Mendelian susceptibility to mycobacterial disease: Clinical and immunological findings of patients suspected for IL12Rβ1 deficiency

Background: Mendelian susceptibility to mycobacterial disease (MSMD) is characterized by increased susceptibility to weakly virulent mycobacteria (Bacillus Calmette-Guerin [BCG] vaccines and environmental mycobacteria), Mycobacterium tuberculosis, Candida spp. and Salmonella spp. The aim of this study is to evaluate clinical features and immunological findings of MSMD patients with interleukin 12 receptor beta 1 (IL12R beta 1) deficiency. Methods: Among 117 screened patients with BCG infection following vaccination, 23 suspected MSMD subjects were recruited to this study by the exclusion of severe combined immunodeficiencies and chronic granulomatous diseases. Flow cytometric assessment for surface expression of IL12R beta 1 was performed. Moreover, the clinical and immunological data from the patients was evaluated. Results: A significant decrease (less than 1%) in the surface expression of IL12R beta 1 was reported in six cases which showed a significant increase in the count of lymphocytes (p = 0.009) and CD8(+) T cells (p = 0.008) as compared to MSMD subjects with normal expression of surface IL12R beta 1. The frequency of disseminated BCGosis (50% vs. 20%, p=0.29), recurrent infection (83.3% vs. 40%, p=0.14) and salmonellosis (33.3% vs. 0.0%, p=0.07) was higher in IL12R beta 1 deficient subjects than IL12R beta 1 sufficient individuals. Conclusion: MSMD patients with childhood onset of mycobacteriosis (mostly after BCG vaccination) and recurrent salmonellosis could be evaluated for IL12R beta 1 expression with flow cytometry for punctual diagnosis. (C) 2019 SEICAP. Published by Elsevier Espana, S.L.U. All rights reserved.