Background Psoriasis vulgaris is a chronic recurrent inflammatory skin disease and psoriatic lesions have shown leucocyte infiltration.
Objectives We aimed to study C-reactive protein (CRP) and leucocyte activation markers/inhibitors as potential monitors of psoriasis vulgaris.
Methods A cross-sectional (n = 73) and a longitudinal study (before, at 3, 6 and 12 weeks of therapy; n = 47) was performed; 10 patients started topical treatment, 17 narrow-band ultraviolet light B (NBUVB) and 20 psolaren associated to UVA (PUVA); psoriasis severity was defined by Psoriasis Area and Severity Index (PASI).
Results Compared with control (n = 38), we found higher CRP levels, total leukocyte/neutrophil count, elastase, lactoferrin and α1-antitrypsin. Increasing PASI was linked to increasing CRP and a trend to higher elastase and lactoferrin, suggesting that worsening enhances inflammatory response with neutrophil activation. CRP correlated with PASI, total leucocytes, neutrophils, elastase, lactoferrin and α1-antitrypsin. NBUVB and PUVA presented similar effects.
Conclusion We propose CRP as a useful marker of psoriasis severity that could be used to monitor psoriasis and its treatment, and, together with PASI and elastase, could also be used as a global index of severity.