Ephraim Gazit

Correlation between genotype and phenotype in patients with cystic fibrosis.

BACKGROUND: Cystic fibrosis is the most common lethal autosomal recessive disorder among whites. Seventy-two percent of patients with this disease are homozygotes or compound heterozygotes for eight mutations of the cystic fibrosis transmembrane conductance regulator gene on chromosome 7: delta F508, G542X, R553X, W1282X, N1303K, 621 + 1G-->T, 1717-1G-->A, and R117H. We studied the relation between genotype and phenotype in patients from 14 countries. METHODS: Each of 399 patients who were compound heterozygotes for delta F508 and one other mutation was matched with the delta F508 homozygote of the same sex who was the closest in age from the same center. A paired analysis was performed of the following outcome variables: age at diagnosis, sweat chloride concentration, growth percentiles, pulmonary-function values, chest-film score, pseudomonas colonization, nasal polyps, pancreatic sufficiency, pancreatitis, diabetes mellitus, meconium ileus, distal intestinal obstruction syndrome, rectal prolapse, cirrhosis, and gallbladder disease. RESULTS: The compound heterozygotes having the genotype R117H/delta F508 clearly differed from the age- and sex-matched delta F508 homozygotes: they more often had pancreatic sufficiency (87 percent vs. 4 percent, P < 0.001), were older when the diagnosis was first made (mean [+/- SD] age, 10.2 +/- 10.5 vs. 2.5 +/- 4.3 years; P = 0.002), and had lower sweat chloride concentrations (80 +/- 18 vs. 108 +/- 14 mmol per liter, P < 0.001). There were no statistically significant differences between delta F508 homozygotes and other compound heterozygotes with regard to any variable tested. CONCLUSIONS: Prenatal and prognostic counseling for patients with the R117H/delta F508 genotype should include the likelihood that they will have long-term pancreatic sufficiency. Patients with the other genotypes should expect the early onset of pancreatic insufficiency. For none of the genotypes studied can predictions be made about the occurrence of common complications or the severity or course of pulmonary disease.

Alleles at four HLA class II loci determined by oligonucleotide hybridization and their associations in five ethnic groups

The use of polymerase chain reaction (PCR) and oligonucleotide hybridization offers a new approach for the definition of HLA class II alleles. It has been possible to determine 43 alleles of DRB1, four of DRB3, two of DRB4, four of DRB5, eight of DQA1, and 14 of DQB1. These alleles are inherited together in members of families and form closely associated groups which are found repeatedly and in characteristics patterns in different populations. We have determined the HLA class II alleles and analyzed their association in 431 healthy unrelated subjects including 161 North American Caucasians, 53 Latin Americans, 61 Blacks, 88 Chinese, and 68 Israeli Jews. For-locus haplotypes (DRB1; DRB3/4/5; DQA1; DQB1) were derived from 79 B cell lines and the analysis of segregation in 34 nuclear families. The B-cell lines yielded 37 and the families showed the same, and 20 other, haplotypic combinations. In addition to these 57 haplotypes, associated alleles were assigned in the unrelated panels following certain rules. The resulting haplotypes were assigned to groups known to share associated alleles. The groups were: (1) DR1, DR2, and DRw10 (13 haplotypes); (2) DR3 and DRw6 (26 haplotypes); (3) DR5 and DRw8 (24 haplotypes); (4) DR4, DR7, and DR9 (24 haplotypes). Their distribution in populations with different ethnic backgrounds was analyzed. The expressed DRB4 allele and its null mutant were determined by PCR and oligonucleotide hybridization. The different DR7 haplotypes resulting from these determinations were analyzed in a panel of 130 North American Caucasoids. This comprehensive analysis of class II HLA haplotypes in human populations should be useful in understanding the role of these genes and in various applications including anthropolgy, disease susceptibility, and transplantation of allogeneic organs and tissues.

TMPRSS2/ERG Promotes Epithelial to Mesenchymal Transition through the ZEB1/ZEB2 Axis in a Prostate Cancer Model

Prostate cancer is the most common non-dermatologic malignancy in men in the Western world. Recently, a frequent chromosomal aberration fusing androgen regulated TMPRSS2 promoter and the ERG gene (TMPRSS2/ERG) was discovered in prostate cancer. Several studies demonstrated cooperation between TMPRSS2/ERG and other defective pathways in cancer progression. However, the unveiling of more specific pathways in which TMPRSS2/ERG takes part, requires further investigation. Using immortalized prostate epithelial cells we were able to show that TMPRSS2/ERG over-expressing cells undergo an Epithelial to Mesenchymal Transition (EMT), manifested by acquisition of mesenchymal morphology and markers as well as migration and invasion capabilities. These findings were corroborated in vivo, where the control cells gave rise to discrete nodules while the TMPRSS2/ERG-expressing cells formed malignant tumors, which expressed EMT markers. To further investigate the general transcription scheme induced by TMPRSS2/ERG, cells were subjected to a microarray analysis that revealed a distinct EMT expression program, including up-regulation of the EMT facilitators, ZEB1 and ZEB2, and down-regulation of the epithelial marker CDH1(E-Cadherin). A chromatin immunoprecipitation assay revealed direct binding of TMPRSS2/ERG to the promoter of ZEB1 but not ZEB2. However, TMPRSS2/ERG was able to bind the promoters of the ZEB2 modulators, IL1R2 and SPINT1. This set of experiments further illuminates the mechanism by which the TMPRSS2/ERG fusion affects prostate cancer progression and might assist in targeting TMPRSS2/ERG and its downstream targets in future drug design efforts.

Behçet's disease in Familial Mediterranean Fever:Characterization of the association between the two diseases

OBJECTIVES Familial Mediterranean fever (FMF) is a genetic disease, characterized by attacks of fever and painful manifestations. Several vasculitides are more common in FMF than in the general population. The aim of the study was to define and characterize the association between FMF and Behcets disease (BD), a form of vasculitis not previously related to FMF. METHODS We conducted a retrospective study in which FMF patients, also suffering from BD (FMF-BD), were recruited from about 4,000 patients registered in our clinic, using a computer survey. Patients identified by the screening process were examined, and those meeting the published criteria for the diagnoses of FMF and BD were classified as FMF-BD cases and compared with unselected FMF and BD controls. RESULTS The prevalence of BD was higher in FMF than in populations known to be rich in BD (eg, 16 per 4,000 in FMF compared with 1 per 104 in Japan, P < .001). FMF-BD cases and FMF or BD controls were comparable in most demographic, clinical, and laboratory aspects studied. However, more cases than FMF-controls were of Iraqi/Turkish origin and responded less favorably to colchicine. A higher proportion of cases than BD controls had skin, central nervous system, and gastrointestinal manifestations, originated from North Africa, and had family history of BD. In most cases, as in most respective controls, the severity of FMF was of intermediate grade and the extensiveness of BD was limited. The HLA B5 antigen was present in 53% of BD cases and 40% of BD controls. CONCLUSIONS BD should be included among the vasculitides complicating FMF. BD and FMF in patients with FMF-BD, and in patients suffering from each of these entities alone, are clinically and demographically comparable.

Clozapine-induced agranulocytosis is associated with rare HLA-DQB1 and HLA-B alleles

Clozapine is a particularly effective antipsychotic medication but its use is curtailed by the risk of clozapine-induced agranulocytosis/granulocytopenia (CIAG), a severe adverse drug reaction occurring in up to 1% of treated individuals. Identifying genetic risk factors for CIAG could enable safer and more widespread use of clozapine. Here we perform the largest and most comprehensive genetic study of CIAG to date by interrogating 163 cases using genome-wide genotyping and whole-exome sequencing. We find that two loci in the major histocompatibility complex are independently associated with CIAG: a single amino acid in HLA-DQB1 (126Q) (P=4.7×10−14, odds ratio, OR=0.19, 95% CI 0.12–0.29) and an amino acid change in the extracellular binding pocket of HLA-B (158T) (P=6.4×10−10, OR=3.3, 95% CI 2.3–4.9). These associations dovetail with the roles of these genes in immunogenetic phenotypes and adverse drug responses for other medications, and provide insight into the pathophysiology of CIAG.

Immunization by Paternal Leukocytes for Prevention of Primary Habitual Abortion: Results of a Matched Controlled Trial

Habitual abortion is a difficult clinical problem, as no cause can be found for abortion in over 50% of patients. At the habitual abortion clinic of the Sheba Medical Center, immunological activity is tested and patients who are considered suitable are offered immunopotentiation with paternal leukocytes. Patients are only treated if they have no other cause for habitual abortion, no lupus anticoagulant and no antipaternal complement-dependent antibodies (APCA). Immunization is thought to potentiate the maternal immune response to paternal antigens encountered on the trophoblast. The production of APCA antibody indicates that an immune response has occurred. Of the 156 patients so far immunized, 109 have developed these antibodies. To date, 79 of these 156 patients have become pregnant. Sixty-seven patients (with 3-12 miscarriages each) belong to the antibody-positive group. Sixty-four of the 89 subsequent pregnancies have been carried past their previous dates of abortion. Forty-seven live births have occurred. By contrast, 12 patients have been pregnant in the antibody-negative group, of the 16 subsequent pregnancies only 6 were successful. A control group is available for comparison. This consists of patients suitable for immunization, but not immunized. Of these patients, only 11 of 30 pregnancies have been carried to term.

Vitiligo and the HLA System

77 Vitiligo patients were investigated for their HLA phenotype. Analysis of this material according to age of onset and ethnic origin revealed some significant characteristics. Young Jewish Moroccan patients showed a high frequency of B13 when compared to matching controls. Young patients of Yemenite origin had a strikingly high frequency of BW35. Jewish Yemenites showed a lack of B13 both in patients and in controls. It is suggested that studies by undertaken to clarify this problem further.

Further Experience with Intravenous Immunoglobulin in Women with Recurrent Miscarriage and a Poor Prognosis

PROBLEM: Women with three or more unexplained miscarriages have a 60% chance of a subsequent live birth. Intravenous immunoglobulin (IVIG) has not been conclusively shown to improve this prognosis. This study assessed the effect of IVIG in patients expected to have a poor outcome if untreated, i.e. women with five or more abortions, who have aborted after paternal leukocyte immunization or who continue to abort despite expressing anti‐paternal complement dependent antibody.
 METHODS: Seventy‐six women received IVIG in a dose of 400 mg/kg body weight, in one day (total 30–45 g) in the follicular phase of a cycle in which pregnancy was planned. A booster dose was administered when pregnancy was diagnosed. Their results were compared to an untreated control group of 74 women.
 RESULTS: Thirty‐five (49%) pregnancies in treated women have resulted in live births or passed their previous stages of abortion compared to 23 (31%) in control patients (P=0.04).
 CONCLUSIONS: These figures indicate that IVIG may prevent further miscarriages in this poor prognosis population. These figures are especially significant considering the doubt concerning the efficacy of IVIG in patients with three miscarriages and therefore a relatively good prognosis.

Pemphigus vulgaris in Jewish patients is associated with HLA-A region genes: mapping by microsatellite markers

Pemphigus vulgaris (PV) is the most severe autoimmune blistering disorder of the skin that is mediated by circulating autoantibodies against desmoglein 3 (Dsg3). It has been reported that in Jews the associated haplotype in PV is human leukocyte antigen (HLA) B38, DRB1*0402, DQB1*0302. Significant associations with HLA were observed also in non-Jews. Dsg3-specific T-cell responses were detected in PV patients but also in healthy individuals who were either carriers of the PV-associated DRB1*0402 allele or alleles that share similar or identical peptide binding motifs to DRB1*0402. This suggests that genes other than the classical major histocompatibility complex (MHC) genes are associated with the development of the autoimmune response. We used 16 microsatellite probes that span the entire MHC region to screen DNA samples from 38 PV patients and 76 healthy controls. Results demonstrated that some markers were associated with class II region including a TAP associated marker. However, four probes, D6S265, C_527, D6S510, and MOGC, which are all mapped to the region of HLA-A, were highly associated with PV. These results suggest that a gene, or genes in the class I region are important in the initiation of the autoimmune cascade. Activation/suppression of these genes might act as the trigger mechanism that starts the autoimmune destructive process.

Intravenous immunoglobulin in women with five or more abortions

PROBLEM: Treatment for recurrent miscarriage has usually been given to all women with three or more abortions of unknown cause. As these patients have a 50–60% subsequent live birth rate, no treatment has been shown to unequivocally improve the live birth rate. Immunoglobulin is the latest treatment to be applied. In order to determine if immunoglobulin improves the live birth rate, we analyzed the results of patients expected to have a poor outcome in the subsequent pregnancy if left untreated, i.e., women with five or more abortions, who have aborted after paternal leucocyte immunization or who continue to abort despite possessing anti‐paternal complement dependent antibody (APCA).