Objective: To evaluate the effects of exogenous interferon gamma treatment in patients with chronic rhinosinusitis and evidence of aberrant production of interferon gamma (IFN-gamma) and its regulatory cytokines.
Methods: Ten patients with treatment-resistant chronic rhinosinusitis (4 males and 6 females) treated with exogenous interferon gamma (50 micro g/m2) were retrospectively evaluated by assessing clinical outcomes compared with clinical and laboratory findings before interferon gamma treatment.
Results: Dysregulated IFN-gamma production was suspected to be characterized by (1) decreased interleukin 12 production (n = 1), (2) defects in interleukin 12 receptor signaling (n = 4), (3) intrinsic defects in interleukin 12 (n = 4), and (4) decreased IFN-gamma production. Eight patients had a history of chronic otitis media with positive bacterial cultures of sinus lavage samples. Adverse skin reactions to various antibiotics were reported in 7 patients. Asthma was reported in 4 patients. Along with sinusitis symptoms, these conditions were better controlled in all 9 patients who received exogenous interferon gamma for longer than 3 months. In 1 patient, interferon gamma treatment was discontinued after 3 weeks secondary to "presumed" tremor that was later diagnosed as a tic. Repeated surgical procedures and hospitalizations were reported in 2 patients after interferon gamma treatment secondary to recurrent chronic otitis media/mastoiditis/catheter infection and G-tube leakage. Interferon gamma treatment was discontinued in 1 of these patients because of a concern about neutropenia that occurred after catheter infection. Adverse effects of using exogenous interferon gamma were generally limited to local skin reactions.
Conclusion: Exogenous interferon gamma may be a therapeutic option in a subset of patients with treatment-resistant chronic rhinosinusitis and evidence of dysregulated IFN-gamma production.