Equine common variable immunodeficiency: lessons from 100 clinical cases.

Area of Science:

• Veterinary Immunology
• Equine Medicine
• Immunodeficiency Disorders

Background:

• Recurrent fevers and infections suggest underlying immunodeficiency in horses.
• Common variable immunodeficiency (CVID) is a rare, late-onset disorder affecting B cells and antibody production.
• Clinical signs include respiratory infections, meningitis, dermatitis, and parasitism.

Purpose of the Study:

• To describe the clinical and immunological findings in 100 horses with CVID.
• To compare CVID in horses with the human disease.
• To highlight diagnostic criteria and management challenges.

Main Methods:

• Analysis of clinical and immunological data from 100 equine CVID cases.
• Serum immunoglobulin (IgG, IgM) concentration measurements.
• Peripheral blood B cell distribution analysis and post-mortem lymphoid tissue examination.

Main Results:

• CVID diagnosis confirmed by persistent hypogammaglobulinemia (IgG < 10.00 g/L) and often low IgM (< 0.50 g/L).
• Severe B cell depletion ( < 6% of lymphocytes) was common, though variable.
• Clinical presentations included diverse infections and immune-mediated conditions.

Conclusions:

• CVID in horses is characterized by B cell dysfunction leading to recurrent infections.
• Diagnosis relies on persistent hypogammaglobulinemia and B cell assessment.
• No genetic or clear environmental risk factors have been identified, complicating management and prognosis.