Peripheral Blood Absolute Lymphocyte Count as a Predictor of Cytomegalovirus Infection in Kidney Transplant Recipients.

Background: Cytomegalovirus viremia and infection have been reported to increase the risks for acute graft rejection and mortality in kidney transplant recipients. Previous studies demonstrated that a lower absolute lymphocyte count in peripheral blood is associated with cytomegalovirus infection. The aim of this study was to investigate whether absolute lymphocyte count could predict cytomegalovirus infection in kidney transplant recipients.

Methods: From January 2010 to October 2021, 48 living kidney transplant recipients in whom both donor and recipient were positive for immunoglobulin G of cytomegalovirus were included in this retrospective study. The primary outcome was defined as cytomegalovirus infection occurring ≥28 days after kidney transplantation. All recipients were followed for 1 year after kidney transplantation. The diagnostic accuracy of absolute lymphocyte count on day 28 post-transplantation for cytomegalovirus infection was analyzed using receiver operating characteristic curves. A Cox proportional hazards model was used to calculate hazard ratios for the incidence of cytomegalovirus infection.

Results: There were 13 patients (27%) with cytomegalovirus infection. The sensitivity and specificity for cytomegalovirus infection were 62% and 71%, respectively; the negative predictive value was 83% when an absolute lymphocyte count of 1100 cells/μL on day 28 post-transplantation was used as the cutoff. The incidence of cytomegalovirus infection was significantly higher when the absolute lymphocyte count was <1100 cells/μL on day 28 post-transplantation (hazard ratio, 3.32; 95% CI, 1.08-10.2).

Conclusion: Absolute lymphocyte count is an inexpensive and easy test that can effectively predict cytomegalovirus infection. Further validation is needed to confirm its utility.