The acute phase response in Sicilian patients with Boutonneuse fever admitted to hospitals in Palermo, 1992-1997

Objectives: To study the modifications of some components of the acute phas e response (APR) in Sicilian patients with boutonneuse fever (BF) caused by Rickettsia conorii. Methods: Sera from 500 Sicilian patients with confirmed BF were studied at the time of diagnosis and every week after treatment, and after recovery fo r the presence of various inflammatory mediators. Tumour necrosis factor al pha (TNF alpha), interleukin(IL)-6, IL-1 alpha, IL-8, soluble TNF receptors (sTNF-R) and sIL-6R were assayed by commercially ELISA kits. C3, C4, facto r B, C-reactive protein (CRP), fibrinogen, ceruloplasmin (Cp) and alpha (1) -antitrypsin (AAT) were assayed by a rate nephelometry. Results: Interferon gamma (IFN-gamma), IL-6, TNF alpha, and IL-10 cytokines were significantly modified, whereas IL-1 and IL-8 were not detectable in the blood in anp phase of infection. sTNF-RI, sTNF-RII and sIL-6 were signi ficantly increased in the first 2 weeks of infection, but sTNF-R levels wer e not related to the plasma levels of TNF alpha, whereas sIL-6 was directly related to serum IL-6 concentrations. C3, C4, factor B and CRP were signif icantly increased in the first 2 week of infection, but afterwards returned to the normal range, even though CRP was still high in the third week and C3 persisted high aft er the fourth week. Fibrinogen was high only in the f irst week in relation to the injury to the endothelial cells (ECs). The ant i-inflammatory proteins, Cp and AAT, were extremely high in the first 2 wee ks of infection acting as a buffer of APR activation. Conclusions: These results suggest that R. conorii is able to elicit, after invasion and proliferation in the ECs, the activation of APR. Further work is required to establish if active inhibitory mechanisms are operating dur ing APR, or if there is a spontaneous decay in the initiation events. (C) 2 001 The British Infection Society.