Objective: To determine the broad-spectrum proteinase inhibitor alpha 2-macroglobulin (alpha 2M) and its functional subforms, i.e., free alpha 2M and alpha 2M/proteinase complexes, in human seminal fluid by using specific enzyme immunoassay systems.
Setting: The study has been performed in the Andrology Department of the Dermatology Clinics and the Laboratory of Immunopathology of the Institute of Immunology. PATIENTS, PARTICIPATES: Routine patients attending the Andrology Department.
Interventions: The data have been obtained without particular interventions before or after collection of seminal fluid.
Main outcome measures: The aim of the study was to determine whether alpha 2M or alpha 2M/proteinase complexes are present in human seminal fluid.
Results: The concentration of total alpha 2M in human seminal fluid ranged from 1 to greater than 1,000 ng/mL, and between 56% and 85% of the inhibitor was complexed with proteinases.
Conclusions: These findings show that alpha 2M and alpha 2M/proteinase complexes have to be considered as functionally relevant biomolecules in male genital tract secretions.