Abstract
BACKGROUND: Newborn screening for severe combined immunodeficiency (SCID) using T cell receptor excision circles (TRECs) identifies patients with other causes of lymphopenia. The risk of opportunistic infection in patients with non-SCID lymphopenia is poorly understood. We aim to describe incidence and risk factors associated with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infection in patients with low TRECs. METHODS: This retrospective study analyzed 289 patients with ≥1 abnormal TREC result. RESULTS: Nineteen patients had CMV or EBV detected by PCR. Most had resolution of infection (n = 13). Two have chronic viremia, and four expired due to disseminated CMV. Risk factors included undetectable TRECs, consanguinity, family history, low NK, naïve CD4, naïve CD8 cells, and phytohemagglutinin. CONCLUSION: Infection with CMV and EBV in patients with low TRECs is rare, however some may benefit from preventative measures. Consideration of risk factors may aid in decision-making and improve outcomes.