Clinical, molecular, and histological characteristics of severely necrotic and fatal mpox in HIV-infected patients.

Background: This case series of 5 patients with severely necrotic mpox highlights the predominantly necrotic nature of lesions seen in cases of severe mpox as shown by skin and lung biopsy, as well as the extensive dissemination of the infection, as shown by polymerase chain reaction (PCR) assessment in different body sites.

Case presentations: Patients were male, the median age was 37, all lived with HIV (2 previously undiagnosed), the median CD4⁺ cell count was 106 cells/mm³, and 2/5 were not receiving antiretroviral treatment. The most common complication was soft tissue infection. Skin and lung biopsies showed extensive areas of necrosis. Mpox PCR was positive in various sites, including skin, urine, serum, and cerebrospinal fluid. The initiation of antiretroviral treatment, worsened the disease, like that seen in immune reconstitution syndrome. Three patients died due to multiple organ failure, presumably associated with mpox since coinfections and opportunistic pathogens were ruled out.

Conclusions: Severely necrotic manifestations of mpox in people living with advanced and untreated HIV are related to adverse outcomes.