C4 Chido 3 and 6 distinguish two diabetogenic haplotypes: HLA-B49, SC01,DR4,DQw8 and B8,SC01,DR3,DQw2.

The combination of the HLA complement allotypes BFS, C2C, C4AQ0 (deleted gene) and C4B1, termed SC01 complotype, usually present in the HLA-B8,DR3,DQw2 diabetogenic haplotype, has also been found in a novel "low frequency" HLA-B49,DR4,DQw8 haplotype associated with Spanish insulin-dependent diabetes mellitus (IDDM). Family studies of C4 antigenic determinants Rodgers/Chido and their specific C4d nucleotide sequences confirm that this novel haplotype bearing Chido -3, -6 is not due to a recent recombination from the common HLA-B8,DR3 haplotype bearing Chido 3,6; moreover, Chido analysis at the serological or DNA level is presently the only way to distinguish both SC01 complotypes, since BF, C2, steroid 21-hydroxylase and C4 genes do not reveal other differences by restriction fragment analysis. On the other hand, HLA-B49,SC01,DR4 is the first DR4-bearing IDDM-susceptible haplotype with a deleted C4 gene described so far and the only DR4-bearing haplotype found in the Spanish population. This report further supports the fact that extended haplotypes with deleted (or "not duplicated") genes in the class III region contain IDDM-susceptibility more often than non-deleted (or "duplicated") haplotypes in the Spanish and other Mediterranean populations.     

Extended HLA-DQw2 haplotypes: molecular analysis.

The HLA-DQw2 specificity, homogeneous in serology, is strongly associated to two HLA-DR specificities: DR3 and DR7. These alleles are found mainly on DQw2 bearing extended haplotypes with strong linkage disequilibrium. We describe, with BamHI, HindIII and RsaI, two restriction fragments length polymorphisms (RFLP) for the A gene of DQw2. These two subtypes correlated with the DR3 and DR7 specificities. Interestingly, by non-equilibrium pH gradient electrophoresis (NEPHGE), two DQ alpha chains were also found, respectively correlated with the same DR specificities. In addition, HincII polymorphism allowed us to distinguish several patterns of B genes for (DR7) DQw2 haplotypes but without any detectable association with another HLA marker. However, only one DQ beta chain was found by NEPHGE in the (DR7) DQw2 haplotype. Furthermore, HincII discriminated the B genes of the two extended haplotypes: (B8, DR3) DQw2 and (B18, DR3) DQw2. The same result was found by NEPHGE: two DQ beta chains were described, corresponding to the same extended haplotypes. The use of exon-specific DQB probes showed that the genomic polymorphism in DQw2 haplotypes is located, at least, at the 3' end of the gene. These data add new characteristics to the different DQw2 extended haplotypes.     

Unusual HLA-DR,DQ haplotypes found in South African families of black, Asian Indian, and mixed ancestral origin.

Four non-Caucasoid families with the unusual HLA-DR,DQ haplotypes DRw17,DQw7; DR9,DQw2; DR4,DQw2; and DR4,DQw5 were studied. All four haplotypes showed identical serological patterns to those seen with the equivalent Caucasoid antigens, but no HLA-Dw specificities could be assigned. TaqI restriction fragment length polymorphism (RFLP) patterns observed using DRB, DQB, and DQA probes showed that the DRw17,DQw7 haplotype may have originated from a homologous crossover between a DRw17,DQw2 haplotype and a haplotype with DQw7. The results obtained for the DR9,DQw2 and DR4,DQw2 haplotypes suggest that these could have resulted from recombination events with an ancestral "black" DQw2 haplotype. From the RFLP data, it is difficult to postulate the origin of the DR4,DQw5 haplotype being from a single recombination event.     

EXTENDED HLA-DQw2 HAPLOTYPES: MOLECULAR ANALYSIS

The HLA-DQw2 specificity, homogeneous in serology, is strongly associated to two HLA-DR specificities: DR3 and DR7. These alleles are found mainly on DQw2 bearing extended haplotypes with strong linkage disequilibrium. We describe, with BamHI, HindIII and RsaI, two restriction fragments length polymorphisms (RFLP) for the A gene of DQw2. These two subtypes correlated with the DR3 and DR7 specificities. Interestingly, by non-equilibrium pH gradient electrophoresis (NEPHGE), two DQα chains were also found, respectively correlated with the same DR specificities. In addition, Hindi polymorphism allowed us to distinguish several patterns of B genes for (DR7) DQw2 haplotypes but without any detectable association with another HLA marker. However, only one DQ(3 chain was found by NEPHGE in the (DR7) DQw2 haplotype. Furthermore, MncII discriminated the B genes of the two extended haplotypes: (B8, DR3) DQw2 and (B18, DR3) DQw2. The same result was found by NEPHGE: two DQβ chains were described, corresponding to the same extended haplotypes. The use of exon-specific DQB probes showed that the genomic polymorphism in DOw2 haplotypes is located, at least, at the 3’end of the gene. These data add new characteristics to the different DQw2 extended haplotypes.     

Haplotypes bearing HLA-A, -B, and -DR: Bf and C4 genes in rheumatoid arthritis families

We have compared haplotypes bearing HLA-A, -B, -DR; Bf and C4 genes in 54 rheumatoid arthritis (RA) and 24 control families. There was no statistically significant differences in C4A or C4B gene frequencies between RA and control groups, although there were trends for C4B*Q0 to be reduced and C4B2 to be increased in DR4 positive RA compared with DR4 positive controls. The lack of any strong association between C4 variants and RA overall makes it unlikely that the association between RA and genes within the MHS represents a direct effect of variants within the C4A or C4B loci themselves. On comparison of DR4-bearing haplotypes, the haplotype B15-BfS-DR4 was increased fourfold and the B44-Bfs-DR4 haplotype was less frequent in the RA group. When C4 variants were also considered, the haplotype B44-C4B*Q0-C4A3-BfS-DR4 was nine times less frequent in RA patients than in controls. The observation that different DR4 bearing haplotypes may confer either increased or decreased susceptibility to RA suggests either that it is unlikely that DR4 itself is involved in the disease process or that specific haplotypic combinations are important. Thirty-two RA patients were HLA-DR4 negative. No single DR4 negative haplotype was found to confer significantly increased susceptibility to RA.     

A high frequency of the A30, B18, DR3, DRw52, DQw2 extended haplotype in Sardinian celiac disease patients: Further evidence that disease susceptibility is conferred by DQ A1*0501, B1*0201

This study characterizes by serological and molecular methods the HLA class I and class II alleles in a group of celiac disease children, their parents and a control group of Sardinian descent. We found the DR3-DQw2 haplotype in all patients which was, in almost all cases (84%), associated with the HLA-A30, B18, DR3, DRw52, DQw2 extended haplotype named "Sardinian haplotype" because of its frequency (12-15%) in this Caucasian population. This is the first time that this DQw2-linked haplotype has been reported with such a high frequency in CD. However, no different distribution of "Sardinian haplotype" was found comparing CD patients with 91 haplotyped DQw2-positive controls. This finding indicates that the DQw2 antigen in Sardinians is almost always associated with the A30, B18, DR3, DRw52, DQw2 extended haplotype. The DQA1 and DQB1 second exon sequence analysis of the B18,DR3 and B8,DR3 haplotypes showed the DQA1*0501 and DQB1*0201 alleles which shared the already published sequences. DPB1 subtyping showed the DPB1*0301 allele more frequently (p less than 0.005) in CD patients but this difference was no longer significant when patients and controls, both heterozygous for the DR3-DQw2 haplotype, were compared. We suggest that the divergent HLA extended haplotypes and DP allele associated with CD, described in different Caucasian populations, can be explained by the particular DQw2 linkage disequilibrium in each population.     

HLA-DQ antigens and DQβ amino acid 57 of Japanese patients with insulin-dependent diabetes mellitus: detection of a DRw8DQw8 haplotype

DQw8 (DQw3.2) on DR4 haplotypes is a susceptibility gene for development of insulin-dependent diabetes mellitus (IDDM) in Caucasoids, possibly because it encodes a non-Asp amino acid (aa) (i.e. Ala) at residue 57 of the DQ beta chain (non-Asp-57). Most Caucasoid IDDM patients are homozygous non-Asp-57. We have examined 14 Japanese IDDM patients, selected to be either DR4 or DRw9 (associated to IDDM among Japanese). Their DQB1 alleles and the aa encoded by their DQB1 codons 57 were identified, using 11 different sequence-specific oligonucleotide probes. Secondly, they were examined with DQw8 specific T lymphocyte clones and with anti-DQ monoclonal antibodies. The DQB1 genes on their DR4 and DRw9 haplotypes in all cases encoded Asp-57. Two patients were Asp-57 homozygous, the rest were Asp-57/non-Asp-57 heterozygous. The DR4 haplotypes all carried DQw4 (rather than DQw8), and the DRw9 haplotypes all carried DQw9. Furthermore, five of six DRw8 positive patients carried a previously undetected DRw8DQw8 haplotype, where both the DQA1 and DQB1 genes were similar to those usually found on the DR4DQw8 haplotype. Thus, the DR/DQ allele combinations and aa residue 57 of the DQ beta chain of Caucasoid and Japanese IDDM patients are largely different.     

HLA and narcolepsy in a German population

In this paper the first MHC data including HLA-A, B, C, DR, DQ and complement BF, C4A, C4B determinants in German narcoleptics are presented together with the first family studies in European Caucasoids. 57 out of 58 unrelated patients (98.3%) were positive for DR2 and DQw1, respectively. In contrast to all other reports, one patient with typical signs of narcolepsy was found to be DR2/DQw1 negative. Data showing significant increase in the frequency of B7, and normal frequencies of B35 were discordant with data from Japanese patients. Definition of the extended DR2 linked haplotypes, deduced from 6 families, revealed that 5 out of 12 were DQw1, DR2, BFS, C4B1, C4A3, B7 (Cw7), while 11/12 had DR2, DQw1, BFS, C4A3, C4B1 in common. In one multiple case family two genotypically different DR2 haplotypes were identified in affected siblings. Results from the family study were concordant with a dominant mode of inheritance with incomplete penetrance of a hypothetical disease susceptibility gene.     

Unique HLA-DR/DQ associations revealed by family studies in Warao Amerindians. Haplotype and homozygosity frequencies

HLA-A, Cw, B and A, Cw, B, DR genotypes have been assigned, respectively, to 318 and 175 Warao Amerindians belonging to 73 sibships, who were tested with International Histocompatibility Workshop reagents. Only 33% of the theoretically possible three-loci and 7% of the possible four-loci haplotypes were found, with 10 and 6 of them accounting, respectively, for 75% of the total observed. This limited haplotype variability, expected in an inbred population, was not accompanied by either an increased or a decreased frequency of homozygous individuals, as demonstrated by population and family analysis. Inheritance of five HLA loci haplotypes in 20 families showed the expected distribution of parental haplotypes in sibling pairs. The study revealed DR2sh (DRw16), DR4 and DRw6 in association with DQw7, and DRw8 with DQw4, and significant positive linkage disequilibria between Bw62 CW1, B51 DRw16, B39 DR4, Bw62 DRw6, and DRw8 DQw4. The DR2-DQw7 and DRw6-DQw7 associations and the first three paired loci disequilibria mentioned are described for the first time in Amerindians and have not yet been found among Japanese, Negroid, or Caucasoid populations.     

Analysis of DR and DQ gene products of the DR4 haplotype in patients with IDDM: Possible involvement of more than one locus

Fifteen DR4-bearing haplotypes from twelve patients with insulin-dependent diabetes mellitus (IDDM) were analyzed serologically, cellularly, and biochemically. The HLA-Dw composition of these DR4-positive haplotypes was Dw4 (46%), Dw14 (22%), and Dw10 (33%). The biochemical analysis by two-dimensional electrophoresis (2D-PAGE) of the DR beta chains showed that each Dw specificity is characterized by a specific DR4 beta chain that appears to be identical in normal and diabetic individuals. Analysis of DQ beta chains in the DR4-bearing haplotypes revealed that certain Dw specificities such as Dw4 are characterized by the presence of either the DQw7 (formerly DQw3.1) or DQw8 (formerly DQw3.2) alleles, which generate the Dw4.1 or Dw4.2 subtypes, respectively. Others such as Dw14 and Dw10 are characterized by the presence of the DQw8 allele. In our sample of 12 patients the Dw4.2 (Dw4, DR4βI-4 DQw8) and Dw10 (Dw10, DR4βI-1, DQw8) subtypes were predominant. It is concluded that individual DR β and DQ β gene products from the DR4-bearing haplotype of IDDM patients are identical to those of normal control subjects and that Dw14 as well as Dw10 are involved in disease susceptibility. We suggest that disease susceptibility may be influenced by more than one locus within the HLA-D region.     

Polymorphism of HLA-DR2,DQwl haplotypes in Asian Indians

We examined the polymorphism of DR2,DQw1 haplotypes in Epstein-Barr virus-transformed B-lymphoblastoid cell lines (HTCs) and unrelated (32 Canadian Caucasians and 24 Asian Indians) individuals by restriction fragment length polymorphism (RFLP) and oligonucleotide typing. The data demonstrate that three subtypes of DR2,DQw1 haplotypes, DRw15(B1.1501).DQw6a(A1.0102,B1.0602),DRw15(B1.1502). DQw6b(A1.0103,B1.0601), DRw16(B1.1601).DQw5(A1.0102,B1.0502) are present in HTCs and Canadian Caucasians. Of these, DRw15(B1.1501).DQw6a (A1.0102,B1.0602) haplotype was present in majority (81.3%) of Caucasians. Among Asian Indians, this haplotype was present only in one DR2,DQw1-positive individual. In addition, three new haplotypes representing different combinations of DRB1, DQA1 and DQB1 genes were demonstrable in Asian Indians. These new haplotypes are DRw15(B1.1501).DQw6b(A1.0103,B1.0601),DRw15(B1.1501). DQw5(A1.0102,B1.0502), and DRw15(B1.1501).DQw6c(A1.0102, B1.0601). The most frequent haplotypes among Asian Indians were DRw15(B1.1502).DQw6b(A1.0103,B1.0601) and DRw15(B1.1501). DQw6b(A1.0103,B1.0601). The distribution of subtypes of DR2,DQw1 haplotypes in Asian Indians was significantly different from that in Canadian Caucasians. The results in the present study have important implications for HLA and for HLA-disease associations.     

Extended major histocompatibility complex haplotypes in celiac patients in the west of Ireland

The highest reported prevalence of celiac disease (gluten-sensitive enteropathy) is found in the West of Ireland. Recent genetic data have suggested that major histocompatibility complex-linked loci may have a dominant genetic effect for disease susceptibility in this population compared with a recessive effect in other groups. To further understand the role of the MHC in celiac disease in the West of Ireland, we analyzed markers for 22 MHC haplotypes from celiac patients and compared them with 18 nontransmitted haplotypes found in the parents of celiac children, and with reported haplotypes from other populations. An extended MHC haplotype including [HLA-B8, DR3, DQw2, Bf*S, C4A*Q0, and C4B*1] accounted for 50% of celiac haplotypes but only 27% of nontransmitted parental haplotypes. Compared with other reported haplotypes in celiacs, patients from the West of Ireland show a higher prevalence of HLA-A1 as a component of this extended haplotype, suggesting that although the core haplotype is similar between Irish patients and others, the celiac population in the West of Ireland differs at other HLA loci. We did not observe any other common haplotypes among our patients unlike the situation in other populations. These differences may underlie the possible dominant effect of HLA-linked loci and the unusually high prevalence of celiac disease in the Irish population. We also found that the serum levels of complement components C3c, C4, and factor B were significantly lower among celiac patients than nonceliacs. The lower serum level of C4 appears to be related to the presence of deletions and null alleles at the C4A and C4B loci in celiacs. © 1993 Wiley-Liss, Inc.     

A new HLA-DR2 extended haplotype is involved in insulin-dependent diabetes mellitus susceptibility

To ascertain why HLA-DR2 seems to confer only a moderate resistance to insulin-dependent diabetes mellitus (IDDM) in the high-incidence population of Sardinia, Italy, 32 families having one individual affected with IDDM (the proband) and 31 families without IDDM history were randomly selected from the same geographical area and serologically and molecularly HLA typed. The 64 haplotypes of the probands were then compared with the 122 haplotypes determined in the parents from the control families. Two haplotypes were found to have the highest percentage in the general population (12.3% and 7.3%, respectively). The first is the already described "Sardinian" extended haplotype A30, Cw5, B18, 3F130, DR3, DRw52, DQw2 (39.0% in IDDM patients). The second is an extended haplotype that has not been identified before (A2, Cw7, B17, 3F31, DR2, DQw1), and, due to the DR2 allele, we expected it to be decreased in IDDM. However, a stratified analysis performed by removing the DR3 and DR4 haplotypes showed that the frequency of this haplotype is significantly increased in IDDM patients. A peculiar feature of this haplotype is its DQw1 allele, which is DQB1*0502 and has serine in position 57 of the DQ beta chain. The absence of an aspartic acid in this position seems to confer susceptibility to IDDM and not resistance. The fact that DQB1*0502 was present in 75% of the Sardinian DR2 haplotypes may explain why, in Sardinia, DR2 is not providing the commonly recognized resistance to IDDM.     

HLA-DR, DQ antigens in North American Caucasians

HLA-DR, DQ specificities are determined by serological methods in 2,586 North American Caucasians. Antigen frequency, gene frequency and haplotype frequency are computed for each phenotype observed. The DR and DQ loci antigen distributions are well-fitted to a Hardy-Weinberg equilibrium (p greater than 0.25 for DR locus, p greater than 0.10 for DQ locus). All World Health Organization (WHO) recognized HLA-DR,DQ specificities were found except HLA-DRw18, which has been identified only in the black population. DR and DQ linkage disequilibria among recently defined splits is observed. The following DR and DQ associations are found: DR1 and DQw5; DR4 and DQw7, DQw8; DR7 and DQw2, DQw9; DR8 and DQw4, DQw6, DQw7; DR9 and DQw2, DQw9; DRw10 and DQw5; DRw11 and DQw6, DQw7; DRw12 and DQw5, DQw7; DRw13 and DQw6, DQw7; DRw14 and DQw5, DQW7; DRw15 and DQw6, DQw7; DRw16 and DQw5; DRw17 and DQw2. In this large study population, the following unusual DR and DQ associations are found: DR4, DQw2; DR4, DQw1; DR1, DQw7; DR7, DQw5; DRw17, DQw6; and other unusual haplotype phenotypes containing DRX, DQX.     

The DR3(w18),DQw4 haplotype differs from DR3(w17),DQw2 haplotypes at multiple class II loci

The polymorphism of HLA class II molecules in man is particularly evident when comparisons between population groups are made. This study describes a DR3 haplotype commonly present in the American black population. Unlike the Northern European population, in which almost all DR3 individuals are DQw2, approximately 50% of DR3-positive American blacks express a DQw4 allelic product. This study characterizes the DR subregion of that haplotype. cDNA sequence analysis has revealed a DR beta gene which differs at several positions from previously described DR3 beta 1 genes. It is postulated that a gene-conversion-like event with a DRw52 beta gene as donor has generated some of these differences. The haplotype carries a DRw52a allele as defined by oligonucleotide hybridization studies. DNA restriction fragment analysis using a family and several unrelated individuals has allowed us to identify DR alpha and beta fragments associated with the DR3(w18),DQw4 haplotype. The most striking observation is that the DR3(w18),DQw4 haplotype differs from DR3(w17),DQw2 haplotypes at multiple class II loci. Several genetic mechanisms including reciprocal recombination, gene conversion, and point mutation were involved in generating the differences between these haplotypes. Once established, the DR3(w18),DQw4 haplotype appears to be relatively stable in the population.     

Increasing complexity of HLA-DR2 as detected by serology and oligonucleotide typing.

Serological and oligonucleotide typing was performed on a number of HLA-DR2-positive cells from different ethnic origin, including DR2 haplotypes with various DQ associations. Exons 2 of DRB1 and DRB5 of DR2-positive individuals were locus-specific amplified and hybridized with a number of different oligonucleotides capable of discriminating between the various Dw2, Dw12, Dw21, and Dw22 associated sequences. The linkage of DRB with DQA1 and DQB1 in these haplotypes was analyzed. Among the DR2- positive cells we could define 10 different DR DQ haplotypes by serology and 13 by oligonucleotide typing. The DR2.ES specificity is a serological DRw15 variant which could not be discriminated by oligonucleotide typing from a DRw15 DQw5 haplotype. The DR2.JA variant represents a unique DRB1*1602 DRB5*0101 haplotype. The DR1+2s haplotype consists of a DRB1 DQ region from a Dw1 and a DRB5 gene from a Dw2 haplotype. Its short DR2 serum pattern can be explained by the absence of a DR2 DRB1 gene product. DRB5*0101 sequences were found in association with DRB1*1501, *1502, *1602, and *0101 alleles. Since the DRB5 gene is capable of such different associations it is comparable to the DRB3 and DRB4 genes. This may have implications for the definition of the broad DR2 specificity which is predominantly encoded by the DRB5 gene product. New DR2 haplotypes included the following DQ combinations: DQw2-positive DQA1/B1*0301/0201 and DQw6-positive DQA1/B1*0102/0601 and *0102/0603 haplotypes.     

Tumour Necrosis Factor-β Gene RFLP Alleles in Finnish IDDM Hapiotypes

The genes located between class II and class I HLA genes including polymorphic tumour necrosis factor (TNF) genes may contribute to the disease susceptibility in IDDM. Restriction fragment polymorphisms of the TNF-beta gene have been found to be fixed in the major IDDM susceptibility haplotypes, the B62,DR4 haplotype being associated with the 10.5-kb fragment and the B8,DR3 haplotype with a 5.5-kb fragment. We studied this TNF polymorphism in a sample of diabetic families. In all IDDM-associated haplotypes (n = 129) the 5.5-kb allele was more frequent than in haplotypes found only in healthy family members (n = 112) (58.1% versus 40.2%, P < 0.01). Among IDDM haplotypes the B62,DR4 haplotype was characterized by the 10.5-kb TNF fragment, whereas two other common Finnish IDDM-associated DR4 haplotypes--A24,B39,DR4 and A2,B56,DR4--had the 5.5-kb TNF fragment. Both IDDM-associated and non-associated DR3 positive haplotypes were linked to the 5.5-kb fragment. The distribution of various combinations of TNF alleles in IDDM probands (n = 63) did not differ from that expected according to the Hardy-Weinberg distribution. Our results indicate that the 10.5-kb allele of TNF-beta gene as such is not a risk factor contributing to DR4/DQ8-associated susceptibility. Alternatively, there may be heterogeneity in pathogenetic effector mechanisms.     

Two HLA-DQ-specific human-human hybridoma antibodies (TrG6;TrC5) define epitopes also expressed by a transcomplementing hybrid DQ molecule (DQw7 alpha/DQw4 beta)

We have generated two IgG human-human hybridoma Abs, TrG6 and TrC5, that define subsets of HLA-DQ. TrG6 combined selectively with lymphoblastoid cell lines that expressed DQw1 or DQw4. By sequential immunoprecipitation, competition with other mAbs of defined specificity for binding to antigen, and experiments where HLA antigens from cell lysates crosslinked pairs of mAbs, it was established that TrG6 bound a DQ-molecule. mAb TrC5 specifically recognized DQw2+DR3+ and DQw7+DR5+ cells. The reaction pattern of TrC5 with HLA-loss mutants indicated that TrC5 bound to DQw2 of the DQw2+DR3+ haplotype. Antigens in lysate from DQw7+DR5+ cells crosslinked TrC5 to the murine mAbs Tü22 (anti-DQ monomorphic) and IVD-12 (anti-DQw7 + DQw8 + DQw9), demonstrating that on these cells the TrC5 epitope is located on DQw7 molecules. Lysates from DQw7+DR5+/DQw4+DRw8+ heterozygous cells crosslinked TrG6 and TrC5, and available evidence indicated that the epitopes defined by these two mAbs were expressed by the transcomplementing DQ-molecule DQw7 alpha/DQw4 beta, where the DQw7 alpha chain specifies epitope TrC5 and the DQw4 beta chain specifies epitope TrG6. Taken together with published nucleotide sequences of DQ alpha and beta genes, our data are consistent with the conclusion that the amino acids at positions 69 and/or 75 of the DQ alpha chain of DQw2+DR3+ and DQw7+DR5+ haplotypes are critical for epitope TrC5. The previously reported human-human hybridoma Ab TrB12 reacts with DQw6, DQw8, and DQw9. The specificity of the murine mAb IIB3 is similar to that of TrB12, but, unlike TrB12, IIB3 also binds DQw4+ cells.     

HLA FIVE-LOCUS HAPLOTYPES IN FINNS

The extreme polymorphism of HLA genes makes them a powerful tool for distinguishing between different genetic populations. Five-locus HLA haplotypes of Finns (from Oulu, Northern Finland) are described here in order to characterize further the migration pathways of the population to Finland after the Ice Age. From random families, 364 haplotypes were obtained. The most frequent Finnish haplotype A3,Cw4,B35,DR1,DQ1 (7.7%) is a Caucasoid ancestral haplotype and is shared with Italians of Celtic and non-Celtic origin. The haplotype A1,Cw7,B8,DR3,DQ2, which occurs in 4.7% of Finns, is the most frequent haplotype in Caucasoids. The haplotypes A3,Cw7,B7,DR2,DQ1 (3.6%) and A2,Cw7,B7,DR2,DQ1 (2.5%) are shared with several Caucasoid populations and the latter also with Jamaican blacks. A2,Cw5,B44,DR5,DQ3 (0.8%) is shared with Italians of Celtic and non-Celtic origin, A2,Cw6,B13,DR7,DQ2 (1.1%) with Caucasoids in the USA and A9,Cw4,B35,DR1,DQ1 (0.8%) with Mongoloids. The haplotypes A2,CW3,B62,DR4,DQ3 (3.0%), A2,Cw2,B27,DR8,DQ4 (1.7%), A2,Cw3,B62,DR6,DQ1 (1.4%) and A2,Cw1,B27,DR4,DQ3 (1.4%) were also found to be among the most frequent in the Finnish population. The most frequent HLA haplotypes are consistent with the postulated ancient migration of populations from southern Scandinavia and Germany to Finland, the most frequent haplotype suggesting a common Celtic origin and one less frequent haplotype suggesting an influence from the east.     

Sequence analysis and oligonucleotide genotyping of HLA-DR“JX6”, a DR“blank” haplotype found in the Japanese population

We analyzed one of the HLA-DR“blank” haplotypes found in the Japanese population using serologic studies, sequence determination, and genotyping with sequence-specific oligonucleotide (SSO) probes. The DR“blank” haplotype, designated DR“JX6”, segregated in a family in association with the DRw52 and the DQw7 specificities. The cDNA and genomic DNA of the DRB1 gene originating from the DR“JX6” haplotype were amplified enzymatically and sequenced after cloning into a plasmid vector. The amino acid sequence of the first domain in the DRβ1 chain of the DR“JX6” haplotype was different from those of other DR haplotypes sequenced so far, but in the first hypervariable region, the sequence was identical to those of the DRw11, DRw13, DRw14, and DRw17 haplotypes. SSO probes were synthesized on the basis of the DR“JX6” haplotype sequence as well as known sequences of the DRB1, DRB3, and DRB4 genes of other DR haplotypes. These SSO probes were used for the genotyping of Japanese donors whose DRB genes were amplified enzymatically and found to show a hybridization profile that was consistent with the results of serologic studies on the DR“JX6” haplotype.