Objective To assess the longitudinal changes in nailfold videocapillaroscopy (NVC) in patients expressing myositis-specific autoantibodies (anti-aminoacyl-tRNA synthetase [ARS], anti-transcriptional intermediary factor 1 [TIF1], and anti-melanoma differentiation-associated gene 5 [MDA5]). Methods This study was performed retrospectively, at a single site, on an observational cohort. Seventy-one idiopathic inflammatory myopathy patients were included (25 patients expressed anti-MDA5 Abs, 24 patients expressed anti-TIF1 Abs, and 22 patients expressed anti-ARS Abs). NVC findings included giant, enlarged, and reduced capillaries, hemorrhages, capillary ramification, disorganization of the vascular array, and capillary loss. NVC findings were compared from baseline to after disease activity stabilization. Results The frequency of enlarged capillaries at baseline was different among the three groups, and was significantly higher in patients with anti-TIF1 Abs compared with those with anti-ARS Abs (88% vs 55%, p< 0.05). Reduced capillaries were significantly increased in patients with anti-TIF1 Abs compared with those with anti-MDA5 (96% vs 44%, p< 0.0001) or anti-ARS Abs (96% vs 50%, p< 0.0005). Both enlarged and reduced capillaries improved after stabilization in patients with anti-MDA5 Abs (p< 0.0001 and p< 0.05, respectively). These improvements were not observed in patients expressing anti-TIF1 and anti-ARS Abs. However, a significant reduction in hemorrhages was observed in all three groups (p< 0.0001 for each group). Conclusions The results of this study demonstrate that longitudinal changes in NVC findings may vary depending on myositis-specific Ab expression. Therefore, it is crucial to assess individual NVC findings separately, since each finding may impact disease activity in a different manner.

Systemic sclerosis (SSc) is an autoimmune disease characterized by skin and lung fibrosis. Over 90% of patients with SSc are positive for autoantibodies. In addition, the serum levels of B‐cell activating factor, a potent B‐cell stimulator, are correlated with SSc severity and activity. Thus, B cells play an important role in SSc pathogenesis. However, two opposing B‐cell subsets exist: effector B cells (Beff) and regulatory B cells (Breg). Interleukin (IL)‐6‐producing Beff have been shown to promote scleroderma in a mouse model, whereas IL‐10‐producing Breg inhibit scleroderma development. In the present study, we investigated the clinical association of effector and regulatory B cells in patients with SSc. The blood levels of IL‐6‐producing Beff and IL‐10‐producing Breg were measured in 30 patients with SSc and 21 healthy subjects by flow cytometry. The frequency of IL‐6‐producing Beff in the blood was significantly (p < 0.0001) elevated in patients with SSc (median, 56.2%; range, 35.3–81.3%) compared with that in healthy controls (median, 41.3%; range, 21.0–61.3%). In contrast, the frequency of IL‐10‐producing Breg in the blood was significantly (p < 0.05) decreased in patients with SSc (median, 1.4%; range, 0.5–2.8%) compared with that in healthy controls (median, 2.0%; range, 1.1–3.8%). The Beff/Breg ratio was significantly increased in patients with SSc. In addition, the Beff/Breg ratio was positively correlated with the skin score and extent of interstitial lung disease. These results suggest that dysregulation of effector and regulatory B‐cell balance contributes to SSc pathogenesis.

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