A PLACEBO-CONTROLLED FLOW CYTOMETRIC STUDY OF THE EFFECT OF LOW-DOSE PREDNISOLONE TREATMENT ON SPERM-BOUND ANTIBODY-LEVELS

In this placebo-controlled study the effect of short term, low-dose pr ednisolone treatment on sperm-bound antibody levels was investigated u sing an objective flow cytometric (FCM) measurement. Twenty infertile men, positive for antisperm antibodies by the mixed antiglobulin react ion (MAR) test, were treated with either 20 mg/day prednisolone (n = 1 0) or placebo (n = 10) for 3 weeks. The two groups were similar with r espect to sperm count, motility and antibody levels. The proportion of spermatozoa positive for IgG and IgA antibodies and the antibody load , expressed as the number of IgG and IgA antibody molecules bound per spermatozoa were measured by FCM. The study showed that, overall, the antibody levels measured before and after treatment with low-dose pred nisolone or with placebo were not statistically different. However, in the prednisolone group a marked decrease in the proportion of spermat ozoa positive for IgG and IgA antibodies was observed in two of the pa tients. An examination of the FCM data of these two patients revealed that, in their ejaculates, only the spermatozoa with low to moderate a mounts of sperm-bound antibodies had responded to prednisolone treatme nt, while spermatozoa with high levels of sperm antibodies had remaine d resistant to prednisolone. These results point to the existence of a n as-yet-undefined subset of prednisolone-responsive, antibody-positiv e spermatozoa.