes at the C4A locus and for gene conversion at the C4B locus. J Exp Med 1990; 171:129-40. [PMID: 2295875 PMCID: PMC2187646 DOI: 10.1084/jem.171.1.129] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The two genes for the C4A and C4B isotypes of the fourth component of human complement are located in the MHC class III region. Previous studies have demonstrated the unusual expression of C4 genes in the form of aberrant or duplicated haplotypes. Null alleles of C4A or C4B (AQ0 or BQ0) have been defined by the absence of gene products and occur at frequencies of 0.1-0.3. However, only some C4 null alleles are due to gene deletions, the remainder were thought to be nonexpressed genes. We have analyzed the C4 gene structure of 26 individuals lacking either C4A or C4B protein. The DNA of individuals with apparently nonexpressed C4 genes was tested for the presence of C4A- and C4B-specific sequences using restriction fragment analysis and isotype-specific oligonucleotide hybridization of DNA amplified by polymerase chain reaction. All nondeleted AQ0 allels had C4A-specific sequences and may thus be described as pseudogenes, whereas the nondeleted BQ0 alleles had C4A-instead of C4B-specific sequences. Gene conversion is the probable mechanism by which a C4A gene is found at the second C4 locus normally occupied by C4B genes.
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Affiliation(s)
- L Braun
- Institute of Legal Medicine, Johannes Gutenberg University, Mainz, Federal Republic of Germany
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49
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Chrispeels J, Bank S, Rittner C, Bitter-Suermann D. Sandwich enzyme-linked immunosorbent assays for the quantification of the C4 isotypes (C4A and C4B) in human plasma. J Immunol Methods 1989; 125:5-12. [PMID: 2607165 DOI: 10.1016/0022-1759(89)90071-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Sandwich enzyme-linked immunosorbent assays were developed to determine the concentration of the isotypes of the fourth component of human complement (C4A and C4B) in human plasma. In the case of C4A a monoclonal antibody against a common determinant of the alpha chain was used to capture the protein. The bound antigen was then detected with a biotinylated monoclonal antibody reacting exclusively with the C4A isotype, followed by peroxidase labeled avidin. For the quantification of C4B, C4B-specific monoclonal antibodies were coated onto a microtitration plate in order to capture the protein. Bound antigen was then detected with a biotinylated monoclonal antibody directed against C4 followed by peroxidase labeled avidin. The assays, which were rapid, selective and specific for C4A and C4B, respectively, provide an alternative to gel electrophoresis and blot procedures for the study of unexpressed alleles ('null alleles') at each of the C4 loci.
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Affiliation(s)
- J Chrispeels
- Institut für Rechtsmedizin, Universität Mainz, F.R.G
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50
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Truedsson L, Awdeh Z, Yunis EJ, Mrose S, Moore B, Alper CA. Quantitative variation of C4 variant proteins associated with many MHC haplotypes. Immunogenetics 1989; 30:414-21. [PMID: 2574157 DOI: 10.1007/bf02421172] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
C4 protein variants were analyzed in 64 individuals, of which 51 were either homozygous or heterozygous for an extended major histocompatibility complex (MHC) haplotype (a fixed combination of MHC alleles). The relative amount of each C4 variant was measured by densitometric scanning of stained immunofixed electrophoretic patterns of neuraminidase- and carboxypeptidase-treated samples. The relative concentrations of C4 variants on any haplotype were stable and inherited in families. In five of the eight extended haplotypes investigated, the amount of one of the C4 variants relative to others in the same pattern was increased: [HLA-B8, SC01, DR3] and [HLA-B7, SC31, DR2] produced an approximately doubled amount of C4B1; [HLA-B18, S042, DR2] an increased amount of C4B2; and [HLA-B44, SC30, DR4] a double amount of C4A3. The extended haplotype [HLA-Bw57, SC61, DR7] gave rise to two to three times as much C4B1 as C4A6. In the extended haplotypes [HLA-B44, FC31, DR7] and [HLA-Bw62, SC33, DR4], the results did not clearly indicate differences in expression of the C4 isotypes. DNA analysis possibly supported an actual gene duplication only for the haplotype [HLA-B7, SC31, DR2]. The results suggest that, in addition to variation in the number of structural genes, other MHC-linked mechanisms may be involved in the regulation of the relative amounts of C4A or C4B protein specified by any haplotype.
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