Clinical, immunological, and immunogenetic aspects of autoantibody production against Ro/SSA, La/SSB and their linear epitopes in primary Sjögren's syndrome (pSS): a European multicentre study

OBJECTIVES

To investigate the clinical and immunogenetic aspects of antibody formation against Ro/SSA and La/SSB as well as their linear B cell epitopes in patients with primary Sjögren's syndrome (pSS) from different European countries.

PATIENTS AND METHODS

Ninety patients with pSS from six European centres were studied. Serum samples from all patients were tested in a control laboratory for anti-Ro/SSA and anti-La/SSB autoantibodies by RNA precipitation assay and autoantibodies to the previously reported B cell linear epitopes of Ro 60 kDa (p169-190aa and p211-232aa) and La/SSB (p147-154aa, p291-302aa, p301-318aa, and p349-364aa). DNA from 88 patients was used for the determination of HLA-DRB1, -DQA1, and -DQB1 genotypes. Analysis of the results was performed in the 88 patients who were genotyped and tested also for antipeptide antibodies.

RESULTS

Antibodies to B cell epitopes of Ro 60 kDa were detected at a low frequency (range 10-37%). In contrast, B cell epitopes of La/SSB were detected frequently (range 58-86%) among the anti-La/SSB positive sera. Autoantibodies to the La/SSB epitope, p349-364aa, were significantly positively associated with longer disease duration (p<0.05), recurrent or permanent parotid gland enlargement (p<0.005), and a higher proportion of non-exocrine manifestations (p<0.005), compared with patients without autoantibodies. The presence of anti-Ro/SSA and anti-La/SSB autoantibodies was significantly associated with the presence of HLA-DRB1*03 and DQB1*02 (p=0.038 and p=0.034, respectively). This association was even more prominent and extended to HLA-DQA1*0501 when patients were stratified according the presence of autoantibodies to discrete La/SSB B cell epitopes in comparison with autoantibody negative patients (p<0.01). They were found also to be highly associated with the alleles HLA-DQB1*02 and HLA-DQA1*0501 as well as the presence of a shared amino acid motif in the region 59-69aa of DQB1 first domain (p<0.01, respectively).

CONCLUSIONS

Autoantibodies against La/SSB, binding to four synthetic peptides, derived from the sequence of the La protein were identified with increased frequency in sera of patients with pSS. The formation of autoantibodies against B cell epitope analogues of La/SSB in European patients with pSS may be dependent on the presence of a permissive HLA-DQ heterodimer, most prominently represented by the HLA-DQA1*0501/DQB1*0201 heterodimer, suggesting that a model of HLA restricted presentation of La/SSB peptide determinants is crucial for the autoimmune response against La/SSB.

Maternal/paternal sharing of DQ-Alpha type II histocompatibility antigens not associated with pregnancy outcome following in vitro fertilization (IVF)-embryo transfer (ET)

PURPOSE

To determine if maternal/paternal sharing of DQ alpha major histocompatibility (MHC) type II antigens is associated with reduced pregnancy and implantation rates following in vitro fertilization-embryo transfer (IVF-ET).

METHODS

Prospective study with type II MHC DQ alpha alleles detected by polymerase chain reaction (PCR) technology using Perkin Elmer Amyli-type HLA DQ alpha PCR amplification and typing kit. The tests were only performed on patients having their first IVF cycle.

RESULTS

No difference was found in clinical pregnancy rates per transfer between those couples sharing DQ alpha I alleles and those who did not (43.7% vs 40%). There were no spontaneous abortions in the group sharing DQ alpha I alleles.

CONCLUSION

Maternal/paternal sharing of DQ alpha I antigens does not reduce fecundity following IVF-ET.

Celiac disease in children with autoimmune thyroid disease

Ninety children and adolescents with autoimmune thyroid disease were screened for celiac disease. All 90 patients were typed for HLA antigen class I and II and for HLA-DQA1 and DQB1 heterodimers. Celiac disease and DQA1*0501, DQB1*02 were found in 7 (7.8%) patients. The prevalence of celiac disease was 1 of 13. Screening for celiac disease is recommended in children with autoimmune thyroid disease.

The HLA class I and class II allele frequencies studied at the DNA level in the Svanetian population (Upper Caucasus) and their relationships to Western European populations

The Caucasus and the Iberian peninsula have been connected from a linguistic (Basque and Kvartelian languages), toponimic and historic perspectives. They also represent places (e.g. Dmanisi in Georgia and Atapuerca in Northern Spain) where the oldest hominoid remains in Europe are being discovered and studied. These circumstances prompted us to study the genetic background of the Svans (living on the southern slopes of the Greater Caucasus in the Republic of Georgia) in comparison with Basques from the semi-isolated Arratia valley as well with other Northern Spanish and Western European populations. DRB1*1101-DQA1*0501-DQB1*0301 and DRB1*1301-DQA1*0103-DQB1*0603 haplotypes were found in Svans at the highest frequency. The second most frequent three-locus haplotypes in this population were DRB1*0701-DQA1*0201-DQB1*0201 and DRB1*1301-DQA1*0103-DQB1*0602. Furthermore, the following 5-locus extended haplotypes were not found in other populations: A3-B8-DRB1*11-DQA1*0501-DQB1*0301, A2-B8-DRB1*13-DQA1*0103-DQB1*0603, A2-B40-DRB1*14-DQA1*0104-DQB1*0501, A2-B51-DRB1*08-DQA1*0401-DQB1*0402, A3-B7-DRB1*03-DQA1*0501-DQB1*0201 and A24-B39-DRB1*08-DQA1*0401-DQB1*0402. Other haplotypes present in Svans were also frequently observed in Northern Spain and in other Western European countries. However, haplotypes reported as characteristic for Basques were not found in the Svans. A dendrogram using HLA class II alleles places the closest genetic distance observed between Svans and Czechs, whereas Slovenes and other Mediterranean populations (Jews, Hungarians, Frenchmen, Sardinians and Greeks) have the greatest genetic distance. When both HLA class I and class II alleles from 17 populations were compared, the smallest genetic distances were with Rumanians, Czechs and Armenians. Northern Spanish populations were placed closer to each other and clearly separated from Svans. In conclusion, the Svan population shows considerable polymorphism. These observations suggest a mixture of alleles in Svans from geographically distinct areas, and probably do not support a common ancestor for these Caucasian inhabitants and people from Northern Spain.

HLA-C mismatches induce strong cytotoxic T-cell reactivity in the presence of an additional DRB/DQB mismatch and affect NK cell-mediated alloreactivity

BACKGROUND

The functional relevance of HLA-C mismatches in an alloresponse is still much debated, putting into doubt the relevance of matching for this antigen in selection of an allogeneic bone marrow donor. In addition to presenting peptides to T cells, HLA-C also functions as a ligand for killing inhibitory receptors (KIRs) on natural killer (NK) cells. In the current study we provide an in vitro basis to address the question of whether mismatches for this antigen are a risk factor for acute graft-versus-host disease (GVHD).

METHODS AND RESULTS

By analysis of cytotoxic and helper T-lymphocyte precursor frequency (CTLp-f and HTLp-f) in 153 pairs, we are able to show that isolated HLA-C mismatches appear less immunogenic than do isolated HLA-A mismatches. Strikingly, the presence of an HLA-C mismatch next to a HLA-DRB or HLA-DQB mismatch leads to a synergistic increase in CTLp-f outcome. Moreover, we are the first to show that absence of a single inhibitory epitope as a result of an HLA-C mismatch can be sufficient to induce NK mediated alloreactivity, that is, kill and proliferate.

CONCLUSIONS

We conclude that, in most cases, isolated HLA-C mismatches may be acceptable with respect to T-cell-mediated alloreactivity; however, the presence of a strong helper epitope (DR/DQ mismatch) appears sufficient to overcome the low immunogenicity of HLA-C. HLA-C mismatches that affect KIR epitopes, can induce NK mediated alloreactivity. This suggests that, in HLA-A-, -B-, -DR-, and -DQ-matched patients, NK cells may play a role in the induction and development of acute GVHD.

The origin of Palestinians and their genetic relatedness with other Mediterranean populations

The genetic profile of Palestinians has, for the first time, been studied by using human leukocyte antigen (HLA) gene variability and haplotypes. The comparison with other Mediterranean populations by using neighbor-joining dendrograms and correspondence analyses reveal that Palestinians are genetically very close to Jews and other Middle East populations, including Turks (Anatolians), Lebanese, Egyptians, Armenians, and Iranians. Archaeologic and genetic data support that both Jews and Palestinians came from the ancient Canaanites, who extensively mixed with Egyptians, Mesopotamian, and Anatolian peoples in ancient times. Thus, Palestinian-Jewish rivalry is based in cultural and religious, but not in genetic, differences. The relatively close relatedness of both Jews and Palestinians to western Mediterranean populations reflects the continuous circum-Mediterranean cultural and gene flow that have occurred in prehistoric and historic times. This flow overtly contradicts the demic diffusion model of western Mediterranean populations substitution by agriculturalists coming from the Middle East in the Mesolithic-Neolithic transition.

Analysis of DNA in minute volumes of blood from stains and crusts

As the first step, the locus D1S80 was amplified by the polymerase chain reaction technique from genomic DNA extracted from artificial bloodstains and crusts with different amount of blood (32 microl, 16 microl, 8 microl, 4 microl, 2 microl, and 1 microl). In all samples of bloodstains and crusts, identification by DNA analysis was possible. As the second step, the locus HLA-DQA1 was amplified from genomic DNA extracted from diluted blood samples (640, 320, 160, 80, 40, 20, 10, and 5 leukocytes). DNA amplification was possible in diluted blood samples with at least 10 leukocytes. Considering the conditions in which the present study was carried out, it was possible to conclude that 1 microl of bloodstains or crusts was enough for identification. It was also concluded that five leukocytes are not enough material to render consistent DNA identification.

HLA and multiple sclerosis. Studies of a spanish population

INTRODUCTION

Family and population studies have shown the existence of genetic susceptibility to have multiple sclerosis (MS). The genes of the HLA system have been the only genetic markers for this tendency to have been confirmed in multiple studies in different countries. A relation has also been found between certain HLA genes and the clinical course or paraclinical parameters of MS.

DEVELOPMENT

In this article we first analyze the structure, function, typing and association of illnesses with the HLA system and their relation with MS. Subsequently we review the articles published or reported on the HLA-MS association in the Spanish population.

CONCLUSION

MS is generally associated with the DR15/DQ6 haplotype (subtypes of DR2/DQ1) in the Spanish population. There may be minor ethnic differences in some regions which explain other associations found. Although the Spanish studies on the association of HLA with clinical and paraclinical factors of MS require confirmation in samples with larger number of patients, the primarily progressive forms and those with a worse prognosis tend to be associated with DR4 and the benign forms with DR2. The DRw 13 (DR6) seems to be a protective allele. The presence of DR2 may be a marker for the development of MS after an optic neuritis.

HLA-DRB1*04 and susceptibility to type 1 diabetes mellitus in a German/Belgian family and German case-control study. The Belgian Diabetes Registry

HLA-DR4 is a primary disease association marker in type 1 diabetes mellitus (IDDM). We therefore analyzed the transmission of 228 DR4+ haplotypes in 183 families with an IDDM proband (95 from Germany and 88 from Belgium). In a separate case-control data set, we investigated the HLA-DRB1*04 and DQ allele distribution in 245 IDDM patients and 177 controls from Germany, all DR4 positive. HLA-DRB1 *0401 and *0402 linked to DQB1 *0302 were significantly more often transmitted to patients in the studied families (81% and 89%) in contrast to DRB1 *0401-DQB1 *0301 (33%). The case-control study of HLA-DQB1 *0302+ individuals revealed -DRB1 *0405 to be more frequent in patients with IDDM and HLA-DRB1 *0403 and -DRB1 *0404 to be less frequent. HLA-DQA1 *0102-DQB1 *0602 and -DQA1 *0501-DQB1 *0301 in trans complementation with DRB1 *0401-DQB1 *0302 were also significantly less frequent in IDDM patients (P<3x 10(-7) and P<0.02). In conclusion, HLA-DRB1 *0403 and -DQB1*0301 alleles in cis as well as protective DQ haplotypes in trans, confer dominant protection against IDDM in a German / Belgian population.

Expression of HSP-65 in jejunal epithelial cells in patients clinically suspected of coeliac disease

BACKGROUND

Coeliac disease (CD) can be classified both clinically and biologically an autoimmune disease. A close relationship obtains between heat shock proteins (HSPs) and numerous autoimmune diseases. HSPs are overexpressed when protecting the host against environmental insult. We sought here to establish whether dietary gluten is such a stress stimulus in patients clinically suspected of CD, and whether the expression of HSP-65 associates with densities of intraepithelial gammadelta+ T cells and/or with expression of mucosal HLA-DR.

METHODS

Seventy-eight children with clinical suspicion of CD underwent a jejunal biopsy. Monoclonal antibodies were used to stain jejunal epithelial HSP-65, intraepithelial lymphocytes and mucosal HLA-DR. Serum IgA-class endomysial autoantibodies (EMA) were measured by an indirect immunofluorescence method. CD susceptibility HLA DQA1*0501 and DQB1*0201 alleles (HLA DQ2) were determined.

RESULTS

Enhanced expression of epithelial cell mitochondrial HSP-65 was found in 80% (16/20) of coeliacs and in 24% (14/58) of children excluded for the disease, but in only 7% (2/28) of control subjects (p < 0.001, p = 0.049, respectively). Children with enhanced expression of HSP-65 had significantly higher gammadelta+ T cell densities than those with normal HSP-65 expression. A clear association between HSP-65 and serum IgA-class EMA were also ascertained in patients with normal jejunal mucosal morphology. HLA DQ2 positivity did not correlate with the HSP-65 expression.

CONCLUSIONS

Gluten might be an environmental insult not only in CD patients but also in some patients excluded for the disease on biopsy. Enhanced expression of epithelial cell stress proteins might be an indicator of such an insult.

Small intestinal T cells of celiac disease patients recognize a natural pepsin fragment of gliadin

Celiac disease is a common severe intestinal disease resulting from intolerance to dietary wheat gluten and related proteins. The large majority of patients expresses the HLA-DQ2 and/or DQ8 molecules, and gluten-specific HLA-DQ-restricted T cells have been found at the site of the lesion in the gut. The nature of peptides that are recognized by such T cells, however, has been unclear so far. We now report the identification of a gliadin-derived epitope that dominantly is recognized by intestinal gluten-specific HLA-DQ8-restricted T cells. The characterization of such epitopes is a key step toward the development of strategies to interfere in mechanisms involved in the pathogenesis of celiac disease.

HLA-DQB1 and HLA-DPB1 genotypes in familial sarcoidosis

Numerous reports on the familial occurrence of sarcoidosis, on regionally different prevalences and on its associations with genetic polymorphisms point to the existence of predisposing genes. We have started to establish a collection of DNA from families with two or more sarcoidosis patients for the purpose of genetic linkage and association studies. In this report we present HLA class II genotypes of affected first-degree relatives from 17 families, including eight instances of affected parent and offspring, six sib pairs, and three sib triplets. Genotyping for HLA-DQB1 revealed an over-representation of DQB1*0603 and DQB1*0604 among alleles shared by affected first degree relatives. The same was found for HLA-DPB1*0201 (Glu69 positive). However, none of the sib triplets had any of these alleles in common.

Association between longevity and allelic forms of human leukocyte antigens (HLA): population study of aged Italian human subjects

Several arguments support the idea of a link between longevity and heredity, both in humans and in experimental animals. We have therefore investigated the possibility of an association between the human leukocyte antigens (HLA) and longevity in two groups of Italian subjects: 108 healthy subjects over 85 years old, and 749 healthy blood donors (controls). Only four antigens showed a higher frequency in the elder group: HLA-A31(19), B7, Cw7 and DQ1. These findings suggest an involvement of HLA antigens in human longevity, but the real biological meaning of these results is still unclear.

[Binding-peptide motifs of HLA class II molecules susceptible to autoimmune diseases]

Recent advances in knowledge of crystal structures of MHC class II molecules has advanced understanding of the molecular basis for interactions between peptides and HLA class II molecules. Polymorphism of HLA class II molecules influences structures of peptides bound to HLA class II molecules. To elucidate mechanisms for statistical association between particular HLA class II alleles and susceptibility to autoimmune diseases, it is important to identify self peptides presented by disease-susceptible HLA class II molecules and triggering disease-causative autoreactive T cells. In this study, we tried to identify self-peptides triggering autoimmune diseases including rheumatoid arthritis, insulin autoimmune syndrome, insulin dependent diabetes mellitus and infant-onset myasthenia gravis. Susceptibility to all of these diseases in the Japanese population are known to be strongly associated with particular HLA-DR-DQ haplotypes unique to Asians, and clinical features of some of these diseases are different between Caucasians and Asians including Japanese. We investigated differences in binding-peptide motifs between disease susceptible and non-susceptible HLA class II molecules and predicted candidates of autoimmune self-peptides carrying binding-motifs to disease-susceptible HLA class II molecules. Indeed the major epitope for insulin-autoreactive CD4+ T cell was successfully identified by this strategy. We also found heterogeneity in immunogenetic background between Western type and Asian type of multiple sclerosis. Our data indicated that our strategy is useful to identify autoimmune self-peptides, and it is suggested that not only disease-susceptible HLA class II but also self-peptides causing diseases are different between Caucasians and Asians. These differences may well correlate to different clinical manifestations of diseases between the two ethnic groups.

HLA-DQ associations and T-cell receptor V-gene usage in peripheral blood of Swedish myasthenia gravis patients

To characterize better the functional aspects of the HLA class II associations with myasthenia gravis (MG), T-cell receptor (TCR) V alpha/beta elements were studied in peripheral blood in 29 Swedish MG patients. HLA typing had previously been done using polymerase chain reaction with sequence-specific primers (PCR-SSP) or combined with sequence-specific oligonucleotide probes (PCR-SSO). The TCR V gene expression was determined by fluorescence-activated cell sorter (FACS) analysis using 12 monoclonal antibodies (mAb) that detected 30-40% of CD4+ and CD8+ T cells. No correlation between HLA-DQ genotype and TCR V elements could be found, nor was any restricted V gene usage seen. Fourteen (48%) of the patients had T cells showing signs of abnormal expansion in peripheral blood. There was an increased expression of TCR V gene elements in CD8+ T cells in patients (13/29) compared with CD4+ T cells in patients (5/29) (P < 0.05) and in unthymectomized patients compared with controls (14/56) (P < 0.005). TCR V gene expression was also increased in the CD8+ population in unthymectomized (7/8) compared with thymectomized patients (6/21) (P < 0.01). There was an increased expression in both CD4+ and CD8+ populations in unthymectomized patients (7/8, 88%), compared with thymectomized patients (7/21) (P < 0.05). We conclude that the abnormal T-cell expansion in peripheral blood could be a reflection of non-specific pathogenic processes in the muscle and thymus.

Genetic association of the HLA DRB1 gene locus on chromosome 6p21.3 with schizophrenia

OBJECTIVE

The authors investigated the human leukocyte antigen (HLA) DRB1*04 gene in schizophrenic patients because it is positively associated with rheumatoid arthritis, an autoimmune disease that exhibits a strong negative association with schizophrenia. The HLA DQB1*0602 allele was also studied because of previous reports of genetic association between it and schizophrenia. Maternal HLA was investigated because of the reported association between prenatal influenza and schizophrenia and the central role of HLA molecules in the immune response to viral infections.

METHOD

Polymerase chain reactions and sequence-specific oligonucleotide probes were used to genotype 94 unrelated patients with DSM-III-R schizophrenia, 92 mothers of schizophrenic offspring who were not related either to each other or to the 94 patients, and 177 healthy comparison subjects.

RESULTS

The frequency of DRB1*04 alleles was significantly lower in both the schizophrenic patients and the unrelated mothers of schizophrenic offspring than in the healthy comparison subjects. No significant differences were found for DQB1*0602.

CONCLUSIONS

DRB1*04 alleles may partially account for the genetic predisposition to schizophrenia. The association reported here may be explained by genetic linkage or by an autoimmune pathophysiology for a proportion of schizophrenia cases. Alternatively, it may be that maternal B lymphocytes that do not express the DR4 antigen encoded by DRB1*04 respond to influenza virus by producing antibodies that perturb neurodevelopment, thus underpinning a proportion of schizophrenia cases.

HLA DRB1/DQA1/DQB1 haplotype determines thyroid autoimmunity in patients with insulin-dependent diabetes mellitus

OBJECTIVE

Thyroid autoimmunity is frequently associated with insulin-dependent diabetes mellitus (IDDM). The genetic factors which contribute to thyroid autoimmunity and IDDM have been described but vary between different races. We have therefore investigated the effect of class II HLA genes at both loci and the HLA haplotypes on the presence of autoimmunity in patients with IDDM in Taiwan.

SUBJECTS AND MEASUREMENTS

Eighty-three patients with IDDM and 105 unrelated normal controls were recruited for the measurement of thyroid autoantibodies and for genotyping of HLA DRB1, DQA1 and DQB1 by polymerase chain reaction-based DNA typing techniques.

RESULTS

Among 83 patients with IDDM, 23 (27.7%) were positive for antithyroid autoantibodies. Compared to those without thyroid autoimmunity, there was a female preponderance for IDDM with thyroid autoimmunity (female: male, 3:20 vs 29:31). Among the DR specificities, DR6 was associated with a weak protective effect against thyroid autoimmunity in IDDM patients. Upon detailed analysis of class II HLA haplotypes, the DRB1*0301/ DQA1*0501/DQB1*0201 haplotype was found to be associated with an increased risk of IDDM regardless of thyroid autoimmunity, while DRB1*0405/DQA1*0301/ DQB1*0401 was significantly increased only in the IDDM patients with thyroid autoimmunity. IDDM individuals with the HLA DRB1*0405/DQA1*0301/DQB1*0302 haplotype were not at risk of thyroid autoimmunity.

CONCLUSIONS

Our data indicated that there was a generalized genetic factor within or associated with the DRB1*0301/DQA1*0501/DQB1*0201 haplotype, and a more restricted effect with the DRB1*0405/DQA1*0301/DQB1*0401 haplotype which led to thyroid autoimmunity in patients with insulin-dependent diabetes mellitus.

Population data on the loci LDLR, GYPA, HBGG, D7S8, and GC in three southwest European populations

Three Southwest European populations: Galicia (NW Spain), a mixed Spanish population from the rest of Spain (outside Galicia), and a population sample from the Coimbra area (Centre of Portugal) have been studied for the Low Density Lipoprotein Receptor (LDLR), Glycophorin A (GYPA), Hemoglobin G Gammaglobin (HBGG), D7S8 and Group Specific Component (GC). The allele and genotype frequencies found have been compared with other previously published data. All loci meet Hardy-Weinberg expectations in the three sampled populations. There was no evidence of association in any of the three population samples, between the five loci studied. No significant differences were found with Caucasian populations, nevertheless, significant differences were observed between our three population studies and the US SW Hispanic and African populations. The AmpliType PM DNA test greatly facilitates DNA testing in forensic laboratories, providing quick results and a good discrimination power from a single test.

Human self-reactive T cell clones expressing identical T cell receptor beta chains differ in their ability to recognize a cryptic self-epitope

Recognition of self-antigens by T lymphocytes is a central event in autoimmunity. Understanding of the molecular interactions between T cell receptors (TCR) and self-epitopes may explain how T cells escape thymic education and initiate an autoimmune reaction. We have studied five human in vivo activated T cell clones specific for the region 535-551 of human thyroid peroxidase (TPO) established from a Graves' patient. Three clones (37, 72, and 73) expressed identical TCR beta and alpha chains rearranging V beta 1.1 and V alpha 15.1, and were considered sister clones. Clone 43 differed from clone 37 and its sisters in the J alpha region only. Clone NP-7 expressed V beta 6.5 but rearranged two in-frame TCR alpha chain, both using the V alpha 22.1 segment. Fine epitope mapping using nested peptides showed that clones using identical TCR beta chains, identical V alpha, but a different J alpha recognized distinct, nonoverlapping epitopes in the TPO 535-551 region. This finding shows that a different J alpha region alone leads to a heterogeneous pattern of recognition. This indicates that the "restricted" TCR V region usage sometimes found in autoimmune diseases may not always correspond to identical epitope recognition. To confirm that clones 37 (and its sisters) and 43 recognize different epitopes, the T cell clones were stimulated with a TPO-transfected autologous Epstein-Barr virus (EBV) cell line (TPO-EBV) that presents TPO epitopes afer endogenous processing. Only clone 37 and its sisters recognizes the TPO-EBV cell line, suggesting that the epitope recognized by clone 43 is not presented upon endogenous processing. We have shown that thyroid epithelial cells (TEC), the only cells that produce TPO, express HLA class II molecules in Graves' disease and can act as an antigen-presenting cells, presenting TPO after endogenous processing to autoantigen-reactive T cell clones. We tested, therefore, whether autologous TEC induced the same pattern of stimulation as TPO-EBV; T cell clone 37 recognizes the TEC, whereas it is stimulated poorly by the TPO loaded to autologous peripheral blood mononuclear cells (PBMC). Clone 43, which fails to recognize the TPO-EBV, also fails to recognize the TEC, but is activated by exogenous TPO presented by autologous PBMC. These results show that exogenous versus endogenous processing in vivo generates a different TPO epitope repertoire, producing a "cryptic" epitope (epitope not always available for recognition). Our findings define a route by which human self-reactive T cells may escape thymic selection and become activated in vivo, thus possibly leading to autoimmunity.

Using multiplex PCR amplification and typing kits for the analysis of DNA evidence in a serial killer case

Analysis of DNA evidence in a serial killer case was performed using the AmpliType HLA-DQ alpha-, AmpliType PM-, and the GenePrint STR Multiplex System PCR Amplification Kits. In addition, a sex typing procedure using the X-Y homologous gene amelogenin was carried out. DNA profiles from a single hair with attached sheath material, recovered from underneath the seat cover of the suspect's car seat were compared with DNA profiles derived from reference head hairs from a homicide victim. From the evidentiary sample only 9 ng of human DNA could be recovered. In a sample, where the quantity of DNA becomes a critical issue a powerful route is the simultaneous amplification of several loci (multiplex PCR). This is the first report where commercially available multiplex PCR amplification and typing kits have been introduced for the analysis of DNA evidence in a serial killer case and the analysis has been admitted in court.

Prenatal diagnosis by analysis of fetal cells in maternal blood

The data accumulated thus far indicate that fetal NRBCs are the target cell type of choice in maternal blood for most investigators, although some groups continue to work with the trophoblast. Reports of persistent circulation of hematopoietic stem cells, lymphoid/myeloid progenitors, and lymphocytes mandate that removal of these cell types must occur before clinical diagnosis of the current pregnancy can be made. In selected cases, accurate detection of fetal aneuploidy has been made from fetal cells in maternal blood; the clinical evaluation sponsored by the National Institute of Child Health and Human Development will determine the sensitivity and specificity of cytogenetic diagnosis in a larger group of pregnant women, but this information will not be available for several years. At present, detection of uniquely fetal, paternally inherited gene polymorphisms or mutations such as the Rh(D) antigen is possible only because the mother lacks these genes; hence, maternal cell contamination does not hinder diagnosis. Currently the presence of large numbers of maternal cells in enriched samples precludes single-gene diagnosis for conditions in which the mother carries a mutant gene, because her cells are preferentially amplified and difficult to distinguish from those of the fetus. It is likely, however, that as techniques of individual fetal cell isolation are perfected, maternal cell contamination will no longer be an issue, and the entire fetal genome will become available for diagnosis and therapy. Pediatricians need to be aware of the progress of research in this field, because fetal cell isolation from maternal blood not only could change prenatal diagnosis but would change the amount of genetic information that arrives with a newborn infant at birth. The ultimate goal of this work is to diagnose noninvasively, in the first trimester, the common fetal aneuploidies and single-gene disorders, to permit in utero treatment, or to allow low-risk pregnant women carrying an abnormal fetus an opportunity for reproductive choice.

HLA class II genes associated with anticentromere antibody in Japanese patients with systemic sclerosis (scleroderma)

OBJECTIVE

To define further HLA class II gene associations with anticentromere antibody (ACA), a major serum antinuclear antibody in patients with systemic sclerosis (SSc).

METHODS

HLA class II genes were determined using polymerase chain reaction/restriction fragment length polymorphisms in 94 Japanese patients with SSc (22 ACA positive and 72 ACA negative) and 50 race matched normal control subjects.

RESULTS

Frequency of DQB1*0501 was increased in ACA positive SSc patients compared with ACA negative SSc patients (36% versus 13%; p = 0.02, odds ratio = 4.0, 95% confidence interval 1.1 to 13.9), but the association of ACA with a polar amino acid at position 26 in the DQB1 beta 1 domain, which was demonstrated in white North Americans, was not observed in Japanese. The DRB1*0101, *0405, and *1302 alleles were associated with high ACA titres, whereas DRB1*1502 was associated with low ACA titres and a low frequency of centromere protein C (CENP-C) reactivity.

CONCLUSIONS

These results suggest that the ACA response is associated with multiple HLA class II genes and that ACA positive SSc patients are heterogeneous in terms of immunogenetic background.

HLA-A, B, C, DR and DQ expression and hepatocellular carcinoma: study of 205 Italian subjects

We have evaluated the frequency of HLA class I and II antigens in 205 Italian patients with hepatocellular carcinoma (HCC) and 749 blood donors (controls). Moreover, we have looked for correlations between HLA antigen frequencies and HBV and/or HCV infections in HCC patients. We found great differences in HLA antigen frequencies considering only two groups: HCC patients and controls. The polymorphism is smaller when we consider the different groups of HCC patients in regard to the previous viral infections (HBV and/or HCV). The most interesting finding is the higher frequency of Cw7, B8 and DR3 in almost all groups of HCC patients. It is well known, that the HLA A1, Cw7, B8, DR3 antigen haplotype is associated with a rapid decline of CD4 cells, and HLA B8, DR3 positive subjects may display some changes in immune parameters and are prone to develop several immunological diseases. Thus HCC might be the result of a lower sensitivity (genetically given) to mitogenic stimuli of HBV and HCV.

Abnormal lymphocyte subsets in Kuwaiti patients with type-1 insulin-dependent diabetes mellitus and their first-degree relatives

Circulating lymphocyte subset imbalance is associated with type-1 insulin-dependent diabetes mellitus (IDDM). To examine the imbalance in these immunoregulatory cells in Kuwaitis with type-1 diabetes and their first-degree relatives we analysed T-lymphocyte subsets and HLA-DR expression (activation) in 18 IDDM patients with a family history of IDDM and 18 non-diabetic first-degree relatives of the IDDM patients. Both IDDM patients and their first-degree relatives showed a mild lymphopenia. Total T lymphocytes, CD3+ cells, in IDDM patients and their first-degree relatives were reduced compared to control subjects (P < 0.001). Total B lymphocytes, CD19+ cells, was increased in IDDM patients (P = 0.001), but was comparable to controls in IDDM patients' first-degree relatives. No quantitative abnormality was demonstrated in CD4+ cells in IDDM patients; however, these cells were higher in their first-degree relatives (P = 0.0089). Suppressor T lymphocytes, CD8+ cells, in first-degree relatives and controls were not significantly different; however, these cells were significantly reduced in IDDM patients (P = 0.001). The ratio of CD4+/CD8+ cells was higher in IDDM patients and their first-degree relatives compared to controls (P = 0.0007 and 0.0103, respectively). Activated T lymphocytes, HLA-DR+ CD3+ cells, were significantly increased in IDDM patients and their first-degree relatives. HLA-DR3 was the most common antigen found in IDDM patients (77% vs. 20% in controls, P = 0.00021). The second most common antigen was HLA-DR4 (55% vs. 24% in controls, P = 0.0566). However, no relationship was found in the levels of CD3+, CD4+ or CD8+ cells in patients possessing either DR3 or DR4. These results suggest that T-lymphocyte subset imbalance not only characterizes the cellular autoimmunity in the pathogenesis of IDDM but may also be significant in early pre-diabetic stages in those with a family history of IDDM.

Superantigenic properties of the group A streptococcal exotoxin SpeF (MF)

Streptococcal pyrogenic exotoxin F (SpeF), previously referred to as mitogenic factor, is a newly described potent mitogen produced by group A streptococci. To investigate whether this protein belongs to the family of microbial superantigens, we analyzed the cellular and molecular requirements for its presentation to T cells and compared it with the known streptococcal superantigen pyrogenic exotoxin A (SpeA) and the nonspecific polyclonal T-cell mitogen phytohemagglutinin (PHA). SpeF and SpeA were efficiently presented by autologous antigen-presenting cells (APCs) and an allogeneic B lymphoma cell line, Raji. In contrast, the monocytic cell line U937, which does not express major histocompatibility complex (MHC) class II molecules, failed to present SpeF as well as SpeA but supported the response to PHA. Thus, the presentation of SpeF by APCs was class II dependent but not MHC restricted. The requirement for HLA class II was further supported by the ability of anti-HLA-DQ monoclonal antibody to block the SpeF-induced proliferative response by 75 to 100%. Paraformaldehyde (PFA) fixation of autologous APCs resulted in an impaired ability of SpeF and SpeA to induce optimal T-cell proliferation. In contrast, fixation of Raji cells did not affect the induced proliferation. The stimulatory effect of PHA remained unaffected by both the use of PFA-fixed APCs and the addition of the HLA class II-specific monoclonal antibodies. The addition of a supernatant enriched in interleukin 1 and interleukin 6 to fixed autologous APCs resulted in an increased SpeF-induced response; thus, the impairment was not due to a requirement for processing, but, rather, costimulatory factors produced by metabolically active APCs were needed. SpeF was found to preferentially activate T cells bearing V beta 2, 4, 8, 15, and 19, as determined by quantitative PCR. The data presented clearly show that SpeF is a superantigen. We also studied the prevalence of the speF gene in clinical isolates by Southern blot analyses, and the gene could be detected in 42 group A streptococcal strains, which represented 14 serotypes.

A K-ras 13Gly-->Asp mutation is recognized by HLA-DQ7 restricted T cells in a patient with colorectal cancer. Modifying effect of DQ7 on established cancers harbouring this mutation?

We have characterized and described in detail 2 CD4+ T-lymphocyte clones (TLC) from a colonic cancer patient. These TLC specifically recognize a K-ras-derived peptide carrying the 13Asp mutation commonly found in adenocarcinomas of the colon. The TLC were independently derived, as they carried 2 different T-cell receptors. The TLC recognized partly overlapping epitopes within the 13Asp peptide, presented by HLA-DQ7 molecules, suggesting that this molecule might confer some protective immunity against the mutation. On the basis of analysis of 251 colonic carcinomas, the presence of HLA-DQ7 did not seem to protect against the establishment of carcinomas carrying the 13Asp mutation, since the frequency of the DQ7 haplotype was not decreased among patients having this mutation. A modifying effect of DQ7 on the development of carcinomas with a 13Asp mutation was, however, observed, resulting in fewer tumours reaching advanced Dukes stages when DQ7 was present.

Overlapping epitopes encompassing a point mutation (12 Gly-->Arg) in p21 ras can be recognized by HLA-DR, -DP and -DQ restricted T cells

Mutations in ras genes which result in transforming gene products carrying amino acid substitutions in position 12, 13 or 61 are common in human cancer. Peptides encompassing these mutations in ras are shown to be immunogenic in both mice and humans. The potential usefulness of such peptides in cancer therapy, depends on their ability to bind to HLA molecules. We therefore stimulated T cells from healthy donors with mutated ras-derived peptides. By repeated in vitro stimulation of peripheral blood mononuclear cells, several T cells clones could be generated which recognized a p21 ras derived peptide carrying a position 12 Gly-->Arg substitution. This peptide (1-25,12 Arg) could be specifically recognized by T cells restricted by either HLA-DQ7 or -DP3. Previously, we showed that this peptide is also recognized by a T cell clone restricted by HLA-DR2. The core region of the peptide was determined to span positions 9-16 for all three HLA restriction elements, and accordingly contains the mutational hot spots in position 12 and 13. The observation that the mutant 1-25,12 Arg ras-derived peptide may contain a promiscuous epitope encompassing the Gly-->Arg mutation in position 12 indicates that lack of peptide presentation by given HLA molecules may not be a major constraint in responsiveness against ras mutations.

High yields of anti-HLA human monoclonal antibodies can be provided by SCID mice

In an attempt to develop a suitable model for increasing the yield of human anti-HLA mAbs, we have used mice with SCID for i.p. injection of two human-mouse heterohybridomas. HMP1 hybridoma secretes a DQB1*0201 allele-specific human mAb whereas HMP12 secretes a human mAb recognizing the DRB1*1101, 1102, 1103, and 1104 alleles. Both hybridomas could be grown in SCID mice as localized tumors with no apparent alteration in the morphology of the cells or in the immunoglobulin secretion. Ascitic fluid was produced that showed a 600- to 1000-fold increase in monoclonal antibody cytotoxic titer as compared with that obtained in tissue culture. HLA-DQB1* and DRB1* alleles recognized by ascites and supernatants from SCID-derived cultures were analyzed by microlymphocytotoxicity assay on a small panel of B-lymphoblastoid cell lines. The results show that HLA specificity was retained after in vivo passage.

Human immunodeficiency virus reverse transcriptase T helper epitopes identified in mice and humans: correlation with a cytotoxic T cell epitope

T cell immunity may be critical to development of a vaccine for human immunodeficiency virus (HIV-1). T helper epitopes were identified in three predominantly conserved regions in the HIV-1 reverse transcriptase by using reverse transcriptase-immunized mice of five major histocompatibility complex haplotypes. One peptide (residues 38-52) that stimulated H-2k T cells also contained an epitope recognized by cytotoxic T cells from the same mice and from HIV-infected patients. Such concordance between helper and cytotoxic T lymphocyte epitopes, observed in four cases, may be important in vaccine development. Peptide 36-52 was recognized by interleukin-2-producing peripheral blood T cells from 9 of 17 HIV-seropositive humans studied, of multiple human leukocyte antigen-DR and -DQ types. The broad recognition of this peptide by both helper and cytotoxic T cells substantiates its potential importance in a vaccine.

In vitro infection of monocytes with HIVBa-L. Effect on cell surface expression of CD4, CD14, HLA-DR, and HLA-DQ

Monocytes from healthy blood donors were inoculated in vitro with a monocyte-tropic strain of human immunodeficiency virus type 1 HIVBa-L. HIV replication was first detected at Day 5 postinoculation, with peak virus activity at Day 17. We assessed the kinetics of the expression of four monocyte surface antigens (CD14, CD4, HLA-DR, and HLA-DQ) on HIV-infected and uninfected monocyte/macrophages, (M phi) by flow cytometry. We consistently found a decreased expression of CD4 and CD14 on HIV-infected M phi compared to their expression on M phi of uninfected controls. In contrast, HLA-DR and HLA-DQ expression was unchanged on HIV-infected M phi.

[A case of narcolepsy with increased cataplectic attacks after suffering from cerebrovascular disease]

It is well known that narcoleptic patients have DR2 and DQw-1 on HLA typing. The development of narcolepsy is considered to depend on the two factors; genetic predispositions and exogenous factors such as head trauma, encephalitis, etc., mainly affecting the brainstem or diencephalon. We reported a 46-year-old man who had occasional sleep attacks after suffering from left thalamic hemorrhage and pontine vascular disorders. Rehabilitation was markedly disturbed due to frequent episodes of cataplectic attacks which was triggered by emotional lability such as laughing, anxiety, and excitement. HLA type examination showed both DR-2 and DQw-1 loci in the proband and his four other siblings. His elder brother also suffered from mild excessive daytime sleepiness during his younger age, but it subsided gradually. Analysis of overnight polysomnography in the patient revealed remarkable paradoxical alpha-blocking and frequent sleep onset REM stages as typically observed in narcoleptic patients. MRI examination showed multiple small hemorrhages and infarctions in the pontine tegmentum, in addition to the left thalamic hemorrhage and multiple subcortical ischemic lesions. Concerning the mechanism of frequent cataplexy in this patient, it is postulated that increased emotional incontinence might have stimulated the descending reticular system in the brainstem which in turn may inhibit anterior horn motor cell activities. Methylphenidate was initially given to the patient, resulting in some relief of attacks, and addition of imipramine dramatically suppressed cataplectic attacks. Imipramine is considered to inhibit the excitatory afferent pathway to the brainstem suppressing the hyperactivity of descending motor inhibitory system due to its anti-muscarinergic action.

Monocyte activation in rheumatoid arthritis: evidence for in situ activation and differentiation in joints

Monocytes, defined by staining with the Mo-2 and Leu-M3 monoclonal antibodies which both detect the CD14 antigen, were studied in peripheral blood of control subjects and patients with rheumatoid arthritis as well as in rheumatoid synovial fluid of the latter for expression of activation/differentiation markers. The monocytes in the rheumatoid synovial fluids showed increased expression of class II major histocompatibility antigens (HLA-DR and -DQ) and decreased positivity for the peanut agglutinin receptor as compared with those from patient and control peripheral blood. There were no differences in phenotype between the control and patient peripheral blood monocytes. These findings are consistent with the hypothesis that monocytes are activated and differentiate into more mature macrophage-like cells after entry into the rheumatoid joint.

The activation of Langerhans cells in oral lichen planus

The numbers of CD1, HLADR, HLADP and HLADQ positive, intraepithelial, dendritic cells were compared in lesions of oral lichen planus and normal oral mucosa using an immunoalkaline phosphatase technique. In normal mucosa, there were equal numbers of CD1 and HLADR positive cells but significantly fewer cells were positive for HLADP (P less than 0.001) and HLADQ (P less than 0.05). In lichen planus, the cells appeared more dendritic and equal numbers of CD1, HLADR, HLADP and HLADQ positive cells were found, with significantly more HLADP (P less than 0.01) and HLADQ (P less than 0.05) positive cells than in normal mucosa. There was no change in the number of CD1 and HLADR positive cells. These results show that although there is no change in the total number of Langerhans cells (CD1 positive cells) in lichen planus, there is an increase in Class II major histocompatibility antigen expression. This suggests that in lichen planus, Langerhans cells are immunologically active and play a role in lesion development.

Structural model for T-cell recognition of HLA class II-associated alloepitopes

In an effort to investigate the structure-function relationship of HLA class II molecules vis-à-vis alloepitope expression, cloned T-cell reagents were used to define polymorphic epitopes associated with DR and DQ molecules. DNA sequences of genes encoding allelic or isotypic DR or DQ molecules that appear to express the same T-cell-defined epitopes were compared in an attempt to identify association of shared sequences with shared epitopes. When sequence sharing is associated with shared epitope expression, we suggest that it is the shared sequence that encodes the epitope in question. Based on the hypothetical three-dimensional structure of the class II molecule, an approximation is made as to which parts of the HLA class II molecule are involved in alloepitope expression. T-cell clones were generated from cells primed against HLA-DR2 haplotypes representing the cellularly defined subgroups Dw2 or Dw21 (previously designated MN2, FJ0, or Tb24). Those clones determined to be DR- or DQ-directed based on monoclonal antibody inhibition assays were tested by panel cell analysis utilizing DR2-positive and DR2-negative target cells. The data support the concept that amino acids 67, 70, 71, and 74 for DR molecules and amino acids 57, 70, and 71 for DQ molecules, which appear to comprise one face of the alpha helix, are of primary importance in T-cell recognition. In other cases, sharing of both the second hypervariable region (amino acids 25-33) and the third hypervariable region (amino acids 67-74) appears necessary to explain epitope sharing for DR molecules. We emphasize that the involvement of these two hypervariable regions may indicate that alloepitope expression involves the complex of class II molecule plus peptide, with the second HVR primarily involved in determining which peptides are bound and the third in T-cell receptor (TcR) recognition and/or peptide binding; we do not rule out that conformational changes of the second HVR can induce conformational changes in the third HVR. Finally, shared alloepitopes detected by some clones could not be explained based on shared primary sequences.