Background In systemic sclerosis (SSc), therapeutic options are limited mainly to the management of complications, halting fibrosis, therefore preventing disease progression is a great challenge. The aim of the present study was to evaluate the immunomodulatory effects of extracorporeal photochemotherapy (ECP) in SSc.

Objectives In the study, we investigated the influence ofECP on lymphocyte activation and cell death by determining CD95, Annexin V, CD69 and HLA-DR expression on circulating T and B cells in SSc patients, and assessing their changing after ECP therapies. Moreover, we evaluated the relationship between lymphocyte activation and changes in certain immune parameters following ECP treatments.

Methods We enrolled 16 SSc patients, who received 12 ECP treatments in total. Blood samples were taken prior to the first therapy and 6 weeks after each cycle. Samples were also obtained from 16 healthy controls. Lymphocyte subgroups were quantified by flow cytometry.

Results Initially, patients had higher numbers and percentages of peripheral CD95+ T cells, but not CD95+ B cells, compared to control values. After ECP treatments, values of CD95+ T cells decreased and became similar to controls. Annexin V expression on T and B cells did not changed during the therapy. We observed significant negative correlation between the changes in percentages of peripheral CD95+ T cells and CD4+ CD25+ Treg cells. Although neither early-activated (CD69+) nor late-activated (HLA-DR+) T lymphocytes showed any changes after ECP, clear negative correlations developed between them and the functional ability of CD4+CD25+ Treg cells after the last treatment.

Conclusions Our results indicate that the initial increase of CD95+ expression in SSc presumably reflects a physiological response to the pronounced autoimmune processes, which can be effectively attenuated by the restoration of regulative T cell numbers and functions as the result of ECP therapy.

Disclosure of Interest None Declared