Mucormycosis is a life-threatening respiratory fungal infection predominantly caused by Rhizopus species. Mucormycosis has incompletely understood pathogenesis, particularly how abnormalities in iron metabolism compromise immune responses. Here we show how, as opposed to other filamentous fungi, Rhizopus spp. establish intracellular persistence inside alveolar macrophages (AMs). Mechanistically, lack of intracellular swelling of Rhizopus conidia results in surface retention of melanin, which induces phagosome maturation arrest through inhibition of LC3-associated phagocytosis. Intracellular inhibition of Rhizopus is an important effector mechanism, as infection of immunocompetent mice with swollen conidia, which evade phagocytosis, results in acute lethality. Concordantly, AM depletion markedly increases susceptibility to mucormycosis. Host and pathogen transcriptomics, iron supplementation studies, and genetic manipulation of iron assimilation of fungal pathways demonstrate that iron restriction inside macrophages regulates immunity against Rhizopus. Our findings shed light on the pathogenetic mechanisms of mucormycosis and reveal the role of macrophage-mediated nutritional immunity against filamentous fungi.
Non chemotherapy drug-induced agranulocytosis is considered a potentially life-threatening idiosyncratic blood dyscrasia, thought to result from a partly elucidated immune and/or toxic damage on myelopoiesis, due to a multitude of drugs. Offending agents include clozapine, ticlopidine, antithyroid compounds, dipyrone, sulfasalzine, trimethropim/sulfomethoxazole, carmabazepine, and to a lesser extent, deferiprone (L1) and probably rituximab. Suspected drugs should be immediately stopped and, in symptomatic patients, once appropriate cultures have been obtained, broad-spectrum antibiotic treatment should be administered. Hematopoietic growth factors may be considered, specifically in patients with poor prognostic factors. Due to improved intensive care treatment and alertness of physicians the case fatality of the disorder has recently been decreased to 5%.
We describe two patients with multiple myeloma (MM) involving the central nervous system (CNS). In both patients, CNS involvement was manifested with extremely rare signs and symptoms. The first patient, a 64-year-old woman, developed obstructive hydrocephalus 10 years after the initial diagnosis of MM. The disease has been successfully treated with intrathecal chemotherapy, radiotherapy and systemic chemotherapy. The other patient, a 65-year-old man, developed hypopituitarism and diabetes insipidus 1 year after MM diagnosis. Disease in this patient proved resistant to both radiotherapy and chemotherapy; the patient died 2 years later. These rare complications add new information on the wide spectrum of clinical and laboratory manifestations of MM. It is obvious that descriptions of additional cases are required to better understand the mechanisms of CNS involvement in MM patients.
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