Introduction: BK and CMV viremias, which are common after kidney transplantations (KT), can affect graft and patient survival, as well as being a warning for overimmunosuppression. Anti-thymocyte globulin-Fresenius (ATG) induction therapy, whose effectiveness has been proven in cadaveric donor kidney transplantations (CDKT), is associated with cytomegalovirus (CMV) and BK virus viremias and infections, especially with high doses and/or longer exposure. However, experience in living donor transplantations (LDKT) is relatively limited. In this study, the relationship between ATG induction, which has been widely used in LDKT patients in our center for more than 10 years, and BK and CMV viremias was investigated.
Method: We enrolled 335 LDKT patients who a) transplanted between 2013 and 2023, b) received ATG induction in doses determined according to immunological risk (1 to 4 days), c) in whom BK viremia (2-4-6-9-12. months) and CMV viremia (4-6-9-12. months) were regularly studied and, d) whose all data were available. All patients were pretransplant CMV IgG positive and received valganciclovir prophylaxis for 3 months. The relationship between total ATG induction dose and BK and CMV viremia was investigated.
Results: The average follow-up period was 58.4±30.7 months. The average age was 44.5±12.3 years, dialysis duration 19±32 months (preemptive KT 27.5%). The number of mismatch antigens was 3.4±1.6 (0-6). PRA was positive in 24 patients (7.2%). The average total induction ATG dose was 9.9±3.8 mg/kg (1.7-25.0). All patients received a steroid+MMF+tacrolimus combination. Rejection occurred in 36 patients (10.7%) within the first year; no graft loss was observed. Urinary stents were placed in 64 patients during or just after KT (19.1%). Early urological complications developed in 24 patients (7.2%). The average creatinine at 12th month was 1.23±0.44 mg/dl (0.66-5.20). BK viremia was observed in 53 patients (15.8%), the titer was <1000 in 26 of them. No relationship was detected between ATG dose and BK viremia. BK viremia was associated with a history of urinary stents; while the rate of BKV viremia were 25% and 11.7% in those with and without stent placement (p=0.007). Similarly, BKV viremia was 25.9% and 13% in patients who had undergone urological revision and who did not (p=0.06). In low titer BK viremias, immunosuppression was reduced to varying degrees; treatment was given to four patients with nephritis. None of them experienced graft loss during follow-up. CMV viremia was observed in one hundred patients (29.9%), and the titer was <1000 in 49 patients. The average total ATG dose was 10.6 mg/kg and 9.7 mg/kg in those with and without CMV viremia (p=0.03). CMV disease occurred in two patients was successfully treated.
Conclusion: The ATG dose used in LDKT patients poses a risk for CMV viremia in the low-risk patient group receiving valgancyclovir prophylaxis for 3 months. Stent use and the presence of urological complications pose risks for BKV viremia.