Treatment of Disseminated Mycobacterial Infection with High-Dose IFN-γ in a Patient with IL-12Rβ1 Deficiency

IFN-gamma has been used in the treatment of IL-12R beta 1 deficiency patients with disseminated BCG infection (BCGosis), but the optimal dose to reach efficacy is not clear. We used IFN-gamma in the treatment of a 2.7-year-old patient with IL-12R beta 1 deficiency and refractory BCG-osis. IFN gamma was started at a dose of 50 mu g/m(2) 3 times per week. The dose was upgraded to 100 mcg/m(2) after 3 months, then to 200 mcg/m(2) 6 months afterwards. Serum mycobactericidal activity and lymphocytes number and function were evaluated throughout the study. There was no clinical response to IFN-gamma with 50 or 100 mu g/m2 doses. However, there was some response to the 200 mu g/m(2) dose with no additional adverse effects. The serum mycobactericidal activity was not significantly different during the whole treatment period. Lymphocytes proliferation in response to PHA was significantly higher after 3 months of using the highest dose as compared to the lowest dose. The tuberculin skin test reaction remained persistently negative. We conclude that in a patient with IL-12R beta 1 deficiency, IFN-gamma at a dose of 200 mu g/m(2), but not at lower dosages, was found to have a noticeable clinical effect with no additional adverse effects.