Study of T helper (17) and T regulatory cells in psoriatic patients receiving live attenuated varicella vaccine therapy in a randomized controlled trial

Background

The use of live attenuated varicella vaccine (Varilrix^®) as an adjuvant treatment in severe cases of psoriasis has recently been postulated. Its efficacy raised questions regarding its possible mechanisms of action.

Objective

To compare the efficacy and safety of combining Varilrix^® and cyclosporine to cyclosporine alone in the treatment of severe psoriasis. Furthermore, to study the expression of T helper (Th)17 and T regulatory (Tregs) cells before and after therapy.

Materials and methods

This randomized controlled trial included 24 psoriatic patients, randomly divided into 2 groups (A and B). All patients received cyclosporine at a daily dose of 2.5 mg/kg/day. In addition, group A received 4 doses of Varilrix^® once/3 weeks, and group B received 4 doses of subcutaneous saline. Skin biopsies were obtained from all patients before and after therapy and from all controls for estimation of interleukin (IL)-17, IL-22 and Forkhead boxP3 (FoxP3) using RT-PCR.

Results

Group A patients showed a significantly higher % of clinical improvement (P = 0.011), which occurred earlier than group B. At baseline, levels of IL-17 and IL-22 were significantly higher while the level of FoxP3was significantly lower in patients (P<0.001) compared to controls. After therapy, both groups showed significant reductions in both IL-17 and IL-22 levels, and significant elevation in FoxP3 (P<0.001). This change was significantly more evident in group A patients.

Conclusion

Live attenuated varicella vaccine could play a role in the treatment of psoriasis when combined with low dose cyclosporine through accentuating the influence on the Th17/Treg balance.