Depression of CD4 T Cell Subsets and Alteration in Cytokine Profile in Boutonneuse Fever

Interferon (IFN)-γ, interleukin (IL)-10, IL-6, and tumor necrosis factor (TNF)-α were significantlyincreased in sera from Sicilian patients with acute boutonneuse fever (BF) compared with those ofhealthy controls. IFN-γ levels dropped sharply within the second week after infection. IL-6, IL-10,and TNF-α levels gradually declined; in convalescent patients only were they in the normal range.In contrast, peripheral blood mononuclear cells (PBMC) stimulated in vitro with phytohemagglutinin(PHA) produced low levelsof IL-10 and IFN-γ in acute BF that were compatible with the reductionin the levels of CD4+, CD4+/CD45RO+, and CD4+ICD45RA+ cells. In vitro production of TNF-α and IL-6 from PBMC stimulated with PHA was not significantly modified during the various phases of the infection compared with control PBMC, which could be due to the persistence of high levels of CD14+ monocytes compensating for the decrease in CD20+ B cells.