CD26/dipeptidyl-peptidase IV and adenosine deaminase serum levels in psoriatic patients treated with cyclosporine, etanercept, and psoralen plus ultraviolet A phototherapy.

OBJECTIVE

The aim of this study is to determine serum levels of soluble forms of CD26/dipeptidyl-peptidase IV (DPP-IV) and adenosine deaminase (ADA), thought to be markers of T-cell activation, and changes in their levels in response to cyclosporine, etanercept, and psoralen plus ultraviolet A (PUVA) treatments with respect to disease activity.

METHODS

This study is designed as a prospective clinical study with a control group and three months of follow-up. The study included 41 patients with psoriasis and 41 healthy controls that were older than 18years of age. There were three different treatment groups: PUVA (n=15), cyclosporine (n=15), and etanercept (n=11). To determine disease severity of patients with psoriasis, psoriasis area and severity index (PASI) scores were calculated.

RESULTS

Only mean serum ADA levels were different between patients with psoriasis [mean1±standard deviation (SD)=13.9±3.3U/ml] and control group (mean±SD=12±3.5U/ml). Mean serum ADA levels were significantly higher before treatment than after treatment (mean±SD=12.4±3.4U/ml). Contrarily, following three months of therapy, mean serum CD26 levels increased significantly from 777.7±214.6 to 835.3±203ng/ml (P<0.05) and mean serum DPP-IV activity increased significantly from 12.1±4 to 15.9±4.2nmol/min (P<0.05). There was no correlation between ADA and CD 26/DPP-IV with PASI values.

CONCLUSIONS

The results show that ADA might be a useful marker indicating disease activity and T-cell activation. As significant changes were observed in serum CD26/DPP-IV before and after treatment, we think CD26/DPP-IV might play a role in psoriasis pathogenesis, which should be clarified by further studies.