# Atypical Presentation of Invasive Aspergillosis during Treatment with Mogamulizumab

## TL;DR

A patient receiving Mogamulizumab developed a fatal case of invasive aspergillosis, highlighting a possible link between immune reconstitution and severe fungal infections.

## Contribution

This case report highlights an atypical and fatal presentation of invasive aspergillosis during treatment with Mogamulizumab.

## Key findings

- A patient on Mogamulizumab developed fatal invasive aspergillosis despite initial asymptomatic lung lesions.
- The patient's immune restoration may have contributed to a catastrophic immune response or masked the progression of aspergillosis.
- Clinicians should be cautious about immune reconstitution syndromes in immunocompromised patients on CCR-4 antagonists.

## Abstract

Treatment with CCR-4 antagonists has been shown to be protective against the development of invasive pulmonary aspergillosis in animal models. Herein, we present a case of fatal invasive pulmonary aspergillosis in a patient receiving Mogamulizumab. A 64-year-old man with refractory mycosis fungoides was found to have diffuse bilateral pulmonary nodules during a chest CT in June 2022. Bronchoalveolar lavage (BAL) fungal and bacterial cultures and galactomannan were negative, as well as serum beta-glucan and galactomannan. Histology showed a lymphoid infiltrate with a negative fungal stain, so a presumptive diagnosis of lymphoma infiltration was made, and the patient started the CCR-4 antagonist Mogamulizumab treatment in August 2022. He had no symptoms until November when he presented to the hematology clinic reporting dyspnea. He had neutrophilic leukocytosis (18.610 cells/µL), his c-reactive protein was 27 mg/dL, and his skin lesions from mycosis fungoides were just starting to improve. A CT scan showed large diffuse bilateral severely necrotic cavitated lesions with thick walls and apparently synchronous evolution. Beta-glucan was 31 pg/mL (wako method), while serum galactomannan 3.6. BAL was positive for Aspergillus fumigatus culture and galactomannan. Patient started voriconazole but, despite being in a stable condition, he suddenly died after two days. Discussion: Paradoxically, worsening of the chronic pulmonary aspergillosis has been reported after nivolumab treatment, and immune reconstitution syndromes are usually seen during neutrophil recovery after intensive chemotherapy. Our patient already presented indolent lung lesions from 5 months before and he remained completely asymptomatic until the aspergillosis diagnosis when he quickly passed away. Even if a progression of the lesions was expected in 5 months, this case had an atypical presentation. During the 5-month period, he had no pulmonary symptoms, and his c-reactive protein was negative. Furthermore, in the setting of the natural progression of subacute/chronic aspergillosis, a different radiological picture was expected with a less severe and probably asynchronous evolution. We think that the immune restoration associated with Mogamulizumab (also supported by the concurrent clinical response of the skin lesions) could have been detrimental in this case, exacerbating a catastrophic immune response or alternatively masquerading the clinical progression of aspergillosis. Clinicians should be aware of immune reconstitution syndromes possibly leading to fatal outcomes in immunocompromised patients starting CCR-4 antagonists.