Background: Interferon gamma receptor 1 (IFNgammaR1) deficiency is a primary immunodeficiency with allelic dominant and recessive mutations characterised clinically by severe infections with mycobacteria. We aimed to compare the clinical features of recessive and dominant IFNgammaR1 deficiencies.
Methods: We obtained data from a large cohort of patients worldwide. We assessed these people by medical histories, records, and genetic and immunological studies. Data were abstracted onto a standard form.
Findings: We identified 22 patients with recessive complete IFNgammaR1 deficiency and 38 with dominant partial deficiency. BCG and environmental mycobacteria were the most frequent pathogens. In recessive patients, 17 (77%) had environmental mycobacterial disease and all nine BCG-vaccinated patients had BCG disease. In dominant patients, 30 (79%) had environmental mycobacterial disease and 11 (73%) of 15 BCG-vaccinated patients had BCG disease. Compared with dominant patients, those with recessive deficiency were younger at onset of first environmental mycobacterial disease (mean 3.1 years [SD 2.5] vs 13.4 years [14.3], p=0.001), had more mycobacterial disease episodes (19 vs 8 per 100 person-years of observation, p=0.0001), had more severe mycobacterial disease (mean number of organs infected by Mycobacterium avium complex 4.1 [SD 0.8] vs 2.0 [1.1], p=0.004), had shorter mean disease-free intervals (1.6 years [SD 1.4] vs 7.2 years [7.6], p<0.0001), and lower Kaplan-Meier survival probability (p<0.0001). M avium complex osteomyelitis was more frequent in dominant than in recessive patients (22/28 [79%] vs 1/8 [13%], p=0.002), and this disorder without other organ involvement arose only in dominant patients (9/28 [32%]). Disease caused by rapidly growing mycobacteria was present in more recessive than dominant patients (7/22 [32%] vs 1/38 [3%], p=0.002).
Interpretation: Recessive complete and dominant partial IFNgammaR1 deficiencies have related clinical phenotypes, but are distinguishable by age at onset, dissemination, and clinical course of mycobacterial diseases. A strong correlation exists between IFNGR1 genotype, cellular responsiveness to interferon gamma, and clinical disease features.