Interleukin-16 expression and release in bullous pemphigoid

Area of Science:

• Immunodermatology
• Molecular Biology
• Cytokine Research

Background:

• Bullous pemphigoid (BP) pathogenesis involves early cutaneous infiltration of CD4(+) T cells and eosinophils.
• Leukocyte trafficking, activation, and cytokine release are critical in BP blister formation.
• Interleukin-16 (IL-16) is a key chemotactic factor for CD4(+) cells and promotes T-cell activation.

Purpose of the Study:

• To evaluate the presence and significance of IL-16 in skin samples, sera, and blister fluids of active BP patients.
• To compare IL-16 levels in BP patients with healthy controls.
• To investigate the relationship between IL-16 levels and markers of Th2 cell and eosinophil activation (sCD30 and ECP) in BP.

Main Methods:

• Analysis of skin biopsies, sera, and blister fluids from 39 active BP patients and healthy donors.
• Assessment of IL-16 expression in lesional skin and body fluids.
• Measurement of serum eosinophil cationic protein (ECP) and soluble CD30 (sCD30) levels.
• Evaluation of IL-16 levels before and after steroid therapy in a subset of patients.

Main Results:

• IL-16 was strongly expressed by keratinocytes and dermal CD4(+) T lymphocytes in BP lesions.
• Significantly higher IL-16 levels were detected in the sera and blister fluids of BP patients compared to healthy donors.
• Serum IL-16 levels showed a positive correlation with ECP and sCD30 levels, indicating a link to Th2 cell and eosinophil activation.

Conclusions:

• IL-16 is significantly upregulated in active bullous pemphigoid.
• IL-16 expression in skin and elevated levels in body fluids suggest its involvement in BP pathogenesis.
• IL-16 likely contributes to the recruitment of Th2 lymphocytes and eosinophils in bullous pemphigoid.