[Type I and II collagens and mast cells expression in the skin lesions from the patients with localized scleroderma]

Area of Science:

• Dermatology
• Pathology
• Immunohistochemistry

Background:

• Morphea en plaques (MP) and atrophoderma Pasini-Pierini (APP) are classified as localized scleroderma (LS) types.
• Despite classification, MP and APP present distinct clinical manifestations.
• Both conditions involve complex fibrotic processes in the dermis, including collagen and extracellular matrix deposition, with potential mast cell involvement.

Purpose of the Study:

• To quantitatively assess the expression of type I and III collagens.
• To determine the number of mast cells within skin lesions of patients diagnosed with APP and MP.
• To investigate the relationship between collagen expression, mast cell counts, and disease characteristics in APP and MP.

Main Methods:

• Immunohistochemical analysis was employed to detect and quantify type I and III collagens.
• Mast cell populations were identified and counted in dermal biopsies.
• 36 patients with either APP or MP were included in the study.

Main Results:

• Patients with APP demonstrated significantly lower expression of type I and III collagens compared to those with MP.
• Type I collagen expression decreased over time exclusively in MP patients; no similar trend was observed for type III collagen.
• High collagen expression (types I and III) was more prevalent in the active disease phase of MP.
• Mast cell counts were elevated in APP patients relative to MP patients.
• In MP, mast cell numbers increased with disease duration, correlating with lower collagen expression.

Conclusions:

• Distinct differences in collagen deposition and mast cell infiltration exist between APP and MP.
• The findings suggest divergent pathomechanisms underlying the fibrotic processes in these localized scleroderma subtypes.
• Further research into the roles of collagen and mast cells could inform targeted therapeutic strategies for MP and APP.