In immune-mediated arthritis, which leukocytes are typically elevated in the joint?

• A. Neutrophils
• B. Eosinophils
• C. Lymphocytes
• D. Macrophages

Answer: (A)

In immune-mediated arthritis, the joint typically shows a neutrophil-dominated inflammatory response. Immune reactions—often immune complex–driven or autoantibody–mediated—activate complement and recruit neutrophils into the synovial fluid. These neutrophils release enzymes and mediators that drive synovitis and cartilage damage, so the inflammatory cell profile in the joint is primarily neutrophils.

Eosinophils would suggest an allergic or parasitic process, lymphocytes are more characteristic of some other chronic autoimmune conditions, and macrophages are important but not the predominant cell type in this sterile, immune-driven arthritis.