Tobacco farmers and diversification: opportunities and barriers

PCR/SSOP typing methods were used to analyze the HLA Class II DRB1, DQA1, DQB1 and DPB1 loci of samples from three African American populations of Colombia. Forty samples from the Cauca (Pacific), and twenty samples each from the Choco (North Pacific Coast) and the Providencia (Caribbean island) populations, were collected and the Class II loci analyzed under the auspices of the Expedicion Humana. Despite the limited number of samples analyzed, the African Colombian populations exhibit a very high degree of class II polymorphism. A great diversity of DRB1 alleles was found, with representatives from all serological classes, including 19 DRB1 alleles in the Providencia, 16 in the Cauca and 14 in the Choco groups. In addition, a novel DQB1*02 allele (*0203) was found in two individuals from the Cauca population of the Pacific Coast. The sequence of the DQB1*0203 allele, associated with DR3, differs from DQB1*0201 by only one nucleotide substitution (C-->A) in the second position of codon 57, resulting in an Ala to Asp change. The addition of DQB1*0203 brings the total number of DQB1 alleles identified to date to 26. HLA class II diversity is much greater in these African Colombian populations than that seen in nearby Amerindian populations. Analysis of regional Colombian African American HLA population genetics is discussed with respect to the Colombian Amerindian HLA genetics described in an accompanying paper.     

Selection of unrelated bone marrow donors by PCR-SSP typing and subsequent nonradioactive sequence-based typing for HLA DRB1/3/4/5, DQB1, and DPB1 alleles

HLA incompatibility between bone marrow recipients and unrelated donors is one of the main obstacles in bone marrow transplantation. HLA class I and generic class II DR and DQ typing is generally performed by serology. Precise subtyping of HLA class II genes, however, can only be achieved by molecular genetic methods. Here, the final selection of serologically pretyped unrelated bone marrow donors by confirmatory PCR-SSP (PCR-sequence-specific primers) typing and subsequent nucleic acid sequence analysis of the second exon of DRB1, DRB3, DRB4, DRB5, DQB1, and DPB1 alleles is presented. Serologically identical potential marrow donors and their corresponding recipients were analyzed for HLA-DRB identity by PCR-SSP analysis. After solid-phase single-strand separation, direct sequencing of the allele- or group-specific DRB amplified products was performed by applying fluorophorlabelled sequencing primers. Electrophoretically separated sequencing products were detected by means of an automated DNA sequencer. Group-specific amplification and sequencing of DQB1 alleles was carried out for all potential bone marrow donors and recipients, while only the final donor-recipient pair was analyzed for DPB1 alleles. Thus, the presented amplification strategy in combination with direct sequencing of PCR products allows matching of bone marrow transplant pairs with the highest degree of reliability for the assessment of HLA class II identity.     

Self-reported energy intake and energy expenditure in elderly women

HLA-DRB1, -DQB1 and -DPB1 allele frequencies were investigated in a sample of the Slovak population by PCR-SSP and PCR-RFLP methods. The most frequent DRB1 alleles were DRB1*1101-5 (0.2038), DRB1*0701-2 (0.1423), and DRB1*1501-2 (0.1231). The most rare alleles found were DRB1*0901 (0.0038), and DRB1*1201 (0.015). The most common DQB1 alleles were DQB1*0301 (0.2448), DQB1*0201 (0.2098), and DQB1*0501 (0.1119), respectively. The alleles with the least occurrence rate were DQB1*0601 (0.0035) and DQB1*0401 (0.007). The most common DPB1 alleles found were DPB1*0401 (0.4329), DPB1*0402 (0.2089), and DPB1*0201 (0.1438), respectively. The least frequent alleles were DPB1*0601, *1101, and *1501 (0.0034). Allele frequencies found in our study were compared to those in Czech, Austrian, and German populations. No statistically significant differences were observed.     

HLA-DR and -DQB1 DNA polymorphisms in a Vietnamese Kinh population from Hanoi

We report here the DNA polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) typing of the HLA-DR B1, B3, B4, B5 and DQB1 loci for a sample of 103 Vietnamese Kinh from Hanoi, and compare their allele and haplotype frequencies to other East Asiatic and Oceanian populations studied during the 11th and 12th International HLA Workshops. The Kinh exhibit some very high-frequency alleles both at DRB1 (1202, which has been confirmed by DNA sequencing, and 0901) and DQB1 (0301, 03032, 0501) loci, which make them one of the most homogeneous population tested so far for HLA class II in East Asia. Three haplotypes account for almost 50% of the total haplotype frequencies in the Vietnamese. The most frequent haplotype is HLA-DRB1*1202-DRB3*0301-DQB1*0301 (28%), which is also predominant in Southern Chinese, Micronesians and Javanese. On the other hand, DRB1*1201 (frequent in the Pacific) is virtually absent in the Vietnamese. The second most frequent haplotype is DRB1*0901-DRB4*01011-DQB1*03032 (14%), which is also commonly observed in Chinese populations from different origins, but with a different accessory chain (DRB4*0301) in most ethnic groups. Genetic distances computed for a set of Asiatic and Oceanian populations tested for DRB1 and DQB1 and their significance indicate that the Vietnamese are close to the Thai, and to the Chinese from different locations. These results, which are in agreement with archaeological and linguistic evidence, contribute to a better understanding of the origin of the Vietnamese population, which has until now not been clear.     

HLA class II DRB1, DQA1 and DQB1 polymorphisms in the Polish population from Wielkopolska

HLA DRB1, DQA1 and DQB1 alleles were determined by DNA PCR-SSO typing in a sample of 99 individuals originating from Wielkopolska (midwestern Poland). A high number of alleles (38 DRB1, 8 DQA1 and 14 DQB1) was detected at each locus, many of them presenting notable frequencies in this population. The three HLA loci are thus characterized by very high heterozygosity levels (93% for DRB1, 85% for DQA1, and 88% for DQB1), which confirms the results found for other European populations. A total of 6 DRB1-DQA1-DQB1 haplotypes are detected with an estimated frequency higher than 5%, namely, DRB1*1501-DQA1*0102-DQB1*0602, DRB1*0701-DQA1*0201-DQB1*0201, DRB1*0101-DQA1*0101-DQB1*0501, DRB1*1101-DQA1*0501-DQB1*0301, DRB1*03011-DQA1*0501-DQB1*0201, and DRB1*1301-DQA1*0103-DQB1*0603. A genetic distance analysis between the Polish and other world populations tested for HLA class II indicates that the Wielkopolska community is close to geographically close, rather than linguistically related populations from Europe. More generally, a good agreement between genetics and geography is found for DRB1 and DQB1 polymorphisms in Europe, suggesting that these two loci are highly informative for assessing historical relationships among humans.     

Primary Sj?gren's syndrome: role of the HLA-DRB1*0301-*1501 heterozygotes

OBJECTIVE: To examine the respective role of the DRB1*, DQB1*, and DPB1* HLA alleles in primary Sj?gren's syndrome (SS) and in the clinical and autoantibody profile of primary SS. METHODS: HLA-DRB1*, DQB1*, and DPB1* alleles were analyzed in 42 patients with primary SS and 200 controls by reverse dot blot hybridization for DRB1* and DPB1* and by polymerase chain reaction-restriction fragment length polymorphism for DQB1*. RESULTS: We found a significant increase of the HLA-DRB1*15-*03 heterozygote genotype frequency (19% primary SS vs 3.5% controls; p<0.0006, OR=6.49) and especially for the HLA-DRBI*1501-*0301 genotype (16.7% primary SS vs 3% controls; p<0.002, OR=6.47). The DQB1*0201-*0602 genotype was also significantly increased in primary SS (17.1% primary SS vs 4% controls; p<0.006, OR=4.86). However, the higher risk to primary SS development was associated with the DRB1*1501-*0301 genotype (OR=6.47 vs 4.86). There were no differences between patients and controls in DPB1* allele frequencies. The HLA-DRB1*15-*03 heterozygote genotype was also associated with systemic features such as hematologic manifestations and Raynaud's phenomenon (RP) and with autoantibody production such as antinuclear, anti-Ro(SSA) or La(SSB) autoantibodies and rheumatoid factor. CONCLUSION: Our data suggest a role of the HLA-DRB1*1501-*0301 heterozygote genotype in susceptibility to primary SS. Moreover, the HLA-DRB1*1501-*0301 genotype was also found to be associated with a particular form of the disease characterized by RP, hematologic manifestations, and autoantibody production.     

An outbreak of hepatitis A during a military field training exercise

Current practice for the selection of unrelated donors involves serological typing of HLA-A, -B and -DR antigens, DNA analysis of the class II region and the MLR. However, even after matching for the class II loci at the DNA level, a significant proportion of matched unrelated pairs remain MLR reactive. Ideal matching for BMT would be a match for the whole MHC haplotype rather than individual HLA loci. In the present study, we have evaluated the complementary role of class III typing in determining MHC identity. A group of 86 donor/recipient pairs, of which 14 were unrelated, was investigated using C4, Bf, HSP70 and TNF DNA probes. Phenotypically HLA-matched siblings were always identical at the C4 locus which is the most polymorphic of all the loci examined. Nine of the 14 HLA serologically matched MLR non-reactive (RRI < 20%) unrelated pairs had class III mismatching. Four of these pairs with class III mismatching were matched at the DRB and DQB loci by RFLP analysis. These results demonstrate that serological identity, DRB/DQB RFLP-matching and a negative MLR do not always match the whole haplotype in unrelated pairs. It can be concluded that the linkage of the class III loci to both HLA regions makes this region a reliable marker of the whole MHC haplotype.     

DRB1*15 and DRB1*03 extended haplotype interaction in primary Sj?gren's syndrome genetic susceptibility

OBJECTIVE: Sj?gren's syndrome (SS) is a chronic autoimmune disease with a genetic component. Among the genetic factors, the role of HLA class II genes has been suggested and a positive association with DRB1*03 allele has been described. However, there is no consensus on a unique HLA locus for this disease nor on the role of the HLA gene product in the disease. The aim of this study was to analyse prospectively MHC region involvement in the genetic susceptibility to SS by studying DRB1, DQB1, DPB1, TAP1, TAP2 genes and TNF microsatellites in a population of 45 primary SS patients. METHODS: All the polymorphisms studied were analysed at the genomic level using PCR-based methodologies. RESULTS: Concerning HLA class II alleles, the highest relative risk to develop the disease was associated with the DRB1*15-DRB1*0301 heterozygous genotype (17.8% vs 3.5% in controls - pc < 0.005, OR = 5.96). Analysing other genes located on the same region allowed us to further determine the DRB1 haplotypes at risk. For instance, the DRB1*0301 haplotype involved in the genetic susceptibility to SS was more often associated with the DPB1* 0201 and TNF-a2 alleles in SS patients than in controls. Moreover, all the DRB1*15-DRB1*0301 SS patients were TAP1-0101, TAP2-0101 homozygous, allowing us to deduce the extended genotype at risk as DRB1*15, TAP1-0101, TAP2-0101/DRB1*0301, TAP1-0101, TAP2-0101 which was carried by only 3 controls out of the 130 tested (p < 0.01, OR = 6.68). CONCLUSION: This study confirmed the role of the MHC region in the susceptibility to Sj?gren's disease, and for the first time suggests a synergistic interaction between two HLA-DRB1 extended haplotypes in the genetic mechanisms controlling the disease.     

HLA-DRB1*04 and DRB1*14 alleles are associated with susceptibility to pemphigus among Japanese

It has previously been demonstrated that susceptibility to pemphigus vulgaris is associated with human leukocyte antigen (HLA)-DR4 serologic specificity among Ashkenase Jews, and with DR4 as well as DR6 (DR14) in other ethnic groups. We genotyped HLA-DRB1, DQA1, DQB1, and DPB1 alleles in 16 patients with pemphigus by polymerase chain reaction-restriction fragment length polymorphism, to find evidence of potential HLA class II allele associations with pemphigus in Japanese patients who have a relatively homogeneous ethnic background. All nine patients with pemphigus vulgaris and five of seven patients with pemphigus foliaceus carried one or two alleles of HLA-DRB1*04 (*0403, *0406) and HLA-DRB1*14 (*1401, *1405, *1406) subtypes. Sequence analysis of these DRB1*04 and DRB1*14 alleles revealed the amino acid homology of phenylalanine at position 26 and valine at position 86 with the DRB1*0402 allele that reportedly confers a strong susceptibility to pemphigus vulgaris in Ashkenazi Jews. Thus our findings, together with previous HLA studies on pemphigus vulgaris patients of different ethnic groups, suggest that HLA-DRB1*04 and DRB1*14 alleles are commonly associated with pemphigus vulgaris across racial barriers. These HLA-DRB1 alleles are likely to be also associated with pemphigus foliaceus. Further studies on more diverse ethnic populations will be helpful in determining the significance of the association between certain amino acid residues of the class II molecules and disease susceptibility to pemphigus vulgaris as well as pemphigus foliaceus.     

Description of a new DRB1*11 allele (DRB1*1132)

We describe a new DRB1*11 allele which is similar to DRB1*11011 except at codon 74, where a GCG is changed for a GTG leading to an alanine/valine substitution. This new allele was carried by a Caucasian patient suffering from rheumatoid arthritis and by her healthy daughter. The motif at codon 74 of the new DRB1*11 is not found in any other known DRB alleles, nor among the published DQA1, DQB1, DPA1 or DPB1 alleles, and therefore suggests a mechanism of point mutation.     

Kindling induced mossy fiber sprouting has no functional significance in developing seizure discharges in rats]

The influence of host immunogenetics on the outcome of vertically transmitted HIV infection in children was examined in a multicenter cross sectional study of long term survivors and rapid progressors. Sequence-based typing was performed for the DRB1, DQB1 and HLA-A loci. 36.7% of 30 children surviving more than 8 years had one or more of the HLA-DR13 alleles, versus none of 14 rapidly progressing children who died within 2 years of age, p = 0.009, Haldane RR = 17.1. The alleles variably associated with this beneficial response to HIV were: DRB1*1301, DRB1*1302, DRB1*1303 and DRB1*1310, suggesting that the DR13 effect acted as a dominant trait. An additional 6 children were typed only by the SSOP method resulting in 44.4% of 36 long term surviving children with a DR13 allele and none of 14 rapid progressors, p = 0.002, Haldane RR = 23.3. No single DQB1 allele accounted for the HLA-DR13 allele association. In contrast, the presence of HLA A*2301 was associated with rapid progression to AIDS, 4% of long term survivors vs. 57.1% of 7 rapid progressors, p = 0.0006, RR = 0.031. Although the sample size is small, the marked differences in allele frequency along with differences between the peptide binding pockets of the HLA-A9 group of alleles including HLA A*2301 and the remainder of the HLA-A alleles suggest a structural basis for the dominant disadvantageous immune response to HIV conferred by A*2301.     

DNA typing of HLA class II genes in B-lymphoblastoid cell lines homozygous for HLA

The HLA class II genotypes were determined in the B-lymphoblastoid cell lines selected for the Tenth International Histocompatibility Workshop. The HLA class II genes were determined by the PCR-SSOP method using the reagents provided by the Eleventh Histocompatibility Workshop. Additional studies have been performed for further characterization of HLA class II polymorphism on these cell lines. It is observed that several cell lines have HLA class II haplotypes with the same DRB1, DQA1 and DQB1 alleles on both haplotypes but different alleles at the other class II loci, confirming that these cell lines are not truly HLA class II-homozygous. Other cell lines carried HLA class II haplotypes which were only different at the DRB1 gene. These results suggest double recombination events or gene conversion-like events in generation of HLA DR, DQ haplotypes. These cell lines provide an important tool as references for HLA DNA typing.     

Cytoplasmic localization and nuclear transport of cofilin in cultured myotubes

The loci encoding the major histocompatibility class II cell surface antigens DR, DQ, and DP exhibit a remarkable degree of allelic polymorphism. Strong linkage disequilibrium is also found between these loci in the human population. To study the evolutionary conservation of this disequilibrium the DQA1, DQB1, and DRB1-6 loci were analyzed in chimpanzee and gorilla by sequencing or/and oligonucleotide hybridization of PCR-amplified DNA. This analysis revealed several new DRB sequences. The distribution of DRB loci differs between human and nonhuman primate haplotypes, and the strong disequilibrium found on human haplotypes between alleles at DQA1 and DQB1 as well as between the DQ loci and the DRB1 locus was not detected in the nonhuman hominoids. Extensive recombination within and between the DR and DQ region appears to have occurred during the 3-7 million years since the divergence of the three species, resulting in little similarity of haplotypes between species. The strong disequilibrium found in the human species between these loci may either reflect haplotype-specific barriers to recombination, recent founder effects in the evolution of humans, or selection for specific haplotypes.     

Effect of matching of class I HLA alleles on clinical outcome after transplantation of hematopoietic stem cells from an unrelated donor. Japan Marrow Donor Program

BACKGROUND: The requirements with respect to HLA compatibility and the relative importance of matching for individual class I and class II HLA alleles in the transplantation of hematopoietic stem cells from unrelated donors have not yet been established. METHODS: We performed retrospective DNA typing of alleles at 11 polymorphic loci of HLA genes in 440 recipients of hematopoietic stem cells from unrelated donors who were serologically identical with their respective recipients for HLA-A, B, and DR antigens. Of these recipients, 80 percent had leukemia; the rest had lymphoma, marrow failure, or a congenital disorder. RESULTS: Multivariate analysis showed that incompatibility for HLA-A alleles and incompatibility for HLA-C alleles were independent risk factors for severe acute graft-versus-host disease (GVHD) (HLA-A, P=0.006; HLA-C, P=0.001). Mismatching of HLA-A, but not of HLA-C, alleles was an independent risk factor for death (P<0.001). Matching [corrected] of HLA-C alleles was a significant risk factor for relapse of leukemia (P=0.035). HLA-B disparity was a significant risk factor for both GVHD and death in the univariate analysis, but not in multivariate analysis. Disparities in class II HLA alleles of the DRB1, DQA1, DQB1, DPA1, and DPB1 loci were not identified as significant risk factors for acute GVHD or death in the multivariate analysis. CONCLUSIONS: Genomic typing of class I HLA alleles adds substantially to the success of transplantation of hematopoietic stem cells from unrelated donors, even if the donors are serologically identical to their recipients with respect to HLA-A, B, and DR antigens.     

Acute necrotizing encephalopathy of childhood: a novel form of acute encephalopathy prevalent in Japan and Taiwan

Molecular genotyping for the major histocompatibility complex (MHC) class II loci, HLA-DRB1, -DQB1 and -DQA1, in 100 patients with relapsing/remitting multiple sclerosis (MS) demonstrated an association with the HLA-DR2, DQw6-associated alleles DRB1*1501, DQB1*0602 and DQA1*0102, thereby extending this finding among MS patients in several countries to an Australian population. Analysis by the relative predispositional effect (RPE) method provided no evidence for a second susceptibility allele at either DQA1 or DQB1. However, our data and that of others suggest a negative association with DQA1*0101. Associations were found with DQB1 alleles sharing sequence homology with DQB1*0602, with DQB1 alleles encoding leucine at residue 26 (Leu 26), with DQA1 alleles encoding glutamine at residue 34 (Gln 34) and with Leu 26 plus Gln 34 alleles, but each was shown by two-loci linkage analysis to be secondary to the DRB1*1501, DQB1*0602, DQA1*0102 association. The recently reported negative association with DQA1 alleles encoding phenylalanine at amino acid 25, leucine at amino acid 69 and arginine at amino acid 52 was not found in this study, although there was a trend towards reduced phenylalanine at amino acid 25. The determination at a molecular level of an explanation for the world-wide association with these alleles remains elusive despite major advances in MHC typing.     

HLA-DRB1*0701 and DRB1*1401 are associated with genetic susceptibility to psoriasis vulgaris in a Taiwanese population

We analysed the allelic frequencies of class II human leucocyte antigen (HLA)-DRB1, DQA1, DQB1 and DPB1 by polymerase chain reaction/sequence-specific oligonucleotide probe hybridization typing in 76 Taiwanese psoriasis vulgaris (PSV) patients and 238 Taiwanese non-psoriatic controls. The analysis revealed the following: (i) the DRB1*0701 allele was positively associated with PSV (relative risk, RR = 6.4, corrected P-value, Pc < or = 0.001); (ii) the DRB1*1401 allele was positively associated with type I PSV (age at onset < 40 years) (RR = 3.5, Pc < or = 0.001); (iii) the DQA1*0501 allele was negatively associated with PSV (RR = 0.4, Pc < or = 0.001); (iv) there was no significant association of HLA-DP genes with PSV; and (v) there was a strong association of beta-chain phenylalanine at position 37 (Phe 37) and glutamate or glutamine at position 74 (Glu 74/Gln 74) with PSV (RR = 3.5, Pc < or = 0.001 for the association of Phe 37 with PSV: RR = 2.2, Pc < or = 0.001 for the association of Glu 74/Gln 74 with PSV). The positive association between PSV and the DRB1*0701 allele is consistent with previous reports. The negative association of the DQA1*0501 allele is reported only in Finland, whereas the positive association between PSV and the DRB1*1401 allele has never been described before. Trans-racial studies may shed further light on the association of class II HLA alleles or other closely linked genes with the development of PSV. Phe 37 (a large, non-polar amino acid) and Glu 74/Gln 74 (both negatively charged amino acids) were the polymorphic residues in pockets 9 and 4, respectively, of the beta-chain, which may have increased their affinity for the small non-polar amino acids and basic amino acids of the psoriatic antigen peptide, thereby activating the T lymphocytes. This finding may facilitate the identification of a psoriatic antigen.     

On the HLA-DQ(alpha 1*0501, beta 1*0201)-associated susceptibility in celiac disease: a possible gene dosage effect of DQB1*0201

The HLA-associated susceptibility to develop celiac disease (CD) seems mainly to be conferred by a particular HLA-DQ heterodimer encoded by the DQA1*0501 and DQB1*0201 genes either in cis or in trans position. To study the possible influence of DRB1 or other DQA1 and DQB1 alleles on the CD susceptibility conferred by these DQ genes, we performed genomic HLA typing of 94 CD patients, selected those who carried at least one copy of the DRB1*0301-DQA1*0501-DQB1*0201 haplotype (N = 89) and compared them to 47 random, healthy Norwegians matched with the patients to carry at least one copy of the above haplotype. We found an excess of DQB1*0201 homozygosity in the patients. This was due to an increased frequency of the DRB1*0301-DQA1*0501-DQB1*0201 and DRB1*0701-DQA1*0201-DQB1*0201 haplotypes present on the other chromosome. We propose that, in individuals carrying the DQA1*0501 and DQB1*0201 alleles, the presence of a second copy of the DQB1*0201 allele increases susceptibility to CD.     

Characteristics of the innervation of the head and neck

The association of HLA-DRB1 and DQB1 genes with IDDM in Koreans was assessed using 115 IDDM patients and 140 nondiabetic controls. DQB1*0201 is the only DQB1 allele positively associated with IDDM while DQB*0602, *0601 and *0301 are negatively associated. Three DRB1 alleles (DRB1*0301, DRB1*0407 and DRB1*0901) are positively associated while four DR allele groups (DRB1*15, DRB1*12, DRB1*10 and DRB1*14) are negatively associated. However, Haplotype analyses indicated that DQB1*0302, DRB1*0405 and DRB1*0401 may confer susceptibility because the DRB1*0405-DQB*0302 and DRB1*0401-DQB1*0302 haplotypes are positively associated with the disease. The lack of association in Koreans with the DQB1*0302 allele, which appears predisposing in studies of non-Orientals, is due to its strong linkage disequilibrium (LD) with the protective DRB1*0403 and *0406 alleles, while the lack of association with DRB1*0405 is because of its strong LD with the protective DQB1*0401 allele. Nine DR/DQ genotypes confer significantly increased risk to IDDM. Seven of the nine genotypes (DR3/4s, DR1/4s, DR4s/13, DR4s/8, DR4s/7, DR9/13 and DR3/9) were also found to be at high risk to IDDM in other populations, while the two others (DR1/9 and DR9/9) are only found in Koreans. Surprisingly, DR4/4 homozygotes are not associated with high risk to IDDM in Koreans. This observation can be explained by the high frequency of protective DR4 subtypes and the protective DQ alleles (0301 and 0401) associated with the susceptible DR4 alleles. Our analyses indicate that the counterbalancing act between susceptible DRB1 and protective DQB1, and vice versa, that has already been observed in Chinese and Japanese, is the major factor responsible for the low incidence of diabetes in Koreans.     

Analysis of allele distribution for six short tandem repeat loci in the French Canadian population of Québec

Short tandem repeat (STR) loci represent a rich source of highly polymorphic markers in the human genome which are useful for the purposes of forensic identification and determination of biological relatedness of individuals. Here, as a part of an ongoing extensive study, we report the analysis of a multilocus genotype survey of 642 to 870 chromosomes in the French Canadian Caucasian population of Québec at six STR loci. The loci HUMCSF1PO, HUMTPOX, HUMTH01, HUMF13A01, HUMFESFPS, and HUMvWA were typed using two multiplex polymerase chain reactions (PCR). Amplified DNA samples were subsequently analyzed by polyacrylamide gel electrophoresis followed by silver staining. The heterozygote frequencies of the loci range from 0.614 to 0.820 (0.661 to 0.818 expected) and the number of alleles from 7 to 12 per locus. Although statistically significant deviation from Hardy-Weinberg expectations of genotype frequencies was noted at some loci by one or more tests, in general, the genotype frequencies are well estimated from the product of allele frequencies at all loci. The most frequent six-locus genotype is expected to occur in the French Canadian population with a frequency of 3.50 by 10(-5) and together, these six loci have an average probability of discrimination of 0.9999985. The study presented here indicates that these six STR loci are informative genetic markers for identity testing purposes in the French Canadian Caucasian population of Québec.     

An increased risk of Crohn's disease in individuals who inherit the HLA class II DRB3*0301 allele

The role of inflammatory T cells in Crohn's disease suggests that inherited variations in major histocompatibility complex (MHC) class II genes may be of pathogenetic importance in inflammatory bowel disease. The absence of consistent and strong associations with MHC class II genes in Caucasian patients with inflammatory bowel disease probably reflects the use of less precise typing approaches and the failure to type certain loci by any means. A PCR-sequence-specific oligonucleotide-based approach was used to type individual alleles of the HLA class II DRB1, DRB3, DRB4, and DRB5 loci in 40 patients with ulcerative colitis, 42 Crohn's disease patients, and 93 ethnically matched healthy controls. Detailed molecular typing of the above alleles has previously not been reported in patients with inflammatory bowel disease. A highly significant positive association with the HLA-DRB3*0301 allele was observed in patients with Crohn's disease (P = 0.0004) but not in patients with ulcerative colitis. The relative risk for this association was 7.04. Other less significant HLA class II associations were also noted in patients with Crohn's disease. One of these associations involved the HLA-DRB1*1302 allele, which is known to be in linkage disequilibrium with HLA-DRB3*0301. These data suggest that a single allele of an infrequently typed HLA class II locus is strongly associated with Crohn's disease and that MHC class II molecules may be important in its pathogenesis.