C9 and leprosy: In line with these findings, we also found a significant correlation between the percentage of complement-immunoreactivity for C3d (r = 0.9692, p = 0.0003) or C9 (r = 0.9682, p = 0.0015) and the bacterial index in nerve biopsies of paucibacillary and multibacillary leprosy patients (Fig. S4a, b).