Distribution of HLA-Dw2 in optic neuritis and multiple sclerosis indicates heterogeneity.

UNLABELLED: The human leukocyte antigen (HLA) phenotype Dw2 is known to be increased in multiple sclerosis (MS), but only slightly in optic neuritis (ON).

MATERIAL AND

METHODS

127 consecutive patients with unilateral monosymptomatic ON were typed genomically for HLA-DR and -DQ genes.

RESULTS

The frequency of HLA-Dw2 among ON patients (47%) was found to be significantly higher than among 250 controls (30%) but significantly lower than in a group of 245 MS patients (60%), all of the same ethnic origin. At the group level, these figures can be calculated to indicate that 53% of the ON patients belong to the group of "MS-type ON" (95% confidence limits 25-78%). A compilation of published data on the frequency of the HLA-DR17(3), DQ2 haplotype, prompted by a slight increase in this material, revealed a significant association with this haplotype in ON, after compensation for the increase of Dw2.

CONCLUSION

ON differs from both MS and controls regarding HLA-Dw2. Thus, a substantial number of patients with ON may suffer from conditions not immuno-genetically related to MS, which might be designated as non-MS type ON. This condition may be more common in men and in young patients of both sexes.