Background: The short-term results of kidney transplantation are mainly attributed to the use of calcineurin inhibitors (CNI). However, opportunistic infections and cytomegalovirus (CMV) infections remain frequent and occur in the case of overimmunosuppression. Measurement of the biological effects of CNI could provide clues to identify overimmunosuppressed kidney transplant recipients (KTR) who would subsequently develop CMV infection.
Methods: Forty-one KTR given cyclosporine (n=18) or tacrolimus (n=23) were followed up every week during 1 month, then every month during 11 months, by measuring the patient's whole blood ability to inhibit interleukin-2 (IL-2) gene transcription and by measuring the patient's intracellular T-cell IL-2, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha) production in response to polyclonal activation.
Results: Cytomegalovirus infection or disease occurred in 19 patients and was significantly associated with CMV serological status D+R- and D+R+ (HR=19.6 and 6.6, respectively, P=0.0001). Immunosuppressive treatment was associated with a long-lasting decrease of all cytokines produced by the patient's T-cells. However, none of these assays taken separately at any of the time points of the follow-up allowed to predict the occurrence of a subsequent CMV infection. We only observed a weak association between cumulative low levels of the percentage of TNF-alpha producing CD8+ T cells before CMV infection and its occurrence just afterwards (HR=1.39 for 1000 unit lower, P=0.04). However, this association did not remain significant after adjustment for CMV serological status.
Conclusions: This study suggests that immunological monitoring is not better than CNI whole blood levels for diagnosis of overimmunosuppression-induced CMV infection in KTR.