Status of autoantibodies to zona pellucida in human reproduction

The sera of 80 patients were tested by the indirect immunofluorescence technique to evaluate the presence of autoantibodies to zona pellucida in human reproduction. The incidence of positive anti-zona activity was 71.4% (25/35) in the infertile women, 40.0% (6/15) in the normal, nonpregnant fertile women, 20.0% (3/15) in the normal pregnant women and 26.7% (4/15) in the normal fertile men, when unabsorbed sera were tested. To overcome false positive reactions due to nonspecific serum components, all the positive sera were absorbed with formalinized porcine red blood cells and retested. However, after absorption, anti-zona activity was lost in all the positive sera from non-pregnant fertile women, pregnant women and fertile men; but it was retained in 51.4% (18/35) of the infertile women. These positive sera (18) were further absorbed with zona-coated eggs and retested. Fluorescence was lost in all the positive sera, thus demonstrating the presence of antibodies specific to zona antigen in the infertile women. The study also revealed that autoantibodies to zona were seen more often in patients of greater age (26 to 40 years) and in those who had been infertile for a greater period of time (greater than 6 years).