Serum levels of IFN-gamma, IL-15 and depressive symptoms in kidney transplant patients

Abstract

Background: Current evidence indicates that both mood disorders and peripheral immune activation are involved in the pathophysiology of kidney transplant patients. Methods: The study included 25 kidney transplant patients and 25 healthy controls, all Mexican. The Calderon depressive syndrome questionnaire was applied and the serum levels of IFN-gamma and IL-15 were determined through the ELISA technique. The Mann-Whitney U test and Spearman correlation method were performed with a significance level set at p<.05. Additionally, Bayesian analysis was performed. Results: In cases and controls, we identified correlations of IFN-gamma with IL-15 (rho=.438, p<.05 and rho=.803, p<.005, respectively) but not with depressive symptom scores. Although we did not find statistical significance of IFN-gamma levels or depressive symptoms between the two study groups; Bayesian analysis indicates that there is greater support than anecdotal evidence to suppose that both IFN-gamma levels (BF=2.27) and depressive symptom scores (BF=1.29) are higher in the group of kidney transplant patients. Conclusions: The results suggest a joint participation of IFN-gamma and IL-15 in peripheral immune activation without direct relationship with the depressive symptomatology score. More robust studies with an experimental design that differentiate depressive processes and large cytokine batteries are required to clarify mechanisms and identify psychoimmune profiles in kidney transplant patients.