*Purpose: Pre-transplant interferon-γ (IFN-γ) enzyme-linked immunospot (IFN- γ ELISPOT) has been proposed as a tool to quantify alloreactivity of memory T cells and estimate the risk of acute rejection (AR) after kidney transplantation, but results varied significantly across studies. We performed a meta-analysis to evaluate the association between pre-transplant IFN-γ ELISPOT and AR and assess its predictive accuracy at the individual level.

*Methods: We searched 3 databases for studies testing pre-transplant IFN- γ ELISPOT as a predictor of AR after kidney transplantation. We estimated the pooled summary of odds ratio (OR) for AR and then joined sensitivity and specificity for predicting AR using random-effects and hierarchical summary receiving operating characteristic (HSROC) model. We employed meta-regression models with the Monte Carlo permutation method to adjust for multiple tests to explain sensitivity and specificity heterogeneity across studies. The meta-analytic estimates of sensitivity and specificity were used to calculate positive and negative predictive values (PPV and NPV) across studies.

*Results: The analysis included 12 studies and 1,181 patients. IFN-γ ELISPOT was significantly associated with increased AR risk (OR: 3.29, 95% CI, confidence interval: 2.34-4.60, Figure 1). HSROC jointly estimated sensitivity and specificity values of 64.9% (95% CI: 53.7-74.6%), and 65.8% (95% CI: 57.4-73.5%), respectively, with moderate heterogeneity across studies. After adjusting for multiple testing, meta-regression models showed that thymoglobulin induction, recipient black ethnicity, living-vs-deceased donor, and geographical location did not affect sensitivity or specificity. Because of the varying AR incidence of the studies, PPV and NPV ranged between 16% – 60% and 70% – 95%, respectively.

*Conclusions: Pre-transplant IFN-γ ELISPOT is significantly associated with increased risk of AR but provides suboptimal predictive ability at the individual level.

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