CLEARANCE OF CIRCULATING FILARIAL ANTIGEN AS A MEASURE OF THE MACROFILARICIDAL ACTIVITY OF DIETHYLCARBAMAZINE IN WUCHERERIA-BANCROFTI INFECTION

Small doses of diethylcarbamazine (DEC) clear microfilariae (MF) from the blood of Wuchereria bancrofti-infected persons, but the dose and r egimen required to kill adult worms is not clearly defined. A prospect ive study was undertaken to examine the macrofilaricidal effect of DEC and the ability of an assay for circulating filarial antigen (CFA) to define the effect. Twenty-five MF-positive subjects and 7 MF-negative but CFA-positive subjects were treated with DEC and followed for 18 m onths. Of the 25 MF-positive patients, 24 cleared MF, and 22 of 26 CFA -positive subjects cleared CFA. A significantly greater decrease in an tifilarial IgG4 was seen in patients who cleared CFA than in those who did not. The complete clearance of CFA observed after therapy with DE C indicates that assessment of CFA clearance is a useful means for det ecting macrofilaricidal effects of antifilarial chemotherapy.