Coccidioidomycosis in patients with various inflammatory disorders treated with tumor necrosis factor α inhibitors

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.

Contribution of Biologic Response Modifiers to the Risk of Coccidioidomycosis Severity

Background

The risk of coccidioidomycosis (CM) as a life-threatening respiratory illness or disseminated CM (DCM) increases as much as 150-fold in immunosuppressed patients. The safety of biologic response modifiers (BRMs) as treatment for patients with autoimmune disease (AI) in CM-endemic regions is not well defined. We sought to determine that risk in the Tucson and Phoenix areas.

Methods

We conducted a retrospective study reviewing demographics, Arizona residency length, clinical presentations, specific AI diagnoses, CM test results, and BRM treatments in electronic medical records (EMR) of patients >18 years old with International Classification of Diseases (ICD-10) codes for CM and AI from 10/01/2017 to 12/31/2019.

Results

We reviewed 944 charts with overlapping ICD-10 codes for CM and AI, of which 138 were confirmed to have both diagnoses. Male gender was associated with more CM (p=0.003), and African ancestry was three times more likely than European to develop DCM (p<0.001). Comparing CM+/AI+ (138) with CM+/AI- (449) patients, there were no significant differences in CM clinical presentations. Patients receiving BRMs had 2.4 times more DCM compared to Pulmonary CM (PCM).

Conclusions

AI does not increase the risk of any specific CM clinical presentation, and BRM treatment of most AI patients does not lead to severe CM. However, BRMs significantly increase the risk of DCM, and prospective studies are needed to identify the immunogenetic subset that permits BRM-associated DCM.