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Abacavir administration is associated with drug-induced hypersensitivity reactions in HIV+ individuals expressing the HLA-B*57:01 allele. However, the immunological effects of abacavir administration in an HLA-B57 mismatched transplantation setting have not been studied. We hypothesized that abacavir exposure could induce de novo HLA-B57-specific allorecognition. HIV-specific CD8 T cell clones were generated from HIV+ individuals, using single cell sorting based on HIV peptide/HLA tetramer staining. The T cell clones were assayed for alloreactivity against a panel of single HLA-expressing cell lines, in the presence or absence of abacavir. Cytokine assay, CD137 upregulation, and cytotoxicity were used as readout. Abacavir exposure can induce de novo HLA-B57 allorecognition by HIV-specific T cells. A HIV Gag RK9/HLA-A3-specific T cell did exhibit interferon-gamma production, CD137 upregulation, and cytolytic effector function against allogeneic HLA-B57, but only in the presence of abacavir. Allorecognition was specific to the virus specificity, HLA restriction, and T cell receptor TRBV use of the T cell. We provide proof-of-principle evidence that administration of a drug could induce specific allorecognition of mismatched HLA molecules in the transplant setting. We suggest that HIV-seropositive recipients of an HLA-B57 mismatched graft should not receive abacavir until further studies are completed.

Historic red blood cell transfusion (RBCT) may induce anti-HLA antibody which, if donor specific (DSA), is associated with increased antibody-mediated rejection (AMR). Whether post-operative RBCT influences this risk is unknown.We examined the RBCT history in 258 renal transplant recipients stratified according to prevalent recipient HLA antibody (DSA, Non-DSA or No Antibody).AMR occurred more frequently in patients who received RBCT both pre and post transplant compared with all other groups (Pre+Post-RBCT 21%, Pre-RBCT 4%, Post-RBCT 6%, No-RBCT 6%, HR 4.1 p=0.004). In the 63 patients who received Pre+Post-RBCT, 65% (13/20) with DSA developed AMR compared with 0/6 in the Non-DSA group and 2/37 (5%) in the No-Antibody group (HR 13.9 p

The long term effect of donor specific antibodies (DSA) detected by Luminex Single Antigen Bead (SAB) assay in the absence of a positive complement-dependant cytotoxicity (CDC) crossmatch is unclear. DSA at the time of transplant were determined retrospectively in 258 renal transplant recipients from 2003 to 2007 and their relationship with rejection and graft function prospectively evaluated. After a median of 5.6 years follow-up 9% of patients had antibody mediated rejection (AMR) (DSA 11/37 (30%), DSA-Neg 13/221 (6%), HR 6.6, p0.001). Patients with anti-HLA class II (HR 6.1) or both class I+II (HR 10.1) DSA had the greatest risk for AMR. The Mean Fluorescent Intensity (MFI) of the DSA was significantly higher in patients with AMR than those with no rejection (p=0.006). Moreover, the strength of the antibody was shown to be important, with the risk of AMR significantly greater in those with DSA8000 MFI than those with DSA8000 MFI (HR 23, p0.001). eGFR progressively declined in patients with DSA but was stable in those without DSA (35.7 ± 20.4 mls/min vs 48.5 ± 22.7) and composite patient and graft survival was significantly worse in those with class II (HR 2.9) or both class I+II (HR 3.7) but not class I DSA. Class II DSA alone, or in combination with class I DSA had the strongest association with graft loss and patient death. Patients with DSA not only have increased rates of acute AMR, but also chronic graft dysfunction, graft loss and death. Antibody burden quantified by SAB assay may identify patients at highest immunological risk and therefore influence patient management and improve long-term patient outcome.

We compared the carriage frequencies of HLA-DRB3 and its major alleles and of HLA-DRB4 and HLA-DRB5 in an Australian sIBM cohort and a population control group who had previously been genotyped for the HLA-DRB1*03:01 risk allele. There was a strong disease association with the carriage of the DRB3*01:01 allele which was accounted for by its linkage disequilibrium with DRB1*03:01. The carriage of HLA-DRB4 was found to be strongly protective and abrogated the risk effect of HLA-DRB1*03:01. The findings indicate that haplotypic combinations of alleles at the HLA-DRB1 and secondary HLA-DRB loci have important risk modifying effects in sIBM.

Numerous retrospective studies have been reported analysing the role of HLA mismatches that confer donor NK alloreactivity towards the recipient on the outcome of haematopoietic stem cell transplantation. A bewildering variety of findings have been observed with different studies showing either beneficial or deleterious effects on outcome. This review organises the reports into those that use similar definitions of NK alloreactivity, suggests possible reasons for such disparate results and assesses whether any recommendations can be made in relation to donor selection. There is growing evidence that the effect of human NK alloreactivity on outcome is transplant protocol dependent. Protocol variables most likely to affect outcome are those that influence donor T cell numbers. At this time, it is not possible to predict how the outcome of unrelated donor transplantation will be affected by HLA mismatches conferring potential donor NK alloreactivity.

Genetic testing of the MHC is required for selection of donors for bone marrow transplantation. The outcome of related bone marrow transplantation is usually superior to that of unrelated bone marrow transplantation. This may be the result of inaccurate or incomplete genetic testing employed for selection of donor for transplantation. Based on MHC haplotype matching, MHC block matching has been developed for selection of potential unrelated donor. Block matching has been shown previously to improve outcome when added to the conventional method of human leukocyte antigen (HLA) typing for selection of donors. In this study, we have retrospectively analyzed 44 donor recipient pairs from the Australian Bone Marrow Donor Registry Repository with respect to matching of HLA-B and HLA-Cw by sequence-based typing and MICA and MICB by polymerase chain reaction-sequence specific primer and MHC beta block matching and correlated these results with survival. Beta block matching was correlated with MIC matching (p < 0.005) and with HLA-B and HLA-Cw matching. Patients who were HLA-B and -Cw matched had significantly improved survival when they were additionally matched for MHC beta block (p(c) = 0.04) or MIC (p(c) = 0.05).

The Killer Ig-like receptors (KIRs) on NK cells regulate NK activity via the recognition of specific HLA class I products on the surface of target cells. To investigate the level at which these genetically polymorphic receptors and ligands influence HIV-1 disease progression, we examined the effect of KIR and HLA genotype on HIV outcome. We observed a significant association between particular combinations of KIR epitopes expressed by HLA-B/-C haplotypes and propose that the repertoire of KIR epitopes expressed by HLA-B and HLA-C alleles within the context of particular haplotypes may be an important component of the NK mediated immune response to HIV and/or other infectious pathogens.

Members of the killer immunoglobulin (Ig)-like receptor (KIR) gene family are tightly clustered on human chromosome 19q13.4. Despite considerable variation in KIR gene content and allelic polymorphism, most KIR haplotypes belong to one of two broad groups termed A and B. The availability of contiguous genomic sequences for these haplotypes has allowed us to compare their genomic organization, nucleotide (nt) diversity and reconstruct their evolutionary history. The haplotypes have a framework of three conserved blocks containing (i) KIR3DL3, (ii) KIR3DP1, 2DL4, and (iii) KIR3DL2 that are interrupted by two variable segments that differ in the number and type of KIR genes. Low (0.05%) nucleotide diversity was detected across the centromeric and telomeric boundaries of the KIR gene cluster while higher SNP density (0.2%) occurred within the central region containing the KIR2DL4 gene. Phylogenetic and genomic analyses have permitted the reconstruction of a hypothetical ancestral haplotype that has revealed common groupings and differences between the KIR genes of the two haplotypes. The present phylogenetic and genomic comparison of the two sequenced KIR haplotypes provides a framework for a more thorough examination of KIR haplotype variations, diversity and evolution in human populations and between humans and non-human primates.

During discussion at the WHO Nomenclature Committee for Factors of the HLA System meeting in Victoria, Canada in May 2002, it was decided to form a subcommittee to coordinate the naming of alleles of the genes encoding the killer-cell immunoglobulin-like receptors (KIRs) (Marsh et al., 2002). These genes are encoded on chromosome 19 (19q13.4) and have varying degrees of polymorphism. The receptors encoded by the KIR genes are expressed by natural killer (NK) cells and a subset of T cells, and some of them have been shown to have specificity for determinants of HLA class I molecules. The extracellular ligand-binding part of KIR consists of two or three immunoglobulin (Ig)-like domains. The discussions which took place in Victoria are further to earlier discussions on KIR nomenclature at the NK Polymorphism meeting (27-29 July 2001) in Cambridge, UK. In addition, a request has been made by the International Union of Immunological Societies (IUIS) to provide a standardized nomenclature for the expressed protein products of the KIR genes.

Here, we compare the architecture of membrane receptors with extracellular Ig-like domains located within the leukocyte Ig-like receptor complex (LRC) of humans and mice. The receptors can be classified broadly into four groups, based on the homology of their Ig-like domains and gene architecture. Receptors in the first group are characterized by the presence of the Ig constant type 2-1 (IgC2-1) and variant Ig (vIg) domains, and include the leukocyte Ig-like receptors (LILRs) and murine paired Ig-activating receptors (PIRs). The second group of receptors possess an IgC2-2 domain and comprise the killer-cell Ig-like receptors (KIRs) and platelet collagen receptor glycoprotein VI (GPVI). The third group consists of receptors with IgC2-1, and IgC2-3 or IgC2-4 domains, and includes the receptor for IgA Fc (FCAR), NKp46 and murine Ly94. The fourth group, with a single extracellular IgC2-1 domain, consists of the leukocyte-associated Ig-like receptors (LAIRs). The genomic organization of and evolutionary associations between these receptors and their domains are examined.

Susceptibility to sIBM is strongly associated with the HLA-DRB1*03 allele and the 8.1 MHC ancestral haplotype (HLA-A1, B8, DRB1*03) but little is known about the effects of allelic interactions at the DRB1 locus or disease-modifying effects of HLA alleles. HLA-A, B and DRB1 genotyping was performed in 80 Australian sIBM cases and the frequencies of different alleles and allele combinations were compared with those in a group of 190 healthy controls. Genotype-phenotype correlations were also investigated. Amongst carriers of the HLA-DRB1*03 allele, DRB1*03/*01 heterozygotes were over-represented in the sIBM group (p

The Jewish population in Israel comprises of inhabitants of heterogeneous ethnic backgrounds. Genetic studies classify the Israeli Jewish population into two major groups: Ashkenazi from Central and Eastern Europe and Sephardic or non Ashkenazi, from the Mediterranean and North Africa. The present study was aimed at elucidating the differential influx of HLA class II alleles in Ashkenazi, in various non-Ashkenazi subgroups and in Israeli Moslem Arabs. Using the PCR-SSOP technique, a large number of alleles were detected at each of the loci examined (DRB1, DQA1 and DQB1). In addition, gene frequencies, characteristic DR/DQ linkage disequilibria, population distances and their corresponding dendogram, were used to study the relationship between Israelis as a group, non Jewish Caucasians and Blacks. These populations could be grouped into three main clusters: the first consists of all the Israeli groups with the exception of the Ethiopian Jews; the second consists of non Jewish Caucasians, with a clear distinction seen between Israelis and non Jewish Europeans and U.S. Caucasians; the third, composed of Blacks, is distinctly different from the other populations. Ethiopian Jews were found to be closer to the Blacks than to any of the Israeli Jewish groups. We have shown that Jews share common features, a fact that points to a common ancestry. A certain degree of admixture with their pre-immigration neighbors exists despite the cultural and religious constraints against intermarriage.

It is argued that HLA matching is not worthwhile in heart transplantation. However, transplanting HLA compatible hearts enhances graft survival and should significantly reduce infection and malignancies related to aggressive immunosuppression. It is our view that the problem is technical and we offer a potential solution.

Conventional matching is based on numbers of alleles shared between donor and recipient. This approach, however, ignores the degree of relationship between alleles and haplotypes, and therefore the actual degree of difference. To address this problem, we have compared family members using a block matching technique which reflects differences in genomic sequences. All parents and siblings had been genotyped using conventional MHC typing so that haplotypes could be assigned and relatives could be classified as sharing 0, 1 or 2 haplotypes. We trained an Artificial Neural Network (ANN) with subjects from 6 families (85 comparisons) to distinguish between relatives. Using the outputs of the ANN, we developed a score, the Histocompatibility Index (HI), as a measure of the degree of difference. Subjects from a further 3 families (106 profile comparisons) were tested. The HI score for each comparison was plotted. We show that the HI score is trimodal allowing the definition of three populations corresponding to approximately 0, 1 or 2 haplotype sharing. The means and standard deviations of the three populations were found. As expected, comparisons between family members sharing 2 haplotypes resulted in high HI scores with one exception. More interestingly, this approach distinguishes between the 1 and 0 haplotype groups, with some informative exceptions. This distinction was considered too difficult to attempt visually. The approach provides promise in the quantification of degrees of histocompatibility.

The Moroccan Jewish community living in Israel shows a relatively large genetic distance from other North African Jewish communities. In this work the polymorphism of HLA class I and class II determinants, as defined by serology and oligotyping, is analyzed in 113 healthy unrelated Jews of Moroccan stock. The class I antigens HLA-A1, -B44, and -Cw7 showed the highest frequency, while the most prevalent class II variants were DRB1 ∗ 0701 and ∗ 1104, DQA1 ∗ 0501, and DQB1 ∗ 0201 and ∗ 0301. HLA A1-B13-DR7, A2-B51-DR10, and A1-B44-DR13 were the most typical three-locus haplotypes. Although the antigen frequency distribution of the Moroccan Jews falls within the Caucasian diversity range, this community has a unique pattern in terms of antigen, gene, and haplotype frequencies. Thus, in the Moroccan Jews DRB1 ∗ 1305, an allele believed to be the result of a recombination event between DRB1 ∗ 1301–1302 and DRB1 ∗ 1101, is represented to a much larger extent than in all the other population groups studied at the 11th IHWS. This allele may therefore be a typical Jewish variant. A particular finding was the high frequencies of HLA-B13, B52, and DR10, alleles common among some Oriental populations. The answer to this enigmatic phenomenon probably must be sought in the tortuous history of this community.

There will be a continuing need for well characterized panels of EBV-transformed lymphoblastoid cell lines. Selection of the 4AOH panel was based on prior MHC typing and was intended to ensure representation of ancestral haplotypes from various racial groups. Cells from nonhuman primates, bone marrow donor-recipient pairs, and patients with IDDM were included. Selected cells from the 10IHW were included to enable further characterization. Cells were distributed to participants in the 4AOHW and were typed at multiple loci by a variety of procedures. Non-HLA genes such as TNF were included. Since the cells were distributed “blind” with hidden replicates, it was possible to evaluate the quality of the typing data. An approach to data management is described. The best current estimates of the typing of these cells are presented. The panel will be useful since in provides standards for most alleles at most loci. Since the cells are so well characterized, they represent a useful resource for MHC sequencing and for the evaluation of new typing procedures. Human Immunology 38, 3–16 (1993)

Background: Susceptibility to sIBM is strongly associated with HLA-DRB1*03 and the 8.1 MHC ancestral haplotype but little is known about the effect of allelic interactions at the DRB1 locus or disease-modifying effects of HLA alleles. Objectives: To determine whether DRB1 allele interactions influence susceptibility to sIBM and disease phenotype. Patients & Methods: HLA-DRB1 genotyping was carried out in 80 biopsy-proven cases of sIBM using high-resolution DNA sequencing in 55 cases and serological typing in 25 cases. Allele frequencies were compared with those in a group of 190 healthy population controls. All patients had manual muscle testing using an expanded 10-point MRC scale as well as documentation of historical aspects of their disease. Results: The strong positive association with HLA-DRB1*03 was confirmed (OR 9.6) while negative associations were found with HLA-DRB1∗04 and DRB1∗07. In addition, amongst those carrying the HLA-DRB1∗03 allele DRB1∗03/∗01 heterozygotes were over-represented in the sIBM group (p < 0.003). DRB1∗03/∗04 was the most significantly under-represented combination (p < 0.008) and remained so when those with DRB1∗03/∗01 were excluded (p = 0.03). Age at onset (AAO) was not associated with any individual allele but the mean AAO was earlier in the HLA-DRB1∗03/∗01 heterozygotes (55.8 years vs 62.3 years, p = 0.006) who also had more severe quadriceps weakness than the rest of the cohort (average MRC grade 3.57 vs 5.63, p = 0.003). Conclusions: The findings indicate that the HLA-DRB1*03 allele interacts with other alleles at the DRB1 locus to influence susceptibility to sIBM as well as AAO of the disease and disease severity.

NK cell receptors and HLA molecules are intimately involved in the immune response against viral infections. The killer immunoglobulin-like receptors (KIRs) on NK cells regulate NK cell responses via the recognition of their particular HLA class I ligands. At the genomic level, both genetic systems are polymorphic and have recognised haplotypes, which adds complexity to their interaction. Previously, we and others have shown the association of HLA class I with HIV progression. Recently, the Carrington group observed a synergistic effect involving the activating KIR3DS1 gene and HLA-B Bw4–80Ile on the rate of depletion of CD4+ T cells. To further investigate the relationship between the two genetic systems, we examined changes in viral load in 249 pre-treatment patients from the Western Australia HIV cohort. Genetic variants known to affect HIV progression including HLA-Bw4–80Ile but not KIR3DS1 were associated with differences in HIV-1 viral load set point. When we examined only those patients with known seroconversion dates, we found that the presence of the KIR3DS1 gene was associated with more rapid decline in the proportion of CD4+ T cells (p=0.01) but were unable to show a KIR3DS1 and Bw4–80Ile interaction. The presence of other KIR genes (viz KIR2DS2, KIR2DL2 and KIR2DS1), all found on KIR B group haplotypes, were also associated with a more rapid progression, whilst some KIR genes found the A haplotype with delayed progression We suggest that multiple KIR genes influence outcome in HIV infection. Further analyses of KIR haplotypes is needed to understand the complex interactions between KIR genes and their ligands in driving NK cell responses to HIV.

The selection in vivo of mutations in HIV-1 that allow viral escape from host HLA class I restricted cytotoxic T lymphocyte (CTL) responses has been documented in individuals. Recently we showed that the many HLA-A and -B allele-specific polymorphisms in HIV-1 reverse transcriptase (RT) suggested extensive CTLescape mutation at a population level. HLA class II restricted CD4 T helper responses have a central role in HIV-1 immunity and associations between HLA class II alleles and HIV-1 disease progression have been reported. However, CD4 T cell escape mutation in HIV-1 has not been proven. We sought to determine whether, as for CTLescape, CD4 T cell escape in HIV-1 was evident at a population level as HLA-DRB1 associated polymorphisms. We analysed the diversity of HIV-1 RT sequences in a large, well characterised cohort of HIV-1 infected patients over 2210 person-years of observation. We examined the relationship between the HLA-A, -B and -DRB1 alleles present in the cohort (as covariates) and polymorphism in HIV-1 RT (as the outcome) in multivariate logistic regression models. Each single residue in HIV-1 RT (positions 20-227) was examined in separate models sequentially. Power calculations and model selection steps were carried out to limit the number of comparisons, and final Bonferroni correction was made to mark out the most significant associations. Polymorphism in HIV-1 RT occurred at sites with least functional constraint against mutation. At these sites, we identified 64 characteristic polymorphisms associated with specific HLA-A or -B alleles (OR > 1, p 1, p < 0.05). Four of the 5 known T helper cell epitopes in HIV-1 RT encompassed sites of HLA-DRB1 allele-specific polymorphism found in our study. There were also 'negative associations' between polymorphism and common HLA alleles, suggesting that the HIV-1 consensus sequence could have been selected by the host population's dominant HLA. This novel, population-based approach shows that polymorphisms in HIV-1 sequence are characteristic for specific HLA class I and II alleles, in keeping with viral adaptation to both the CTLand CD4 T helper cell responses of a human host population. These findings suggest that HLA has a central role in HIV-1 primordial and contemporary evolution and has implications for epitope mapping and predicting HIV-1 dynamics in individuals.

Suppressor lymphocyte activity measured by a concanavalin A stimulation method was reduced in myasthenia gravis patients with HLA-B8 and DRW3. These patients also had cold reactive lymphocytotoxic antibodies but these two abnormalities did not correlate with disease activity or acetylcholine receptor antibody. It is concluded that impaired suppressor lymphocyte function is not involved in the pathogenesis of myasthenia gravis, although it is associated with other features which may be seen in patients with this disease. The relationship between diminished suppressor activity and HLA may indicate that the major histocompatibility complex is involved in immunoregulation in man as well as in mice.