Elevated Absolute Lymphocyte Count is an Indicator for Acute Cellular Rejection in Intestinal Transplant

Introduction: Acute cellular rejection (ACR) is a common adverse event in the early period post intestinal transplantation, occurring in up to 80% of patients. Identifying ACR early is imperative as timely diagnosis and treatment can help prevent morbidity and mortality related to intestinal ACR, including development of exfoliative rejection. Methods: We performed a single-center retrospective cohort study evaluating children age <18 years who received an isolated intestinal transplant or combined intestinal and liver transplant from 2000-2021 at Cincinnati Children’s Hospital Medical Center. Patients were divided into 3 groups based on development of no ACR, mild or moderate ACR, and exfoliative rejection within the first 45 days post-transplant. Baseline demographics and operative characteristics were compared between the 3 groups. Bivariate analysis was used to compare risk factors for development of ACR including differences in immunosuppression regimen, infections, and absolute lymphocyte count (ALC). Results: Using univariate and bivariate analysis, baseline demographic and operative characteristics were similar between all groups (p > 0.05). There were also no differences between infections pre- and post-transplant (including EBV/CMV mismatch between donor and recipient). No differences between the 3 groups were noted with regards to the immunosuppression regimen including total dose of anti-thymocyte globulin induction, time to achieve tacrolimus (TAC) trough > 10, and TAC trough at time of rejection. However, patients with mild to moderate ACR had significantly higher ALC at time of their rejection compared to those who had exfoliation (1460 vs 462) or never developed early ACR (1460 vs 642) with ALC at day 45 post-transplant being used for comparison in this group (p = 0.0025). During further analysis of those patients with exfoliative rejection, it was found that these patients also had elevated ALC at time of their initial mild or moderate rejection which decreased at time of exfoliation. Conclusion: Elevated ALC may be an early sign of mild or moderate ACR in intestinal transplant patients. Further prospective studies are needed to validate these findings.