Antigen-specific immune complexes in urine of patients with lymphatic filariasis

Lymphatic filarial subjects with disease manifestations exhibit significantly elevated levels of immune complexes (ICs) in their circulation. The objective of the study was to explore the possible excretion of filaria-specific soluble ICs in urine of subjects with lymphatic filariasis. Paired urine (overnight) and serum samples were analyzed for complement activating filarial antigen containing immune complexes by enzyme-linked immunosorbent assay (ELISA). Antigen-specific ICs were detected in urine samples of 34% of subjects with filarial disease manifestations while the frequency of occurrence was low in microfilaremic subjects. The titer of urine ICs is significantly high in subjects with chronic filariasis as compared to microfilaria (mf) carriers. The occurrence of filaria-specific ICs in urine and their passage through the filtering structures of the kidney is suggestive of the focal or diffuse damage in those subjects. Detection of ICs in urine may provide a noninvasive means of assessing the extent of renal damage in patients with lymphatic filariasis.