Prognostic Value of Low PCR Cytomegalovirus Load in Kidney Transplant Recipients.

Abstract

Cytomegalovirus (CMV) infection after kidney transplantation is associated with significant morbidity and mortality. Use of Polymerase Chain Reaction (PCR) is recommended for diagnosis and/or monitoring of CMV infection. Nevertheless the PCR value threshold to start treatment has not yet been defined. Material and methods: In this retrospective monocentric study, we included all kidney recipients between 05/2012 and 07/2013. CMV PCR (whole blood, detection threshold = 1,79 log, Abbott® RealTime CMV) was performed weekly during the first four months after transplantation and then monthly during one year except for low risk patients (D-/R-). Prophylaxis (valganciclovir) was given for 3 months for R+ and 6 months for D+/R-. All patients with at least one positive PCR were included in our analysis. Curative treatment (ganciclovir iv or oral valganciclovir) was started in case of high CMV load (> 4 log) and/or clinical/biological abnormalities associated with positive CMV load (whatever the level). We assessed indications and incidence of curative treatment. Results were expressed as mean ±SD. Results: During the 14-month period, a first positive CMV PCR occurred in 59 /140 patients after 6,4 ± 5,2 months (5 patients under prophylaxis). Twenty seven (45%) were treated (55,5% D+/R-; 33,3% D-/R+; 11,1% D+/R+). Initial PCR level was similar between treated and non-treated patients (2,9 ± 0,99 log and 2,8 ± 0,96 log respectively). All patients with a PCR level higher than 4 log initially or during the follow-up were treated (n=16, 59%). Thirty two patients (55%) were not treated (50% D+/R+; 40,6% D-/R+; 6,25% D+/R-; 3,12% D-/R-). Interestingly, 26 non-treated patients (81%) had spontaneous undetectable CMV load after two controls and no further positive CMV PCR load was observed during the follow-up. Conclusion: We suggest that a “wait-and-see” attitude may be indicated for patients with low positive CMV load (threshold <4log on whole blood) in the absence of clinical or biological abnormalities.