好中球減少患者における診療指針

Abstract

Invasive fungal infections (IFIs) are a major cause of morbidity and mortality in neutropenic patients with leukemia and those undergoing hematopoietic stem cell transplant (HSCT). Two major IFIs are systemic candidiasis (including candidemia, chronic disseminated candidiasis and pneumonia) and invasive pulmonary aspergillosis. Recently, the incidence of the latter has been increasing. Three levels of diagnosis are specified in the Japanese guidelines for the diagnosis and treatment of IFIs. Proven fungal infections are diagnosed by histological/microbiological evidence of fungi at the site of infection or positive blood culture (fungemia). Clinically documented fungal infections are diagnosed by typical radiological findings such as halo sign on chest CT plus positive serological/molecular evidence of fungi such as Aspergillus galactomannan, beta-glucan or fungal DNA. Possible fungal infections are diagnosed by typical radiological findings or positive serological/molecular evidence of fungi. For patients with high risk such as those undergoing HSCT, antifungal prophylaxis using oral antifungal agents is recommended. For possible fungal infections, empiric therapy with fluconazole (FLCZ) or amphotericin B (AMPH) is recommended. For patients with proven fungal infections or clinically documented fungal infections, targeted therapy is warranted. In case of candidemia, the best choice is FLCZ (400 mg/day) or AMPH (0.5-0.7 mg/kg/day), and for invasive pulmonary aspergillosis, a higher dose of AMPH (1.0-1.5 mg/kg/day) is indicated. Micafungin (MCFG), recently licensed in Japan, is an active agent for both Candida and Aspergillus. This drug seems useful for empiric and targeted therapy of IFIs.