Reversal in microfilarial density and T cell responses in human lymphatic filariasis

This study reports reversals in microfilarial density and the accompanying changes in cellular immune responses to filarial antigens of 39 individuals (11 microfilaria-positives, 22 microfilaria-negatives and six converters) living in an area endemic for brugian filariasis. Microfilarial counts decr eased from April, the end of the rainy season to July middle of the dry sea son (g.m. 88 mf/ml and 38 mf/ml, respectively; P = 0.001) and subsequently increased in November, the beginning of the rainy season (P = 0.088). Where as the proliferative responses remained low throughout the study period in microfilaraemic individuals, in amicrofilaraemics these responses changed i n the opposite direction to that of microfilarial densities. In three conve rters, proliferation changed in the opposite direction to the presence or a bsence of microfilariae, Cytokine analysis in the converters revealed that interferon-gamma was most affected by the shifts in microfilarial densities . In contrast, interleukin-4 responses showed little correlation with chang es in parasite densities.