Are the Serum Igg Titers for Cytomegalovirus a Risk Factor for Disease Development in the Moderate-Risk Group in Kidney Transplant Recipients?

Abstract

Introduction: Cytomegalovirus (CMV) is the most common opportunistic virus affecting kidney transplant recipients. According to the donor and recipient's serostatus the vast majority (90%) of recipients in developing countries belong to the moderate risk group. The aim of this study was to determine a cutoff in serum IgG titers for CMV that represented a risk factor for disease development in kidney transplant recipients with moderate risk in a single-center in a developing country. Methods: A cohort of 333 kidney transplant recipients was reviewed from January 2008 to December 2010. Of these, 190 recipients met the following inclusion criteria: Belonged to the group of moderate risk for CMV (D+/R+ and D−/R+), were older than 17 years old, first time transplant recipients, with one month minimum follow-up and were without thymoglobulin induction nor CMV prophylaxis. All patients were treated with triple immunosuppression (CsA or TAC/MMF or EC-MPS/steroids). The cutoff in serum IgG titers for CMV was calculated using the ROC curve. The serum titers were obtained pre-transplant using the microparticle enzyme immune assay method (AxSYM®/Abbott Laboratories). An univariate comparison was performed using Cox regression to detect the risk factors for CMV disease, defined as the presence of typical clinical signs and symptoms combined with the detection of CMV in blood and/or the involved organs. Results: The value of serum IgG titers estimated as an appropriate operational cutoff was 572Au/ml (AUC: 0.66 [95% CI, 0.59 - 0.73]), with a sensitivity of 91% and a specificity of 35%, suggesting a good performance as a predictive risk factor. CMV disease occurred in 23 patients (11.9%), of which 21 presented IgG titers below the estimated cutoff. Univariate analysis on risk factors for CMV disease identified that IgG titers below 572Au/ml (HR[95%CI]: 5.27[1.2-22]) were associated with a higher risk for CMV disease.[Table 1. Risk factors for Cytomegalovirus disease][Figure 1. KM-Curve showing the time to CMV Disease]Conclusions: Our data suggest that recipients with IgG titers below 572Au/ml showed a higher risk for developing CMV disease in the moderate risk group. This observation can lead to the optimization of ganciclovir/valganciclovir profilaxis, and to make a more exhaustive evaluation for CMV infection. Nevertheless, a prospective study must be done in order to verify this observation.