Basophils and IgE contribute to mixed connective tissue disease development

Area of Science:

• Immunology
• Autoimmune Diseases
• Rheumatology

Background:

• Mixed connective tissue disease (MCTD) is a rare autoimmune disorder with overlapping features of lupus, scleroderma, and myositis.
• It is characterized by anti-U1 RNP antibodies and often involves severe lung disease.
• The underlying mechanisms of MCTD and effective treatments remain unclear.

Purpose of the Study:

• To investigate the involvement of basophils and immunoglobulin E (IgE) in the pathology of MCTD.
• To explore potential therapeutic targets for MCTD based on these findings.

Main Methods:

• Assessed basophil activation and autoreactive IgE in MCTD patients and a mouse model.
• Utilized basophil-depleted and IgE-deficient mice to evaluate their roles in lung pathology.

Main Results:

• MCTD patients exhibited basopenia with activated, CCR3-overexpressing basophils.
• Nearly 80% of patients had IgE targeting U1 RNP, the primary autoantigen.
• The mouse model showed similar basophil and IgE activation, with basophil accumulation in lymph nodes and lungs.
• Reducing basophils lessened lung pathology, while IgE deficiency prevented it.

Conclusions:

• Basophils and IgE are integral to MCTD's development and progression.
• These components represent promising therapeutic targets for managing MCTD and its associated lung disease.