MONOCYTES MACROPHAGES EXPRESSION OF Ml OR M2 PHENOTYPES IN LATENT TUBERCULOSIS, ACTIVE DISEASES AND UNINFECTED MIGRANTS AND SICILIAN PATIENTS

The high grade ofphenotype plasticity of monocytes macrophages, is resumed in two different cell subsets named M1 or M2. Several studies of microbial infections in vitro and in vivo, showed that, during the early stage of infection, macrophages are polarized toward Ml phenotype that should be protective against pathogen, while during the chronic phase of infection/disease macrophages polarize toward M2 phenotype to avoid damages from a prolonged Ml type activation.Obiettivo: In order to investigate if Mycobacterium tuberculosis infection can drive circulating monocytes toward the expression of Ml or M2 phenotypes, we have analyzed by flow cytometry monocytes obtained from patients with active tuberculosis (TB) at early phase of disease and during anti mycobacterial therapy, subjects with latent TB and healthy uninfected control. Risultatil Analysis of surface markers expression showed no clearcut Ml/M2 polarization in all tested groups, but we found a very high percentage of RANK+ monocytes in patients with active TB disease before treatment, while RANK expression was very faint in monocytes from all other experimental groups. Moreover the statistical analysis of geometric MFI of RANK showed a signifìcant difference between patients with active disease compared to all the others groups. Conclusioni: Given that the available in vitro diagnostic tests are limited in discriminating subjects with latent or active disease, as well as response to therapy,,we speculate that the evaluation of RANK expression on monocytes could represent an additional biomarker useful to support diagnosis of active disease and monitor the response to therapy.