NBS for SCID: only early diagnosis will change the overall survival of the disease?

Severe combined immunodeficiency (SCID) is a heterogeneous genetic disease characterized by severe T-cell lymphopenia with a profound impairment of T- and B-cells’ function and, in some types, also NK cells. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment currently available in Brazil. Late diagnosis and treatment are the main factors affecting the survival of these children. This study aims to describe the demographic, phenotypic, genotypic, and clinical characteristics of twenty SCID patients (including typical SCID, leaky-SCID, and Omenn Syndrome) followed at a Brazilian reference center and correlate this data with their clinical outcome. The children were analyzed into two groups: patients diagnosed early at birth, by newborn screening (NBS) or family history, n=7, and patients with late diagnosis, by clinical presentation, n=13. The 2-year overall survival (OS) of the late group was 29.2%, in contrast to the 2-year OS of the early diagnosis group of 71.4% (p=0.053). Despite the early diagnosis in the first group, the time between diagnosis and HSCT in both groups was similar, with a median of 11 months. The OS after HSCT was not different between the groups (p=0.774). This research shows that early diagnosis alone does not change the prognosis of SCID newborns after HSCT. The reality in developing countries still needs public policies to change the harsh reality of these patients.