Interleukin-8 receptors in normal and psoriatic polymorphonuclear leukocytes

Area of Science:

• Dermatology
• Immunology
• Cell Biology

Background:

• Polymorphonuclear leukocyte (PMNL) infiltration is a hallmark of psoriatic skin lesions.
• Interleukin-8 (IL-8), a pro-inflammatory peptide, is found in psoriatic scales and attracts neutrophils, suggesting a role in psoriasis pathogenesis.
• Neutrophil migration is mediated by specific IL-8 receptors on PMNL.

Purpose of the Study:

• To investigate if functional abnormalities in circulating PMNL, specifically altered IL-8 receptor density or affinity, contribute to PMNL infiltration in psoriasis.
• To compare IL-8 receptor characteristics on PMNL from patients with psoriasis, atopic eczema, and healthy controls.

Main Methods:

• Radioligand binding studies were conducted to quantify IL-8 receptor affinity (Kd) and density on PMNL.
• The study included 10 patients with psoriasis, 10 with atopic eczema, and 11 healthy controls.

Main Results:

• No significant differences in IL-8 receptor affinity (Kd) were observed between psoriatic patients, atopic eczema patients, and normal controls.
• A statistically significant increase in IL-8 receptor density was found on PMNL from psoriatic individuals (31,230 ± 3,237 sites/cell) compared to normal controls (24,152 ± 2,643 sites/cell) and atopic eczema patients (24,092 ± 2,743 sites/cell).

Conclusions:

• The findings suggest that an increased number of IL-8 receptors on circulating PMNL may contribute to the intraepidermal accumulation of PMNL in psoriasis.
• This elevation in IL-8 receptor density, in conjunction with elevated IL-8 levels in psoriatic skin, could be a key factor in psoriasis development and progression.