Utilizing a PTPN22 gene signature to predict response to targeted therapies in rheumatoid arthritis

Area of Science:

• Immunology
• Genetics
• Rheumatology

Background:

• Rheumatoid arthritis (RA) lacks reliable predictors for selecting targeted therapies.
• A PTPN22 gene signature, linked to impaired induction in peripheral blood mononuclear cells (PBMC), is found in at-risk individuals.
• Downstream targets and regulatory mechanisms of PTPN22 remain largely unknown.

Purpose of the Study:

• To investigate the presence and clinical relevance of the PTPN22 gene signature in RA patients.
• To explore the molecular mechanisms regulating PTPN22 expression.
• To determine if in vitro normalization of PTPN22 expression can predict clinical response to targeted RA therapies.

Main Methods:

• Analysis of PTPN22 gene signature in PBMC from RA patients and healthy donors.
• Correlation analysis of PTPN22 expression with over 1000 genes in Th cells.
• In vitro testing of targeted RA therapies on PTPN22 expression in RA patient PBMC.
• Longitudinal cohort study correlating in vitro PTPN22 normalization with clinical response.

Main Results:

• The PTPN22 gene signature is present in active RA patients and reverses with effective treatment.
• PTPN22 expression correlates with numerous genes in Th cells and is modulated by TNFα and CD28 signals.
• In vitro targeted therapies normalize PTPN22 expression in RA patient PBMC.
• In vitro PTPN22 normalization strongly correlates with clinical response in RA patients.

Conclusions:

• The PTPN22 gene signature is a potential biomarker in rheumatoid arthritis.
• In vitro normalization of PTPN22 expression by targeted therapies can predict clinical response.
• This finding may facilitate personalized treatment selection for RA patients.