Persistent T Cell Lymphopenia: An Algorithim for Follow up Care

There are patients who have persistent T cell lymphopenia following a positive newborn screen (NBS), that do not qualify for a diagnosis of SCID, DiGeorge syndrome, or other identifiable immunodeficiency disorders. The follow up care for these infants has not been standardized in the literature. We propose, and are utilizing, an algorithm in order to standardize the workup, intervention and follow up of these infants. A retrospective chart review from time of NBS implementation in Michigan at the Children's Hospital of Michigan (September 2011 to July 2014). 91 out of 189 infants with low TRECs detected on NBS in Michigan were followed at our center: 2 were diagnosed with SCID; 1 with combined immune deficiency; 9 DiGeorge Syndrome (3 severe partial; 6 with partial); 2 with lymphopenia secondary to thymectomy; 5 families are refusing follow up care; 5 died with complications of other diseases and 2 pending cases. 65 has persistent lymphopenia without a diagnosis: 48 were discharged from care with normal flow cytometry and 16 were discharged from care because of normal T cell proliferation (PHA≥ 10 times the control value) despite low T cells; one remains in follow-up with low T cell proliferation assay without a diagnosis. Of those 16 patients, 56.5% were discharged by 12 months of age. We propose a new algorithm to approach and manage infants with persistent T cell lymphopenia identified by NBS which should minimize morbidity and decrease family anxiety.