Characterization and frequency distribution of sperm acrosome reaction among normal and infertile men.

L Calvo
L Dennison-Lagos
S M Banks
R J Sherins


We studied the acrosome reaction (AR) in human spermatozoa from 58 normal fertile men and 232 infertile patients. The median AR in the normal population was 17%; AR was > 9% in 83% of the subjects studied and only 2% of fertile individuals had a failed AR (< 5%). We calculated the within person variability using multiple specimens from each subject; the 95% confidence interval for each subject was 4 AR units above and 4 AR units below his mean value. In contrast, the median AR for the infertile population was 3%. AR values were below the normal range (< 5%) in 60% of the patients and only 26% of the patients had AR values > 9%. Because patients entered the study sequentially, without regard to the aetiology of infertility, the patient population comprised a wide variety of subjects ranging from individuals with good to extremely poor semen quality. There was a progressively greater number of individuals with a failed AR as semen quality deteriorated (P < 0.01). However, among patients with good count, motility and morphology, 20% unexpectedly had a failed AR, and among patients with severely impaired semen quality, 29% had a positive AR. We also analysed the relationship of AR values with other semen measurements. The frequency of acrosomal reactions was significantly correlated (Spearman, P < 0.001) with morphology (r = 0.509), concentration (r = 0.524), progression (r = 0.416) and percentage motility (r = 0.356), but not with the percentage of sperm moving at a curvilinear velocity of < or = 40 microns/s.(ABSTRACT TRUNCATED AT 250 WORDS)