C. B. Sanjeevi

Association of MHC Class I chain-related A (MIC-A) gene polymorphism with Type I diabetes

Aims/hypothesis. A distinct family of MHC genes has been identified in the class III region and denominated MHC Class I chain-related genes (MIC). The MIC-A gene is located between the TNFA and the HLA-B genes. The aim of our study was to test the association of the polymorphism of the MIC-A gene with Type I (insulin-dependent) diabetes mellitus and evaluate the interaction between MIC-A and TNFA, HLA-B, HLA-DR and HLA-DQ gene polymorphism.¶Methods. Type I diabetic (n = 95) and healthy (n = 98) Italian subjects were typed for exon 5 of MIC-A and for HLA-DRB1, HLA-DQA1, HLA-DQB1 and TNFA alleles. All subjects were also typed for the presence of HLA-B8 or HLA-B15.¶Results. The frequency of MIC-A5 was increased in diabetic subjects (53 % vs 15 %) (OR = 6.1) (corrected p, pc < 0.0005). Among HLA class II haplotypes, both HLA-DRB1*03-DQA1*0501-DQB1*0201 (DR3-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) (“at-risk class II haplotypes”) were positively associated with diabetes (OR = 6.7 and 6.0, respectively) (pc < 0.003). Also HLA-B8 was more frequent among Type I diabetic subjects than among healthy control subjects (OR = 2.8, p = 0.01). None of the TNFA alleles were statistically significantly associated with Type I diabetes. The MIC-A5 exon was negatively associated with age at clinical onset of diabetes (p = 0.012). Thus, 68 % diabetic subjects younger than 25 years and 29 % older than 25 years were carrying this allele. Both MIC-A5 and the at-risk class II haplotypes were independently associated with Type I diabetes and the combined association of the two markers had the highest relative risk (OR = 172). In subjects younger than 25 years, the OR of MIC-A5 was as high as 21.7 and was more than twofold that of at-risk class II haplotypes (OR = 9.5). The MIC-A5 exon was not in linkage disequilibrium with any of the HLA-class I, class II or TNFA alleles studied.¶Conclusions/interpretation. The MIC-A gene polymorphism is associated with genetic risk for Type I diabetes and the combination of MIC-A5 and at-risk class II haplotypes is now to be seen as the strongest genetic marker for this disease. [Diabetologia (2000) 43: 507–514]

Increased risk for endocrine autoimmunity in Italian type 2 diabetic patients with GAD65 autoantibodies

Glutamic acid decarboxylase (GAD)65 autoantibodies (GAD65Ab) in type 2 diabetic subjects with secondary failure to sulphonylurea treatment identify the so‐called latent autoimmune diabetes of the adult (LADA). The aim of our study was to estimate the risk for endocrine autoimmunity in type 2 diabetic subjects with GAD65Ab.

Different HLA-DR-DO haplotypes are associated with cervical intraepithelial neoplasia among human papillomavirus type-16 seropositive and seronegative Swedish women

To analyze whether HLA may be a determinant of the risk of developing cervical cancer precursor lesions, the association between HLA and cervical neoplasia among HPV16‐seropositive and ‐negative subjects was determined in a population‐based cohort in the Västerbotten county of Northern Sweden. HLA genotyping of DR and DQ was done by PCR in 74 patients and 164 healthy controls matched for age, sex and area of residence. The presence of DQA1*0102 was weakly associated with cervical neoplasia in HPV16‐seropositive patients. DQB1*0602 was weakly associated with disease in all patients, but was strongly increased among HPV16‐seropositive patients compared to HPV16‐seropositive controls. DR15 had an association with disease that was particularly strong among HPV16‐seropositive subjects. The haplotype DQA1*0102‐DQB1*0602 (DQ6) was also weakly associated with disease in all patients and significantly increased among HPV16‐positive patients when compared to HPV16‐positive controls. A similar association was seen when analysis was restricted to CIN 2–3 patients. DQA1*0501‐DQB1*0301 (DQ7) was more common among HPV16‐negative patients than among HPV16‐negative controls and was also more common among HPV16‐negative patients than among HPV16‐positive patients. In conclusion, DQA1*0102‐DQB1*0602 (DQ6) is associated with an increased risk of cervical neoplasia among HPV16‐seropositive subjects and DQA1*0501‐DQB1*0301 (DQ7) with an increased risk among HPV16‐seronegative subjects.

Negative association between type 1 diabetes and HLA DQB1*0602-DQA1*0102 is attenuated with age at onset

HLA-associated relative risks of type 1 (insulin-dependent) diabetes mellitus were analysed in population-based Swedish patients and controls aged 0-34 years. The age dependence of HLA-associated relative risks was assessed by likelihood ratio tests of regression parameters in separate logistic regression models for each HLA category. The analyses demonstrated an attenuation with increasing age at onset in the relative risk for the positively associated DQB1*0201-A1*0502/B1*0302-A1*0301 (DQ2/8) genotype (P = 0.02) and the negatively associated DQB1*0602-A1*0102 (DQ6.2) haplotype (P = 0.004). At birth, DQ6.2-positive individuals had an estimated relative risk of 0.03, but this increased to 1.1 at age 35 years. Relative risks for individuals with DQ genotype 8/8 or 8/X or DQ genotype 2/2 or 2/X, where X is any DQ haplotype other than 2, 8 or 6.2, were not significantly age-dependent. An exploratory analysis of DQ haplotypes other than 2, 8 and 6.2 suggested that the risk of type 1 diabetes increases with age for DQB1*0604-A1*0102 (DQ6.4) and that the peak risk for the negatively associated DQB1*0301-A1*0501 haplotype is at age 18 years. There was also weak evidence that the risk for DQB1*0303-A1*0301 (DQ9), which has a positive association in the Japanese population, may decrease with age. We speculate that HLA-DQ alleles have a significant effect on the rate of beta cell destruction, which is accelerated in DQ2/8-positive individuals and inhibited, but not completely blocked, in DQ6.2-positive individuals.

Polymorphism at NRAMP1 and D2S1471 loci associated with juvenile rheumatoid arthritis

OBJECTIVE To examine the role of NRAMP1 in susceptibility to juvenile rheumatoid arthritis (JRA). METHODS DNA from 119 JRA patients (72 pauciarticular, 47 polyarticular) and 111 healthy controls from Latvia was genotyped for a functional repeat polymorphism in the promoter of NRAMP1 and a linked (<150 kb) microsatellite D2S1471. The findings were compared with those from HLA-DQ alleles typed previously. Chi-square analyses were performed using the Mantel-Haenszel test and stratification according to pure Latvian or pure Russian descent. Haplotype analysis was performed using the Associate program to implement the expectation-maximization algorithm based on the gene-counting technique. RESULTS Allele 3 at NRAMP1 conferred increased risk (odds ratios [ORs] 2.26, 2.31, and 2.19; P = 0.0006, 0.003, and 0.019) of disease in the JRA, pauciarticular, and polyarticular patient groups, respectively. Allele 2 conferred protection (OR 0.44, 0.43, and 0.46). Alleles at D2S1471 that conferred susceptibility (6 and 12) or protection (11) did so only when on a haplotype with alleles 3 or 2, respectively, at NRAMP1. Allele 3 at NRAMP1 was additive with HLA-DQ7 for susceptibility (OR 3.71, 3.71, and 4.02), and allele 2 at NRAMP1 was additive with HLA-DQ5 for protection (OR 0.19, 0.08, and 0.12). CONCLUSION The NRAMP1 allele conferring susceptibility to JRA drives high levels of NRAMP1 expression, while the allele associated with protection drives low levels. These 2 alleles are inversely associated with susceptibility to infectious disease, consistent with their maintenance in populations through balancing selection.

Polymorphic Amino Acid Variations in HLA-DQ Are Associated With Systematic Physical Property Changes and Occurrence of IDDM

The association between human leukocyte antigen (HLA) and insulin-dependent diabetes was studied in a large population-based investigation using genotyping of 425 new-onset patients, 0–14 years of age, and 367 matched control subjects. As many as 97% of patients compared with 75% of control subjects were positive for one or several of DQA1*0301, DQA1*0501, DQB1*0302, or DQB1*0201. Asp-57 DQB was present among 28% of patients, indicating that this residue alone does not confer protection. Combining Asp-57 DQB1 with either Arg-52 DQA1 or Leu-69 DQA1 did not explain susceptibility or protection either. DQA1*0301-DQB1*0302 (DQ8) and DQA1*0301-DQB1*0301 (DQ7) are identical except for four amino acid substitutions in the β-chain, but DQ8 was positively (odds ratio 8.07; P < 0.001) and DQ7 negatively (odds ratio 0.38; P < 0.001) associated with the disease. Molecular modeling was used to determine whether physiochemical properties such as steric factors and surface electrostatic potentials also differ in a systematic way for various DQ molecules. Amino acids were substituted systematically at the four polymorphic sites, and the solvent-accessible surfaces and electrostatic potentials were computed for each molecule. Dramatic alterations in electrostatic potential were seen for double substitutions at position 45 (G45E) and 57 (A57D) of DQB1. The variation of physicochemical properties due to polymorphic substitutions may be significant to the mechanism of HLA-DQ association with insulin-dependent diabetes, via the effect these property variations have on peptide antigen binding selectivity and subsequent interactions with specific T-cell receptors.

Killer Cell Immunoglobulin-like Receptor Genes in Latvian Patients with Type 1 Diabetes Mellitus and Healthy Controls

Abstract: T1DM is very common in Sweden and is positively associated with HLA class II genes. Approximately 89% of the newly diagnosed patients carry the high‐risk HLA DR4‐DQ8 and DR3‐DQ2. The remaining 11% develop T1DM without them. This can be due to involvement of other genes and environmental factors. Natural killer (NK) cells of the innate immune system are important in antiviral and antitumor immunity. They are implicated in the etiology of autoimmune T1DM. Human NK cells express killer cell immunoglobulin‐like receptors (KIR) that belong to the polymorphic multigene family in chromosome 19q3.4. They modulate NK cell response by interacting with HLA class I. In addition, polymorphic MICA in HLA class I interacts with non‐polymorphic NKG2D receptor on NK cells. We have studied, in addition to HLA‐DR and ‐DQ, genes of the innate immune system MICA and KIR in Latvian patients (n= 98) with T1DM and controls (n= 100). They were genotyped using standard PCR‐based typing methods. MICA allele 5 is positively associated with T1DM. KIR2DL2 and KIR2DS2 were both positively associated. Combined association of MICA4 and KIR2DL2 gave an odds ration (OR) of 26.7. However, the combined risk of KIR2DL2 and HLA class II genes, HLADR3 (OR = 73.4), DR4 (OR = 66.8), and DR3 and DR4 (OR = 88.3), was higher. The maximum risk was when KIR2DL2, MICA5, and DR3/DR4 were in combination. In conclusion, our results suggest that a balance between innate and acquired immunity is important, and an imbalance coud lead to T1DM.

Different genetic backgrounds for malnutrition-related diabetes and Type 1 (insulin-dependent) diabetes mellitus in South Indians

SummaryHLA-DRB, -DQA and -DQB genes were studied in ten South Indian malnutrition-related diabetic patients, ten Type 1 (insulin-dependent) diabetic patients and 45 control subjects, by TaqI restriction fragment length polymorphism analysis. The DR7,DQw9 haplotype was found to be frequent in patients with malnutrition-related diabetes (p<0.01). The DRw17,DQw2 haplotype was overrepresented in the patients with Type 1 diabetes compared to control subjects (p<0.05). In vitro amplification of the polymorphic second exon of DQB genes by the polymerase chain reaction technique was performed on DNA from 10 malnutrition-related diabetic patients, 10 Type 1 diabetic patients and 13 control subjects, as they belong to a new population. Hybridization with sequence-specific oligonucleotide probes for DQB1 alleles showed homozygosity of aspartic acid at position 57 in 7 of 10 malnutrition-related diabetic patients compared to 2 of 10 Type 1 diabetic (p<0.05) and 15 of 45 control subjects (p<0.05). Homozygosity of non-aspartic acid at position 57 was present in 7 of 10 Type 1 diabetic compared to 0 of 10 malnutrition-related diabetic patients (p<0.005) and 3 of 45 control subjects (p<0.05). This study has confirmed the association of DQB1 57 non-asp in South Indians with Type 1 diabetes. In addition, our data clearly show that the genetic background of malnutrition-related diabetes mellitus is different from that of Type 1 diabetes.

POPULATION ANALYSIS OF PROTECTION BY HLA-DR AND DQ GENES FROM INSULIN-DEPENDENT DIABETES MELLITUS IN SWEDISH CHILDREN WITH INSULIN-DEPENDENT DIABETES AND CONTROLS

A negative association between insulin‐dependent diabetes mellitus (IDDM) and HLA‐DR, DQA1 or DQB1 was found in a large population‐based investigation of childhood‐onset patients (more than 420 patients) and controls (more than 340 controls) from Sweden. The relative risk was decreased for several haplotypes that were negatively associated with IDDM: DR15‐DQA1*0102‐DQB1*0602, DR7‐DQA1*0201‐DQB1*0303, DR14‐DQA1*0101‐DQB1*0503, DRI1‐DQAI*0501‐DQB1*0301, DR13‐DQA1*0103‐DQB1*0603 and DR4‐DQA1*0301‐DQB1*0301. In a relative predispositional effect (RPE) analysis, however, only the DR15‐DQA1*0102‐DQB1*0602 haplotype was significantly decreased, which suggests that the major protective effect for IDDM is carried by this haplotype. This was supported by the observation that all genotypes which were negatively associated with IDDM, except DR7/13, included at least one allele from the DR15‐DQA1*0102‐DQB1*0602 haplotype. Relative predispositional effect (RPE) analysis of genotypes showed further that the DR15‐DQA1*0102‐DQB1*0602 haplotype was also negatively associated with IDDM when combined with any other haplotype, whether negatively or positively associated with IDDM. This supports previous suggestions that DR15‐DQA1*0102‐DQB1*0602 acts dominantly. However, both the stratification and the predispositional allele test failed to distinguish the negative association between IDDM and DR15 from that of DQBT0602. On the other hand, these tests indicated that DQA1*0102 was not likely to explain the negative association between IDDM and the DR15‐DQA1*0102‐DQB1*0602 haplotype. We conclude that the

Prospective study of human papillomavirus (HPV) types, HPV persistence, and risk of squamous cell carcinoma of the cervix.

Background: The link between squamous cell cervical carcinoma and human papillomavirus (HPV) 16/18 is well established, but the magnitude of the risk association is uncertain and the importance of other high-risk HPV (HRHPV) types is unclear. Methods: In two prospective nested case-control series among women participating in cytologic screening in Sweden, we collected 2,772 cervical smears from 515 women with cancer in situ (CIS), 315 with invasive squamous cell carcinoma (SCC), and individually matched controls. All smears were tested for HPV with PCR assays, and the median follow-up until diagnosis was 5 to 7 years. Conditional logistic regression was used to estimate relative risks (RR) and 95% confidence intervals (95% CI). Results: The presence of HPV16/18 in the first smear was associated with 8.5-fold (95% CI, 5.3-13.7) and 18.6-fold (95% CI, 9.0-38.9) increased risks of CIS and SCC, respectively, compared with women negative for HPV. Infection with other HRHPV types in the first smear was also associated with significantly increased risks for both CIS and SCC. Persistence of HPV16 infection conferred a RR of 18.5 (95% CI, 6.5-52.9) for CIS and 19.5 (95% CI, 4.7-81.7) for SCC. The HPV16/18 attributable risk proportion was estimated at 30% to 50% for CIS, and 41% to 47% for SCC. Other HRHPV types also conferred significant proportions. Conclusions: Our large population-based study provides quantification of risks for different HPV types and prospective evidence that non-16/18 HRHPV types increase the risk for future cervical cancer. Impact: This study gives further insights into cervical cancer risk stratification with implications for HPV-based prevention strategies. Cancer Epidemiol Biomarkers Prev; 19(10); 2469–78. ©2010 AACR.