The Role of Immature Granulocyte Count and Percentage as Novel Indicators of Systemic Inflammation in Plaque Psoriasis

Abstract

Background/Objective: Psoriasis is a chronic immune-mediated inflammatory disease with systemic involvement. Immature granulocytes (IGs) are potential inflammatory markers, but their role in psoriasis is unclear. We evaluated immature granulocyte count (IG#) and percentage (IG%) in plaque psoriasis, their associations with disease severity and treatment response, and their ability to distinguish patients from healthy controls. Methods: This retrospective study included 85 adults with plaque psoriasis and 85 healthy controls. Severity was assessed by the Psoriasis Area and Severity Index (PASI). IG#, IG%, and inflammatory markers were measured before treatment and after at least 3 months of systemic therapy. Group comparisons, correlations, and receiver operating characteristic (ROC) analyses were performed. Results: Pre-treatment IG# and IG% were higher in patients than in controls (both p < 0.001). IG# decreased after treatment (p = 0.004), whereas IG% did not (p = 0.072). Despite clinical improvement, post-treatment IG#, IG%, and C-reactive protein remained higher than controls. Pre-treatment IG# correlated weakly with PASI (r = 0.24, p = 0.020), whereas other PASI–IG correlations were non-significant. Discriminatory performance was modest for IG# (AUC = 0.697) and IG% (AUC = 0.658). Conclusions: IG# and IG% are elevated in plaque psoriasis. IG# decreases with treatment and may be a potential marker of inflammatory changes, while the persistence of elevated IG# and IG% levels after treatment relative to healthy controls may reflect residual inflammation. However, weak associations with disease severity and modest discriminatory performance do not support their use as standalone clinical tools. As these parameters are routinely available from complete blood counts, they may complement clinical assessment. Further prospective studies are required to establish their clinical relevance.