Comparison between treatment naive juvenile and adult dermatomyositis muscle biopsies: difference of inflammatory cells phenotyping

Abstract

Background: Different inflammatory cells (i.e., CD4, CD8, CD20 and CD68) are involved in pathogenesis of DM muscle. In this context, the aim of this study was to assess and compare these inflammatory cell phenotyping in muscle samples of treatment naive juvenile and adult patients with dermatomyositis. Methods: This is a cross-sectional study, in which 28 untreated juvenile and 28 adult untreated dermatomyositis patients were included. Immunohistochemical analysis was performed on serial frozen muscle sections. Inflammatory cell phenotyping was analyzed quantitatively in endomysium, perimysium, and perivascular (endomysium and perimysium) area. Results: Mean age at disease onset was 7.3 and 42.0 years in juvenile and adult dermatomyositis, respectively. Both groups had comparable time duration from symptom's onset to biopsy performance. CD4 and CD8 positive cells distributions were similar in both groups in all analyzed area, except for more predominance of CD4 in perimysium at juvenile muscle biopsies. The CD20 and CD68 positive cells were predominantly observed in adult muscle biopsy sections, when compared to juvenile samples, except for similar distribution of CD20 in perivascular endomysium, and CD68 in perimysium. Conclusions: These data show that the differences between juvenile and adult dermatomyositis may be restricted not only to patients' age, but also to different inflammatory cell distribution, particularly, in new-onset disease. Further studies are necessary to confirm the present study data and to analyze meaning of the different inflammatory cell phenotyping distribution finding in these both diseases.

CD8+ T Cell Phenotype and Function in Childhood and Adult-Onset Connective Tissue Disease

“…In addition to muscle inflammation, DM is also characterized by inflammation in the skin. Skin biopsies in DM patients have shown the presence of CD8 + T cell infiltrates, however their distribution and number were similar to CD4 + T cells and no differences in CD8 + T cell number or distribution were found between JDM and ADM [ 163 ]. Furthermore, CD8 + T cells have been detected in higher number than CD4 + T cells in lung biopsies of PM/DM patients with interstitial pneumonia [ 164 ].…”

Adult and juvenile dermatomyositis treatment

“…Muscle biopsies in adults showed predominance of CD20 and CD68‐positive cells. Distribution of CD20 in perivascular endomysium and CD68 in perimysium was similar in both groups 5 . Plasma levels of hsa‐miR‐4442 may be a useful biomarker for the diagnosis and disease activity of dermatomyositis 10 …”

“…Dermatomyositis can occur in adults and children. The reported mean age of disease onset in adult and children is 42 and 7.3 years 5 . In another study, mean age at disease onset for juvenile dermatomyositis was 81.97 months with a female predominance 6 .…”

“…The reported mean age of disease onset in adult and children is 42 and 7.3 years. 5 In another study, mean age at disease onset for juvenile dermatomyositis was 81.97 months with a female predominance. 6 Many common features and differences exist in the presentation, associated conditions, and prognosis in adult versus juvenile dermatomyositis.…”

“…Distribution of CD20 in perivascular endomysium and CD68 in perimysium was similar in both groups. 5 Plasma levels of hsa-miR-4442 may be a useful biomarker for the diagnosis and disease activity of dermatomyositis. 10 Dermatomyositis may present as paraneoplastic syndrome or with malignancies of different organs.…”