Polymorphism in the angiotensin II type 1 receptor (AGTR1) is associated with age at diagnosis in pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare, lethal disease associated with single gene disorders, connective tissue disease, exposures to anorexigens, and often, idiopathic etiology. Genes can modify the risk of PAH: (1) monogenic disorders associated with PAH are incompletely penetrant, and (2) not all patients with associated conditions at increased risk for PAH develop the disease. The renin angiotensin aldosterone system (RAAS) provides a set of candidate genes that could modulate pulmonary vascular disease similar to its effects on renal and peripheral vasculature.

METHODS

We studied 247 patients with PAH, comprising 177 with idiopathic PAH (IPAH), 63 with PAH/connective tissue disease (CTD), and 7 with PAH associated with anorexigens. Patients were genotyped for 5 common polymorphisms in angiotensinogen (AGT), angiotensin-converting enzyme (ACE), cardiac chymase A (CMA1), angiotensin II type 1 receptor (AGTR1), and aldosterone synthase (CYP11B2). Genotypes were tested for associations with age at diagnosis, hemodynamic parameters at diagnosis, and/or response to acute pulmonary vasodilator testing at diagnosis.

RESULTS

Associations were demonstrated for AGTR1 and age at diagnosis in IPAH (p = 0.005). Homozygotes for the 1166C allele (n = 13) were associated with an age at diagnosis 26 years later than those with A/A (n = 139) or A/C (n = 90) genotypes. No associations were demonstrated for AGT, ACE, CMA1, or CYP11B2.

CONCLUSIONS

The 1166C polymorphism in AGTR1 appears to be associated with a later age at diagnosis in IPAH, suggesting that this pathway could be involved in the biologic variability that is known to occur in PAH.

Evolutionary conservation and mutational spectrum of BMPR2 gene

A variety of mutations in the bone morphogenetic protein receptor type 2 (BMPR2) have been identified in patients with pulmonary arterial hypertension. In this study, using our BMPR2 mutation database and BMPR-II protein sequences from eight distantly related species, we defined the relationship among evolutionary conservation, mutation frequency and mutation distribution. As a whole, BMPR2 is evolving slower than the average for mammalian protein-encoding genes. As expected, the kinase domain is evolving more slowly than the extracellular ligand-binding and C-terminal domains. A detailed map of evolutionary conservation shows that there are repeating peaks and valleys within the C-terminal domain, representing higher and lower evolutionary conservation. We observed a strong correlation between evolutionary conservation and the distribution of mutations along the gene. All except two, of the nineteen missense mutations occur in absolutely conserved amino acids among the vertebrate homologs. In addition, we identified six mutational hotspots (P<0.05) by comparing the observed distribution of mutations to the pattern expected from a random multinomial distribution. Furthermore, analysis of the sequence environment surrounding the mutations revealed a specific pattern of mutagenesis. Over 22% of all single base-paired substitutions and 30% of all deletions and insertions are situated within tandem or non-tandem direct repeats of at least 5-bp and may be explained by slipped-mispairing model of mutagenesis. Also, over 59% of single base-paired substitutions versus 20% of deletions and insertions are located in perfect palindromic sequences that could produce "hairpin-loop" secondary structures with relatively high thermodynamic stability under physiological conditions. In addition, 3.7% of single base-paired substitutions versus 30% of deletions and insertions are located either within or in close proximity to the Krawczak and Cooper consensus sequence (TG A/G A/G G/T A/C). Further study of the mechanism of mutagenesis in BMPR2 may help identify other potentially mutable sites and differentiate between deleterious mutations and harmless polymorphic variants.

Bone morphogenetic protein receptor type II C-terminus interacts with c-Src: implication for a role in pulmonary arterial hypertension

Mutations of bone morphogenetic protein receptor type II (BMPR-II) have been associated with familial and idiopathic pulmonary arterial hypertension (PAH). BMPR-II is a member of the transforming growth factor-beta receptor superfamily. It consists of extracellular, transmembrane, and kinase domains, and a unique C-terminus with mostly unknown function. However, a number of PAH-causing mutations are predicted to truncate the C-terminus, suggesting that this domain plays an important role in the homeostasis of pulmonary vessels. In this study, we sought to elucidate the functional role of this C-terminus by seeking its interacting partners. Using yeast two-hybrid screening, we identified c-Src tyrosine kinase as a binding partner of this C-terminus. In vitro co-immunoprecipitation confirmed their interaction. Mutations truncating the C-terminus disrupted their interaction, while missense mutation within kinase domain reduced their interaction. In addition, BMPR-II and c-Src tyrosine kinase colocalized within intracellular aggregates when overexpressed in HEK293 cells. Moreover, mutations truncating the C-terminus disrupted their colocalization, whereas missense mutation within kinase domain had no effect on their colocalization. Furthermore, BMP ligand stimulation decreased c-Src-activating phosphorylation at Tyrosine 418 in pulmonary smooth muscle cells in both time- and concentration-dependent manners. Mutations that truncated the C-terminus abolished this response. Taken together, these results suggest a model in which proliferative effect of c-Src by vasoactive molecules is balanced by opposing effect of BMP signaling in basal state, and the loss of this balance due to BMPR2 mutations leads to increased c-Src activity and subsequently cell growth.

BMPR2 mutations in pulmonary arterial hypertension with congenital heart disease

The aim of the present study was to determine if patients with both pulmonary arterial hypertension (PAH), due to pulmonary vascular obstructive disease, and congenital heart defects (CHD), have mutations in the gene encoding bone morphogenetic protein receptor (BMPR)-2. The BMPR2 gene was screened in two cohorts: 40 adults and 66 children with PAH/CHD. CHDs were patent ductus arteriosus, atrial and ventricular septal defects, partial anomalous pulmonary venous return, transposition of the great arteries, atrioventicular canal, and rare lesions with systemic-to-pulmonary shunts. Six novel missense BMPR2 mutations were found in three out of four adults with complete type C atrioventricular canals and in three children. One child had an atrial septal defect and patent ductus arteriosus; one had an atrial septal defect, patent ductus arteriosus and partial anomalous pulmonary venous return; and one had an aortopulmonary window and a ventricular septal defect. Bone morphogenetic protein receptor 2 mutations were found in 6% of a mixed cohort of adults and children with pulmonary arterial hypertension/congenital heart defects. The current findings compliment recent reports in mouse models implicating members of the bone morphogenetic protein/transforming growth factor-beta pathway inducing cardiac anomalies analogous to human atrioventricular canals, septal defects and conotruncal congenital heart defects. The small number of patients studied and the ascertainment bias inherent in selecting for pulmonary arterial hypertension require further investigation.

Primary pulmonary hypertension in families with hereditary haemorrhagic telangiectasia

Primary pulmonary hypertension (PPH) is a rare but severe and progressive disease characterised by obstructive lesions of small pulmonary arteries. Patients with PPH often have mutations in the bone morphogenetic protein receptor type II (BMPR2) gene, whereas some carry mutations in the activin receptor-like kinase 1 (ALK-1) gene, generally associated with hereditary haemorrhagic telangiectasia (HHT) type 2, a vascular dysplasia affecting multiple organs. The aim of this study was to determine whether members of families with PPH and confirmed or probable HHT had ALK-1 mutations. ALK-1 and BMPR2 mutation analysis was performed on deoxyribonucleic acid from affected members of four families with PPH and confirmed or suspected HHT. ALK-1 mutations were identified in all four families and three novel mutations found in exon 10, leading to truncated proteins. In the fourth family, a missense mutation, previously reported in four independent HHT families, was detected in exon 8. Analysis of the BMPR2 gene revealed no exonic mutations in the probands with both PPH and HHT. The present data bring to 10 the number of reported families with primary pulmonary hypertension and hereditary haemorrhagic telangiectasia type 2, representing 16% of the 61 families with known activin receptor-like kinase 1 mutations. Such mutations might predispose to primary pulmonary hypertension, and specialists should be aware of the potential link between these two disorders.

Genetic studies of pulmonary arterial hypertension

These genetic studies of primary pulmonary hypertension (PPH) initially tried to define immunogenetic subsets. Because only small subsets could be classified when defined by HLA/autoantibody associations and the familial form of PPH failed to segregate with the HLA class II locus, the focus shifted to a genome scan of families with PPH (FPPH). This approach identified a gene on chromosome 2q33,34 called PPH1. Mutations in this gene, now known to be bone morphogenetic protein receptor 2 (BMPR2), can cause PPH. Mutations in a second gene, ALK-1, present in families with hereditary hemorrhagic telangiectasia type 2, also causes PPH. Both genes, involved in TGF-B signaling, provide exciting clues for defining the pathogenesis of PPH.

Prognostic factors for survival in human immunodeficiency virus-associated pulmonary arterial hypertension

We report a large monocentric case series of 82 patients with human immunodeficiency virus-associated pulmonary arterial hypertension (PAH). No germline mutations of the PPH1 gene (bone morphogenetic protein receptor-II) were found in any of the 19 patients tested. PAH was the direct cause of death in 72% of cases. Survival rates of the overall population at 1, 2, and 3 years were 73, 60, and 47%, respectively. Survival was significantly poorer in patients in New York Heart Association functional class III-IV at the time of diagnosis, as compared with those in functional class I-II with respective rates of 60, 45, and 28% versus 100, 90, 84% at 1, 2, and 3 years (p < 0.0001). Subsequently, we analyzed prognostic factors in patients in functional class III-IV. Univariate analysis indicated that CD4 lymphocyte count of more than 212 cells mm(-3), the use of combination antiretroviral therapy (CART), and epoprostenol infusion were related with a better survival. On multivariate analysis only CD4 lymphocyte count was an independent predictor of survival, presumably because CART and epoprostenol infusion were strongly linked in our patient population. These results suggest that patients with severe human immunodeficiency virus-associated PAH should be considered for long-term epoprostenol infusion in association with CART.

BMPR2 germline mutations in pulmonary hypertension associated with fenfluramine derivatives

This study investigated whether patients developing pulmonary arterial hypertension (PAH) after exposure to the appetite suppressants fenfluramine and dexfenfluramine have mutations in the bone morphogenetic protein receptor 2 (BMPR2) gene, as reported in primary pulmonary hypertension. BMPR2 was examined for mutations in 33 unrelated patients with sporadic PAH, and in two sisters with PAH, all of whom had taken fenfluramine derivatives, as well as in 130 normal controls. The PAH patients also underwent cardiac catheterisation and body mass determinations. Three BMPR2 mutations predicting changes in the primary structure of the BMPR-II protein were found in three of the 33 unrelated patients (9%), and a fourth mutation was found in the two sisters. No BMPR2 mutations were identified in the 130 normal controls. This difference in frequency was statistically significant. Moreover, the mutation-positive patients had a somewhat shorter duration of fenfluramine exposure before illness than the mutation-negative patients, a difference that was statistically significant when the two sisters were included in the analysis. In conclusion, the present authors have detected bone morphogenetic protein receptor 2 mutations that appear to be rare in the general population but may combine with exposure to fenfluramine derivatives to greatly increase the risk of developing severe pulmonary arterial hypertension.

Genetic aspects of pulmonary arterial hypertension

This paper concentrates on the genetic aspects of pulmonary arterial hypertension (PAH), a diagnostically based subclass of pulmonary hypertension that includes primary pulmonary hypertension (PPH). During the past year, patients with familial and sporadic PPH were found to have germline heterozygous missense, nonsense and frameshift mutations in bone morphogenetic protein receptor II (BMPR2). Mutations in BMPR2, a member of the transforming growth factor-beta (TGF-beta) receptor superfamily, are predicted to interrupt the bone morphogenetic protein (BMP) signalling pathway, resulting in proliferation, rather than apoptosis of cells within small arterioles. Mechanistically, haploinsufficiency was found by using in vitro gene expression experiments, but a dominant-negative mechanism has not been excluded. The failure to find BMPR2 mutations in all families with familial PPH and in all patients with sporadic PPH suggests that other genes remain to be identified. Mutations in ALK1, a TGF-beta type 1 receptor, previously known to cause type 2 hereditary haemorrhagic telangiectasia (HHT), have also been reported in a few HHT families with clinical and histological features of PPH. The clinical development of PPH, as in neoplasia, appears to require 'two hits' The two hits can be provided either by genetic or environmental factors.

Elevated plasma tissue plasminogen activator and anti-THP-1 antibodies are independently associated with decreased graft survival in cardiac transplant recipients

Hemostatic and immunologic factors have been implicated in future cardiac events in patients with coronary artery disease. The role of these factors and their interaction is less established in cardiac transplant recipients. We sought to characterize the role of these factors in these patients. Cardiac transplant patients who presented for surveillance coronary angiography and/or endomyocardial biopsy were eligible for enrollment. Ninety-nine consecutive patients were enrolled. Plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1, von Willebrand factor, fibrin D-dimer, and anti-t-PA antibody were determined by enzyme-linked immunosorbent assays. Anti-THP-1 cell antibodies directed against a monocytic leukemia cell line were detected by incubating patient plasma with THP-1 cells. Bound antibody was detected using goat peroxidase-labeled immunoglobulin G directed against human immunoglobulins. Lipids were measured by enzymatic methods. Multivariate analysis identified the presence of anti-THP-1 cell antibodies (risk ratio 4.41, p = 0.002), t-PA antigen (risk ratio 1.10, p = 0.033), donor age 20 to 26 years (risk ratio 8.83, p = 0.042), and donor age >36 years (risk ratio 15.53, p = 0.009) as predictors of allograft failure. Altered hemostatic function, as demonstrated by elevated plasma t-PA antigen levels, is predictive of subsequent allograft failure in cardiac transplant recipients. In addition, the presence of anti-THP-1 cell antibodies in these patients is predictive of allograft failure.

Familial primary pulmonary hypertension (gene PPH1) is caused by mutations in the bone morphogenetic protein receptor-II gene

Familial primary pulmonary hypertension is a rare autosomal dominant disorder that has reduced penetrance and that has been mapped to a 3-cM region on chromosome 2q33 (locus PPH1). The phenotype is characterized by monoclonal plexiform lesions of proliferating endothelial cells in pulmonary arterioles. These lesions lead to elevated pulmonary-artery pressures, right-ventricular failure, and death. Although primary pulmonary hypertension is rare, cases secondary to known etiologies are more common and include those associated with the appetite-suppressant drugs, including phentermine-fenfluramine. We genotyped 35 multiplex families with the disorder, using 27 microsatellite markers; we constructed disease haplotypes; and we looked for evidence of haplotype sharing across families, using the program TRANSMIT. Suggestive evidence of sharing was observed with markers GGAA19e07 and D2S307, and three nearby candidate genes were examined by denaturing high-performance liquid chromatography on individuals from 19 families. One of these genes (BMPR2), which encodes bone morphogenetic protein receptor type II, was found to contain five mutations that predict premature termination of the protein product and two missense mutations. These mutations were not observed in 196 control chromosomes. These findings indicate that the bone morphogenetic protein-signaling pathway is defective in patients with primary pulmonary hypertension and may implicate the pathway in the nonfamilial forms of the disease.

Fine specificity of anti-fibrillin-1 autoantibodies in primary pulmonary hypertension syndrome

Autoantibodies to fibrillin-1 (Fbn-1) have been found in systemic sclerosis (SSc), calcinosis, Raynaud's esophagael dysmotility, sclerodectyly, and telaengectasia (CREST) and mixed connective tissue disease (MCTD) diseases. The purpose of this study was to determine whether patients with primary pulmonary hypertension (PPH) and appetite-suppressant-associated PPH have anti-Fbn-1 autoantibodies. In addition we assessed the human leucocyte antigen (HLA) class II alleles (DRB1, 3, 4, 5 and DQB1) in these patients in order to determine whether the response is genetically restricted. The frequency of anti-Fbn-1 autoantibodies in patient groups was compared with that of a control group of 88 healthy patients, and HLA was correlated similarly with a group of 51 healthy subjects. Anti-Fbn-1 autoantibodies were found at high frequency in PPH: in 70 of 75 adults with PPH (93%), in 28 of 33 children with PPH (84.8) and in 12 of 18 (67%) patients with appetite-suppressant-associated PPH. Utilization of two Fbn-1 fusion proteins allowed us to determine the dominant determinant region, recognized by anti-Fbn-1 autoantibodies, which may be located on the N-terminal fragment of the Fbn-1 protein. No significant immunogenetic correlations were found when the PPH patient groups were compared with normal controls. This novel category of autoantibodies is found in diseases characterized by endothelial and extracellular matrix protein alterations and fibrosis.

Fine mapping of PPH1, a gene for familial primary pulmonary hypertension, to a 3-cM region on chromosome 2q33

Familial primary pulmonary hypertension (PPH) is a rare autosomal dominant disease characterized by distinctive changes in pulmonary arterioles that lead to increased pulmonary artery pressures, right ventricular failure, and death. Our previous studies had mapped the disease locus, PPH1, to a 27-cM region on chromosome 2q31-q33, with a maximum multipoint logarithm of the odds favoring genetic linkage score of 3.87 with markers D2S350 and D2S364. To narrow the minimal genetic region for PPH, we physically mapped 33 highly polymorphic microsatellite markers and used them to genotype 44 affected individuals and 133 unaffected individuals from 17 families with PPH. We observed recombination events that substantially reduced the interval for PPH1 to the approximately 3-cM region that separates D2S311 and D2S1384. This entire region lies within chromosome 2q33. A maximum two-point lod score of 7.23 at a recombination fraction of zero was obtained for marker D2S307. A maximum multipoint lod score of 7.41 was observed close to marker D2S1367. The current minimal genetic region contains multiple candidate genes for PPH, including a locus thought to play a role in lung cancer.

Mapping of familial primary pulmonary hypertension locus (PPH1) to chromosome 2q31-q32

BACKGROUND

The pathogenesis of primary pulmonary hypertension (PPH) is unknown, although in some instances families with multiple affected members suggest a genetic etiology.

METHODS AND RESULTS

We used microsatellite markers and linkage analysis in a large family with PPH to determine the chromosomal location of their disease gene. We tested a second, ethnically distinct, family for cosegregation of disease with markers from the linked region. We mapped the disease locus PPH1; GDB/HUGO designation (GDB:1381541; July 1996), approved when this work was accepted for publication in abstract form (Circulation. 1996;94[suppl I]:1-49.), in these families to a 27-cM region on chromosome 2q31-q32, with a maximum lod score of 3.87 associated with markers D2S350 and D2S364.

CONCLUSIONS

Cosegregation of this region with disease in different ethnic groups suggests that we mapped an important locus in familial PPH. Careful study of additional families and sporadic cases will be required to confirm this localization of PPH1 and characterize its overall role.

Primary pulmonary hypertension, tissue plasminogen activator antibodies, and HLA-DQ7

Antibodies to fibrin-bound tissue plasminogen activator (tPA) have been found in autoimmune diseases with vascular injury, such as systemic lupus erythematosus and scleroderma. The purpose of this study was to determine whether patients with primary pulmonary hypertension (PPH) have an immunogenetically determined response to fibrin-bound tPA. Antibodies to fibrin-bound tPA were determined in three patient groups: 45 adults with PPH, 41 children with PPH, and 40 children with anatomically large congenital pulmonary to systemic communications (PHT+shunt). The frequencies of the HLA class II (DRB1,3,4,5, and -DQB1) alleles in these three patient groups were compared with those of 51 healthy Caucasian control subjects. Fibrin-bound tPA antibodies were found in four of 45 (9%) adults with PPH, four of 41 (10%) children with PPH, and one of 40 (2.5%) children with PHT-shunt. HLA class II typing, which was available for seven of nine Caucasians with fibrin-bound tPA antibodies, revealed that six of seven (86%) patients typed HLA-DQ7 (DQB1*0301) and one typed HLA-DQ6. The 86% frequency of HLA-DQ7 in the antibody positive patients was significant compared with the 29% frequency in the healthy control subjects (p = 0.007, p corrected [pc] = 0.05, OR = 14.4). Of interest, these antibody-positive patients, although lacking antiphospholipid antibodies, shared an amino acid epitope, common to HLA-DQB1*06,07 and 08 subtypes, which was previously reported to be associated with the lupus anticoagulant. In conclusion, antibodies to fibrin-bound tPA and HLA-DQ7, and possibly the same epitope associated with the lupus anticoagulant, defined a small subset of children and adults with PPH.

Primary pulmonary hypertension: immunogenetic response to high-mobility group (HMG) proteins and histone

HLA class II alleles (DNA typing) and antibodies to HMG-1,2,14,17 proteins and H1 histone were determined in three predominantly Caucasian groups of patients with pulmonary hypertension (PHT). Forty-four adults had primary pulmonary hypertension (PPH), 42 children had PPH, and 41 children had PHT associated with anatomically large congenital pulmonary to systemic shunts (PHT + shunt). The HLA class II alleles in the Caucasian patients were compared with those of 51 healthy Caucasian controls. Eight (18%) of 44 sera from adults with PPH bound HMG-14 and 23 (52%) bound H1. None of 42 sera from children with PPH bound either HMG-14/17 or HMG-1/2, whereas four (10%) bound H1. In the PHT + shunt group of 41 children, two (5%) bound HMG-14, one (3%) bound HMG-17, four (10%) bound HMG-1 and/or HMG-2, and six (15%) bound H1. Among the 12 HMG antibody-positive patients, HLA-DQ6 was present in nine of 10 HLA typed patients (six PPH adults and three PHT + shunt children), seven of whom had antibodies to HMG-14 and one to HMG-17. The 100% frequency of HLA-DQ6 in seven Caucasian patients with antibodies to HMG-14/17 was statistically significant when compared with the 41% frequency of -DQ6 present in 51 healthy Caucasian controls (pc = 0.027, pc = Bonferroni correction, OR = 21.3). In contrast, when compared with controls, 25 patients with PPH and anti-H1 antibodies (21 adults and four children) had increased frequencies of HLA-DQ7 and -DR5 (60% versus 29%, P = 0.010, OR = 3.6 and 48% versus 22%, P = 0.018, OR = 3.4), which were not significant after correction. In essence, antibodies to HMG-14 and to H1 proteins were present predominantly in adults with PPH, suggesting that the pattern of response to HMG-14/17 was similar to that previously reported in systemic lupus erythematosus (SLE) and drug-induced autoimmunity. This is the first report of an association between autoantibodies directed against HMG and H1 with immunogenetic markers. These data suggest that a subset of patients with PPH may have an autoimmune disease.

Surviving the "air evac": medical and logistical issues of evacuating psychiatric patients by air from Korea to the United States

Active duty soldiers who need a physical evaluation board for incapacitating psychiatric symptoms may be evacuated by air to the United States. The Aeromedical Evacuation (air evac) process involves many overlapping organizations, including the Army, Air Force, command, medical, and flight personnel. There are often communication problems between the different systems. Which soldiers are returned to the United States, how they get there, whether to send a medical attendant, and which medications to use for the flight are discussed. The air evac process is in transition. We hope that this paper will facilitate cooperation between the different systems and improve patient care.

Primary pulmonary hypertension in HIV infection: an outcome determined by particular HLA class II alleles

Primary pulmonary hypertension (PPH) may have an autoimmune basis that is influenced by host immunogenetics. The pathogenesis of primary pulmonary hypertension in human immunodeficiency virus (HIV) infection is unclear. The objective of this study was to determine whether patients with PPH and HIV infection have distinctive immunogenetic profiles. Ten racially mixed HIV-infected patients with PPH were typed for human leukocyte antigen (HLA) class II (DRB1, 3, 4, 5 and DQB1) by DNA-PCR sequence-specific oligonucleotide probes. Results were compared with two control groups: 128 HIV-negative Caucasians and a previously reported group of 97 HIV-positive, racially mixed control subjects. In those with PPH, there was a significantly increased frequency of HLA-DR6 (-DRB1*1301/2 subtypes) and of HLA-DR52 (DRB3*0301 subtype). These findings suggest that HIV-associated PPH reflects a host response to HIV-1 determined by one or more HLA-DR alleles located within the major histocompatibility complex. The same HLA-DR6 subtype found at increased frequency in our patients has previously been associated with the development of a CD8 lymphocytic host response to HIV-1, termed diffuse infiltrative lymphocytosis syndrome (DILS), which resembles autoimmune Sjogren's disease and is associated with prolonged survival. Together, these findings suggest that HIV-positive PPH may represent a clinical outcome that has similarities with that resulting from the immunogenetically determined host response present in DILS.

Position 26 of the first domain of the HLA-DQB1 allele in post-silicone implant scleroderma

OBJECTIVE

To determine whether women with scleroderma (systemic sclerosis, SSc) and silicone implants have the same or distinctive immunogenetic findings compared to those reported for idiopathic scleroderma.

METHODS

In this case-control study, 9 Caucasian women with SSc and silicone implants (7 breast, 1 chin, 1 toe) and 128 healthy Caucasian controls were typed for HLA class II (DRB1,3,4,5, and DQB1) by DNA polymerase chain reaction (PCR) sequence specific oligonucleotide probes (SSOP).

RESULTS

All women with SSc had HLA-DQ5 or DQ7 (DQB1*0301). These 2 alleles have glycine (Gly) or tyrosine (Tyr), and not hydrophobic leucine (Leu), at position 26 in the 2nd hypervariable region of the DQB1 first domain. The increased frequency of at least one Leu 26 negative allele (Gly + or Tyr +) in the women with SSc (100%) compared with controls (73%) was not statistically significant. In contrast, the low frequency of one Leu 26+ allele in the patients (28 vs 57%, p = 0.03, RR = -3.3) and 2 Leu 26+ alleles (0 vs 35%, p = 0.03, RR = -10.4) was significant.

CONCLUSION

The presence of Gly 26 or Tyr 26 in the HLA-DQB1 first domain in our cases with SSc and silicone implants is consistent with immunogenetic findings reported in Caucasian with idiopathic SSc anticentromere autoantibodies. Whether all the immunogenetic features in SSc associated with silicone implants remain indistinguishable from those seen in idiopathic.

Characteristics of human immunodeficiency virus and chlorpromazine induced antiphospholipid antibodies: effect of beta 2 glycoprotein I on binding to phospholipid

OBJECTIVE

To investigate the nature of the target epitope for human immunodeficiency virus (HIV) and chlorpromazine (CPZ) induced antiphospholipid antibodies (aPL) by evaluating the effect of the aPL cofactor (beta 2 glycoprotein I) on phospholipid binding and to compare this with known binding patterns of infection induced and autoimmune aPL.

METHODS

aPL positive sera from 17 patients with HIV and 16 patients with schizophrenia treated with CPZ were tested and compared with aPL positive sera from 20 patients with syphilis and 35 with autoimmune disease. Both the sera and either IgG fractions prepared by affinity chromatography or IgM fractions prepared by euglobulin precipitation and gel filtration were tested for binding to cardiolipin (CL) in ELISA in the presence and absence of purified human beta 2 glycoprotein I (beta 2-GPI). Competition studies evaluated biotinylated CPZ IgM aPL binding and the effect on this of added aPL, placental anticoagulant protein I--a phospholipid binding protein that inhibits autoimmune aPL--and CL vesicles.

RESULTS

HIV IgG aPL binding to CL was inhibited by beta 2-GPI (51-53%), like syphilis IgG aPL and in contrast to autoimmune IgG aPL. CPZ IgM aPL, like autoimmune IgM aPL, bound more efficiently in the presence of beta 2-GPI, with binding increases of 31-149%. Binding of biotinylated CPZ IgM aPL to CL was competitively inhibited by autoimmune IgG aPL (47%) and CPZ aPL (92%) but not by HIV IgG aPL or normal IgG. Placental anticoagulant protein I and CL vesicles completely prevented binding of CPZ IgM aPL to CL (100 and 96% inhibition, respectively).

CONCLUSIONS

Findings indicate that CPZ aPL resembles the autoimmune aPL, whereas aPL found in HIV infection do not appear to be of autoimmune type.

Angioedema presenting as chronic gastrointestinal symptoms

Gastrointestinal complaints may be the presenting feature of patients with acquired or hereditary angioedema. We describe two patients with episodic nausea, abdominal pain, and cramping secondary to C1 inhibitor deficiency. In one patient, an acquired deficiency arose as a paraneoplastic syndrome with abdominal complaints preceding the diagnosis of an occult lymphoma. The second patient presented at age 61 with abdominal complaints secondary to a hereditary deficiency of C1 inhibitor. The patients' symptoms were due to gastrointestinal angioedema, resulting from episodic unregulated complement activation. The biochemical mechanism of this unusual syndrome and its diagnostic importance are discussed. A C1 inhibitor deficiency should be considered in patients with unexplained abdominal symptoms suggestive of intestinal pseudo-obstruction.

Familial pulmonary hypertension: immunogenetic findings in four Caucasian kindreds

A postulated association between primary pulmonary hypertension (PPH) and autoimmune diseases prompted this study. To see if autoantibodies and an association with the major histocompatibility locus (MHC) accompany the familial form of pulmonary hypertension (PHT), we determined human leukocyte antigen (HLA)-class I (A,B,C) and HLA-class II (DR,DQ) typing serologically, serum immunoglobulin (Ig) isotypes, and antinuclear (ANA)-autoantibodies in three families in which more than one member had PPH (FPPH) and in a fourth family with PPH and PHT associated with congenital heart disease. The three FPPH families had 15 PPH + members, eight (in whom the alleles were determined or could be inferred) typed for HLA-DRw52 and seven for HLA-DR3,DRw52,DQw2. These three families each had one PPH+,DR3+ member, with an immunoglobulin isotype deficiency, one with IgA and two with mild IgG. The fourth family differed in that both the patient and asymptomatic relatives had varying autoantibodies and different HLA associations. This family had an anti-centromere+ child with PHT and a congenital heart lesion, a mother who died of PPH, and asymptomatic ANA+ relatives (father anti-Sm+/anti-RNP+; autoantibodies unknown in fraternal twin sister and in maternal grandmother). HLA typing showed that the proband and her fraternal twin sister received DR5,DRw52,DQw3 from their father whereas the proband received DR4,DRw53,DQw3 from the mother and her sister received DR2,DQw1. In summary, three FPPH families had multiple PPH+ members who lacked autoantibodies and typed for HLA-DR3,DRw52,DQw2, whereas a fourth family with familial PHT had PHT+ and PHT- members with autoantibodies and different HLA associations.

Evidence for the association of unexplained pulmonary hypertension in children with the major histocompatibility complex

BACKGROUND

A link between primary pulmonary hypertension (PPH) and autoimmune disorders has been postulated. To investigate this relation, we performed immunofluorescent antinuclear antibody tests (ANA) and serological human leukocyte antigen (HLA)-A, B, C, DR, and DQ typing on two groups of Caucasian children with unexplained pulmonary hypertension (PHT) and their parents.

METHODS AND RESULTS

Group 1 consisted of 17 children with PPH including two patients with familial PPH and three patients with trivial congenital pulmonary to systemic communications. Group 2 consisted of 13 children with advanced PHT and anatomically large congenital pulmonary to systemic communications (PHT + shunt). Both groups had comparably severe pulmonary vascular disease documented by cardiac catheterization. The following statistically significant data (p less than 0.05) were obtained when the study groups were compared with those published for normal controls. Although positive ANAs and varying titers of autoantibodies were found in both groups of children and mothers (not fathers), +ANAs were only significant for the maternal groups. The PPH (group 1) children had increased frequencies of HLA-DR3, DRw52, and DQw2 and decreased DR5, whereas the group 2 (PHT + shunt) children (also their parents) had no statistically significant alterations in any of the DR or DQ alleles. The PPH mothers had decreased DQw3, an allele in linkage disequilibrium with DR5.

CONCLUSIONS

These immunogenetic data suggest that childhood PPH appears to be associated with the major histocompatibility complex alleles HLA-DR3, DRw52, and DQw2. This newly found correlation of juvenile PPH with these alleles adds this disease to the DR3+ group of autoimmune diseases. Further studies are needed to determine whether there is also an immunological or autoimmune component in some children with PHT + shunt lesions because this group lacked an HLA association.

Isolated pulmonary hypertension in the grandchild of a kindred with scleroderma (systemic sclerosis): "neonatal scleroderma"?

We report a small kindred in which the father and daughter with positive antinuclear antibodies (ANA) (proband) had diffuse cutaneous and visceral scleroderma (systemic sclerosis, SSc), antitopoisomerase autoantibodies and shared the HLA-A23 C- B- DR5 DRw52 DQw3 haplotype. The ANA- granddaughter (daughter of the proband) was noted to have severe isolated pulmonary hypertension within the first 6 months of life, and had the other maternal HLA-A1 Cw8 B14 DR1 DQw1 haplotype, which included a B1, B2 duplication of the C4B allele. All 3 members shared DRw52. The possibility that neonatal pulmonary hypertension represents an isolated autoimmune disease or a hitherto undescribed neonatal syndrome is proposed and the immunogenetic autoantibody implications are discussed.

Heterogeneity of proteins in commercial preparations of human chorionic gonadotropin (hCG) demonstrated by Western blotting

Immunoblotting has been utilized to detect the presence of human chorionic gonadotropin (hCG), its alpha and beta subunits, the Tamm-Horsfall protein (uromodulin), immunoglobulins G (IgG) and M (IgM), kappa (K) and lambda (L) chains, and serum albumin in commercially available preparations of hCG intended for human use. Concentrated pregnancy, postpartum, and normal urines were studied as a comparison. Those hCG batches prepared from pooled first-trimester pregnancy urine contained all of the hCG and non-hCG proteins listed above or their fragments, with the single exception of the IgM mu chain. The conflicting literature regarding the immunomodulatory properties of hCG requires reevaluation, since many previous reports of immunologic activity utilized these preparations, containing intact and degraded IgG, K, and L chains, and the Tamm-Horsfall protein, all of which may contribute to an altered immune response. Since hCG can be prepared in high yields, free of these contaminants, these data suggest that patients are being unnecessarily exposed to contaminating substances when receiving parenteral injections of hCG.

Pregnancy-associated growth factor. II. A T-dependent polyclonal activator of human adult peripheral blood lymphocytes (PBL)

This study examined the ability of pregnancy-associated growth factor (PAGF), a substance found in crude human chorionic gonadotropin (hCG), to induce plaque-forming cells (PFC) in cultured human peripheral blood lymphocytes (PBL). PAGF, 0.25 to 1 mg/ml, induced maximal PFC at 6 to 7 days as measured by the staphylococcal protein A-coupled SRBC reverse hemolytic plaque assay with a rabbit anti-human Ig antiserum. PAGF-induced PFC/culture ranged from 1800 to 39,000 with a mean of 11,524 in unfractionated PBL (N = 24), as compared to 540 to 77,840 with a mean of 17,303 for pokeweed (PWM) (N = 22). Comparison of PAGF- and PWM-induced PFC showed that both induced specific IgG, IgA, and IgM PFC. In most individuals, PAGF induced more IgM and PWM more IgG PFC. The kappa: lambda ratio was 1.5 for unstimulated PBL, and approximately 3.5 for PAGF and PWM. To see if PAGF was a T-dependent polyclonal activator of B cells, T and non-T populations were obtained by SRBC rosettes and negatively selected T4 and T8 cells by complement-mediated lysis of SRBC+(T) cells. Only the recombined subsets which included T4 cells and non-T cells supported PAGF- and PWM-induced PFC. These data indicate that PAGF, a substance derived from commercial extracts of pregnancy urine, is a T4-dependent polyclonal activator of normal human B cells.

Pregnancy-associated growth factor. II. A T-dependent polyclonal activator of human adult peripheral blood lymphocytes (PBL)

This study examined the ability of pregnancy-associated growth factor (PAGF), a substance found in crude human chorionic gonadotropin (hCG), to induce plaque-forming cells (PFC) in cultured human peripheral blood lymphocytes (PBL). PAGF, 0.25 to 1 mg/ml, induced maximal PFC at 6 to 7 days as measured by the staphylococcal protein A-coupled SRBC reverse hemolytic plaque assay with a rabbit anti-human Ig antiserum. PAGF-induced PFC/culture ranged from 1800 to 39,000 with a mean of 11,524 in unfractionated PBL (N = 24), as compared to 540 to 77,840 with a mean of 17,303 for pokeweed (PWM) (N = 22). Comparison of PAGF- and PWM-induced PFC showed that both induced specific IgG, IgA, and IgM PFC. In most individuals, PAGF induced more IgM and PWM more IgG PFC. The kappa: lambda ratio was 1.5 for unstimulated PBL, and approximately 3.5 for PAGF and PWM. To see if PAGF was a T-dependent polyclonal activator of B cells, T and non-T populations were obtained by SRBC rosettes and negatively selected T4 and T8 cells by complement-mediated lysis of SRBC+(T) cells. Only the recombined subsets which included T4 cells and non-T cells supported PAGF- and PWM-induced PFC. These data indicate that PAGF, a substance derived from commercial extracts of pregnancy urine, is a T4-dependent polyclonal activator of normal human B cells.

Pregnancy-associated growth factor. I. A proliferative agent which expands adult and cord T4 cells in unfractionated cultures

Experiments were designed to examine the effects of pregnancy-associated growth factor (PAGF), a substance found in commercial preparations of crude human chorionic gonadotropin (hCG), on unfractionated human cord blood cells (CBC) and adult peripheral blood lymphocytes (PBL) cultured in 5% fetal calf serum (FCS). Comparisons of PAGF-induced [3H]TdR incorporation in nine pairs of simultaneously cultured CBC and PBL with phytohemagglutinin (PHA) and tetanus toxoid (TT) showed that all CBC and PBL responded to PAGF and PHA whereas all PBL and one CBC responded to TT. The rank order of potency for CBC and PBL was PHA greater than PAGF greater than TT. To examine phenotypic changes induced by PAGF, flow cytometry was performed on precultured cells, control cultures, and PAGF-stimulated cultures at 2, 5, 7, and 9 days. The monoclonal antibodies (mAbs) included T3, T4, and T8 (T cells), T9 (transferrin receptor), Tac (IL-2 receptor), 12 (Ia or DR-framework antigen), and T10 (putative activation and/or maturation antigen). PAGF-stimulated cultures had statistically significant increased percentages of T3, T4, T9, T10, and Tac but not T8 when compared to precultured cells and control cultures. PAGF also increased PBL but not CBC Ia. In PAGF-stimulated cultures, CBC had more T3 and T4 cells with increased fluorescence intensity than PBL. Maximal expression of phenotypes usually occurred at Days 7 and 9, 2 days after maximal [3H]TdR incorporation. In comparison to PAGF, PHA-stimulated PBL had earlier expression of these phenotypes but included T8. These data indicate PAGF induces proliferation, activation antigens, and T3 expansion predominantly confined to the T4 subset in both CBC and PBL.

Extracts of pregnancy urine contain a mitogen for human peripheral blood lymphocytes (PBL)

A mitogen for human peripheral blood lymphocytes (PBL) has been found in commercial batches of crude human chorionic gonadotropin (hCG), which is obtained from pregnancy urine. These crude hCG preparations, as well as column eluates free of hCG and a previously noted immunosuppressive factor, are mitogen for normal human PBL cultured in fetal calf serum. This mitogen is designated pregnancy-associated growth factor (PAGF) because of its source. PAGF induces 3H-thymidine incorporation of mixed Ia+ non-T cells and T cells, probably confined to the helper subclass; proliferation is abolished by complement-mediated lysis using monoclonal antisera to Ia, mature T cells (OKT3), and the Th (OKT4) subset, but not by antisera to the Ts (OKT8) subset. The proliferating cell is a T cell because irradiation of these cells, but not the non-T cells, abolished PAGF mitogenicity. In addition, PAGF augments the autologus mixed lymphocyte reaction. Preliminary experiments indicate that its m.w., in the range of 18,000 to 22,000, is different from epidermal growth factor, the only previously described growth factor found in crude hCG preparations. In addition epidermal growth factor failed to stimulate PBL under similar conditions.

Extracts of pregnancy urine contain a mitogen for human peripheral blood lymphocytes (PBL)

A mitogen for human peripheral blood lymphocytes (PBL) has been found in commercial batches of crude human chorionic gonadotropin (hCG), which is obtained from pregnancy urine. These crude hCG preparations, as well as column eluates free of hCG and a previously noted immunosuppressive factor, are mitogen for normal human PBL cultured in fetal calf serum. This mitogen is designated pregnancy-associated growth factor (PAGF) because of its source. PAGF induces 3H-thymidine incorporation of mixed Ia+ non-T cells and T cells, probably confined to the helper subclass; proliferation is abolished by complement-mediated lysis using monoclonal antisera to Ia, mature T cells (OKT3), and the Th (OKT4) subset, but not by antisera to the Ts (OKT8) subset. The proliferating cell is a T cell because irradiation of these cells, but not the non-T cells, abolished PAGF mitogenicity. In addition, PAGF augments the autologus mixed lymphocyte reaction. Preliminary experiments indicate that its m.w., in the range of 18,000 to 22,000, is different from epidermal growth factor, the only previously described growth factor found in crude hCG preparations. In addition epidermal growth factor failed to stimulate PBL under similar conditions.

Autologous and allogeneic mixed lymphocyte reactions in progressive systemic sclerosis

The autologous and allogeneic mixed lymphocyte reactions (MLR), observed when peripheral blood mononuclear cells from 20 patients with progressive systemic sclerosis were used, were compared with those of age-, sex-, and race-matched normal controls. Such cells were separated by gradient centrifugation of sheep red blood cell (E) rosettes into stimulator (E- or non-T cell) and responder (E + or T cell) populations. The autologous MLR of both the progressive systemic sclerosis and normal peripheral blood mononuclear cells varied widely but there was no statistical difference between the means of each group. In the allogeneic MLR, proliferation between progressive systemic sclerosis non-T cells and normal T cells was significantly less than that of normal non-T cells and progressive systemic sclerosis T cells (P = 0.001). A decreased autologous MLR, while noted with other autoimmune diseases, was lacking in progressive systemic sclerosis. This suggests a different defect. The differences in the allogeneic MLR also suggest that either progressive systemic sclerosis non-T cells were poor stimulators or T cells associated with this disease were better responders when compared with similarly prepared cell populations from normal individuals. The MLR differences could have also resulted from compositional subset alterations or the sharing of a common antigen. HLA-DR5 was found in 9 of the 17 white patients with progressive systemic sclerosis. Although these individuals were evenly distributed as low, medium, and high responders, this finding showed that some progressive systemic sclerosis non-T cells shared a common antigen.

Inhibition of lymphocyte proliferation stimulated by lectins and allogeneic cells by normal plasma lipoproteins

Lipoproteins, isolated by sequential flotation at densities 1.006, 1.019, 1.063, and 1.21, were examined for their ability to inhibit human lymphocytes stimulated by allogeneic cells and by lectins (phytohemagglutinin-P and concanavalin A). All the classes of normal plasma lipoproteins inhibited lymphoproliferation when peripheral blood lymphocytes were cultured in autologous, heterologous, or lipoprotein-deficient plasma (d greater than 1.21). The rank order of inhibitory potency was intermediate density lipoprotein (IDL) greater than very low density lipoproteins (VLDL) greater than low density lipoproteins (LDL) greater than high density lipoproteins (HDL), regardless of the mode of stimulation. The concentrations of IDL, VLDL, and LDL required for complete inhibition of stimulated lymphoproliferation were considerably below the levels of each of these lipoproteins normally found in human plasma. In addition, the concentration of HDL required for 50-90% inhibition was in the range of HDL levels normally found in human plasma. Moreover, at relatively higher concentrations, lipoproteins suppressed the incorporation of [3H]thymidine into DNA below the levels seen with reseting, unstimulated lymphocytes. The results suggest that circulating lymphocytes may normally be highly suppressed by the combined effects of all the endogenous lipoproteins and that the lipoproteins may play important roles in vivo in modulating lymphocyte functions and responses.

The mitogenic effect of the lymphocytosis promoting factor from Bordetella pertussis on human lymphocytes

The purified lymphocytosis promoting factor (LPF) from Bordetella pertussis was found to be a potent mitogen for peripheral blood lymphocytes (PBL) from normal adults as well as for cord blood lymphocytes. Proliferation occurred in autologous plasma or fetal calf serum, regardless of previous exposure to pertussis infection or immunization. Only one adult human serum, from a physician constantly working with B. pertussis, inhibited the mitogenic response to LPF and this serum was shown to contain precipitating antibody against LPF. The proliferative effect of LPF was characteristic of a "nonspecific" mitogen and not of antigen stimulation of sensitized cells.LPF, phytohemagglutinin, and concanavalin A were approximately equal in potency although variation occurred depending upon the cell donor. Experiments with lymphocyte subpopulations obtained by rosetting techniques employing sheep erythrocytes, mouse erythrocytes, and sheep erythrocytes coated with antibody and complement suggested the requirement of a multicellular system for LPF mitogencity.PBL from most patients with chronic lymphatic leukemia and lymphosarcoma cell leukemia were even less responsive to LPF than to phytohemagglutinin, whereas PBL from patients with lymphosarcoma usually responded to both mitogens. It can be inferred from the results of experiments with both normal and leukemic cells that LPF, which is a murine thymus-derived (T)-cell mitogen, is also a T-cell mitogen for human PBL. The exact cell requirement and mode of action, however, are as yet unknown.

Lymphocyte response to mitogens in progressive systemic sclerosis

Lymphocyte responses to the mitogens phytohemagglutinin P(PHA-P), concanavallin A (Con A), and pokeweed (PWM) were studied in 18 patients with progressive systemic sclerosis (PSS). A subgroup of these patients with multisystem involvement showed a significantly decreased lymphocyte response to both Con A and PWM when compared to normal controls. However those PSS patients with myositis, although having multisystem involvement, had normal lymphocyte response to all three mitogens. PHA-P stumulation was normal in all PSS patients. Antinuclear antibodies, elevated sedimentation rates, and positive latex fixation were noted only in the multisystem disease group with abnormal lymphocyte function.