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Relative chemokine and adhesion molecule expression in Mediterranean spotted fever and African tick bite fever

Jan K Damås1, Giovanni Davì, Mogens Jensenius

  • 1Research Institute for Internal Medicine, Rikshospitalet University Hospital, 0027 Oslo, Norway. jan.k.damas@ntnu.no

The Journal of Infection
|December 19, 2008
PubMed
Abstract

Insights

Mediterranean spotted fever (MSF) caused by Rickettsia conorii is severe, while African tick bite fever (ATBF) caused by Rickettsia africae is mild. R. conorii triggers greater inflammation in endothelial cells, explaining MSF

Area of Science:

  • Infectious Diseases
  • Immunology
  • Cell Biology

Background:

  • Mediterranean spotted fever (MSF) and African tick bite fever (ATBF) are distinct rickettsioses with differing clinical severity.
  • Rickettsia conorii causes MSF, a potentially lethal disease, while Rickettsia africae causes ATBF, a self-limiting illness.

Purpose of the Study:

  • To investigate the differential inflammatory potential of R. conorii and R. africae in endothelial cells.
  • To correlate in vitro findings with clinical inflammatory marker levels in patients with MSF and ATBF.

Main Methods:

  • Assessed mRNA and protein levels of MCP-1, IL-8, and adhesion molecules in endothelial cells stimulated with heat-inactivated R. africae and R. conorii.
  • Analyzed serum samples from MSF and ATBF patients for inflammatory markers before and after therapy.

Main Results:

  • R. conorii significantly upregulated MCP-1, IL-8, and adhesion molecules in endothelial cells via TLR4 activation.
  • R. africae induced MCP-1 but had minimal effects on IL-8 and adhesion molecules.
  • Elevated IL-8 and adhesion molecule levels in MSF patients mirrored the in vitro pro-inflammatory response of R. conorii, unlike in ATBF patients.

Conclusions:

  • R. conorii exhibits a stronger inflammatory potential in endothelial cells compared to R. africae.
  • This differential inflammatory response likely contributes to the distinct clinical severity observed in MSF and ATBF.

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