HLA and hypertrophic Hashimoto's thyroiditis in Shanghai Chinese

Major histocompatibility complex class II (DRB1*, DQA1*, and DQB1*) and DRB1*04 subtypes' associations of Hashimoto's thyroiditis in a Greek population

Hashimoto's thyroiditis (HT) is an autoimmune disease resulting from complex interactions between genetic and environmental factors. The disease is associated with certain human leukocyte antigen (HLA) class II alleles in various populations. We aimed to determine in this study, for the first time in a Greek population, the association of HLA-DRB1*, -DQA1*, and -DQB1* alleles with HT. HLA-DRB1*, -DQA1*, and -DQB1* alleles' and -DRB1*04 subtypes' distribution was evaluated in 125 patients with HT and in 500 healthy control individuals by using a DNA-based sequence-specific primer method. Chi(_)squared tests and Bonferroni correction method were applied in the statistical analysis of the data. Significantly higher frequency of DRB1*04 (24.8% vs 7.7%, P < 0.0001) was observed in HT patients, while HLA-DRB1*07 was significantly decreased (2.8% vs 7.9%, P < 0.05). HLA-DRB1*04 subtyping showed a significant increase of DRB1*0405 (21% vs 7.8%, P < 0.0001) in HT patients. Also significant high frequencies of DQB1*0201 (14.8% vs 8.2%, P < 0.001), DQB1*0302 (18.8% vs 7.0%, P < 0.0001), and DQA1*0301 (25.6% vs 7.8%, P < 0.0001) were recorded in the patient group. Conducting the first research of this kind in a Greek population, our study tries to provide an evaluation of the prevalence of HT relating to HLA-DRB1*0405, and we report a relative risk of 2.7 for HT in a Greek population.

The presence of glutamic acid at positions 71 or 74 in pocket 4 of the HLA-DRbeta1 chain is associated with the clinical course of multiple sclerosis

BACKGROUND

Primary progressive multiple sclerosis (PP-MS) differs from relapsing-remitting or secondary progressive MS (RR/SP-MS) in ways suggesting differences in the pathogenic pathways. Susceptibility to both PP-MS and RR/SP-MS is linked to carriage of the HLA molecule DRB1*1501. Several serologically defined HLA-DR groups (DR1, DR4, DR6, and DR9) occur less often in RR/SP-MS than in controls. Some or all of the HLA-DR molecules encoded by alleles in these serologically defined groups have a negatively charged glutamic acid at residue 71 or 74 of the beta1 chain (beta1(71)/beta1(74)). Residues at these positions are important in the formation of pocket 4 in the antigen binding site of the HLA-DR molecule.

OBJECTIVES

To investigate whether the presence of alleles encoding HLA-DR molecules containing glutamic acid at beta1(71)/beta1(74) correlates with the course of MS.

METHODS

HLA-DR and HLA-DQ alleles and genotypes were analysed in 121 MS patients (50 with PP-MS) and 109 controls by molecular typing.

RESULTS

Alleles encoding HLA-DR molecules containing a glutamic acid at beta1(71)/beta1(74) occurred less often in patients with RR/SP-MS than in those with PP-MS or controls. In subjects not carrying the DRB1*1501 allele, a much higher proportion of PP-MS patients carried alleles encoding HLA-DR molecules containing a glutamic acid at beta1(71)/beta1(74) than did RR/SP-MS patients or controls.

CONCLUSIONS

The amino acid residues involved in determining the shape and charge of pocket 4 of the HLA-DR beta1 chain could influence the clinical course of MS by determining protection against RR/SP-MS or susceptibility to the development of PP-MS.

Polymorphisms of HLA class II predispose children and adolescents with type 1 diabetes mellitus to autoimmune thyroid disease

To determine the prevalence of autoimmune thyroid disease (AITD) in children and adolescents with type 1 diabetes mellitus (DM), and assess whether the development of AITD is correlated with specific DQ-A and DQ-B loci of the HLA class II antigens, we analyzed thyroid function using anti-thyroid antibodies and HLA-DQ-A and -DQ-B polymorphisms in 69 patients with type 1 DM, in 75 normal healthy controls, and in 21 patients with AITD but without type 1 DM. Eighteen patients (26%) in the diabetic patients had AITD. In the diabetic patients, DQA1*0301 and DQB1*0302 occurred more frequently than in controls [DQA1*0301: OR = 1.939, 95% CI = 1.210-3.109 (P = 0.008, P(c) (corrected P) < 0.05); DQB1*0302: OR = 2.558, 95% CI = 1.354-4.832 (P = 0.005, P(c), > 0.05)]. Compared with controls, non-diabetic subjects with AITD showed higher frequency of DQA1*0301 (P(c), < 0.05) and DQB1*0601 (P(c) > 0.05), but these alleles were not contributing factors in the development of AITD in diabetic patients. In diabetic patients, DQB1*0201, known as susceptible allele of type 1 DM was not a contributing factor in the development of AITD in diabetic patients. Unlike DQB1*0201, DQB1*0401 was more frequently found in diabetic patients with AITD than in controls [OR = 4.053, 95% CI = 1.607-10.221 (P = 0.0017, P(c) < 0.05)] or than in non-diabetic AITD patients [OR = 15.769, 95% CI = 1.905-130.530(P = 0.002, P(c) < 0.05)]. In non-diabetic subjects, DQB1*0401 did not provide susceptibility for AITD. Our results suggest that HLA DQB1*0401 is a predisposing genetic marker for the development of AITD in patients with type 1 DM in Korea.

A new categorization of HLA DR alleles on a functional basis

In this analysis, we introduce a new categorization of HLA DR alleles which are important members of HLA class II genes encoding cell surface glycoproteins that function to present antigenic peptides to T cells. We have grouped all HLA DR molecules into seven different functional categories on the basis of their ability to bind and present antigenic peptides to T cells and their association with susceptibility or resistance to disease. This novel categorization of DR alleles on the basis of function allows for the prediction of seven similar subregion structures (supertypes or supermotifs) within pocket 4 of HLA DR peptide binding groove as the molecular basis for grouping these alleles. The physicochemical characteristics of HLA DR supertype residues, charge in particular, may influence the selectivity for binding peptide, dominate promiscuous T-cell recognition of antigenic peptides, and affect HLA DR disease associations. To rationalize the functional categories of DR alleles, we have further combined the seven DR supertype patterns into three groups based on the charges of residues within the supertypes. Grouping HLA DR alleles into functional categories may assist in understanding the mechanistic basis of autoimmunity, resolving current paradoxes in HLA disease associations, and developing new immunotherapy strategies.

Promiscuous T-cell recognition of a rubella capsid protein epitope restricted by DRB1*0403 and DRB1*0901 molecules sharing an HLA DR supertype

Two T cell clones derived from different donors with HLA-DRB1*0403 or DRB1*0901 phenotype recognize a rubella capsid peptide, C(265-273) in the context of several different HLA-DR molecules in addition to DRB1*0403 and DRB1*0901. All DR molecules restricting the T-cell clones have in common residues, R or Q at position beta 70, R at position beta 71, and E at position beta 74 in pocket '4' of the DR peptide binding groove, suggesting that a DR subregion structure or supertype, "Q/RRE" underlies the promiscuous T-cell recognition of this peptide. Single amino acid substituted analogs of peptide C(263-275) at anchor position 4 for natural residue R were tested for their ability to induce clonal T-cell cytotoxic responses. The results indicated that a positively charged residue, R or K, was required for T-cell recognition, suggesting a possible mechanism of electrostatic interactions between the negatively charged residue E at position beta 74 of these DR molecules and the positively charged residue at anchor position 4 of the peptide in T-cell recognition.

HLA-A and -DRB4 genes in controlling the susceptibility to Hashimoto's thyroiditis

HLA-linked genetic factors involved in the pathogenesis of HT were studied in 71 patients with HT by serologic typing for HLA-A, -B, -C, -DR, and -DQ specificities and by DNA typing for HLA-DRB1, -DRB3, -DRB4, -DRB5, -DQA1, -DQB1, AND -DPB1 genes using the PCR-SSOP method. Typing results demonstrated significant positive associations of HT with HLA-A2 and -DRB4*0101 (DR53) (p < 0.01, RR = 2.03, EF = 0.61 and p < 0.0001, RR = 4.48, EF = 0.69, respectively). Although HLA-DR8, -DRB1*0403, -DQA*03, and -DQB1*0303 were statistically more prevalent in the patient group than in the controls, these associations were presumably due to the strong linkage disequilibria of these alleles with HLA-A2 or -DRB4*0101 in the Japanese population. Ninety-seven percent of the patients (69 out of 71) were positive for HLA-A2 or -DRB4*0101 compared to 79% in controls (RR = 8.7, p < 0.0005). The combination of HLA-A2 and -DRB4*0101 showed higher OR of risk for HT (OR = 12.8) than HLA-A2 (OR = 7.3) or DRB4*0101 (OR = 7.5) alone. These observations suggest that at least two loci, HLA-A and HLA-DRB4 together, may control the susceptibility to HT. On the other hand, the frequency of DQA1*0102 was significantly decreased in the patient group, suggesting that DQA1*0102 might confer resistance to HT.

HLA Bw46 and DR9 associations in Graves' disease of Chinese patients are age- and sex-related

The HLA-A, -B antigens in 159 Chinese patients with Graves' disease were compared with those of 330 controls. The HLA-DR antigens of the patients were also studied in 100 normals. Analysis of the increased prevalence of Bw46, according to the sex and age of onset of disease of the patients, showed that the strong association of Bw46 resided with male patients (n = 58), Pc = 0.0000052, RR = 4.2. Although the frequency of Bw46 was also increased in female patients (n = 101), it was statistically not significant. For the DR9 antigens, the strong association with male patients was also observed, viz. Pc = 0.019, RR = 3.2. Males also had higher risks of Graves' disease if they had homozygous Bw46 at presentation. Further analysis by age of onset of disease revealed the segregation of significant association with Bw46 for the males at 1-19 yr, Pc = 0.0011, RR = 17.5 HLA associations (Bw46 and DR9) with Graves' disease in Chinese are observed primarily in males, especially those whose known ages of onset of the disease are between 1-19 yr (Bw46).