Aspergillus felis in Patient with Chronic Granulomatous Disease

Inborn errors of immunity and invasive fungal infections: presentation and management

PURPOSE OF REVIEW

We review the clinical presentations of invasive fungal infections in a selection of inborn errors of immunity. In addition, we review the particularities of their management, including antifungal therapy, prophylaxis, and immunomodulatory treatments.

RECENT FINDINGS

Patients with chronic granulomatous disease and with signal transducer and activator of transcription 3 (STAT3) deficiency are particularly prone to aspergillosis. Mold-active antifungal prophylaxis should be prescribed to all patients with chronic granulomatous disease, and in patients with STAT3 deficiency and underlying parenchymal lung disease. Invasive fungal infections are rare in patients with STAT1 gain-of-function mutations, while the clinical phenotype of caspase-associated recruitment domain-containing protein 9 deficiency encompasses a wide range of superficial and invasive fungal infections. Most patients with inborn errors of immunity and invasive fungal infections require prolonged durations of antifungals. Hematopoietic stem cell transplantation should be considered early for patients with chronic granulomatous disease, but results have been more mixed for other inborn errors of immunity with active invasive fungal infections.

SUMMARY

Inborn errors of immunity can confer increased susceptibility to a variety of invasive fungal infections, which can present with specific clinical and radiological features. Management of fungal infections in these patients is often challenging, and relies on a combination of antimicrobial prophylaxis, antifungal treatments, and immunomodulation.

Case report: a fatal case of Aspergillus felis infection in an immunocompetent host

We report a fatal case of Aspergillus felis invasive rhinosinusitis with secondary cerebral abscesses in an immunocompetent host despite aggressive surgical debridement and combination antifungals. Whilst this organism is known to cause fatalities in cats, only a few cases in humans have been documented, all of which had significant immunosuppression. This is the first human death due to A. felis described in an immunocompetent host.

Overlapping infection of Nocardia farcinica and Aspergillus fumigatus in a child with X-linked chronic granulomatous disease: a case report

Background

Chronic granulomatous disease (CGD) is a rare inherited primary immunodeficiency syndrome, manifested as recurrent infections and inflammatory complications. Although prophylactic treatment with antibiotics and antifungals improved the outcome of CGD patients, infections remain the major cause of mortality.

Case presentation

A boy aged 3 years and 8 months was admitted to hospital complaining of lip swelling with fever for half a month and neck abscess for 11 days. After a thorough examination, severe pneumonia, respiratory failure, oral and maxillofacial space infection, and perianal abscess were confirmed. However, his condition didn’t improve after initial comprehensive therapy. Subsequently, overlapping infections of Nocardia farcinica and Aspergillus fumigatus were identified by metagenomic next-generation sequencing. He was treated with imipenem, linezolid, and voriconazole intravenously, plus taking oral compound sulfamethoxazole. Later, his condition improved. Through whole-exome sequencing, the child was ultimately diagnosed as X-linked chronic granulomatous disease (X-CGD) caused by CYBB gene mutation. Allogeneic hematopoietic stem cell transplantation was the potential sanative approach but there were no available human leukocyte antigen compatible donors for the child. The family requested to transfer to a superior hospital for further treatment. Two months later, we followed up the child’s family. Unfortunately, the child had expired due to severe infection.

Conclusion

To our knowledge, this is the first case of overlapping infection of Nocardia farcinica and Aspergillus fumigatus identified by metagenomic next-generation sequencing in a child with X-CGD from China. For infectious pathogens that are hard to diagnosis by traditional detection methods, metagenomic next-generation sequencing is recommended as an adminicle or indispensable approach for microbial identification. Patients with X-CGD have poor prognosis, early diagnosis and intervention of X-CGD may reduce the mortality.

Complete clinical response to combined antifungal therapy in two cats with invasive fungal rhinosinusitis caused by cryptic Aspergillus species in section Fumigati

Cryptic species in Aspergillus section Fumigati are increasingly reported to cause invasive aspergillosis in humans and animals. These infections are often refractory to treatment because of intrinsic antifungal resistance. We report two cases of invasive fungal rhinosinusitis in domestic cats caused by A. udagawae and A. felis. Clinical signs resolved after combined therapy including posaconazole, caspofungin and terbinafine. Both cases remained asymptomatic more than 2 years from initial presentation.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

Disseminated invasive aspergillosis caused by Aspergillus felis in a cat

A 2‐year‐old male desexed Ragdoll cat with a 1‐year history of sneezing and nasal discharge presented with a large subcutaneous cervical mass, identified as the right medial retropharyngeal lymph node on computed tomography (CT). A right orbital mass, destructive sino‐nasal cavity disease and multiple pulmonary nodules were also identified. Aspergillus felis was cultured from the lymph node. After treatment with posaconazole and liposomal amphotericin B the lymph node enlargement and orbital mass resolved but left frontal sinus involvement and pulmonary lesions persisted despite additional caspofungin therapy. The cat was euthanized 14 months after diagnosis with dysphagia and chronic progressive exophthalmos. A meningeal granuloma with intravascular fungal hyphae was identified at post‐mortem and A felis was cultured from the left frontal sinus and a right retrobulbar fungal granuloma. This case demonstrates that disseminated disease is a possible sequel to invasive fungal rhinosinusitis caused by A felis in cats.

Aspergillus fumigatus Infection in Humans With STAT3-Deficiency Is Associated With Defective Interferon-Gamma and Th17 Responses

In humans, loss-of-function mutation in the Signal Transducer and Activator of Transcription 3 (STAT3) gene is frequently associated with susceptibility to bacterial as well as fungal infections including aspergillosis, although its pathogenesis remains largely unknown. In the present study, we investigated the immune responses obtained after stimulation with Aspergillus fumigatus in STAT3-deficient patients. A. fumigatus conidial killing efficiencies of both monocytes and neutrophils isolated from whole blood samples of STAT3-deficient patients were not different compared to those of healthy controls. After stimulation with A. fumigatus conidia, lower concentrations of adaptive cytokines (IFN-γ, IL-17 and IL-22) were secreted by peripheral blood mononuclear cells from STAT3-deficient patients compared to those from healthy controls. Moreover, the frequency of IFN-γ and IL-17 producing CD4+ T cells was lower in STAT3-deficient patients vs. healthy controls. Among the STAT3-deficient patients, those with aspergillosis showed further lower secretion of IFN-γ upon stimulation of their PBMCs with A. fumigatus conidia compared to the patients without aspergillosis. Together, our study indicated that STAT3-deficiency leads to a defective adaptive immune response against A. fumigatus infection, particularly with a lower IFN-γ and IL-17 responses in those with aspergillosis, suggesting potential therapeutic benefit of recombinant IFN-γ in STAT3-deficient patients with aspergillosis.