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Vaccination with peptides that induce a specific immune response is a potential prophylactic or therapeutic strategy against viral infections and tumors. Because of the extensive polymorphism of the HLA loci, synthetic peptide vaccines must consist of a cocktail of peptides that bind specifically to different HLA molecules. Such cocktails should be optimized for the target population as each population has its specific HLA gene frequencies. To achieve maximum population coverage with a minimum number of peptides, information is needed on the ranking of the most frequent HLA phenotypes. We introduce the minimal phenotype panel, which is the smallest combination of HLA antigens selected so that the proportion of individuals in a population that express at least one of the antigens in the panel exceeds a desired minimum value. We developed a method for assembling minimal phenotype panels based on known HLA class I gene frequencies. We give an example based on a set of 2446 well-defined HLA-typed, random, healthy, unrelated, Dutch Caucasoid individuals. In addition, we discuss the possibility of assembling minimal phenotype panels based on two-locus haplotypes, which enables the assembly of phenotype panels from the antigens of both loci.

We analyzed the HLA-A, -B, -C, -DR and -DQ phenotypes of 2,440 healthy, unrelated, Dutch Caucasoid blood donors and of 20,814 Dutch blood donors who were registered as volunteer bone marrow or platelet donors. Phenotype and gene frequencies, Hardy-Weinberg equilibrium fit and homozygosity were calculated as well as 2- and 3-locus haplotype frequencies, deltas, relative deltas and significance levels of the deltas. The population appears to be in Hardy-Weinberg equilibrium. Many haplotypes are in strong positive linkage disequilibrium. A phylogenetic tree, based on the HLA-A, -B and -DR gene frequencies of blood donors in different Dutch regions, reflects the limited but manifest heterogeneity of the Dutch population. Additionally we introduce a stepwise test for Hardy-Weinberg equilibrium and discuss the applicability of this test and of the single test for Hardy-Weinberg equilibrium for tissue typing quality control and for selection of split antigens prior to gene and haplotype frequency analyses.

In bone marrow transplantation, the advantages of family donors over unrelated donors are threefold. (1) Family donors are better matched because they share complete haplotypes. (2) The time between the start of the search and the actual transplantation can be much shorter than for unrelated donors. (3) Related bone marrow transplantation is cheaper. We developed a procedure for calculating the probability of finding a suitable donor among cousins and blood-related aunts and uncles (the extended family). The procedure calculates the following probabilities (P): (1) P that any blood-related uncle or aunt is a suitable donor, (2) P that a suitable donor exists in all blood-related uncles/aunts (from [1]), (3) P that any cousin is a suitable donor (as in [1]), (4) P that a suitable donor exists in all cousins (from [3]), (5) P that a suitable donor exists in the entire extended family (from [2] and [4]). Additionally, we discuss the suitability of this procedure in the daily practice of donor procurement. The procedure is also suitable to search for family donors who have a single antigen mismatch with the patient. We also discuss the differences between our method and the one recently described by Kaufman (Bone Marrow Transplant 15:279, 1995).

Some combinations of HLA-A, -B and -DR antigens occur more frequently than would be expected from their gene frequencies in the population. This phenomenon, referred to as Linkage Disequilibrium (LD) has been the origin of many speculations. One hypothesis to explain LD is that some haplotypes are protected from recombination. A second hypothesis is that these HLA antigens preferentially recombine after cross-over to create an LD haplotype. We tested these 2 hypotheses: from a pool of over 10,000 families typed in our department, we analyzed 126 families in which HLA-A:B or B:DR recombinant offspring was documented. To overcome a possible bias in our material, we used the non-recombined haplotypes from the same 126 families as a control group. Our results show that the number of cross-overs through LD haplotypes is not significantly lower then would be expected if recombination occurred randomly. Also the number of LD haplotypes created upon recombination was not significantly increased.

HLA-disease associations may be important for understanding the pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection. Therefore, 106 homosexual men from the Amsterdam Cohort Study on AIDS with a known date of HIV-1 seroconversion were serologically typed for HLA. Several significant associations between HLA type and pathogenic features of HIV-1 infection were observed: Subjects with fever and skin rash during primary HIV-1 infection showed an increased frequency of HLA-B62 (relative risk [RR], 5.8; P = .005). The frequency of HLA-B35 was increased in subjects with a rapid decline in CD4+ T lymphocytes (RR, 3.2; P = .021). Kaplan-Meier survival analysis revealed a significant association between HLA-B35 and a decrease in CD4+ cells to < 200/microL (P = .01). The strongest association was found between HLA-DR1 and AIDS-related Kaposi's sarcoma (RR, 22.5; P < .001), also confirmed in survival analysis (P = .001). In AIDS patients with only opportunistic infections, increased frequencies of HLA-DR3 (P = .011) and -DQ2 (P = .007) were observed. Finally, the occurrence of syncytium-inducing HIV-1 variants was significantly associated with HLA-DQ2 (P = .01).

This study characterizes the HLA class I and class II antigens in a group of patients with vitiligo and a control group, both of Dutch descent. Earlier reports had shown a significant positive association with DR4 and a significant negative association with DR3. We found that, after correction for the broad antigens studied, only Cw7 and DR6 were significantly associated with vitiligo. The significant positive association of DR6 with vitiligo is interesting since vitiligo has an autoimmune component in its pathogenesis and DR6 may be a marker for high immune responsiveness.

The clinical use of clozapine in psychiatry is restricted by the associated risk of agranulocytosis. This risk is significantly higher than that associated with conventional antipsychotic medications. In order to identify a possible parameter to detect susceptible individuals before treatment, 103 patients with a history of clozapine-induced granulocytopenia or agranulocytosis and 95 matched control patients were typed for human leucocyte antigen (HLA)-A, -B, -C, -DR, -DQ and for a number of neutrophil-specific alloantigens. No significant association between certain HLA alleles or neutrophil antigens and susceptibility to clozapine-induced granulocytopenia or agranulocytosis was observed.

In a group of 52 patients with a chronic inflammatory demyelinating polyneuropathy (CIDP), no significant associations were found with any of the HLA-A, B, C, DR or DQ antigens. No HLA association was found between the presence or absence of anti-neural antibodies or between the group of patients improving or not improving after intravenous immunoglobulin. These findings mean that we could not confirm results from the literature that suggest that CIDP is associated with the HLA-A1,B8,DR3 haplotype or--as recently was suggested--with the HLA-Cw7 or DR2 antigen.

Several arguments support the idea of a link between longevity and heredity, both in experimental animals and in the human species. In mice, genes in the major histocompatibility complex (MHC) are associated with a significant effect on life span. Results of analogous studies in man are confusing and contradictory. We have therefore investigated the question of an association of the human leucocyte antigen (HLA) and longevity in a large and ethnically homogeneous population. Our study population consisted of all 964 available inhabitants aged 85 years and over in the Dutch community of Leiden (pop. 104,000). Our control group comprised 2444 young inhabitants, aged 20-35 years, with an identical ethnic and demographic background. In addition, control groups of different age-brackets from the same region were used. Two antigens differed in frequency: HLA-B40 was lower and HLA-DR5 was higher in the group of 85 years and over, as compared to the control group, aged 20-35 years. Both differences were more evident in females. No major disease associations with HLA-B40 or HLA-DR5 have been reported. It is unlikely that these results are a chance observation: the overall similarity of the HLA pattern of the old and young age groups is a confirmation of their identical ethnic and demographic background and the changes as observed in the different age-groups were gradual. The biological meaning of these results is still unclear.

The effect of matching for the HLA antigens has been well established as important in the prognosis of kidney grafts. By analyzing the effect of matching on first transplants from unrelated donors in specific intervals up to 3 years posttransplantation, we show that the effect of HLA-DR matching is strongest in the first 5 months following transplantation (relative risks of graft failure 1.31 and 1.77 for 1 and 2 HLA-DR mismatches, respectively, compared with no mismatches). For patients whose grafts remained functioning after 5 months, there was no significant further improvement in graft survival to 3 years (relative risks 1.16 and 0.98 for 1 and 2 HLA-DR mismatches, respectively, compared with no mismatches)--i.e., the gain in graft survival by matching for HLA-DR appears to be due to its influence in the first 5 months following transplantation. For HLA-B, the matching effect was evident both before and after 5 months (relative risks 1.11 and 1.27 for 1 and 2 HLA-B mismatches, respectively, compared with no mismatches and modelled as constant over the 3-year period), whereas no effect of HLA-A matching was evident in the period up to 3 years.

A retrospective review of 288 penetrating keratoplasties (PKP) for herpes simplex keratitis demonstrated a 60.4% survival rate of clear grafts at 3 years. A highly significant difference in corneal graft survival in severely vascularized corneas (57.1% at 3 years) versus non- or slightly vascularized corneas (82.8% at 3 years) was observed (P = 0.009). Prospectively HLA-A and -B matched grafts in vascularized corneas revealed a significantly improved graft survival when compared to unmatched grafts (P = 0.035). Corneal graft survival in eyes grafted 'à chaud' was not significantly below the graft survival of vascularized corneas with a clinically non-active herpetic corneal disease. Recurrence of herpes simplex in the graft was observed in an earlier postoperative period in HLA-A and -B matched grafts (P = 0.0004).

Fifty-four patients with clinically definite multiple sclerosis were typed for HLA-A, B, C, DR and DQ antigens. HLA-DQ was not a better disease marker than the previously described HLA-DR and B markers. The patients were subdivided according to the clinical evolution of their disease, age at onset and sex. HLA-DR2 was significantly associated with females having a relapsing-remitting course of the disease and HLA-B8 and B35 were significantly associated with males having a chronic-progressive course of the disease. A role is postulated for defects in the sex hormone balance in females and for microbial infections in males as dominant environmental triggers in the development of autoreactivity.

A reassessment of HLA-A and B antigen associations in patients with severe aplastic anaemia confirmed the significantly elevated frequency of HLA-A2 in Caucasoid patients reported by Albert et al. (1976). In addition, a highly significant increase in the frequency of HLA-B14 in Italian patients was observed in an initial sample of 25 patients and confirmed in a second sample of 16 patients. This latter finding was cancelled out when the Italian Caucasoid patients were pooled with the non-Italian Caucasoid patients. These results suggest that the classification of populations as "Caucasoids", without examining their ethnic origins, may introduce a serious confounding error into HLA and disease studies.

Twenty-eight patients with scleroderma were typed for 40 HLA antigens. A highly significant increase in the frequency of HLA-B8 and HLA-DR3 was observed, which was not related to the severity of the disease. In vitro lymphocyte stimulation tests were performed in 26 patients. In addition, humoral and in vitro cellular immune responses to a primary test antigen were measured in 12 of them. Although the group of scleroderma patients as a whole had an impaired cellular response, only the B8/DR3+ patients had a strongly depressed response, whereas the immune response of the others was normal. These findings suggest an association of the haplotype B8/DR3 with impaired cellular immunity.

Histocompatibility antigen testing has been carried out in 20 unrelated normotensive English Caucasoids with hypertrophic cardiomyopathy and in 17 relatives, six of whom also had the disease. A strong association with the HLA-DRw6 antigen complex was found (P = 0.0036) but it was no longer significant after correction for the 52 antigens tested (P = 0.1701).

The status of the W4, W6 system as related to the HL-A system was re-evaluated by means of segregation and mating studies in 200 Dutch families with 755 children. Inclusion analyses were performed on the Fifth Workshop human populations and related to a reference analysis on the main file in Leiden. The results of the mating and segregation analyses showed a good fit for W4 and W6 as a genetic system. The inclusion analyses showed a high degree of concordance. Based on those results, and other cited evidence, it was suggested that W4 and W6 may represent the basic substance of the HL-A antigens in the FOUR series.

We compared family distances of homozygotes and heterozygotes for HLA-A and -B. When matched on number of inhabitants per birthplace, no significant differences were found. However, when homozygotes were compared with heterozygotes from larger birthplaces, homozygotes showed significantly smaller family distances in the grandparental generation. We suggest that matching for population size of birthplace and the choice of the geographic study area are important factors in studies of family distances.

Comparisons of the HLA antigen frequencies in normal controls and in different subsets of patients with malignant choroidal melanoma, partitioned on the basis of histological tumour cell types and inclusion of the splits of all the HLA-A and -B locus antigens, revealed significant heterogenity only in HLA-B (P = 0.043) in the 'pure spindle' cell type choroidal melanomas. In the 'not pure spindle' cell type choroidal melanomas, borderline heterogenity in HLA-B (P = 0.064) was observed. A comparison of the HLA antigen frequencies in the 'pure' and 'not pure spindle' cell choroidal melanoma patients revealed only one antigen with a significant difference before correction, namely B27. A significant difference in ABO bloodgroup distributions, divided into O and non-O, in the two tumour classes was observed (Exact P(1) = 0.0036).

The frequencies of the HLA-A, B, C, D, DR and MB antigens have been determined in a homogeneous Shanghai Chinese population. Comparisons with the HLA-A and -B frequencies in other subsets of the Chinese population revealed some marked differences. No comparisons were possible for the D, DR and MB antigens since there were no previous studies of the antigens in those loci. We suggest that studies of the Chinese population should be confined to clearly defined homogeneous subsets. In this manner, the confounding effect of population heterogeneity may be avoided, and it is this heterogeneity which calls for extensive surveys of the huge Chinese population.

We have compared the distribution of histocompatibility antigens of 22 Turkish and 14 British patients with Behçet's disease with those of their respective controls. There was a strong association of B5, specifically its Bw51 split, with the disease. A modest increase in the incidence of HLA B27 was noted in British patients, but numbers were too small for analysis. The incidence of DRw2 and DRw4 antigens among Turkish and British patients did not differ from that of their respective controls.

In mice it has been shown that mating preference is genetically associated with the Major Histocompatibility Complex (MHC). In the present study, an approach is described to study homologous aspects of the MHC in man. After selection of families with one or more children, a given parental HLA antigen was selected and the frequencies of the spouse's HLA antigens were determined. Assuming a random distribution, these frequencies should not be statistically different from those of the total population. Evidence is presented that this distribution is not random for a number of maternal and paternal HLA antigens.

We have shown that the application of Piazza's formula for the estimation of the "three-locus interaction delta" should not be used for that purpose. In addition, the method of Porta & McHugh, for the demonstration of haplotype interaction in associations between HLA and disease, leads to completely erroneous conclusions. Other methods of calculation that have been used to analyse haplotype interactions also appear to be based on erroneous concepts. We suggest that nothing more than the estimation of heterogeneity in simple 2 X 2 contingency tables should be used for the analysis of linkage disequilibria. This principle is applied to the HLA-A, -B and -C haplotype frequency tables of Baur & Danilovs. For the greater part of the HLA-B alleles, three-locus haplotype frequencies can be explained from the A, B and the B, C disequilibria, without any further haplotype interactions. The predominant exceptions in that respect are haplotypes containing the B44 allele, which has been shown to contain two subgroups and therefore, we are not justified to conclude that this exceptional behaviour of haplotypes with B44 should be attributed to three-locus haplotype interactions.

Seventy-seven patients with rheumatoid arthritis were investigated to examine the frequency of HLA antigens and their relationship to clinical and serological manifestations of extra-articular disease. The phenotype frequencies of DR4, DRw53, Bw62 and Cw3 were significantly increased, compared to normal controls, and there were negative associations with DR2 and DR7. The HLA antigen in strongest association with rheumatoid arthritis was DR4 (73.6%) and the relationship with DRw53 appeared to be secondary. The frequency of DR4 rose to 92% in seropositive patients with extra-articular disease manifestations whose serum contained immune complexes. A high frequency of DR4 was also seen in male patients (86%), reaching 100% in the small group of seropositive male patients with immune complexes. It is suggested that extra-articular disease represents a manifestation of severe classical rheumatoid arthritis and is not an 'overlap' syndrome. We propose that the HLA haplotype Cw3-Bw62-Dw4-DR4-DRw53 makes a greater genetic contribution to disease susceptibility in both extra-articular and male rheumatoid arthritis patients than in other subsets of RA.

We examined all available data on HLA-A and -B antigen distributions in patients with Crohn's disease and ulcerative colitis. The risk of Crohn's disease was significantly increased in individuals with HLA-A2, having a relative risk of 1.25, in 730 pooled Caucasoid patients compared with 10 863 pooled controls, and decreased in individuals with HLA-A11, having a relative risk of 0.62. The risk of ulcerative colitis was also significantly increased in individuals with HLA-B27 and -Bw35, having a relative risk of 1.81 and 1.41 respectively, in 560 pooled Caucasoid patients compared with 6151 pooled controls, whilst in 144 pooled Japanese patients who were compared with 442 pooled controls, the risk of colitis was increased in individuals with HLA-B5 with a relative risk of 2.79. All differences remained significant after correction for the number of antigens examined. The bases for these genetic associations are unclear.

The main purpose of Eurotransplant, an international organ exchange organisation, is to maximize the survival time of transplanted organs through tissue typing and matching. Regular proficiency testings are necessary to assess the reproducibility and the reliability of the HLA typings performed by the individual typing centres. Two different protocols have been used: 1) since 1978, 35 samples of blood and donor spleen were used for cell exchanges (CE) and typed by all participating laboratories; 2) since 1977 samples of donor spleen have been shipped to the reference laboratory in Leiden for retyping (RD) resulting in over 2600 comparable HLA typings. The discrepancy rates of the HLA-A, B, C and DR specificities were analysed over the years. A large number of discrepancies was due to false negative assignments which led to assumed homozygosity at one or more HLA-loci. The recognition of HLA-DR has improved dramatically but with much variation per DR specificity. The concordancy rates for HLA-AB + DR have improved from 40% in 1981 to 91% for CE and 80% for RD typings in 1984. The reproducibility of DR typings in individual laboratories also has improved greatly but there is still considerable variation between the different laboratories.

Frequencies of 35 HLA A, B, C, and DR antigens were determined in 1,834 leukemic Caucasoids to evaluate possible associations between HLA and leukemia. In comparison with the frequencies of HLA antigens in published controls, the frequency of Cw3 was significantly higher in patients with acute lymphoblastic leukemia (relative risk = 2.64, P less than 0.0002), acute myelogenous leukemia (relative risk = 1.92, P less than 0.0007), and chronic myelogenous leukemia (relative risk = 2.07, P less than 0.002; P values adjusted for multiple comparisons). The frequency of Cw4 was elevated in patients with acute lymphoblastic leukemia (relative risk = 2.01, P less than 0.0003), acute myelogenous leukemia (relative risk = 2.06, P less than 0.0002), and chronic myelogenous leukemia (relative risk = 2.14, P less than 0.0008). The frequency of Aw19 was significantly decreased in patients with acute myelogenous leukemia (relative risk = 0.68, P less than 0.01) and chronic myelogenous leukemia (relative risk = 0.59, P less than 0.005). None of the other 32 HLA antigens investigated had a statistically significant association with leukemia. The data suggest that Cw3 and Cw4 may be markers for leukemia susceptibility genes, while Aw19 may be a marker for decreased susceptibility to leukemia.

Data on the effect of HLA-A and HLA-B matching between unrelated donors and recipients focus mainly on graft survival. After linking the follow-up data of the European Dialysis and Transplant Association and those of the Eurotransplant Foundation, the effect of HLA-A and HLA-B matching on recipient survival could be studied. Recipients of well-matched kidneys--i.e., without mismatches for the HLA-A and B antigens--had 51 per cent graft survival at five years, whereas recipients of grafts mismatched for four antigens had 32 per cent graft survival at five years. The overall P value between the five different mismatch classes was 0.0005. Patient survival at five years was 72 per cent in recipients of a kidney without HLA-A and B mismatches and 54 per cent in recipients of a completely mismatched donor kidney (overall, P = 0.001). These results suggest that matching for the HLA antigens has a beneficial long-term effect not only on renal-allograft survival but also on patient survival.

Frequencies of HLA A, B, C, and DR antigens were calculated in 1009 leukaemia patients, all of whom had been treated with bone-marrow transplantation and reported to the International Bone Marrow Transplant Registry. Cw3 (relative risk = 2 X 26, p = 0 X 00002) and Cw4 (relative risk = 2 X 18, p = 0 X 00003) were significantly associated with acute leukaemia (p values adjusted for multiple comparisons). Cw3 (relative risk = 2 X 97, p = 0 X 00002) and Cw4 (relative risk = 2 X 10, p = 0 X 004) were also significantly associated with acute lymphoblastic leukaemia and Cw4 was significantly associated with acute myelogenous leukaemia (relative risk = 2 X 39, p = 0 X 0003). The data suggest that Cw3 and Cw4 may be markers for leukaemia susceptibility genes, genes that code for low immune responsiveness to putative leukaemia viruses, or genes that regulate the response to chemotherapy and, therefore, the attainment of remission, since most of these patients underwent transplantation during remission.

The distribution of HLA-A, -B, -C and -DR antigens was investigated in 154 patients with immune thrombocytopenia (99 adults and 55 children). An increased frequency of HLA-Bw56 (a split of HLA-Bw22) was found both in the adults (RR = 4.30) as well as in the children (RR = 7.91). Differences in HLA antigen distributions have also been analysed in patient subgroups with a good and a bad response to corticosteroids and splenectomy. The frequency of HLA-DR4 was low in those patients with a good response to prednisone as compared with those with a poor response. The opposite was found in splenectomized patients. In 22 patients who did not respond to splenectomy, LB4 (a local split of HLA-DR4) was completely absent. These results suggest that HLA-DR4 (LB4) may be a predictive marker for therapy in ITP patients, i.e. a bad response to corticosteroids and a favourable outcome of splenectomy. However, none of the differences were significant after correction was made for the number of antigens tested.

We think that the determination of acceptable mismatches is an efficient approach to increase the chance of finding a crossmatch-negative donor for highly sensitized patients. This approach has several advantages (4,5) namely: 1. There is no need for distribution of patient sera to other tissue typing centers. 2. Rather than performing crossmatches with all donors, most of which will be positive, selection is based on a predictable negative crossmatch. 3. Selection of potential donors is based on data obtained by the recipient centers, which has all the information concerning the patient's immunological background (transfusion, specific alloantibodies, autoantibodies) rather than on a negative crossmatch at another tissue typing center. 4. Selection is based on HLA-DR compatibility between donor and recipient, which is, both in our and other analyses (6), important for an optimal prognosis of graft survival in highly immunized patients. Of course, there are still patients for whom this protocol is not very helpful (rare HLA-types, hardly any or no acceptable mismatches). For these patients it might be that other approaches, including removal of circulating antibodies (7), may be the only solution.

A population study to test whether associations between HLA and sporadic--i.e. non-familial--tuberculoid leprosy exist was undertaken in a hyperendemic area in India. Since previous family studies in the same area had shown both non-random haplotype segregation in the family members affected with tuberculoid leprosy and the preferential segregation of HLA-DR2 into tuberculoid leprosy patients, an increased frequency of DR2 among the "sporadic" patients was expected. However, no heterogeneity for HLA was detected between patients and controls. These findings could indicate that tuberculoid leprosy is a heterogeneous disease with regard to genetic background.

Sixty-two Dutch patients with the diagnosis paranoid schizophrenia (SCH) were HLA-A-, -B- and -C-typed. An increase in the frequencies of A9 (P = 0.02, relative risk 1.8) and B5 (P = 0.04, relative risk 1.9) was found. Although these correlations do not remain significant after correction for the number of antigens tested, both findings confirm other data from the literature, including the first published report from a population in Sweden. From all hitherto published literature data, the combined relative risks for A9 and B5 is significantly increased. These data strongly indicate that the distribution of HLA antigens among SCH patients is different from the control population.