Cell-mediated immunity in psoriatic arthritis

Area of Science:

• Immunology
• Rheumatology
• Cellular Biology

Background:

• Psoriatic arthritis (PsA) is a chronic inflammatory disease.
• Immune system dysregulation is implicated in PsA pathogenesis.
• Mitogen-induced lymphocyte proliferation is a measure of immune cell function.

Purpose of the Study:

• To investigate the mitogen response of peripheral blood lymphocytes in patients with psoriatic arthritis (PsA).
• To compare lymphocyte responses in PsA patients with those in rheumatoid arthritis (RA) patients and healthy controls.
• To assess the relationship between mitogen response and disease activity in PsA.

Main Methods:

• Peripheral blood lymphocytes from 32 PsA patients, RA patients, and normal subjects were stimulated with phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and purified protein derivative (PPD).
• Lymphocyte proliferation was measured as an indicator of mitogen response.
• Sequential studies were conducted in a subset of PsA patients to correlate responses with disease activity.

Main Results:

• Mitogen responses (PHA, Con A, PWM) were significantly depressed in the PsA group compared to controls.
• The degree of mitogen response depression in PsA was comparable to that observed in active RA patients.
• In sequential studies, lymphocyte mitogen responses in PsA patients paralleled disease activity, increasing with disease improvement.

Conclusions:

• Lymphocyte mitogen responses are impaired in psoriatic arthritis, similar to active rheumatoid arthritis.
• The degree of immune cell dysfunction in PsA correlates with disease activity.
• These findings suggest a role for altered T-cell function in the immunopathogenesis of psoriatic arthritis.