Pretransplant Lymphopenia is a Novel Prognostic Factor in CMV and Non-CMV Invasive Infection After Liver Transplantation

Infection following liver transplantation (LT) remains a leading cause of morbidity and mortality. Risk of infection after LT is highest in those who are most immunosuppressed; yet, to date no standard blood marker of one’s degree of immunosuppression or risk index has been established. The purpose of this study was to determine if pretransplant lymphopenia (absolute lymphocyte count < 500 cells/mm3 within 24 hours before LT) is a candidate marker of immunosuppression and useful in predicting risk of cytomegalovirus (CMV) disease and non-CMV invasive infection after LT. Data was extracted from medical records for all primary, solitary liver transplants performed at Tufts Medical Center from 1999–2009. 276 patients had sufficient data to be included in the analysis. Of these, 52% developed CMV or non-CMV invasive infection within 5 years of LT. By 2 years, 23 (8%) had CMV disease and 103 (37%) at least one non-CMV invasive infection. More lymphopenic than non-lymphopenic patients developed CMV (21% versus 4%, P < 0.0001) and non-CMV invasive infection (50% versus 33%, P = 0.02). In multivariable survival analysis, pretransplant lymphopenia was the strongest independent predictor of CMV disease (hazards ratio [HR] 5.52, 95% confidence interval [CI] = 2.31–13.1; P = 0.001) after adjustments for known risk factors, including CMV serostatus (HR 4.72, 95% CI = 2.01–11.1; P < 0.0001). Both pretransplant lymphopenia (HR 1.64, 95% CI = 1.14–2.53; P = 0.03) and CMV (HR 2.93, 95% CI = 1.23–6.92; P = 0.02) independently predicted non-CMV infection. Our results suggest that pretransplant lymphopenia is a novel independent predictor of both CMV disease and non-CMV invasive infection after LT and a candidate marker of immunosuppression in LT recipients.