Early diagnosis and monitoring of adaptive immune response in a cohort of mild mpox patients during the 2022 wave

Our study wants to describe the kinetics of serological and adaptive immune responses in mpox patients. Methods. Fourteen patients with a laboratory-confirmed mpox were tested at different time points after symptoms onset. An immunofluorescence assay was performed to evaluate seroconversion kinetics of specific IgA, IgM, and IgG. Moreover, the characterization of the adaptive immunological profile of T- and B-cells was performed. Results. Antibody kinetics revealed faster and more effective seroconversion of specific IgA than IgM. Moreover, we detected an increase of Active B memory cells and CD8+ cells in the early phases of infection, and a reduction of CD4+ T- in mpox patients with respect to controls; with a different CD8 active T-cells profile in HIV+ compared to HIV- subjects. Moreover, we found the presence of higher levels of Treg cells in HIV+ patients in the early phase of infection. Conclusion: Our data highlighted the relevance of specific IgA testing early after SO, suggesting a possible role as a marker in early diagnosis, especially in close contact subjects. Furthermore, after symptoms’ onset we observed a different maturation state of effector cells in HIV+ patients that, together with high Treg levels, may lead us to better understand the role of MPXV-HIV co-infection in disease progression.