CD8+ cell changes in psoriasis associated with roxithromycin-induced clinical improvement.

Area of Science:

• Immunology
• Dermatology

Background:

• Psoriasis is associated with altered T cell populations, specifically decreased CD8+ T cells expressing T cell receptor BV2 and BV8 in peripheral blood.
• T cells that migrate to the skin express cutaneous lymphocyte-associated antigen (CLA), a process enhanced by bacterial superantigens involved in psoriasis.
• Roxithromycin, an antibiotic, has demonstrated immunomodulatory effects and its potential therapeutic benefit for psoriasis has been investigated.

Purpose of the Study:

• To investigate the effects of roxithromycin on T cell receptor BV usage and CLA expression in CD8+ T cells from psoriatic patients.
• To determine if roxithromycin alters the skin-homing potential of T cells in psoriasis.

Main Methods:

• Monitoring of T cell receptor BV usage in circulating CD8+ T cells before and after roxithromycin therapy.
• Assessing the expression of CLA on CD8+ T cells following in vitro stimulation with bacterial superantigens, before and after roxithromycin treatment.

Main Results:

• Roxithromycin treatment led to an increase in circulating CD8+ T cells expressing BV2 and BV8.
• CD8+ T cells from patients treated with roxithromycin showed reduced CLA expression upon in vitro stimulation with bacterial superantigens.
• These findings suggest roxithromycin downregulates CLA expression, potentially reducing T cell skin homing.

Conclusions:

• Roxithromycin may improve psoriasis by downregulating CLA expression on CD8+ T cells, thereby reducing their migration to the skin.
• The observed increase in circulating BV2- and BV8-positive CD8+ T cells suggests a redistribution or altered homing pattern.
• These immunomodulatory effects of roxithromycin contribute to the therapeutic improvement seen in psoriasis patients.