Characterization of monocyte/macrophage subsets in the skin and peripheral blood derived from patients with systemic sclerosis

Abstract

IntroductionRecent accumulating evidence indicates a crucial involvement of macrophage lineage in the pathogenesis of systemic sclerosis (SSc). To analyze the assembly of the monocyte/macrophage population, we evaluated the expression of CD163 and CD204 and various activated macrophage markers, in the inflammatory cells of the skin and in the peripheral blood mononuclear cells (PBMCs) derived from patients with SSc.MethodsSkin biopsy specimens from 6 healthy controls and 10 SSc patients (7 limited cutaneous SSc and 3 diffuse cutaneous SSc) were analyzed by immunohistochemistry using monoclonal antibody against CD68 (pan-macrophage marker), CD163 and CD204. Surface and/or intracellular protein expression of CD14 (marker for monocyte lineage), CD163 and CD204 was analysed by flow cytometry in PBMCs from 16 healthy controls and 41 SSc patients (26 limited cutaneous SSc and 15 diffuse cutaneous SSc). Statistical analysis was carried out using Mann-Whitney U test for comparison of means.ResultsIn the skin from SSc patients, the number of CD163+ cells or CD204+ cells between the collagen fibers was significantly larger than that in healthy controls. Flow cytometry showed that the population of CD14+ cells was significantly greater in PBMCs from SSc patients than that in healthy controls. Further analysis of CD14+ cells in SSc patients revealed higher expression of CD163 and the presence of two unique peaks in the CD204 histogram. Additionally, we found that the CD163+ cells belong to CD14brightCD204+ population.ConclusionsThis is the first report indicating CD163+ or CD204+ activated macrophages may be one of the potential fibrogenic regulators in the SSc skin. Furthermore, this study suggests a portion of PBMCs in SSc patients abnormally differentiates into CD14brightCD163+CD204+ subset. The subset specific to SSc may play an important role in the pathogenesis of this disease, as the source of CD163+ or CD204+ macrophages in the skin.

Histone Deacetylase 7 Promotes Toll-like Receptor 4-dependent Proinflammatory Gene Expression in Macrophages

“…Nonetheless, our in vitro data suggest that Hdac7 is a candidate target for diseases in which innate immune cells contribute to pathology. In this respect, HDAC7 has been proposed previously as a potential proinflammatory target in systemic sclerosis (55), a disease in which both macrophages (56) and ET-1 (57) are implicated. HDAC7 expression was also up-regulated in cartilage from osteoarthritic patients and correlated with an increase in matrix metalloproteinase 13 expression and cartilage degradation (58).…”

Immunophenotypical Characterization of Macrophages in Rat Bleomycin-Induced Scleroderma

“…13 These macrophages might be associated with the production of fibrogenic mediators such as TGF-b1. 13,14 TGF-b1 might be produced by CD68þ and CD163þ cells, but this should be investigated in further studies. Definite roles of these macrophages in human scleroderma remained to be established.…”

“…24,38 Although it has been reported that CD68 expression is associated with the M1 phenotype, and CD163 is highly expressed in M2 macrophages, more detailed studies are needed to know the functions of macrophages with different immunophenotypes. 13,14,23 Bleomycin injection has been reported to induce apoptosis of hair follicles, resulting in alopecia. 43,44 In this study, apoptotic bodies were often seen in the hair follicles.…”

EBI3 Downregulation Contributes to Type I Collagen Overexpression in Scleroderma Skin

“…Control serum samples were collected from 15 healthy volunteers. PBMCs were obtained from heparinized venous blood of SSc patents, SLE patients and healthy volunteers using gradient centrifugation over Vacutainer CPT (BD, Franklin Lakes, NJ) (17,18). The skin biopsy specimens from SSc patients were obtained from lesional skin.…”