EXTRACORPOREAL PHOTOCHEMOTHERAPY IN PSORIASIS AND PSORIATIC ARTHRITIS

Background: Psoriasis is the most prevalent chronic dermatosis of an autoimmune origin that is characterized by increasing incidence of both severe clinical forms and complications, the most threatening of which is psoriatic arthritis. Its treatment includes aromatic retinoids, immunosuppressant therapies (immunosuppressant agents, glucocorticosteroids), PUVA-therapy and other methods. However, these are insufficiently effective in clinical practice and are frequently associated with serious adverse reactions and complications. Aim: To increase the efficacy of treatment for psoriasis associated with psoriatic arthritis by means of incorporation of a new immunobiological method, the extracorporeal photochemotherapy (EPCT) into the standard treatment protocol. Materials and methods: We conducted a  prospective cohort study with an active control. Seventy patients with various forms of psoriasis associated with psoriatic arthritis were randomized with stratifi-cation into two groups. The patients of the main group (n = 35) were treated with EPCT, whereas those from the control group (n = 35) received the standard treatment. The EPCT method included isolation of mononuclear cells preliminary sensitized with 8-methoxypsoralen with a cell separator Haemonetics MCS+. After the cell suspension was treated with UV А  (λ = 320–400  nm), it was re-infused to the patient. The treatment course included 4 sessions performed every other day. Results: The analysis of clinical efficacy of EPCT in the combination treatment of psoriasis associated with psoriatic arthritis demonstrated that in the majority of cases a  significant therapeutic effect was achieved. The mean PASI index decreased from 28.5 ± 1.63 to 6.6 ± 1.7 (p < 0.05), the activity of psoriatic arthritis (DAS score), from 3.7 ± 0.35 to 1.7 ± 0.36 (p < 0.05). This significant treatment effect was associated with a  decreased correlation between expression of activation molecules HLADr by natural killer cells (r = 0.6, p < 0.05) and of integrin adhesion molecule CD11b (r = 0.7, p < 0.001). Restoration of apoptosis of autoaggressive cytolitic cells (CD8) determined an improvement in homeostatic imbalance between activation and tolerance. Conclusion: Incorporation of EPCT into the standard protocol of treatment of patients with psoriasis associated with psoriatic arthritis is considered to be highly effective and pathophysiologically based treatment method that allows for cessation of the pathological process within a  short time, with further regression of clinical symptoms. The treatment effect is explained by correction of immune regulatory mechanisms that provide restoration and maintenance of immune homeostasis.