Coccidioidomycosis in Allogeneic Stem Cell Transplant Recipients: Case Series and Review of the Literature

The Known and Unknown "Knowns" of Human Susceptibility to Coccidioidomycosis

Coccidioidomycosis occurs after inhalation of airborne spores of the endemic, dimorphic fungus, Coccidioides. While the majority of individuals resolve the infection without coming to medical attention, the fungus is a major cause of community-acquired pneumonia in the endemic region, and chronic pulmonary and extrapulmonary disease poses significant personal and economic burdens. This review explores the literature surrounding human susceptibility to coccidioidomycosis, including chronic pulmonary and extrapulmonary dissemination. Over the past century of study, themes have emerged surrounding factors impacting human susceptibility to severe disease or dissemination, including immune suppression, genetic susceptibility, sex, pregnancy, and genetic ancestry. Early studies were observational, frequently with small numbers of cases; several of these early studies are highly cited in review papers, becoming part of the coccidioidomycosis "canon". Specific genetic variants, sex, and immune suppression by TNF inhibitors have been validated in later cohort studies, confirming the original hypotheses. By contrast, some risk factors, such as ABO blood group, Filipino ancestry, or lack of erythema nodosum among black individuals, are repeated in the literature despite the lack of supporting studies or biologic plausibility. Using examination of historical reports coupled with recent cohort and epidemiology studies, evidence for commonly reported risk factors is discussed.

A review of endemic mycoses after hematopoietic stem cell transplantation

BACKGROUND

Endemic mycoses after hematopoietic stem cell transplantation (HSCT) are rarely reported. We aimed to comprehensively review the clinical presentation and outcomes of endemic mycoses in this immunocompromised population.

METHODS

Multiple databases were reviewed from inception through May 31, 2023 using endemic fungi as keywords (e.g., coccidioides, histoplasma, blastomyces, talaromyces, and paracoccidioides). Only hematopoietic transplants were included.

RESULTS

There were 16 publications on endemic mycoses after HSCT that reported nine unique cases of histoplasmosis, seven coccidioidomycosis, and two talaromycosis. No cases of paracoccidioides and blastomycoses were identified. Fifteen cases were allogeneic hematopoietic transplant recipients and three were autologous. Many were male (14/18, 77.8%) and overall median age was 50 (range 21-75) years. Among the 16 patients with coccidiodomycosis or histoplasmosis, fever, cytopenias and disseminated disease were the most common clinical presentations, with median onset of 8 or 12 months after HSCT, respectively. Likewise, the two HSCT patients with talaromycosis presented with disseminated disease at 12 and 48 months after transplantation. The vast majority were not on effective azole prophylaxis at the time of presentation, and many had recent intensification of immunosuppression. Nine of 18 patients died (50%), and all deaths occurred among patients with disseminated endemic mycoses.

CONCLUSION

Endemic mycoses among HSCT are uncommon. Onset was late, after discontinuation of azole prophylaxis, or was associated with intensification of immunosuppression. Disseminated disease was a common presentation, manifested by fever and cytopenias. Attributable mortality was high, and emphasizes the need for a high index of clinical suspicion so that prompt diagnosis and treatment is provided.

Endemic or regionally limited parasitic and fungal infections in haematopoietic stem-cell transplantation recipients: a Worldwide Network for Blood and Marrow Transplantation (WBMT) Review

There is a scarcity of data on endemic and regionally limited fungal and parasitic infections in recipients of haematopoietic stem-cell transplantation (HSCT) outside western Europe and North America. This Worldwide Network for Blood and Marrow Transplantation (WBMT) Review is one of two papers aiming to provide guidance to transplantation centres worldwide regarding prevention, diagnosis, and treatment based on the currently available evidence and expert opinion. These recommendations were created and reviewed by physicians with expertise in HSCT or infectious disease, representing several infectious disease and HSCT groups and societies. In this paper, we review the literature on several endemic and regionally limited parasitic and fungal infections, some of which are listed as neglected tropical diseases by WHO, including visceral leishmaniasis, Chagas disease, strongyloidiasis, malaria, schistosomiasis, histoplasmosis, blastomycosis, and coccidioidomycosis.

Current Landscape of Coccidioidomycosis

Coccidioidomycosis, also known as Valley fever, is an endemic fungal infection commonly found in the southwestern parts of the United States. However, the disease has seen an increase in both in its area of residency and its prevalence. This review compiles some of the latest information on the epidemiology, current and in-development pharmaceutical approaches to treat the disease, trends and projections, diagnostic concerns, and the overlapping dynamics of coccidioidomycosis and COVID-19, including in special populations. This review provides an overview of the current diagnostic and therapeutic strategies and identifies areas of future development.