TRANSIENT T CELL LYMPHOPENIA IN A NEWBORN FROM MATERNAL IMMUNOSUPPRESSIVE MEDICATIONS

Abstract

Introduction The newborn screen for Severe Combined Immunodeficiency (SCID) utilizes real time quantitative PCR for T cell receptor excision circles (TRECs) and is highly sensitive for detection of SCID, with a negative predictive value of 100%. However, T cell lymphopenia from other primary and secondary causes is also detected, often posing diagnostic and treatment dilemmas. We present the case of a female newborn with transient T cell lymphopenia from maternal medications administered during pregnancy. Case Description The patient was a female child born at 34 weeks via Cesarean section for fetal decelerations. Maternal antenatal steroids were administered and the post-natal course was unremarkable. Two newborn screens resulted with very low TRECs. At 2 weeks of age during immunology clinic visit, the patient's mother was found to have a history of lupus with prior kidney transplant for which she had been on hydroxychloroquine, tacrolimus, azathioprine, and prednisone throughout pregnancy. Family history was negative for immunodeficiency or unexplained deaths. Initial flow cytometry showed severe pan-lymphopenia although normal percentages of naive T cells. Proliferation to mitogens was low/normal. Immunoglobulins A and M were low/undetectable, although IgE was normal. Adenosine deaminase and purine nucleotide phosphorylase enzyme activity were normal. Interestingly, TRECs normalized upon recheck the following week. Flow cytometry completely normalized within 4 months and initial abnormalities were ultimately attributed to maternal immunosuppressive medications, antenatal steroids, prematurity, and peri-natal stress. The patient is currently 4 months old and doing well. Discussion This case demonstrates decreased fetal/neonatal thymic output, thought to be from maternal immunosuppressive medications, which ultimately recovered spontaneously.