Immune Function Assay (Immunknow) Drop Over First 6 Months After Renal Transplant: A Predictor of Opportunistic Viral Infections? M. Quaglia a, *, T. Cena b , R. Fenoglio a , C. Musetti a , D. Cagna a , E. Radin a , S. Roggero c , A. Amoroso c , C. Magnani b , and P. Stratta a a Nephrology and Transplant Unit, Department of Translational Medicine, “Maggiore della Carità” University Hospital and Interdisciplinary Research Center Autoimmune Disease (IRCAD), “A. Avogadro” University, Novara, Italy; b Medical Statistics and Cancer Epidemiology Unit, “A. Avogadro” University, Novara, Italy; and c Transplantation Immunology Service, “San Giovanni Battista” University Hospital, Turin, Italy ABSTRACT Background. The Immuknow assay (IKA; Cylex) is a T-cell immune function assay that evaluates immunoreactivity in immunocompromised patients. The aim of this study was to analyze IKA values in a cohort of kidney transplantation (KT) recipients to investigate correlations between singleetime point low IKA values and their trend over time with cytomegalovirus (CMV) or BK virus (BKV) reactivation. Methods. A total of 118 adult patients receiving deceased-donor KT were enrolled (55.6  11.9 years old; 79 [66.9%] male). IKA CMV and BKV viremia determinations and were performed at months 1, 3, and 6 after surgery. Results. Overall, 272 IKA determinations were performed: IKA values significantly decreased from month 1 (422  184 ng/mL) to month 3 (330  159 ng/mL; P < .001) and from month 3 to month 6 (300  128 ng/mL; P ¼ .030). IKA values did not correlate with renal function or viral reactivation at any time. However, patients with either CMV or BKV viremia had a trend to higher IKA values at month 1 and lower IKA values at month 6, even if the difference did not reach a statistical significance (P ¼ .115). Conclusions. Our study suggests that presence of low immunologic reactivity (IKA <225 ng/mL) is not associated with an increased risk of CMV and BKV reactivation over the 1st 6 months after KT. However, a trend to a more pronounced drop in IKA values over time was observed in patients with viral reactivation. These preliminary results suggests that drop in IKA values within the 1st post-KT months, unlike singleetime point immune function assay, may predict the risk of opportunistic viral infections. T HE IMMUKNOW assay (IKA) is a T-cell immune function assay that evaluates CD4þ T-cell response to a nonspecific mitogenic stimulus through quantification of intracellular ATP release. In 2002 the United States Food and Drug Administration approved it as a tool to assess cell- mediated immunoreactivity in immunocompromised pa- tients [1,2]. Because cellular response is involved both in acute rejection (AR) and in prevention of opportunistic in- fections (OI) [3], IKA was expected to have the potential to predict these untoward events and consequently provide a guide to modulate immunesuppression [4]. However, although several small studies in different organ trans- plantations showed that IKA values are low during clinically evident infection and increase after recovery from disease, the role of IKA monitoring in the asymptomatic and stable patient is still debated [5e9]. Two meta-analyses provided conflicting results about its effectiveness as a screening tool to stratify patients according to their risk of future infection and rejection [10,11]. The predictive value of singleetime *Address correspondence to Dr Marco Quaglia, Nephrology and Transplantation, Dipartimento di Medicina Traslazionale and Interdisciplinary Research Center Autoimmune Disease (IRCAD), “Amedeo Avogadro” University, Ospedale “Maggiore Della Car- ità,” Corso Mazzini 18, 28100 Novara, Italy. E-mail: marco. quaglia@gmail.com 0041-1345/14 http://dx.doi.org/10.1016/j.transproceed.2014.07.050 ª 2014 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 2220 Transplantation Proceedings, 46, 2220e2223 (2014)