Immune monitoring of immunosuppression withdrawal of liver transplant recipients

Abstract Several studies have shown that some liver transplant recipients may tolerate immunosuppression withdrawal. Mechanisms and biomarkers of tolerance are not well known. Methods Twenty-four LT patients with immunosuppression side-effects underwent progressive immunosuppression withdrawal. Peripheral lymphocyte populations and secretion of cytokines were analyzed at baseline and during withdrawal until tolerance (n = 15) or rejection (n = 9), as well as 3 months after tolerance achievement or rejection resolution (as follow-up). Immunological markers were compared among groups. Results The percentages of CD3 + CD4 + cells progressively decreased in both groups. CD3 + CD8 + cells gradually increased in tolerant patients. B lymphocytes gradually decreased in tolerant and initially in non-tolerant patients, reverting at rejection. Regulatory T cells progressively increased until rejection in non-tolerants, decreasing to basal levels after renewing immunosuppression; no significant changes were found in tolerant patients. The percentages and absolute counts of natural killer cells significantly increased in both groups, being more evident in tolerant patients. The secretion of several cytokines was higher in non-tolerant patients when rejection was diagnosed. Conclusions The greater increase of natural killer cells in tolerant patients suggests their potential role in the tolerance phenomenon.