Impact of Donor and Recipient Human Cytomegalovirus Status on Kidney Transplantation

Abstract

Human cytomegalovirus (HCMV) is considered to be a major pathogen that affects the outcome of solid organ transplantation. Both recipient and donor may be HCMV positive, therefore HCMV reinfection is possible after transplantation. However, little is known how cytomegalovirus transmitted from an infected donor to an infected recipient modulates the recipient's already suppressed immunity, and what the clinical consequences are. To investigate these issues, 52 kidney recipients were followed up for two years after transplantation. T, B, and natural killer lymphocytes, naïve and memory T subsets, CD28 expression, relative telomere length, cytomegalovirus-specific lymphocytes, and serum cytokines were measured several times posttransplant. Patients were monitored for signs of cytomegalovirus viremia and other infections. The most importantly observation was that cytomegalovirus-specific lymphocytes expand vastly in HCMV infected recipients who received kidneys from infected donors, in comparison to uninfected donors. Despite this, higher rate of HCMV viremia was found. Immune deterioration was found as an increased number of CD28 negative T lymphocytes, inverted CD4/CD8 index and shortened telomeres. This was superior in HCMV infected recipients transplanted from infected donor, when compared to uninfected. In conclusions, cytomegalovirus alters the immune system in kidney transplant recipients and promotes immune exhaustion.