Utility of umbilical cord blood absolute Lymphocyte count in screening for severe Combined immunodeficiency disease – a one Year longitudinal study

Abstract

Background: SCID is a severe inherited disorder that affects the function of T-cells and B-cells, making it one of the most critical and fatal types of inherited primary immunodeficiency. Newborns with SCID typically appear healthy at birth but often develop recurring infections in infancy, leading to high mortality within the first year. Most SCID patients have low lymphocyte counts from birth, and regular testing of absolute lymphocyte count (ALC) in umbilical cord blood samples can aid in presymptomatic detection and early intervention for neonates with SCID. Measuring cord blood ALC is a simple, rapid and cost-effective method for newborn screening of SCID and related T-cell lymphopenia, especially in resource-limited settings. The true incidence of absolute lymphopenia in newborns in India still remains unknown. We hereby present the first ever SCID screening in India and the fourth worldwide, involving 1550 newborns screened using cord blood ALC. Early diagnosis is indeedlife saving and allows children with SCID the opportunity to lead a healthy life post hematopoetic stem cell transplant therapy. Objectives: • Primary Objective: To estimate the incidence of absolute lymphopenia in umbilical cord blood samples of newborns and to determine its utility in screening for Severe Combined Immunodeficiency Disease (SCID). • Secondary Objective: 1. To evaluate other causes of lymphopenia in newborns. ix 2. To study the impact of early detection of SCID on improvement in the patient outcome by prompt referral for curative management