RESUMEN
T-B-NK+ severe combined immunodeficiency (SCID) is an autosomal recessive disease that is caused mainly by a defect in the recombination activating genes (RAG). Patients with SCID usually experience life-threatening opportunistic infections in early infancy and complications after vaccination with bacille Calmette-Guérin (BCG). We report a patient of consanguineous parents who was referred to our center with subaxillary lymphadenitis and respiratory distress. Laboratory studies confirmed the diagnosis of T-B-NK+ SCID and molecular studies revealed homozygous mutations in the RAG2 gene. The patient died despite administration of antituberculosis drugs, antibiotics, and intravenous immunoglobulin. Inoculation of live vaccines such as BCG should be postponed in families with a positive history of SCID until screening tests rule out this condition.