The chemokine receptor CCR5 Δ32 allele in natalizumab-treated multiple sclerosis

ObjectiveThe chemokine receptor CCR5 may be important for the recruitment of pathogenic T cells to the CNS in multiple sclerosis (MS). We hypothesized that this chemokine receptor might still be important for T-cell migration during treatment with anti-very late antigen (VLA)-4 antibody. We therefore analysed whether natalizumab-treated MS patients carrying the CCR5 32 deletion allele, which results in reduced expression of CCR5 on the cell surface, had lower disease activity. MethodsCCR5 32 was analysed in 212 natalizumab-treated MS patients. ResultsCCR5 32 status had no significant impact on the frequency of relapses 1year prior to natalizumab treatment or during the first 48weeks of treatment. The multiple sclerosis severity score (MSSS) was significantly lower at baseline in patients carrying CCR5 32 (P=0.031). ConclusionsCCR5 32 is not associated with lower disease activity in MS patients treated with natalizumab. We found lower MSSS scores in patients carrying CCR5 32 compared with the remaining patients, which is consistent with previous studies reporting an association with a more favourable disease course. Further studies are, however, needed before the relationship between CCR5 32 and disease activity in MS can be definitely established.