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.

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.

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.

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.

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.