A Treatment and Monitoring Protocol for Tocilizumab in Refractory Macrophage Activation Syndrome with Systemic Juvenile Idiopathic Arthritis

Summary

This protocol describes the use of tocilizumab, combined with glucocorticoids and cyclosporine A, as salvage therapy for refractory macrophage activation syndrome in children with systemic juvenile idiopathic arthritis.

Abstract

This study evaluated the therapeutic effectiveness and safety of tocilizumab (TCZ) in patients with systemic juvenile idiopathic arthritis (sJIA)-associated refractory macrophage activation syndrome (MAS). A total of 100 patients diagnosed between 2021 and 2022 were included. Patients receiving standard therapy (glucocorticoids plus cyclosporine A) were assigned to the control group (n = 30), while those receiving add-on TCZ were assigned to the study group (n = 70). The treatment protocol included intravenous methylprednisolone pulses followed by oral prednisone tapering, cyclosporine A with trough monitoring, and TCZ administered every 2 weeks. Outcomes included laboratory parameters, cytokine profiles (IL-6, IL-18, IFN-γ, sCD25, sCD163), sJADAS27 scores, clinical response, and adverse events over 24 months. The TCZ group demonstrated faster normalization of laboratory indices and greater reduction in inflammatory cytokines (P < 0.05). Remission rates were higher (71.4% vs. 33.3% at Day 14), with lower recurrence and reduced glucocorticoid exposure. Adverse event rates were lower in the TCZ group (25.7% vs. 46.7%, P < 0.05). These findings demonstrate that TCZ-based combination therapy provides an effective and well-tolerated salvage strategy for refractory sJIA-MAS and support further prospective evaluation of this protocol.

Introduction

Systemic juvenile idiopathic arthritis (sJIA) is an autoinflammatory subtype that represents approximately 10–15% of juvenile idiopathic arthritis (JIA) diagnoses and is characterized by quotidian fever, a transient salmon-colored rash, and arthritis¹. Macrophage activation syndrome (MAS), a life-threatening complication of sJIA, results from excessive T-cell and macrophage activation, leading to a cytokine storm and multi-organ failure². Approximately 10% of patients with sJIA develop overt MAS, with mortality rates reaching 20%–40% in severe cases^3,4

Protocol

This retrospective study, which analyzed anonymized clinical archives, was approved by the Ethics Committee of the Maternity and Child Healthcare Hospital, Qinhuangdao (Approval No.: QFY000286) in accordance with the Declaration of Helsinki. Due to the study's retrospective nature and the use of pre-existing anonymized clinical data, the ethics committee waived the requirement for informed consent. The reagents, chemicals, and software used are listed in the Table of Materials.

1. Patient selection and cohort formation

1. Screen the electronic medical record system to identify all children diag....

Results

A total of 100 children with sJIA-MAS were included in this study, divided into 30 cases in the control group and 70 cases in the study group according to treatment modality. Baseline comparisons demonstrated no statistically significant differences between the two groups in demographic variables (age, sex, body mass index), clinical features (fever, rash, hepatomegaly, splenomegaly, lymphadenopathy, liver dysfunction, encephalopathy, pulmonary edema, circulatory failure, arthritis), laboratory indices (PLT, WBC, NEU, LY.......

Discussion

This retrospective controlled analysis demonstrates that tocilizumab (TCZ) combined with glucocorticoids provides significant therapeutic benefit in refractory sJIA-MAS, accelerating normalization of laboratory parameters, promoting clinical remission, and reducing the risks of glucocorticoid dependence and long-term recurrence. A multidimensional evaluation integrating serial laboratory parameters, dynamic cytokine profiling (IL-6, IL-18, IFN-γ, TNF-α, sCD25, sCD163), disease activity scores, and long-term out.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Medications
Tocilizumab	Shanghai Roche Pharmaceutical Co., Shanghai, China	S20130020	Recombinant humanized anti-IL-6 receptor monoclonal antibody; 80 mg/4 mL per vial
Methylprednisolone	Pfizer Manufacturing Belgium NV, Puurs, Belgium	H20130301	40 mg per vial; used for intravenous pulse therapy
Cyclosporine A	Roche Pharma (Schweiz) Ltd	S20130020	Immunosuppressant; 80 mg/4 mL oral solution
Blood Collection Materials
Serum separator tubes	Becton, Dickinson and Company, Franklin Lakes, NJ, USA	367983	5 mL, with clot activator and gel separator
EDTA tubes	Becton, Dickinson and Company, Franklin Lakes, NJ, USA	367855	3 mL, K2 EDTA for complete blood count
Sodium citrate tubes	Becton, Dickinson and Company, Franklin Lakes, NJ, USA	363083	3 mL, 3.2% buffered sodium citrate for coagulation tests
Cryovials	Corning Inc., Corning, NY, USA	430659	2 mL, sterile, for serum storage at −80 °C
Cytokine Assay Platform
ProcartaPlex Human Cytokine Panel 1B 25plex	Invitrogen (Thermo Fisher Scientific), San Diego, CA, USA	EPX250-12166-901	Luminex-based multiplex immunoassay; detects IL-6, IL-18, IFN-γ, TNF-α, and 21 other cytokines; requires 25 µL serum
Luminex Instrument	Luminex Corporation, Austin, TX, USA	Luminex 200	For multiplex cytokine detection; xMAP technology
ELISA Kit for sCD25	Boster Bio	EK0400	Sensitivity: 5 pg/mL
ELISA Kit for sCD163	R&D Systems, Minneapolis, MN, USA	DC1630	Sandwich ELISA; detection range: 1.6–100 ng/mL; sensitivity: 0.613 ng/mL; for human serum
ELISA Equipment
Microplate reader	Shanghai Kehua Laboratory System Co., Ltd., Shanghai, China	ST-360	8-channel absorbance reader; filters at 405, 450, 492, 630 nm; reading speed: 5 s/96-well; for ELISA detection
Automatic plate washer	Shanghai Kehua Laboratory System Co., Ltd., Shanghai, China	ST-36W	96-channel plate washer; residual volume ≤1 μL/well; adjustable dispense volume 0–3000 μL; with bottom wash function
Incubator	Shanghai Xin Nuo Instrument Group Co., Ltd., Shanghai, China	EHP-55K	Forced-air convection incubator; temperature range: Amb+5–70 °C; temperature fluctuation ≤±0.2 °C; for ELISA incubation at 37 °C
Adjustable pipettes	Dlab Scientific (Beijing) Co., Ltd., Beijing, China	HiPette/TopPette series	Single-channel pipettes; volumes: 0.5–10 µL, 10–100 µL, 100–1000 µL; for reagent and sample dispensing
Clinical Laboratory Instrumentation
Automated Hematology Analyzer	Mindray, Shenzhen, China	BC-6800Plus	For complete blood count (CBC) including PLT, WBC, NEU, LYM
Chemistry Analyzer	Siemens Healthineers, Erlangen, Germany	ADVIA 1800	For CRP, ESR, liver enzymes (ALT, AST), triglycerides, fibrinogen, D-dimer, ferritin
Coagulation analyzer
ESR measurement system
Statistical Software	IBM SPSS	Version 25.0	Used for all statistical analyses
Diagramming Software	Lucidchart	Online version	Used for generating study flowchart
G*Power Software	Heinrich-Heine-Universität Düsseldorf	Version 3.1.9.7	Used for sample size calculation
Centrifuge	Thermo Fisher Scientific, Waltham, MA, USA	75007201	Sorvall™ ST 8 benchtop centrifuge; for serum separation at 1,500 × g; 4 °C capable
Ultra-low temperature freezer	Thermo Fisher Scientific, Waltham, MA, USA	Forma™900	−80 °C freezer for long-term serum storage
Software
Statistical software	IBM Corp., Armonk, NY, USA	SPSS Statistics version 25.0	Used for all statistical analyses
Sample size calculation software	Heinrich Heine University Düsseldorf, Düsseldorf, Germany	G*Power version 3.1.9.7	Used for power analysis and sample size calculation
Diagramming software	Lucid Software Inc., South Jordan, UT, USA	Lucidchart (online version)	Used for generating study flowchart