Immunomodulation Therapy for Invasive Aspergillosis: Discussion on Myeloid Growth Factors, Recombinant Cytokines, and Antifungal Drug Immune Modulation

Abstract

Understanding fungal pathogenesis and host-pathogen immune interaction at various stages of infection is critical to examine strategies for bolstering antifungal immune defenses. Recombinant myeloid growth factors, especially granulocyte-macrophage colony-stimulating factor and the protagonist T helper (Th) 1 cytokine, interferon-γ, are most frequently used in patients with refractory invasive aspergillosis. These cytokines are given alone or in combination and have also been used together in neutropenic patients receiving donor granulocyte transfusions. Recently, a number of investigators have presented provoking data regarding auxiliary effect of conventional antifungal drugs on hosts' immune response and pathogen's susceptibility for antifungal immune defenses. Antifungal immunotherapy and its ameliorative role in treatment for Aspergillus disease will need clinical trials that 1) consider well-characterized fungal disease; 2) illustrate underlying immune defect(s) (such as Th1 vs Th2, vs Th17 and functional status of natural killer and effector scavenger cells); 3) include a more specific patient population; 4) include standardized antifungal drug therapy; and importantly 5) consider its impact on hosts' immune response and changes in pathogen's susceptibility and virulence. At present, immunotherapy is reserved for patients with life-threatening invasive fungal disease in whom conventional antifungal drug therapy has failed, or for patients with advanced fungal disease and with factors associated with high probability of failure of conventional therapy alone.