Neonatal screening for absolute lymphopenia
Background: Blood counts with manual differentials could diagnose nearly all cases of severe combined immune deficiency (SCID) at birth. Objective: The aim of this study was to outline the prevalence of neonatal lymphopenia among newborns of Obstetrics and Gynecology Hospital, Ain Shams University as an entry to neonatal screening for SCID. Methods: Complete blood counting (CBC) with manual differential was performed in the cord blood of 500 newborns. Absolute lymphopenia was considered if the count was less than 2500 lymphocytes/mm3. Parents of lymphopenic infants were advised not to give them any live attenuated vaccines before doing further investigations. The lymphopenic infants were followed up by another CBC after one month. Results: In the present study, absolute lymphopenia was found in 8 (1.6%) neonates at delivery. Among our series 44.4% were primigravida and 55.6% were multigravida. Also, 84 (16.8%) experienced pre-mature rupture of membrane, 89 (17.8%) reported maternal diseases and maternal drug intake was reported in 73 (14.6%). Three neonates had congenital anomalies, one only experienced dysmorphic features and 8 (1.6%) had family history of unexplained death but these data could not be linked to the presence of lymphopenia in the studied sample. APGAR scores at 1 and 5 minutes were significantly lower in neonates with lymphopenia (p = 0.001). A significant positive correlation was elicited between the absolute lymphocyte count (ALC) and maternal age, total leukocyte count, and HCT (p = 0.003, 0.001 and 0.031 respectively). Also a significant negative correlation was found between ALC and gestational age, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration (p = 0.013, 0.003 and < 0.001 respectively). Conclusion: Lymphopenia is not an uncommon finding among neonates at screening and is noted to be associated with a lower Apgar score. Serial counting and follow up is needed before considering the diagnosis of SCID.
Keywords: Lymphopenia; neonatal screening; SCID