NATURAL AUTOANTIBODIES, IGG ANTIBODIES TO TETANUS TOROID AND CD5(-CELLS IN PATIENTS WITH MEDITERRANEAN VISCERAL LEISHMANIASIS() B)

Natural autoantibodies (NaAb) and IgG antibodies to tetanus toroid (TT ) were analysed in the sera of 38 children with active visceral leishm aniasis (VL) previously vaccinated with TT and in 30 healthy controls matched for sex and age. Patients exhibited high levels of NaAb to a p anel of self antigens (tubulin, myosin, myoglobin, actin) contrasting to a low level of IgG to TT. Analysis of the circulating B cells in 26 untreated patients showed a low percentage of CD5(+) per total B cell s (3-66%, mean 36.6%) compared with 14 normal controls (17.8-66.6%, me an 52.7%) (P < 0.001). Evaluation of these parameters after antimonial therapy showed a significant decrease of the level of the NaAb (P < 0 .0005), and a spontaneous increase of the level of the IgG to TT witho ut any vaccine boosting (P < 0.01). In contrast, there was a significa nt increase in CD5(+) B cells (P < 0.0005). This result suggests that CD5(+) B cells may be sequestrated in parasitized lymphoid organs and may be released after remission. These findings show that the polyclon al B cell activation that occurs during active VL involves mainly B ce lls bearing NaAb and are in favour of a functional dichotomy of B cell s.