In vivo interferon-γ therapy augments the in vitro ability of chronic granulomatous disease neutrophils to damage Aspergillus hyphae

During the recently completed double-blind, placebo-controlled, randomized trial of recombinant interferon-γ (rIFN-γ) therapy in chronic granulomatous disease (CGD), a metabolic assay of neutrophil damage to Aspergillus fumigatus hyphae was used to monitor neutrophil function before and during therapy. In this assay, 5 × 10⁴ conidia that had germinated into hyphae were exposed to 5 × 10⁵, 15 × 10⁵, or 50 × 10⁵ CGD neutrophils. By analysis of variance, neutrophils from patients on rIFN-γ were found to produce significantly more damage to hyphae than those from the placebo group (P < .01). In subgroup analysis, this effect was best seen in the hyphae exposed to 50 × 10⁵ CGD neutrophils, where neutrophils from patients receiving rIFN-γ produced significantly more damage to the hyphae than those from the placebo group (P < .05). In vivo rIFN-γ therapy improves the ability of CGD neutrophils to damage Aspergillus fumigatus hyphae in an in vitro assay.