Myeloperoxidase of polymorphonuclear leukocytes in psoriasis vulgaris.

The specific activity of myeloperoxidase (MPO), an enzyme located in the primary granules of polymorphonuclear leukocytes, was measured in patients with psoriasis vulgaris and compared with that in patients with atopic dermatitis and in healthy subjects. MPO catalyzes the oxidation of guaiacol into tetraguaiacol in the presence of H2O2. The activity was determined by photometric measurement of tetraguaiacol. The specific MPO activity showed no statistically significant difference between the healthy subjects and the patients with atopic dermatitis. In comparison to these two groups the specific MPO activity of the psoriatic patients showed a slight reduction which was, however, not statistically significant.