PUVA therapy for localized scleroderma: a study of histological, morphometric, and immunohistochemical expression of TGF-b3 changes

Background Scleroderma is a connective tissue disorder in which hardening of the skin and fibrosis of the affected tissue are the most prominent features. The etiology of localized scleroderma (LS) is still unknown, but immunologic factors usually play an important role in the pathogenesis. Objective This study was designed to evaluate the therapeutic effect of psoralen and ultraviolet light A (PUVA) on LS using histological, morphometric, and immunohistochemical (IHC) techniques. Patients and methods Group I included seven volunteers without any skin diseases, representing the control group. Group II included 23 female patients with localized cutaneous scleroderma. Group III included the same 23 female patients, who were subjected to assessment after cutaneous scleroderma. Skin biopsy specimens were taken from all participants. Specimens were processed and stained with hematoxylin and eosin, Masson’s trichrome, and acid orcein stains, and IHC staining for the detection of transforming growth factor-b3 (TGF-b3). Results Specimens from the LS group showed a significant increase in the epidermal thickness. The dermis showed mononuclear cellular infiltration, increased collagen content, and marked fragmentation of elastic fibers as compared with the controls. The IHC study indicated a highly significant increase in TGF-b3 immunoreactivity in the dermis. After PUVA therapy, there was a significant decrease in epidermal thickness, collagen content, and TGF-b3 immunoreactivity compared with group II. Conclusion TGF-b3 plays an important role in the pathogenesis of scleroderma and the decrease in its expression after PUVA could point to the mechanism by which PUVA exerts its suppression of inflammatory mediators and collagen, causing a reduction in sclerodermatic skin lesions.