Phenotypical characterization of circulating cell subsets in pyoderma gangrenosum patients: the experience of the Italian immuno-pathology group

Background No data are available as to the phenotype of circulating lymphocyte subsets in pyoderma gangrenosum (PG). Aim To analyse the expression of different chemokine receptors associated to T-helper (Th)1 (CCR5), Th2 (CCR4) and Th17 (CCR6), as well as the regulatory T-cell subset (Treg) and dendritic cell polarization in the blood of newly diagnosed untreated PG patients. Materials and methods Multi-parameter flow cytometry was performed on blood samples from 10 PG patients collected at first diagnosis among centres belonging to the Italian Immuno-pathology Group. Blood samples from 10 age- and sex-matched healthy controls (HC) were used as controls. Results PG patients are characterized by an over-expression in the blood of the CD4+CCR5+ and CD4+CCR6+ and a down-regulation of CD4+CCR4+ counts with respect to healthy subjects. Moreover, they show increased levels of myeloid derived dendritic cells type1 and reduced levels of the Treg CD4+CD25highFOXP3+ subset. Conclusions The pattern of chemokine expression argues in favour of a Th1 (CCR5+) and Th17 (CCR6+) polarization with a down-regulation of Th2 (CCR4+).