BACKGROUND: Many 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