Introduction: Cytomegalovirus (CMV) infection is an important complication after kidney transplantation (KT). Anti-thymocyte globulin (ATG) increases a risk of CMV infection and the American society of transplantation recommended CMV prophylaxis with valgancyclovir 900mg per day during 3 to 6 months after ATG induction. Unfortunately, in Korea, cost of valganciclovir is too high; one capsule of 450mg costs 22 US dollars, so totally 7,920 US dollars are needed for the prophylaxis therapy for three months. We used a modified prophylaxis regimen as intravenous ganciclovir during the admission (for 14 days) only and performed further preemptive therapy on the basis of weekly CMV PCR result if needed. However, the incidence of CMV infection in our center was relatively high (25%). We planned to do optimal prophylaxis in selective high risk recipients. This study was aimed to figure out the high risk recipients.
Methods: We hypothesized that a difference of lymphocyte suppression and recovery may affect the CMV reactivation, so we focused on the lymphocyte subset results. Lymphocyte subset test was checked at preoperative day, postoperative day (POD) #1, 8 and 14. Lymphocyte subset test reported the proportion of CD3+, CD4+, CD8+, CD19+, CD56+ lymphocyte. We investigated a failure of complete recovery of the proportion of these lymphocytes at POD #14 (the point of time to cease the CMV prophylaxis). Patients were divided into two groups according to a presence of CMV infection within one year.
Results: Total 227 patients were included. CMV infection was more common in the patients who underwent desensitization therapy before transplantation. There was no difference in general characteristics and dose of ATG (mg/kg) in both groups. The failure of complete recovery at POD #14 of CD3 and CD4 was frequent in CMV infection group with statistical significance. (p=0.018 and 0.018, respectively)
Conclusions: Desensitization therapy combined with ATG therapy increase the risk of CMV infection and these recipients need sufficiency CMV prophylaxis. Lymphocyte subset test may give useful information to select patients who are in risk of CMV infection.