HLA antigens in three populations of India

In blood samples from a Hindu population of Uttar Pradesh (North India) and from two Muslim groups, one from Andhra Pradesh (South India) and the other from Gujurat (West India), frequencies of 38 HLA-A, -B and -C antigens were investigated. Eight antigens - A23, A25, A29, A32, Bw45, B21, Bw22 and Bw53 - were absent in the Hindu population, four different antigens - A29, Bw52, B14 and Bw42 - were absent in Hyderabad Muslims, two antigens - A31 and Bw45 - were lacking in Surat Muslims. The three populations showed considerable genetic heterogeneity. The genetic difference between the two Muslim groups was small, but the Hindu population showed pronounced differences from each of the Muslim groups.     

Distribution of HLA antigens in Polish and German populations in Milwaukee,Wisconsin

Gene and haplotype frequencies for HLA-A and HLA-B antigens were determined in Milwaukee blood donors of German and Polish descent. Gene frequencies for A25 and B18 were significantly higher in Poles than in Germans. Significant gametic associations were noted for A1-B8, A29-B12 and AW30-B13 in both populations. Gametic association for A3-B7 was only found in Germans, while the A25-B18 haplotype frequency was significantly increased in Poles. Since the latter haplotype has also been found in Yugoslavs, Ukrainians and Czechs, it is possible that A25-B18 represents a Slavonic marker.     

HLA antigens in cardiomyopathic Chilean chagasics.

The distribution of HLA antigens in a sample of 124 Chagas serologically positive Chilean individuals was studied. The sample was subdivided according to the presence or absence of chagasic cardiomyopathy, in order to search for genetic differences associated with this pathological condition. The frequency of antigen B40 in the presence of antigen Cw3 was found to be significantly lower in subjects with cardiomyopathy. We tentatively suggest that the presence of these antigens among noncardiomyopathics is associated with a decreased susceptibility to develop chagasic cardiomyopathy in the Chilean population.     

Class I HLA antigens in two long-separated populations: Melanesians and South Amerinds

Class I HLA antigens have been compared in 5,835 Melanesians of Papua New Guinea and 2,028 Amerindians of South America. The sample includes 50 PNGMel ethnolinguistic groups and 22 SAmlnd groups. Both carry 15 serologically defined antigens and an undefined C allele. Except for A2 in Papua New Guinea and Cwl in South America, these antigens are widely distributed in their respective populations. Nine (A2 and A24, B39, B60 and B62, and Cwl, Cw3, Cw4, and Cw7) are common to both. This commonality suggests that these two populations derive from an ancestral population with less polymorphism than modern East Asians. In both populations several theoretically possible haplotypes were absent, and other haplo-types were in positive disequilibrium in both. The parallels in disequilibria suggest that haplotypes are subject to selective forces acting on the level of allelic interaction. Based on three locus haplotype frequencies, the PNGMel groups form five clusters with internally typical linguistic and geographic characteristics and a miscellaneous category, but Samlnd groups show no cluster. © 1995 Wiley-Liss, Inc.     

HLA antigens and affective disorders

A total of 168 patients with different types of affective disorders were examined with respect to their HLA antigens. The frequency of the A10 antigen was found to be increased in the patients particularly in those with the unipolar type of disease. The frequency of the A1 antigen was decreased among unipolar patients. A decreased frequency of the B7 antigen was found in the total material of patients, and in particular in those with a bipolar type of disease. Our results were in disagreement with findings by other investigators. So far there is no conclusive evidence for association between any HLA antigen and affective disorders.     

Shared HLA antigens and reproductive performance among Hutterites.

Shared histocompatibility antigens between spouses may affect reproductive outcome adversely as a result of prenatal selection against compatible fetuses. Evidence from both animal and human studies suggest that histocompatible fetuses may not initiate a maternal immunologic response that prevents rejection of the embryo. Therefore, parents sharing HLA antigens may produce compatible fetuses and consequently experience a greater frequency of early fetal losses and show poorer reproductive outcome than couples not sharing antigens. In the Hutterites, an inbred human isolate that proscribes contraception, we tested the hypothesis that couples sharing HLA antigens have poorer reproductive outcomes than couples who do not. The Hutterites are characterized by high fertility and large family sizes. Couples that share zero (no. = 21), one (no. = 15), and more than one (no. = 10) HLA-A or HLA-B antigens were compared for reproductive performance. Median intervals between births were larger among couples that share more than one antigen in eight of 11 intervals examined. In addition, the median intervals from marriage to first, fifth, and tenth birth were consistently larger among couples that share more than one antigen. Differences among the groups appear to become larger with increasing parity, suggesting that the effect of histocompatibility on reproductive performance becomes more evident in later pregnancies. These differences in reproductive performance between couples that share zero, one, or more than one HLA-A or HLA-B antigens may have significant evolutionary consequences. However, our results demonstrate that sharing HLA antigens does not preclude normal pregnancy and caution should be exercised before concluding that shared HLA antigens are solely responsible for repeated fetal losses.     

Macrophage Ia antigens. I. macrophage populations differ in their expression of Ia antigens

By indirect immunofluorescence and microcytotoxicity it was demonstrated that different populations of murine macrophages bear different amounts of Ia antigens on their membranes. At least three subpopulations could be distinguished: those that lack Ia antigens and predominate in peritoneal exudate; cells bearing I-A antigens that are the majority of splenic macrophages and a minor population in the peritoneum; and cells bearing I-C antigens that are a minor population in both spleen and peritoneum. Internal radioisotope labeling studies confirmed that the I region molecules are synthesized by the macrophages. It is suggested that these different macrophage subpopulations may play distinct roles in the immune response.     

Biologic and chemical characterization of HLA antigens in human serum.

HLA antigens of both the A and B loci were shown to be associated with the high density lipoprotein fraction of serum prepared by ultracentrifugal flotation. HLA-A9 antigens were purified 100-fold with essentially complete recovery by a simple procedure of high density lipoprotein preparation involving precipitation with polyanions and ultracentrifugal flotation. The purified lipid-associated antigen was immunogenic since it elicited the formation of cytotoxic xenoantibodies in rabbits. Serum HLA-A9 antigens were found by immunoprecipitation and gel electrophoresis to consist of a 45,000 m.w. heavy chain associated with beta2-microglobulin. The size of the HLA-lipid complex (less than 190,000 m.w.) and of the HLA-deoxycholate complex (less than 102,000 m.w.) suggests that HLA antigens are shed into plasma as a complex of a single HLA molecule and a single beta2-microglobulin chain, associated with boundary lipid.     

HLA antigens in Brazilian patients with paracoccidioidomycosis

Eighty patients with paracoccidioidomycosis were typed for 43 HLA specificities from loci A, B, C and DR. A highly significant increased frequency of HLA-B40 (relative risk 29.2) and HLA-Cw 1 (relative risk 8.8) were found in patients compared to control subjects. The frequencies HLA-A2, B7 and B21 were also increased in patients and haplotypes-B40-Cw1 and -A2-B40 were positively correlated with the disease. DR antigen frequencies were not significantly altered in the patients and evidence of a protective effect was not found for any of the 43 antigens tested. These findings further support the involvement of the HLA system in the genetic susceptibility to paracoccidioidomycosis and the importance of ethnic variability in this association.     

Blood groups and HLA antigens in paracoccidioidomycosis

The frequencies of blood groups, Rh and HLA antigens were studied in a series of patients with paracoccidioidomycosis as well as in control subjects. Statistical analysis of the results showed that only 2 antigens (HLA-A9 and HLA-B13) had a significantly increased frequency among patients with paracoccidioidomycosis compared with healthy controls. Among patients with paracoccidioidomycosis antigen HLA-A9 was significantly more prevalent in progressive pulmonary forms of the disease than in patients with extra pulmonary involvement. These observations suggest that HLA-A9 may influence susceptibility to the mycosis as well as its course.     

HLA antigens, phytohemagglutinin stimulation, and corticosteroid response.

Although it is clear that the major histocompatibility complex is associated with lymphocyte glucocorticoid sensitivity in mice, there has been less evidence for a similar relationship in man. We have typed 158 individuals for: (1) 13 A locus and 16 B locus antigens, (2) degree of stimulation of their purified lymphocytes by phytohemagglutinin A (PHA), and (3) degree of inhibition of the PHA stimulation by prednisolone and prednisolone-21-hemisuccinate. In contrasts of individuals with a particular antigen (homozygous or heterozygous) with all remaining individuals, HLA-B7 was found to be associated with an enhancing effect on the log stimulation by PHA while other antigens of these series did not have significant associations. In similar contrasts, A10 was associated with a decrease in sensitivity to glucocorticoid inhibition of PHA stimulation as measured by the log I50 of the suppression of PHA stimulation. Other antigens of these series were not found to have significant associations with the glucocorticoid sensitivity of lymphocytes in this assay.     

HLA DR antigens and susceptibility to insulin-dependent diabetes mellitus.

Two novel analytic methods to evaluate the roles of the HLA alleles of the human major histocompatibility complex in disease predisposition have been formulated and applied to insulin-dependent diabetes mellitus (IDDM). The HLA-DR antigens, as they are presently defined, are shown not to directly predispose individuals to IDDM. This result does not discount the possibility that subdivision of the DR antigens will yield the predisposing agents. In Caucasian populations, after consideration of the predisposing effect of the antigens DR3 and DR4, the protective effect of DR2 in predisposition is demonstrated. Additionally, DR1 and possibly DRw8 exhibit a higher than expected frequency in patients.     

HLA antigens and acetylcholine receptor antibodies in penicillamine induced myasthenia gravis.

Antibodies to the acetylcholine receptor and HLA antigens have been studied in patients with myasthenia gravis occurring in association with penicillamine treatment. The properties of the antiacetylcholine receptor in these patients differed from those in patients with idiopathic myasthenia gravis in terms of specificity and affinity. These patients had an increased prevalence of HLA Bw35 and DR1 compared to controls and a decreased frequency of B8 and DR3 compared to patients with idiopathic myasthenia gravis. Likewise, they had a decreased frequency of DR4 compared to patients with rheumatoid arthritis. These data provide supportive evidence for a role for penicillamine in the induction of myasthenia gravis in genetically predisposed individuals.     

Frequency of HLA antigens in patients with psoriasis or psoriatic arthritis.

A study of 138 patients with psoriasis--74 with psoriasis alone and 64 with psoriatic arthritis--revealed a significantly increased frequency of the HLA antigens A1, A28, B13, DR7 and MT3 in those with psoriasis alone and of Bw39 in those with psoriatic arthritis. The frequency of B17 was higher in both patient groups than in a control group of healthy individuals. The frequency of DRw6 was slightly higher in the patients with psoriasis alone (17.8%) than in the controls (4.7%), and that of DR7 was higher in the patients with psoriatic arthritis (52.9%) than in the controls (32.6%). Elevated levels of serum IgG and IgA along with positive results of tests for antinuclear antibody or rheumatoid factor or both were present in less than a tenth of the patients with psoriatic rash alone and in up to a third of those with psoriatic arthritis. Psoriatic arthritis was found to be less likely to develop in patients with purely guttate psoriasis than in those with other types of psoriasis. Clinical subtypes of psoriatic rash or psoriatic arthritis were not associated with the presence of particular HLA antigens.     

Internalization of insulin receptors and HLA antigens in human hepatoma cells.

Human HepG2 hepatoma cells express a high number of insulin receptors. Growing cells exhibit 70% of their insulin receptors on the plasma membrane. Moreover, cell-surface insulin receptors form molecular complexes with class I major histocompatibility antigens, as determined by co-immunoprecipitation of the receptors by anti-class I monoclonal antibodies. On exposure to saturating concentrations of insulin, the hormone is rapidly internalized into a Pronase-resistant compartment. Internalization of insulin is accompanied by a rapid (t1/2 = 2-3 min) redistribution of insulin receptors from the cell surface to an intracellular compartment. On removal of insulin from the medium, functional receptors recycle back to the plasma membrane, where they can bind insulin again. With chronic exposure of HepG2 cells to insulin, the initial redistribution of receptors is followed by a slow (t1/2 = 9 h) down-regulation of the receptors. Finally, notwithstanding their interaction at the cell surface, insulin receptors and class I major histocompatibility antigens are internalized at different rates and with independent regulation.