BEHAVIOR OF SPECIFIC IGM, IGG AND IGA CLASS ANTIBODIES IN HUMAN LEPTOSPIROSIS DURING THE ACUTE-PHASE OF THE DISEASE AND DURING CONVALESCENCE

The behaviour of specific IgM, IgG and IgA class antibodies in human l eptospirosis was studied by ELISA. Two groups of patients were followe d up, 57 of them in the acute phase and 10 during convalescence, the l atter with a mean follow-up of 10.5 months. IgM class antibodies were detected starting on the 2nd day of symptoms and were observed in 100% of patients up to the 5th month, in 66.7% up to the 7th month and in 50% up to the 12th month after the onset of symptoms. IgG class antibo dies were first detected on the 7th day of symptoms in 9.1% of patient s, with maximum reactivity (87.5%) between the 2nd and 3rd month, and were not detected at all in one patient. IgA class antibodies were det ected starting on the 5th day of symptoms in 7.7% of patients, and in all patients on the 15th day, persisting in 100% of cases up to the 9t h follow-up month. During the 12th month, they were observed in 83.3% of patients. The results indicate that an anti IgA ELISA could be of g reat value in seroprevalence studies on human leptospirosis.