Mycobacterium simiae infection in two unrelated patients with different forms of inherited IFN-γR2 deficiency.

Interferon-γ receptor 2 (IFN-γR2) deficiency is a rare primary immunodeficiency characterized by predisposi- tion to infections with weakly virulent mycobacteria, such as environmental mycobacteria and BCG vaccines. We describe here two children with IFN-γR2 deficiency, from unrelated, consanguineouskindredsofArabandIsraeli descent.Thefirst patient was a boy who died at the age of 4.5 years, from recurrent, disseminated disease caused by Mycobacterium simiae. His IFN-γR2 defect was autosomal recessive and complete. The second patient was a girl with multiple