Biomedical subjects
Publications and source records attributed to B Genetet.
HLA-A, B and DR antigens were tested in 45 unrelated patients with IgA nephropathy (Berger's disease). A significant association with HLA-DR4 was noted. An unusual finding was a secondary association with the A2-B12 antigen combination.
HLA-A, -B, and -C antigens were tested by a standard lymphocyte microcytotoxicity technique in 86 Caucasians patients from western France with Graves' disease, and the data were compared with findings in 356 healthy controls. For HLA-DR antigen typing performed by lymphocyte microcytotoxicity testing using a long incubation time, the data were compared to findings in 100 healthy controls. An increase was found in the frequency of HLA-DRw3 [51.16% of patients vs. 20% of controls, corrected P (Pc) < 0.0003; relative risk (rr), 4.19) associated with an increased frequency of HLA-B8 (44.19% of patients vs. 22.47% of controls; Pc < 0.001; rr, 2.73) and HLA-A1 (40.7% of patients vs. 28.93% of controls; Pc < 0.03; rr, 1.71). In contrast, a diminished frequency was found for HLA-B12 (12.79% vs. 31.74%; Pc < 0.01). The antigen combination B8-DRw3 was noted in 37 of the 86 Graves' disease patients compared with 13 of 100 controls (Pc < 0.00003). No association was observed between HLA antigens and the different manifestations of the disease, such as the presence of goiter and/or exophthalmos, or the severity of clinical or biochemical signs. The present findings confirm the reported increase in the frequency of HLA-B8 in patients with Graves' disease. The most striking finding was the prevalence of HLA-DRw3, which, together with recent reports on lymphocyte-defined D locus determinants pointing to an increase frequency of HLA-Dw3, suggests that the gene or genes conferring susceptibility to Graves' disease may be located close to the HLA-D (DR) region of the sixth chromosome.
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The hypothesis has been advanced that the two genes on chromosome 6 determining idiopathic hemochromatosis are not identical alleles and therefore that the disease is not recessively inherited, but rather that two different genes are involved. A study of 63 families points to: (a) the rarity with which a single hemochromatosis gene finds biochemical expression (in only 1 of 5 cases), as revealed through determinations of serum iron, serum ferritin and the desferrioxamine test; (b) no difference in HLA-antigen marking between genes with and those without biochemical expression: (c) no difference other than that produced by chance in the biochemical expression of the two genes in families; and (d) the finding in one highly informative family of identical expression of the two genes. It is concluded that idiopathic hemochromatosis is determined by two homologous alleles in accordance with the classical mode of recessive inheritance.
To determine whether a correlation exists between the biochemical expression of hemochromatosis and the HLA genotype, we studied 174 family members of 32 persons with the disease. Persons who shared both HLA haplotypes with the proband (and presumably having two hemochromatosis alleles) differed significantly from those who shared only one haplotype (and presumably having one hemochromatosis allele) in terms of serum iron (P less than 0.001 for both sexes), unsaturated iron-binding capacity (P less than 0.01 for female and P less than 0.0001 for male subjects) and serum ferritin (P less than 0.0001 for female and P less than 0.00001 for male subjects). The only significant difference between relatives having one hemochromatosis allele and age and sex-matched controls was related to serum ferritin values in male subjects (P less than 0.05, despite considerable overlap). In our hands, serum ferritin was the best indicator of disordered iron metabolism and was elevated among most homozygous but among few heterozygous family members.
We studied iron overloading and HLA genotype in two families with overt forms of idiopathic haemochromatosis in two successive generations. In each family the spouse of the patient with overt haemochromatosis in the first generation had clinical and laboratory signs of moderate iron overload and a HLA haplotype A3, B14 and A3, B7 respectively--which is frequently associated with the haemochromatosis gene. This specific HLA haplotype had been transmitted to the second generation patient with overt disease, which thus could be considered as having received a haemochromatosis gene from each parent. Although the finding of cases of overt disease in successive generation firstly suggests a dominant transmission the genetical analysis of these families lead to further strong argument in favour of recessive inheritance of idiopathic haemochromatosis.
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HLA-A and B antigens were defined in 154 unrelated idiopathic hemochromatosis patients. The study confirmed the highly significant positive association with HLA antigens A3 (corrected P less than 10(-10)) and B14 (corrected P less than 10(-9)). HLA-DR typing showed increased frequency of the specificity DRw6, which was frequently associated with the phenotype A3, B14 and antigen B14, suggesting linkage disequilibrium. This was borne out by PLT data.
HLA typing was performed in 90 unrelated patients with chronic alcohol-associated pancreatitis. Compared with 523 healthy controls, an increased frequency was found for the HLA-B series antigen, B40 (Pless than 0.00041, corrected P less than 0.011). The increase was slightly more pronounced in patients without pancreatic calcifications than in those with calcifications. Factors such as alcohol consumption, age of disease onset and the presence of diabetes did not affect antigen frequency distribution.
A retrospective study in 71 cadaver renal transplant patients showed a significantly better 2-year graft survival rate (62%) in patients who received pretransplant transfusions or who were parous than in nontransfused patients or patients who have not been pregnant (29%). The beneficial influence of blood transfusion and of pregnancy is thus confirmed. An additive effect of blood transfuion and pregnancy is suggested by the results of this study.
Comparison of 105 patients suffering of chronical renal failure with 108 normal persons showed that, in the former group, a relation could be established between HLA A2, A3, and B12 histocompatibility antigens as well as haplotype association A2-B12, and chronic infection by herpes virus. The high number of herpes virus observed in patient group bearing the BW 35 antigen was discussed.
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Certain genes of the complement system are carried by the 6th chromosome and are sometimes linked to particular genes of the HLA system. This study shows that in 15 patients suffering from hereditary angioneurotic oedema the gene(s) controlling the synthesis of C1 esterase inhibitor is not linked to the genes HLA-A or B and is not on the 6th chromosome.
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We studied iron overloading and HLA types in 24 sibships of patients with idiopathic hemochromatosis, of which 15 had at least two subjects with overt forms. HLA types of 84 unrelated patients were also investigated. Among siblings there was a significant association (P less than 0.0001) between the presence of hemochromatosis and the possession of the same two HLA haplotypes. The fact that overt forms of hemochromatosis depend on the presence of two specific homologous chromosomes strongly supports a recessive mode of transmission for the overt disease. The haplotypic equilibrium demonstrated in the unrelated patients group is another supporting argument. The lod-score value (2.239 for theta = 0.005) in six families available for study further supports the conclusion that a hemochromatosis gene is closely linked to the HLA-A locus. HLA typing in families with hemochromatosis could provide a means of early detection of subjects at risk before appearance of any sign of iron overload.