Effect of Anti-Tumor Necrosis Factors Therapy on Hematological Parameters in Patients with Ankylosing Spondylitis in Merjan Teaching Hospital

Background: Ankylosing spondylitis (AS) is a chronic immune-mediated inflammatory disease frequently associated with hematological abnormalities such as anemia, thrombocytosis, and altered indices including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). Anti-TNF therapy has revolutionized the treatment of AS, yet, the impact of anti-TNF therapy on hematological parameters in Iraqi patients remains underexplored. Objectives: to evaluate the effect of anti-TNF therapy on hematological parameters and disease activity in patients with AS at Merjan Teaching Hospital as well as documenting adherence, adverse events, and potential confounders. Methods: A prospective observational cohort study was conducted between January 2024 and July 2025, enrolling 85 biologic-naïve AS patients fulfilling modified New York or ASAS criteria. Patients received infliximab, adalimumab, or etanercept according to clinical judgment. Baseline and follow-up assessments included complete blood count (CBC), derived indices (NLR, PLR, SII), Erythrocyte Sedimentation Rate, c-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The statistical analyses were completed using paired t-tests, repeated measures ANOVA, correlation analysis and multivariate regression with adjustment for covariates. Results: The cohort comprised predominantly males (87%) with a mean age of 40.9 years. Baseline disease activity was high (mean BASDAI 6.26 ± 1.39; CRP 45.27 ± 44.61 mg/L; ESR 49.84 ± 15.28 mm/h). Anti-TNF therapy significantly reduced BASDAI, ASDAS, CRP, and ESR over 12 weeks. Hematological improvements included increased hemoglobin, reduced platelet counts, and normalization of NLR and PLR. Adherence exceeded 80%, with minor adverse events reported; no severe hematological toxicities occurred. Conclusions: Anti-TNF therapy in Iraqi AS patients effectively improved disease activity and corrected hematological abnormalities. Indices such as NLR and PLR may serve as reliable biomarkers of treatment response, underscoring the dual clinical and hematological benefits of biologic therapy in AS management.