Background and aim of the study: The study aim was to investigate the xenoreactive immune response directed at Galalpha1, 3-Galbeta1-4GlcNAc-R (alpha-Gal) which is known to be a major barrier in xenotransplantation, and to identify factors such as age, gender, ABO group and type of implanted tissue that might affect the anti-alpha-Gal immune response in adults subjected to bioprosthetic heart valve (BHV) implantation.
Methods: A total of 103 early survivors aged > 20 years who underwent cardiac surgery using cardiopulmonary bypass was enrolled. Among the patients (45 males, 58 females; mean age 62.8 years), 66 who underwent BHV implantation were assigned as a study group, while the remainder were assigned to a control group. Serum samples were obtained from all patients on three occasions: before surgery (TO); on postoperative day 1 (T1); and on postoperative day 14 or at discharge (T2). A serum sample was also obtained from 31 patients in the study group at the out-patient clinic (T3) at a mean of 38 days after surgery.
Results: Anti-alpha-Gal antibody reactivity at TO was higher in patients aged < 65 years. Anti-alpha-Gal IgM and IgG reactivity at T2 was higher in the study group when compared to that in controls. In the study group, anti-alpha-Gal IgM and IgG reactivities were decreased at T1, but then increased at T2 when compared to that at TO. Anti-alpha-Gal IgG reactivity remained elevated at T3, but the IgM reactivity declined in the study group. None of the factors, including age, gender, ABO group and type of implanted tissue, had any effect on the anti-alpha-Gal immune response after BHV implantation.
Conclusion: BHV implantation in adults elicits an increased formation of anti-alpha-Gal antibodies, with different patterns for each isotype. Based on the study results, host factors including age, gender and blood type might be less important in the anti-alpha-Gal immune response following BHV implantation in adults.