Mycobacterium bovis BCG-itis and cervical lymphadenitis due to salmonella enteritidis in a patient with complete interleukin-12/-23 receptor β1 deficiency

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare disorder with predisposition to severe, sometimes lethal, disease caused by otherwise poorly virulent, non-tuberculous environmental mycobacteria and poorly virulent salmonellae. In patients with MSMD, mutations have been identified in five genes that encode for the proteins IL-12/IL-23p40, IL-12/ IL-23Rβ1, IFN-γR1, IFN-γR2 and STAT1. These proteins play important roles in the type-1 cytokine pathway, which is crucial for human host defence against intracellular pathogens such as mycobacteria and salmonellae. We report a girl with mild Mycobacterium bovis Bacille Calmette-Guérin (BCG) disease and Salmonella enteritidis cervical lymphadenitis. Despite treatment, she has remained a fecal carrier of S. enteritidis for the past 14 years. She was found to have complete IL-12/IL-23Rβ1 deficiency. A homozygous r.518G>C IL12RB1 mutation was identified, leading to a non-functional R173P substitution in the IL-12/IL-23Rβ1 protein. This mutation abrogated IL-12/IL-23Rβ1 cell-surface expression and resulted in complete lack of T cell responsiveness to both IL-12 and IL-23. © 2010 Urban & Vogel.