A study of serum nitric oxide levels in psoriasis.

BACKGROUND M any inter and intracellular mediators have been implicated in the pathogenesis of psoriasis. Nitric oxide has been shown to play an important role in many diseases. Previous studies have demonstrated raised levels of nitric oxide in psoriatic plaques which may be attributed to its effect on keratinocytes, on local cGMP levels or its ability to induce angiogenesis. AIMS To detect serum nitric oxide (NO) levels in patients with active psoriasis, to correlate these levels with severity of disease and compare them with those in normal individuals. METHODS Thirty six patients with active psoriasis were selected after written consent. All patients on topical or systemic treatment for fifteen days prior to the study were excluded. Disease severity was assessed by PASI score and serum nitric oxide levels were detected by Greiss method and compared with age and sex matched controls. Statistical analysis of all data was done by unpaired t test. RESULTS Out of 36 patients, 30 had chronic plaque psoriasis (mean NO 157.5), 4 had erythroderma (mean NO 120.2) and 2 had generalized pustular psoriasis (mean NO 144.3). The mean NO level in the psoriatic group was 157.7 with SD 50.4 while in the control group it was 32.8 with SD 4.03. The difference was statistically significant (t=13.8, P < 0.001). In the chronic plaque group, as the duration of disease increased, the NO levels increased significantly. CONCLUSIONS Nitric oxide levels were significantly increased in patients with psoriasis and these levels showed a positive correlation with severity and duration in the chronic plaque type group.