The IL-10 -1082G polymorphism is associated with clearance of HPV infection.

The role of cytokines in protecting against human papillomavirus (HPV) and HPV-associated disease is not fully understood. We compared the frequency of the interleukin (IL)-10 polymorphism (G allele) at position --1082 and the distribution of GG/GA/AA genotypes among 116 HPV-positive women, grouped according to their cervical cytological profiles, with 119 HPV-negative controls with normal smears. No difference was observed in genotype frequency between the groups. Among women in the HPV-positive, smear-normal group, who were re-tested for HPV after 12 months, there was a significant inverse association between presence of at least one variant G allele (high activity) and HPV persistence (OR per G allele = 0.082 [95% CI 0.009-0.73], P= 0.001; after controlling for ethnicity). This association remained significant after controlling for age, smoking and hormonal contraception (OR = 0.028 [95% CI 0.001-0.66], P= 0.001). This preliminary study suggests that higher levels of IL-10 may prevent cervical neoplasia through their role in eliminating HPV.

A two-stage, genome-wide screen for susceptibility loci in primary Raynaud's phenomenon.

OBJECTIVE: To identify chromosomal regions containing genes involved in the susceptibility to primary Raynaud's phenomenon (RP). METHODS: Six extended families with multiple individuals affected with primary RP (n = 37) were examined for linkage in a 2-stage, whole-genome screen, using a total of 298 microsatellite markers. RESULTS: Multipoint, nonparametric linkage analysis identified 5 areas of possible linkage, with a nominal level of significance of P < or = 0.05. Analysis of a finer map of markers in these regions defined the regions of linkage as 21.4 cM on 6q13-6q23.3 (D6S261; P = 0.0004), 10.2 cM on 7p22-7p15 (D7S664; P = 0.014), 1.6 cM on 9p23-9p22 (D9S156; P = 0.0075), 5.1 cM on 17p13.1-17p12 (D17S1791; P = 0.036), and 11.8 cM on Xp11.4-Xp11.23 (DXS8054; P = 0.006). Three potential candidate genes map to these regions: the beta subunit of the muscle acetylcholine receptor and the serotonin 1B and 1E receptors. CONCLUSION: These results provide evidence of the presence and location of genes that are involved in the genetic susceptibility to primary RP.

Corticotropin releasing hormone (CRH) promoter polymorphisms in various ethnic groups of patients with rheumatoid arthritis.

UNLABELLED: The regulatory region of the corticotropin releasing hormone (CRH) is highly conserved and plays a crucial role in the response of the organism to stress. Release of CRH initiates a cascade of events leading to the release of cortisone and the regulation of inflammatory and immune events. OBJECTIVE: Since it has been postulated that the impaired corticotropin releasing hormone (CRH) response to stress in patients with rheumatoid arthritis (RA) has a genetic basis, we investigated the distribution of CRH alleles in a cohort of UK patients as well as in South African RA patients. METHODS: Restriction fragment length polymorphism of PCR amplified DNA products of the CRH promoter. We compared the allele frequencies in the RA patients with the respective healthy control population described previously. RESULTS: As in the control populations we found two biallelic polymorphic sequences (named A1 and A2 and B1 and B2, respectively) in the CRH promoter which could be assigned to compound alleles. The A2B1 compound allele was protective against development of RA in a large group of UK Caucasoid patients (p = 0.03; odds ratio 0.43, 95% confidence interval 0.21-0.88). In contrast, A1B1 was positively associated with RA in a cohort of black South African RA patients (p = 0.05; odds ratio 1.78, 95% confidence interval 1.01-3.15). CONCLUSION: Taken together, these findings support the hypothesis that CRH promoter polymorphism represents a new genetic marker for RA susceptibility and may prove useful for the prediction of RA risk in the future when further genetic and environmental risk factors are determined.

Identification of further DLA-DRB1 and DQA1 alleles in the dog.

Three novel DLA-DRB1 alleles and one novel DQA1 allele have been identified in a panel of 367 dogs. These were suggested by unusual reaction patterns found in sequence specific oligonucleotide probing (SSOP) data. Four new alleles were confirmed using DNA cloning and sequencing.

The influence of HLA-DRB1 alleles and rheumatoid factor on disease outcome in an inception cohort of patients with early inflammatory arthritis.

OBJECTIVE: There are conflicting data concerning the role of HLA-DRB1 alleles in disease outcome in early rheumatoid arthritis. The exact role of these alleles in short-term outcome is determined in this large, prospective, population-based study. METHODS: We recruited 532 patients with inflammatory polyarthritis from the Norfolk Arthritis Register and typed their sera for HLA-DRB1 alleles using polymerase chain reaction-based methods. Disease outcome was assessed at 2 years in terms of persistent joint inflammation, functional disability, and radiologic erosions. Results are expressed as risk ratios (RR) with 95% confidence intervals (95% CI). RESULTS: There was no influence of HLA-DRB1 alleles, in any combination, on the likelihood of disease persistence, and only a modest effect on functional disability (Health Assessment Questionnaire score > or = 1). The most obvious effect was on the development of erosions (RR 1.9, 95% CI 1.4-2.6 for those who carried at least 1 DRB1 shared epitope [SE] allele), with slightly greater effects for those who were homozygous for SE-bearing alleles (RR 2.5, 95% CI 1.8-3.6). This effect of HLA-DRB1 was restricted to patients whose sera were negative for rheumatoid factor. Among patients with erosions, HLA-DRB1 had no influence on the severity of radiologic damage (defined as the number of eroded joints, or total Larsen score). CONCLUSION: These data do not support routine HLA-DRB1 screening of patients with early arthritis to identify those at risk for subsequent severe disease.

Interbreed variation of DLA-DRB1, DQA1 alleles and haplotypes in the dog.

Although 36 DLA-DRB1 and 10 DLA-DQA1 allele sequences have been published to date, no data on individual allele frequencies exists, either for specific breeds or cross breeds, and the full extent of the polymorphism at each of these loci is still not known. We have used sequence-specific oligonucleotide probing (SSOP) to characterise a series of 367 dogs for their DRB1 and DQA1 alleles. These included individual animals from over 60 different breeds, with numbers per breed ranging from 1 to 39. DLA types were generated from 218 dogs for DRB1 and from 330 dogs for DQA1, while 181 dogs were characterised for both these loci. The frequency of individual DRB1 and DQA1 alleles showed considerable interbreed variation, e.g. 83% of West Highland White Terriers were DRB1*01 as opposed to 9% of Collies. No breed had >9 of the 22 DRB1 types defined in this study; several breeds had only two DRB1 types. DLA-DQA1 showed less variation in allele numbers per breed, but also showed considerable interbreed frequency variation. Haplotype analysis revealed over 44 different DRB1/DQA1 combinations. Of these, 25 were in a number of animals, and also in an animal that was homozygous for one or both of these loci. Some DRB1 alleles could be found in combination with several different DQA1 alleles, while others were only present in one haplotypic combination. DLA allele frequency data in normal dogs will be critical for disease association studies. It may also be possible to use haplotype data to establish the genetic relationships between different dog breeds.

Distribution of corticotropin-releasing hormone promoter polymorphism in different ethnic groups: evidence for natural selection in human populations.

The regulatory region of the corticotropin-releasing hormone (CRH) is highly conserved across species and plays a crucial role in the response of the organism to stress. Release of CRH initiates a cascade of events leading to the release of cortisol and the regulation of inflammatory and immune events. In this report we describe polymorphisms in the 5' regulatory region of the CRH gene in humans. We studied the distribution of CRH alleles in three different African populations, in white UK Caucasoids, and in a Chinese population. In the African and UK populations we found three new polymorphisms which cosegregated, resulting in two alleles, A1 and A2. Gene frequencies for A1 and A2 were extremely divergent between the African and the UK populations. The African A1 frequency ranged from 0.27-0.3, while the UK Caucasoid frequency was 0.9. Compound alleles could be assigned by taking into account the previously described biallelic polymorphism at position 225 in the CRH promoter. The A2B1 compound allele is the commonest in contemporary African human populations (allele frequency range 0. 44-0.61) and was the only allele observed in a population of chimpanzees from Sierra Leone. Wright's F(ST )for the A2B1 allele over the four sampled populations was 0.612, a value exceeded in human populations only by loci which have apparently been subject to natural selection. Taken together, these findings support A2B1 as the ancestral allele and suggest that the CRH genomic region may have been subject to strong disruptive selection throughout human evolution.

Quantifying the exact role of HLA-DRB1 alleles in susceptibility to inflammatory polyarthritis: results from a large, population-based study.

OBJECTIVE: To accurately determine the contributions of HLA-DRB1 alleles in explaining susceptibility to inflammatory polyarthritis in a large, true population-based cohort of new-onset cases. METHODS: A cohort of 680 consecutive patients with inflammatory polyarthritis, of whom 404 satisfied the American College of Rheumatology (ACR) criteria for rheumatoid arthritis (RA), was recruited from the population-based Norfolk Arthritis Register. All cases were compared with 286 local population controls. A standardized clinical assessment was performed on all patients. HLA-DRB1 phenotypes, including DR4 subtypes, were determined using a semiautomated, reverse dot-blot method. Results were expressed as odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: There was only a modest association (OR 1.8, 95% CI 1.4-2.4) between inflammatory polyarthritis and the presence of any shared epitope (SE) allele; the strongest individual risk was with DRB1*0404 (OR 3.5, 95% CI 1.8-6.8). Comparison of the genotypes demonstrated that the effect of being SE homozygous (OR 2.1, 95% CI 1.5-3.0) was only moderately greater than the effect of being SE heterozygous (OR 1.3, 95% CI 1.1-1.6). The exception to this was genotypic combinations that included HLA-DRB1*0404, which exhibited ORs ranging up to 18.0. There were no differences between either the phenotype or genotype data when the patients were stratified by RA status (defined by the ACR criteria). In contrast, the associations were substantially stronger in patients who were positive for rheumatoid factor. CONCLUSION: Previous studies had not been able to clarify whether the influence of HLA-DRB1 on RA was related to disease susceptibility or to disease severity and progression. These data on a unique population-based incident cohort suggest only weak effects on susceptibility, with the exception of the clearly distinct influence of HLA-DRB1*0404.

DLA-DRB1 polymorphisms in dogs defined by sequence-specific oligonucleotide probes (SSOP).

To date, DNA sequences for 29 dog DLA-DRB1 alleles have been reported. However, no data exists on the frequencies of these alleles within the general dog population, nor is there any indication of whether there is interbreed variation of allele distribution. We have addressed this by establishing a molecular based sequence-specific oligonucleotide probing (SSOP) method to identify all of the known broad DRB1 types and we have used this to type a random panel of dogs. A series of oligonucleotide probes were designed to detect known polymorphisms in the three DRB1 hypervariable regions, together with two distinctive motifs in other regions of exon 2. This set of probes enabled us to assign broad DRB1 types. Two hundred and eighteen dogs were SSOP typed for DRB1. All but 4 of the published DLA-DRB1 alleles were identified in these animals. Interbreed variation in both allele distributions and allele frequencies were observed, which may be useful in the study of genetic variation between breeds. This variation also has implications for the selection of control groups for studies aimed at identifying MHC associations with disease susceptibility in the dog.

Allelic markers close to prolactin are associated with HLA-DRB1 susceptibility alleles among women with rheumatoid arthritis and systemic lupus erythematosus.

OBJECTIVE: To investigate linkage disequilibrium between HLA-DRB1 disease susceptibility alleles and microsatellite markers close to the prolactin gene, among women with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and normal controls. METHODS: DNA from 89 women with RA, 76 women with SLE, and 94 controls was typed for HLA-DRB1 status and D6S422 and D6S285, 2 highly polymorphic microsatellite markers close to the prolactin gene. RA patients were stratified by DRB1*0401 status, and SLE patients were stratified by *0301 status. RESULTS: There was an excess frequency of D6S422*1 among SLE patients with DRB1*0301 (odds ratio [OR] 3.1). The frequency of this allele was also slightly in excess among RA patients with DRB1*0401 (OR 1.9). D6S285*5 was also in excess among female RA patients with DRB1*0401 (OR 3.5), and was slightly increased among female SLE patients with DRB1*0301. None of these alleles were found to be increased among *0401-positive or *0301-positive controls. CONCLUSION: These data indicate that there may be linkage disequilibrium between HLA-DRB1 alleles and microsatellite marker alleles close to the prolactin gene among women with RA and SLE. This suggests the possibility of extended haplotypes encoding for HLA-DRB1 susceptibility and high prolactin production, which contribute to susceptibility to both RA and SLE.

Are both genetic and reproductive associations with rheumatoid arthritis linked to prolactin?

The risk of rheumatoid arthritis (RA) seems to be associated with reduced fecundity and with breastfeeding; these apparently contradictory risk factors can be explained by their association with high prolactin concentrations. The only consistent genetic association with RA is for genes encoded in the HLA complex, particularly HLA DR4. We have identified some data indicating that the effects of breastfeeding and nulliparity are modified by HLA DR4 status, suggesting an interaction between genetic and reproductive risk factors in the aetiology of RA. The prolactin gene is in close proximity to the HLA region on the short arm of chromosome six. We therefore propose the hypothesis that the associations between DR4 and reproductive risk factors in RA are due to linkage disequilibrium between DR4 and an abnormally regulated prolactin gene polymorphism.

Maternal exposure to paternal HLA does not explain the postpartum increase in rheumatoid arthritis.

The postpartum period, particularly after the first pregnancy, represents a time of increased risk for the development of rheumatoid arthritis (RA). The present study was undertaken to investigate whether this increase in risk may be due to maternal exposure to fetally inherited paternal HLA-DR antigens that were either 1) similar to their own or 2) had an increased likelihood of being one of the two specific types, HLA-DR1 and DR4, implicated in the etiology of RA. We recruited 94 families where the mother had developed RA within 12 months of a pregnancy, and HLA typed the mother, father, and relevant child of each family. Mothers were not more likely to share HLA-DR genes with their partners than would be expected, and children whose parents shared one HLA-DR gene were not more likely to inherit the shared gene from their father as opposed to the non-shared gene. Further, those children whose fathers were heterozygous for HLA-DR1 or DR4 were not more likely to inherit these genes as opposed to the non-DR1/DR4 gene. In conclusion, maternal exposure during pregnancy to either fetally inherited paternal HLA-DR1 and DR4 genes or to paternal DR genes similar to their own does not appear to contribute to postpartum maternal susceptibility of RA.