Role of the cutaneous extraneuronal cholinergic system in the pathogenesis of psoriasis: a case–control study

Summary Background Although during recent years there have been considerable advances in elucidating the mechanisms of psoriasis pathogenesis, its full understanding is still distant. A cholinergic dysfunction has been proposed in the pathophysiology of some inflammatory and autoimmune diseases, including psoriasis. Aim To determine tissue levels of acetylcholine (ACh) and its muscarinic and nicotinic receptors (mAChR and nAChR) in psoriasis vulgaris lesions in comparison with normal control skin. Methods This case–control study included 30 patients with psoriasis vulgaris and 30 controls. A 4‐mm punch skin biopsy was taken from the psoriatic plaques of patients and normal skin of controls. ACh level was measured in tissues using the colorimetric method, while mAChR and nAChR gene expression was determined by real‐time PCR. Results The level of ACh was significantly higher in patients (mean ± SD: 5.95 ± 2.69) than in controls (1.12 ± 0.34) (P