Low Absolute Lymphocyte Count Associated With Anti‐Thymocyte Globulin Induction May Be a Predictor of Early Cytomegalovirus Infection in Pediatric Heart Transplantation

TL;DR

Low lymphocyte counts after anti-thymocyte globulin treatment in heart transplant patients may predict early cytomegalovirus infection.

Contribution

Identifies low absolute lymphocyte count during induction as a novel predictor of CMV infection in pediatric heart transplant recipients.

Findings

Patients with ALC ≤ 0.3 × 10⁹ cells/L had a 28% CMV viremia rate versus 0% in higher ALC groups.

Low ALC remained a significant predictor of CMV even after adjusting for CMV serostatus.

Low ALC groups had higher rejection rates but this difference was not statistically significant.

Abstract

Cytomegalovirus (CMV) can cause serious morbidity in transplant patients. Lymphocyte depletion by anti‐thymocyte globulin (ATG) may persist for 6 months post‐induction, and lower absolute lymphocyte counts (ALC) may increase the risk for CMV. We sought to find the relationship between ALC at induction and CMV viremia in the first 6 months post‐transplant.

An analysis of transplant recipients within a set period of time with uniformed induction therapy and CMV prophylaxis. ATG was a primary component of induction and ganciclovir or valganciclovir as prevention of CMV infection. The cohort was dichotomized into low ALC (≤ 0.3 × 109 cells/L) and high ALC (> 0.3 × 109 cells/L) based on lowest ALC during the first 14 days and their clinical characteristics analyzed. CMV viremia was defined as PCR value of > 137 IU/mL regardless of symptoms.

A total of 44 patients were included in this study. CMV viremia occurred in 18% (n = 8). Patients were more likely to develop CMV if post‐induction ALC was ≤ 0.3 × 109 cells/L (28% vs. 0%, p = 0.029) and remained significant when adjusted for CMV serostatus (p = 0.04). The total ATG dose (7.5 vs. 4.5 mg/kg) was not predictive of CMV (37% vs. 17%, p = 0.3) nor was treatment for rejection (25% vs. 14%, p = 0.5. Rejection occurred in 7% compared to 20% of patients in the low vs. high ALC group (p = 0.4).

In pediatric heart transplant recipients, there is a higher incidence of CMV if ALC ≤ 0.3 × 109 cells/L during induction, regardless of serostatus. Low ALC levels during induction may identify a high‐risk group that could benefit from an altered CMV prophylactic regimen.

In pediatric heart transplant recipients, there is a higher incidence of cytomegalovirus if ALC ≤ 0.3 × 109 cells/L during induction, regardless of serostatus. Low ALC levels during induction may identify a high‐risk group that could benefit from an altered CMV prophylactic regimen.

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