Partial Interferon-gamma Receptor Deficiency in Patients with Disseminated Tuberculosis

Background : Interferon-gamma (IFN-gamma) is essential in the immune response to mycobacterial infections, and a complete or partial deficiency in the IFN-gamma receptor 1 (IFN gamma R1) or the IFN-gamma receptor 2 (IFN.R2) have been reported to confer susceptibility to a disseminated infection with nontuberculous mycobacteria. However, similar mutations in the IFN-gamma receptor have not been specifically examined in the patients with clinical tuberculosis. Methods : This study searched for mutations in the IFN-gamma receptor gene that resulted in a partial IFN-gamma receptor deficiency in six patients with disseminated tuberculosis. The previously identified IFN gamma R1 and IFN gamma R2 coding regions were sequenced after amplification. Results : There was no partial IFN gamma R1 deficiency including a homozygous recessive missense mutation causing an amino-acid substitution in the extracellular domain of the receptor (I87T) and a hotspot for small deletions (818delT, 818del4, 818insA) found in any of the patients. In addition, a partial IFN gamma R2 deficiency of the homozygous missense mutation (R114C) was not found in any of the patients. Conclusion : Genetic defects causing a partial IFN-gamma receptor deficiency were not identified in our patients with disseminated tuberculosis.