Association of HLA DRB1-DQB1 Haplotypes with the Risk for Neuromyelitis Optica among South Indians.

BACKGROUND

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder, mainly characterized by severe optic neuritis, transverse myelitis and the high levels of antibodies against NMO-immunoglobulin G (IgG) or aquaporin-4 (AQP4). HLA-DR and HLA-DQ alleles within the HLA class II region on chromosome 6p21 are known to play a significant role in several autoimmune diseases including NMO. The rationale of the current case-control study is to explore the association of HLA-DRB1 and HLA-DQB1 alleles with the risk of NMO and its association with the clinical and serological markers.

METHODS

A total of 158 samples (38 NMO cases and 120-age and ethnicity matched controls) were genotyped for the HLA-DRB1 and HLA-DQB1 alleles by using PCR-SSP method.

RESULTS

Our analysis showed significant association of HLA-DRB110 allele (OR 2.63, 95% CI: 1.18-5.83, p=0.02) with NMO whereas DRB114 showed protective role against NMO (OR 0.33: 95% CI: 0.11-0.94, p=0.043). HLA-DRB110 allele also showed significant association in patients with NMO-IgG positive antibody (OR 3.28: 95% CI: 1.42-7.5, p=0.006). There was no association of HLA DQB1 alleles with NMO and also with NMO-IgG antibody. Among the haplotypes groups, HLA-DRB110-DQB105 (OR 2.61, 95% CI: 1.11-6.1, p=0.03), HLA-DRB115-DQB103 (OR 4.5, 95% CI: 1.81-11.5, p=0.001) were strongly associated with the risk of NMO, whereas DRB114-DQB1*05 (OR 0.20, 95% CI: 0.060-0.721, p=0.008) showed negative association with NMO.

CONCLUSION

From this study, it is concluded that the HLA-DRB110 and DRB110-DQB105 and HLA-DRB115-DQB103 haplotypes may influence the susceptibility to NMO among the South Indians. Additionally we found DRB114 allele and DRB114-DQB105 haplotype showed protective role for NMO.