IMMUNOASSAY OF CIRCULATING TRYPANOSOMAL ANTIGENS IN SLEEPING SICKNESSPATIENTS UNDERGOING TREATMENT

Sera from 99 patients infected with Trypanosoma brucei rhodesiense and undergoing treatment, were analyzed for circulating trypanosomal anti gens using a sandwich antigen-trapping enzyme-linked immunosorbent ass ay (ELISA). Trypanosomal antigens were detected in 83 (84%) of the pat ients. Post-treatment antigen profile in 67 patients showed five disti nct patterns: in 48% of the patients antigen levels remained elevated throughout the time of hospitalisation and follow-up; in 31%, antigens dropped to the negative value by the second month; in 7.5%, antigens dropped to the negative level and became elevated afterwards; in 7.5%, antigen levels were negative initially, but later, became elevated an d remained so throughout the observation period; in 6%, antigen levels remained below the negative value throughout. All patients who relaps ed on follow-up had earlier shown evidence of elevated antigen profile . There were no cases of relapses among 21 patients whose antigen leve ls dropped subsequent to treatment. This ELISA trypanosome antigen det ection test could be useful in evaluating treatment success, when used together with parasitological diagnostic techniques.