Cover
Vol. 4 No. 1 (2026)

Published: June 1, 2026

Pages: 49-60

Review Article

Tocilizumab and IL-6 Signaling in Rheumatoid Arthritis: Clinical Implications for Infection Detection and CRP Limitations (Narrative Review with a Retrospective Case Series)

Baker Thamer Alany 1 Mohanad AbdulSahib 1
1 Department of Clinical Pharmacy , College of Pharmacy, Al-Nahrain University, Baghdad, Iraq
History
  • Received: January 11, 2026
  • Revised: April 11, 2026
  • Accepted: April 18, 2026
  • Available Online: June 1, 2026

Abstract

ABSTRACT objective: To consolidate current knowledge regarding the diagnostic challenges associated with interleukin-6 (IL-6) inhibition, to describe reported clinical infections occurring during tocilizumab (TCZ) therapy, and to evaluate its therapeutic efficacy and safety profile. Methods: A retrospective case series was conducted at Tel Aviv Medical Center (Helsinki Committee approved). Nine patients with rheumatoid arthritis receiving tocilizumab who developed confirmed infections between 2022 and 2025 were included. Data collected included C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell (WBC) count, and clinical outcomes. Infection was confirmed based on clinical findings, laboratory investigations, and imaging studies. Results: Nine hospital admissions that met the inclusion criteria were identified. Seven patients were receiving tocilizumab for rheumatoid arthritis, while two were treated for giant cell arteritis. TCZ was administered intravenously once monthly in seven patients and subcutaneously once weekly in two patients. Conclusion: Tocilizumab is effective in rheumatoid arthritis but may mask inflammatory responses by suppressing CRP levels. Clinicians should not rely solely on CRP for infection detection and should incorporate clinical assessment and alternative biomarkers to avoid delayed diagnosis. Keywords: "tocilizumab", "IL-6 blockade", "CRP suppression", "rheumatoid arthritis", and "infection"

Keywords

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