Could Blood Cell-Based Inflammatory Markers Be Used to Monitor Response to Biologic Therapy in Psoriasis?

Objectives: Despite extensive research, there is currently no specific biomarker that reliably and universally indicates treatment response in psoriasis. Multiple studies have evaluated systemic inflammation markers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), and systemic immune response index (SIRI) in psoriasis patients. However, there are limited studies investigating changes in these markers with biologic therapy. The goal of this study was to investigate the impact of biologic therapy on parameters including NLR, PLR, MLR, SII, and SIRI in patients with psoriasis. Methods: In this cohort study, we retrospectively evaluated 108 psoriasis patients who were on biological treatment, including interleukin (IL)17, IL23, and IL12/23 inhibitors, for a minimum of 12 weeks. We analyzed Psoriasis Area Severity Index (PASI) scores, complete blood count parameters, and C-reactive protein (CRP) levels both before and after 12 weeks of treatment. Results: The NLR, PLR, MLR, SII, SIRI, and CRP values all demonstrated a significant decrease, regardless of the specific type of biologic agent (p=0.001, 0.007, 0.011, <0.001, <0.001 and <0.001, respectively). Furthermore, we observed a statistically significant but low correlation between the reduction in PASI scores and PLR, SII, and SIRI values (p=0.036, r=0.202; p=0.042, r=0.196; p=0.023, r=0.219, respectively). Conclusion: The NLR, MLR, especially PLR, SII, and SIRI might be used as simple, convenient, and inexpensive laboratory markers to monitor the degree of inflammation and response to treatment after biologic therapy in daily practice.