The presence of 2 million or more peroxidase-positive white blood cell
s per ml of semen, or the diagnosis of male accessory gland infection,
is associated with important biochemical and biological changes in se
men plasma and in the spermatozoa, reducing their fertilizing potentia
l in vitro and in vivo (e.g., during intra-uterine insemination). In a
ddition to the effects of reactive oxygen species, and its influence o
n the essential fatty acid composition of the sperm membrane, potentia
lly unfavourable effects can occur through the intermediate of increas
ed concentrations of certain cytokines, and decreased activity of enzy
mes such as alpha-glucosidase. In contrast, lower numbers of white bro
od cells may exert beneficial effects on spermatozoa thanks to the inc
reased production of hepatocyte growth factor/scatter factor (a tissue
repairing substance), and the stimulation of immune-competent cells b
y particular cytokines (e.g., Interleukin-6).