Hemophagocytic syndrome associated with Mycobacterium bovis in a patient with X-SCID: a case report

BACKGROUND: Mycobacterium bovis could infect patients with immunodeficiency or immunosuppressive conditions via Bacillus Calmette-Guérin (BCG) vaccination. Tuberculosis-related hemophagocytic syndrome (HPS) is reported, but not HPS caused by Mycobacterium bovis in children. CASE PRESENTATION: A 4-month Chinese boy presented fever and cough. The initial laboratory investigation showed the lymphocyte count of 0.97 × 10(9)/L, which decreased gradually. HPS was diagnosed based on the test results that fulfilled the HLH-2004 criteria. In addition, Mycobacterium tuberculosis complex was detected from his peripheral blood via metagenomic next-generation sequencing (mNGS) and M. bovis was identified by polymerase chain reaction-reverse dot blot (PCR-RDB). Thus, the patient was treated with Isoniazid, Rifampin, and Pyrazinamide, but not improved. However, parents refused to accept further therapy, and was discharged on the day 12 of admission. To confirm the pathogenesis, genetic analysis was performed. Mutation in the interleukin-2 receptor subunit gamma gene: Exon 6: c.854G > A; p. Arg285Gln was detected in the patient and the mother, which could underlie X-linked severe combined immunodeficiency. CONCLUSIONS: A boy with X-SCID was diagnosed with M. bovis-associated HPS, emphasizing that X-SCID should be considered when M. bovis is detected in a male infant with low lymphocyte counts.