Performance of the ImmuKnow assay in differentiating infection and acute rejection after kidney transplantation: a meta-analysis

Background: The ImmuKnow test is an assay for determining the functional activity of immunocytes, which reflects cell-mediated immune responses in populations undergoing organ transplantation.

Methods: Electronic and manual searches were conducted to identify studies of the ImmuKnow test. After methodological quality assessment and data extraction, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were assessed, and summary receiver operating characteristic analysis was performed systematically. The extent of heterogeneity was explored.

Results: Six studies were identified for analysis. The pooled sensitivity, specificity, PLR, NLR, and DOR of ImmuKnow for predicting the risk of infection were 0.51 (95% confidence interval [CI], 0.45-0.57), 0.75 (95% CI, 0.71-0.78), 1.97 (95% CI, 0.91-4.26), 0.67 (95% CI, 0.38-1.19), and 3.56 (95% CI, 0.80-15.89), respectively. A DOR of 13.81 (95% CI, 0.79-240.44), with a sensitivity of 0.51 (95% CI, 0.40-0.61), a specificity of 0.90 (95% CI, 0.87-0.93), a PLR of 4.45 (95% CI, 0.91-21.74), and an NLR of 0.35 (95% CI, 0.08-1.45), was found in the analysis of the predictive value for acute rejection. The summary receiver operating characteristic curve values for ImmuKnow in distinguishing patients with infections from those with acute rejections were 0.631 ± 0.215 and 0.986 ± 0.015, respectively.

Conclusions: Our analysis did not support the use of the ImmuKnow assay to predict or monitor the risks of infection and acute rejection in renal transplant recipients. Further studies are needed to confirm the relationships between the ImmuKnow assay and infection and acute rejection in kidney transplantation.