Introduction:
MSMD is caused by genetic defects in the mononuclear phagocyte/T helper cell type1 (Th1) pathway. Common to all the infections seen in MSMD are defects in the interferon gamma (IFN-gamma)-interleukin 12(IL-12) pathway and/or supporting accessory pathways.
Purpose: case report of a girl with MSMD by default expression of IL-12RB1
Observation:
This is a 07-year-old girl.She presented a disseminated BCG infection at age of 7 months, a cutaneous and ganglionic tuberculosis at the age of 13 months. Treated with antituberculosis,. A salmonella cervical adenitis at the age of 5 years. She received second-line anti-tuberculosis.The IFN gamma assay is negative with no secretion after mitogen stimulation and tuberculous antigens.The genetic study has found a mutation in the gene encoding the IL-12 receptor beta1 (IL-12RB1).The child presented for one year a tubulo-interstitial nephritis secondary to anti tuberculosis treatment currently in end-stage renal failure under dialysis.
Discussion:
IL-12Rbeta1 deficiency may present with disseminated tuberculosis or nontuberculous mycobacterial and Salmonella infections in the setting of IL-12 unresponsiveness.
The treatment consists of a suitable and prolonged antibiotherapy, especially in the case of disseminated infections with non-typhoid salmonella as in our patient. IFNγ is sometimes useful when the well-managed anti-mycobacterial treatment does not allow eradication of infectious foci.
It is a disease of good prognosis. In our patient the prognosis was clouded by toxic tubulointerstitial nephritis secondary to prolonged antibiotic therapy.