Background Interleukin-23 (IL-23), a key inflammatory regulator in the pathogenesis of psoriasis, is suspected to play a role in the onset of pulmonary dysfunction (chronic obstructive pulmonary disease) in psoriasis. Despite that, pulmonary function tests are rarely studied in these subjects. This study aims to seek a possible relation between pulmonary function in psoriasis patients serum IL-23. Methods For this analytical cross-sectional study, male psoriasis patients in the age group of 25-45 years were recruited from dermatology out patient department (n = 40). Age and BMI matched apparently healthy individuals were recruited as control group (n = 40). After obtaining demographic and personal details, anthropometric parameters and blood pressure were recorded. The severity of psoriasis was assessed using Psoriasis Area and Severity Index score. Pulmonary function was assessed using computerized spirometry, and serum IL-23 was measured using ELISA. Results Forced vital capacity, forced expiratory volume in 1 s, peak expiratory flow rate, and forced expiratory flow at 25%-75% of the pulmonary volume (FEF25%-75%) were significantly reduced in psoriasis. Based on the percentage of predicted values FEF25%-75% was significantly reduced in psoriasis. Serum IL-23 (pg/mL) was significantly higher in psoriasis. The increase in IL-23 in psoriasis subjects does not correlate with their pulmonary function. Conclusions Psoriasis may be associated with a reduced lung function even when the disease is in the mild stage. Increased IL-23 found in these subjects is suggestive of systemic inflammation, which indirectly lowers lung function.
Keywords: IL-23; psoriasis; spirometry.