Different HLA class II (DRB1 and DQB1) alleles determine either susceptibility or resistance to NMO and multiple sclerosis among the French Afro-Caribbean population

Abstract

BACKGROUND: Despite similarities, neuromyelitis optica (NMO) can be distinguished from multiple sclerosis (MS) by clinical, radiological and serological findings. OBJECTIVE: This case-control study aimed to determine whether patients with NMO or with MS in an Afro-Caribbean population originating from French West Indies shared the same or different HLA class I and II pattern distribution. METHODS: The association with HLA class II (DRB1 and DQB1) alleles was tested in 42 NMO patients, 163 MS patients and 150 healthy controls. HLA-DRB1 and DQB1 typing was undertaken on genomic DNA extracted from peripheral blood leucocytes. RESULTS: By comparison with healthy controls, significantly increased frequency of HLA-DRB1 03 (26.2% vs. 13%, odds ratio 2.4, 95% confidence interval 1.31-4.28, p after correction, cp 0.045) was observed in patients with NMO. By contrast, in MS patients, HLA-DRB1 15 (24.8% vs. 13%, odds ratio 2.21, 95% CI 1.45-3.36, cp < 0.0015), but not DRB1 03 allele, was positively associated with the disease. Moreover, a modest protective effect of HLA-DRB1 11 in the MS group, independently of DRB1 15 association, was found (13.7% vs. 7% in controls, odds ratio 0.48, p 0.006), but did not survive Bonferroni correction. CONCLUSION: In conclusion, comparison of the HLA-DRB1 and DQB1 distribution in NMO and MS in this Afro-Caribbean population shows important differences in the HLA associations among NMO and MS.