Since the pathogenesis of morphea, or localized scleroderma, is still unclear, we undertook immunohistochemical(IHC) study using several antibodies presumed to be relevant. A tissue microarray comprising paraffin-embedded skin sections from skin lesions of 55 patients with morphea or systemic sclerosis(SSc) and age-, sex-and site-matched normal skin of 55 subjects were assessed for smooth-muscle actin(SMA), vascular cell adhesion molecule 1(VCAM1), CD31, CD34, serglycin, c-kit (for mast cell), LC3A, and LC3B (for autophagy). Each stain was analyzed for intensity and proportion of positivity by 2 dermatologists. Of total 55 patients, 14 had generalized morphea, 36 had non-generalized morphea, and 5 had SSc. The mean age of patients was 45.0 years (range, 11 to 90); 13(23.6%) were male and 42(76.4%), female. When morphea lesions were compared with control, SMA, VCAM1, and c-kit showed significantly higher expression in the patient group (p¼0.000, p¼0.035, and p¼0.000, respectively), while CD34 stromal stain showed lower expression in the patient group (p¼0.000). CD34 positivity was negatively correlated with SMA, VCAM1, and c-kit stains (p¼0.044, p¼0.037, and p¼0.001, respectively). Between morphea and SSc lesions, CD34 expression was significantly higher in morphea (p¼0.042). Within morphea lesions, it was higher in non-generalized group (p¼0.021). CD34, a commonly used marker of hematopoietic progenitor cells and endothelial cells, also stains a subpopulation of dermal dendritic cells. In this study, CD34-expressing stromal cells diminished in morphea and more so in SSc; moreover, in subtype analysis they seemed to disappear as the extent of disease increases. Since the expression of SMA, a marker of myofibroblast, increased in scleroderma and had negative correlation with CD34, it is plausible that dermal dendritic cells progressively convert to myofibroblasts with progression of the disease. CD34 may be a useful marker in predicting the prognosis of patients with scleroderma.
