HLA-A,B, C,DR alleles in congenital adrenal hyperplasia

Summary HLA markers (A, B, C, DR loci) were determined for the members of 52 unrelated families with at least one child suffering from congenital adrenal hyperplasia due to 21 hydroxylase deficiency, permitting genotyping.The gene frequencies of the 52 index cases were compared with those obtained from the parents' normal haplotypes and with those of a control reference panel.No significant differences were observed, except a clear decrease in the frequency of HLA-B8 among the haplotypes that carry the gene for congenital adrenal hyperplasia.     

Alloantigens expressed on activated human T cells different from HLA-A,B, C,and DR antigens

This study investigates alloantisera containing antibodies directed against antigens which are expressed on alloactivated human T lymphocytes but are absent on resting T and B cells. Among 39 defined anti-HLA-DR sera from multiparous women we found six sera giving positive reactions (more than 25 percent cytotoxicity) on in vitro alloactivated T cells, though negative reactions with resting B or T cells from the donors of either the responding or stimulating cell populations used for alloactivation. Two such sera were submitted to absorption and elution studies. Absorption of these sera with activated T cells did not remove the anti-HLA-DR activity. Furthermore, the antibodies eluted from activated T cells did not react with B cells but were positive only on activated T cells. In addition, we absorbed the sera with B cells and observed that they remained positive on activated T cells. The positive reactions do not seem to be due to either the passive acquisition of antigens from the stimulating population or to low levels of HLA-specific antibodies. As one of the sera we studied intensively gave clear positive and negative reactions on a panel of activated T lymphocytes, we believe it may recognize an antigen of an allogeneic system expressed on alloactivated human T cells.     

Linkage disequilibrium of HLA-SB1 with the HLA-A1, B8, DR3, SCO1 and of HLA-SB4 with the HLA-A26, Bw38, Dw10, DR4, SC21 extended haplotypes

Homozygous typing cells from 13 normal HLA-A1, B8, Dw3, DR3 and five normal HLA-A26, Bw38, Dw10, DR4 individuals were typed for the following markers: HLA-SB, MB, MT; complement proteins BF, C2, C4A, C4B; and GLO. Ninety-one percent of A1, B8, Dw3, DR3 homozygous individuals (HI) tested were homozygous for BF ^* S, C2 ^* C, C4A ^* QO, and C4B ^*1 (SCO1 complotype), which indicates that the SCO1 complotype is in linkage disequilibrium with the A1, B8, DR3 haplotype in randomly selected normal populations. Sixty-seven percent of HLA-A1, B8, Dw3, DR3, SCO1 positive HI also expressed SB1; since the frequency of SB 1 in random Caucasian populations is 11.2%, this finding indicates that SB1 is in linkage disequilibrium with the A1, B8, DR3, SCO1 extended haplotype. All HI with the A26, Bw38, Dw10, DR4 haplotype were homozygous for both SC21 and SB4, suggesting that SC21 and SB4 should be included in the A26, Bw38, Dw10, DR4 extended haplotype. On the other hand, neither of the GLO markers were found in association with either haplotype. The results of this study indicate that HLA-SB is included in some extended haplotypes and may be important in these markers for diseases such as insulin-dependent diabetes mellitus. This study also demonstrated an apparent influence of HLA-SB on primary mixed lymphocyte culture (MLC) responses. The mean relative response of primary MLCs between individuals matched for HLA-A, B, D, DR, MB and MT but not SB was 40% of that for the MLCs with mismatched HLA-D, significantly higher than the MLCs matched for all HLA and complotypes.     

Diversity and diversification of HLA-A,B,C alleles

The nucleotide sequences encoding 14 HLA-A,B,C and 5 ChLA-A,B,C molecules have been determined. Combining these sequences with published data has enabled the polymorphism in 40 HLA-A,B,C and 9 ChLA-A,B,C alleles to be analyzed. Diversity is generated through assortment of point mutations by recombinational mechanisms including gene and allelic conversions. The distribution and frequency of silent and replacement substitutions indicate that there has been positive selection for allelic diversity in the 5' part of the gene (exons 1 to 3) and for allelic homogenization and locus specificity in the 3' part of the gene (exons 4 to 8). These differences may correlate with the lengths of converted sequences in the two parts of the gene and frequency of the CpG dinucleotide. Locus-specific divergence of HLA-A,B, and C demonstrates that recombinational events involving alleles of a locus have been more important than conversion between loci. This contrasts with the predominance of gene conversion events in the evolution of mutants of the H-2Kb gene. However, a striking example of gene conversion involving HLA-B and C alleles of an oriental haplotype has been found. Comparison of human and chimpanzee alleles reveals extensive sharing of polymorphisms, confirming that diversification is a slow process, and that much of contemporary polymorphism originated in ancestral primate species before the emergence of Homo sapiens. There is less polymorphism at the HLA-A locus compared to HLA-B, with greater similarity also being seen between HLA-A and ChLA-A alleles than between HLA-B and ChLA-B alleles. Although greater diversity is seen in the 5' "variable" exons of HLA-B compared to HLA-A, there is increased heterogeneity in the 3' "conserved" exons of HLA-A compared to HLA-B.     

HLA-A,B, C gene and haplotype frequencies in Vienna

Summary The HLA-A, B, C haplotype frequencies determined through family investigations in 500 unrelated individuals of the Viennese population were calculated, as well as the gene frequencies of 37 HLA determinants and the linkage disequilibria between the three HLA SD loci (HLA-A, HLA-B, and HLA-C). The existence of HLA-A, B, C superhaplotypes could be confirmed.National Blood Group Reference Laboratory (WHO) and National Tissue Typing Reference Laboratory (Council of Europe)     

Control of HLA-A,B,C synthesis and expression in interferon-treated cells

Cytofluorimetric analyses with monoclonal antibodies were used to follow the specific effect of highly purified human leucocyte interferon (IFN-alpha) on the expression of transplantation antigens (HLA)1 in Molt 4, a thymus leukaemia cell line. After a lag period of approximately 10 h the amount of HLA steadily increases to reach a maximum at day six of approximately 10 times its original. The effect is reversible and due to an increase in the rate of synthesis of HLA and beta 2m molecules as demonstrated by analysis of [35S]methionine incorporation into specific proteins after a 3-h pulse of Molt 4 cells treated with IFN-alpha for one or six days. A dramatic increase in the amount of mRNA that hybridised with a [32P]cDNA probe containing HLA sequences has also been demonstrated. Surface iodination of IFN-treated Molt 4 cells showed an increase in the iodinated HLA and beta 2m chains and in addition another, apparently unrelated, component with an apparent mol. wt. of 16 000. This component, which appears after incubations with IFN-alpha for longer than 1 h at 37 degrees C, was also detected in the B lymphoid cell lines RAJI and DAUDI.     

Stimulation of HLA-A,B,C by IFN-alpha. The derivation of Molt 4 variants and the differential expression of HLA-A,B,C subsets.

Spontaneous mutants with altered HLA-A,B,C response to interferon-alpha (IFN-alpha) were isolated from the human thymus leukemia cell line Molt 4. Using fluorescein isothiocyanate (FITC)-conjugated W6/32 (a monoclonal antibody to HLA-A,B,C) and the fluorescence-activated cell sorter, the cells with highest and lowest fluorescence after 24-48 h of IFN-alpha treatment were selected and expanded. After several cycles of selection, mutant clones with low (greater than 10% of wild-type) and high (three times better) response were obtained. A similar protocol was employed to derive high responder mutants with the monoclonal antibody YT76, which recognises a subset of HLA strongly induced by IFN-alpha. Stable clones were derived for which YT-HLA induction was 7-fold that of Molt 4 cells and for which HLA induction occurred at 100-fold lower concentrations of IFN-alpha. The high response phenotype of the mutants was not accompanied by a significant increase in the constitutive level of expression of HLA-A,B,C (in the absence of IFN). The increase in the level of HLA-A,B,C expression after IFN-alpha treatment is mostly accounted for by the increase in the expression of a subset of HLA molecules, detected by the monoclonal antibody YT76 including HLA-B molecules.     

Molecular characterization of HLA-A,B homologues in owl monkeys and other nonhuman primates

Mouse anti-HLA-A, B monoclonal antibodies have been used to study the homologues of HLA-A, B antigens in other primate species. Immunoprecipitates of primate histocompatibility antigens from extracts of radioactively labeled lymphocytes were analyzed by SDS-polyacrylamide electrophoresis. Primate histocompatibility antigens appear to have similar molecular structure to human HLA antigens. Owl monkeys, which react polymorphically with some monomorphic anti-HLA antibodies, showed biochemical differences which correlated with the serological polymorphism. An antibody (W6/32) which only reacts with the HLA/β ₂-microglobulin complex in humans and not with the free HLA heavy chain has the reverse specificity in some owl monkeys.     

Correlation between classification of human urothelial cell lines and HLA-A,B,C expression

Summary Quantitative changes in major histocompatibility class I antigen expression in tumour cells are believed to affect the host immune response against the tumour. In tumourigenic (TGrIII) human urothelial cell lines the apparent loss of polymorphic HLA-A,B epitopes has previously been demonstrated. In the present study, 3 non-tumourigenic (TGrII) and 6 tumourigenic (TGrIII) human urothelial cell lines have been investigated for their quantitative expression of monomorphic HLA-A,B,C and B₂-microglobulin. Evidence is provided that an inverse correlation exists between tumourigenicity and HLA-A,B,C and B₂-microglobulin expression. Furthermore, treatment of the cells with neuraminidase partly restored the expression of monomorphic HLA-A,B,C suggesting that at least some of the observed quantitative differences could be due to masking of the membrane bound HLA antigens by sialic acid-containing glycoconjugates.     

内蒙古地区蒙古族HLA-A、B、DRB1基因座多态性分析

应用序列特异性寡核苷酸探针反向斑点杂交技术对内蒙古地区蒙古族106名无关健康个体的HLA-A、B和DRB1 基因座进行基因分型, 以研究内蒙古地区蒙古族人群HLA-A、B、DRB1基因座的等位基因及其组成的单倍型频率分布特征。 采用最大数学预期值算法计算HLA基因座的等位基因频率和单倍型频率。106 名内蒙古地区蒙古族个体的HLA-A、B、DRB1基因座分别检出13、29、13个等位基因。高频单倍型分别为 HLA-A*02-B*46 (0.0510); HLA-A*02-B*13(0.0495); HLA-A*02-B*51(0.0442); HLA-B*13-DRB1*07 (0.0555); HLA- B*46-DRB1*09(0.0378); HLA-B*35-DRB1*13(0.03300); HLA-A*02-B*13-DRB1*07(0.033019); HLA-A*02-B*46- DRB1*09(0.031985)。研究表明: 内蒙古地区蒙古族人群HLA基因座的等位基因和单倍型具有较高的遗传多态性。HLA- A*24-B*14, HLA-A*32-B*63在该民族具有极强的连锁不平衡。     

Agonal phase,ischaemic times,and renal vascular abnormalities and outcome of cadaver kidney transplants.

A retrospective study of 250 cadaver kidney transplants was carried out to determine the effects of the agonal period, the warm and cold ischaemic times, and the use of kidneys with vascular anomalies on the primary success and failure and the subsequent level of function of the transplants. Kidneys with vascular anomalies or from non-ventilated donors had a primary failure rate of over 30%, whereas those with normal vasculature or from ventilated donors had a rate of 17%. An initial warm ischaemic time of more than 60 minutes was associated with a primary failure rate of 57% and a cold ischaemic time of over 550 minutes with a primary failure rate of 47%. The interrelationship between the warm and cold ischaemic times in the primary success or failure of the transplants was examined and criteria defined for selecting potentially viable cadaver kidneys for transplantation, as follows: (1) The donor should be (a) ventilated, (b) aged 6-50 years, and (c) have normal ante-mortem renal function and have secreted more than 1-5 1 of urine in the 24 hours before death (or an equivalent volume if the urinary output was recorded for less than 24 hours before death); (2) the kidney should have normal renal vasculature enabling single arterial and venous anastomoses to be performed; (3) kidneys with I.W.I.T.s of longer than 60 minutes should not be used; (4) for kidneys with I.W.I.T.s of less than 20 minutes the C.I.T. is not critical but should not exceed 12 hours; (5) for kidneys with I.W.I.T.s of 20-60 minutes the C.I.T. should not exceed 450 minutes.