Assessment of the Percentages of T-lymphocyte Subsets in the Peripheral Blood of Mediterranean Spotted Fever Patients

Purpose: Mediterranean spotted fever (MSF) is a rickettsial disease. The aim was to evaluate the host immunе response to Rickettsia conorii. Material and methods: 62 patients were assigned into three groups: with mild, moderate or severe clinical forms of MSF. Controls were 32 healthy individuals. The diagnosis of MSF was confirmed by the indirect immunofluorescence assay. Immunophenotyping was performed using Epics XL-MCL Coulter. Results: The percentage of immune competent (CD3+) cells decreased, whereas that of helper/inducer (CD3+CD4+) and suppressor/cytotoxic (CD3+CD8+) did not change compared to controls. All three T-cell subset percentages did not parallel the disease severity. Naïve T-cells (CD4+CD45RA+) showed reduced levels, whereas activated memory (CD4+CD45RO+) T-cells did not change significantly. The percentage of activated (CD3+HLA-DR+) T-cells increased regardless of the disease severity, till the rise of stimulatory molecules (CD38+total) matched the disease severity forms. The percentage of costimulatory CD28-molecules corresponded to the disease severity as their levels increased significantly in mild forms and showed an evident downward trend towards the severe ones. Conclusion: Reduced T-lymphocyte subsets are likely related to trans-migration into perivascular inflammatory foci. The increased percentage of T-lymphocytes armed with stimulatory molecules probably reflects the mobilization of cell-mediated immune response in the healing process.