| Description |
Background: As a form of severe combined immunodeficiency (SCID), JAK3 deficiency can be fatal from severe infections in children, especially after inoculation of live-attenuated vaccines. We report a unique case of JAK3 deficiency with two novel compound heterozygous JAK3 mutations, complicated by disseminated BCG disease and Pneumocystis pneumonia. Case description: A 5-month-old Chinese girl presented with recurring fever and productive cough after BCG vaccination and ineffective antibiotic treatment. Chest CT demonstrated bilateral infiltrations, enlarged mediastinal and axillary lymph nodes, and hypoplasia of thymus. Mycobacterium tuberculosis and Pneumocystis jirovecii were detected from blood sample by sequencing. Acid-fast bacilli were also found from sputum and gastric aspirate. Lymphocyte subset analyses indicated T-B+NK- immunodeficiency, and gene sequencing identified two unreported heterozygous missense mutations in the Janus homology 7 domain of JAK3. The patient received rifampicin, isoniazid, ethambutol, and trimethoprim/sulfamethoxazole and was discharged against advice. Outcome: The patient died at 13 months of age due to severe infections and hepatic damage. Discussion: SCID should be recognized before inoculation of live-attenuated vaccines in children. Newborn screening for SCID is advocated. Further investigations are needed to better understand the molecular mechanism of JH7 domain of JAK3. |
