Interferon-α induces altered transitional B cell signaling and function in Systemic Lupus Erythematosus

Area of Science:

• Immunology
• Molecular Biology
• Rheumatology

Background:

• Systemic Lupus Erythematosus (SLE) is characterized by B cell hyper-responsiveness to B cell receptor (BCR) crosslinking.
• Previous studies have not clarified if this hyper-responsiveness stems from altered B cell signaling or distinct B cell subpopulations in SLE patients.
• Understanding these mechanisms is crucial for elucidating SLE pathogenesis and developing targeted therapies.

Purpose of the Study:

• To investigate the signaling pathways and subpopulations of B cells in SLE patients.
• To determine the role of pro-inflammatory factors in B cell hyper-responsiveness in SLE.
• To explore the contribution of altered B cell function to the loss of self-tolerance in SLE.

Main Methods:

• Development of a novel Phosflow technique to analyze cell signaling in distinct B cell subpopulations.
• Stratification of B cells based on developmental stage and cell surface IgM levels.
• Assessment of SYK phosphorylation, apoptosis, and proliferation in B cells from SLE patients and healthy controls.

Main Results:

• Naïve B cells in SLE patients exhibit hyper-responsiveness to IgM receptor crosslinking, evidenced by increased SYK phosphorylation.
• Transitional B cells show the most pronounced hyper-responsiveness, with decreased apoptosis and increased proliferation.
• Hyper-responsiveness fluctuates over time and can be induced in healthy B cells by Type I Interferons (IFNs) or SLE plasma, and blocked by anti-IFN-α antibody.

Conclusions:

• Pro-inflammatory factors, particularly Type I IFNs, modulate B cell function in SLE.
• This modulation contributes to the breach of self-tolerance observed in SLE.
• The findings highlight a potential therapeutic target for managing SLE.