Serum KL-6 level is a prognostic marker in patients with anti-MDA5 antibody-positive dermatomyositis associated with interstitial lung disease.

This study aimed to investigate the clinical significance of Krebs von den Lungen-6 (KL-6) serum levels in patients with anti-MDA5 antibody-positive dermatomyositis (anti-MDA5+ DM) having interstitial lung disease (ILD), especially in the amyopathic DM phenotype. The serum KL-6 level was measured using a chemiluminescence enzyme immunoassay (CLEIA) in patients with anti-MDA5+ DM, including clinically amyopathic dermatomyositis (CADM)-ILD and classic DM-ILD, and healthy donors. The baseline and post-treatment serum KL-6 levels were determined in 39 patients with CADM-ILD who experienced remission or acute exacerbation. The association between laboratory findings, high-resolution computed tomography (HRCT) scores, pulmonary function tests (PFTs), and the predictive value of baseline KL-6 level for death was analyzed. The serum KL-6 levels were significantly higher in patients with CADM-ILD (1339 ± 1329 U/mL) compared with DM-ILD (642.3 ± 498.4 U/mL) and healthy donors (162.4 ± 54.01 U/mL). The KL-6 levels correlated positively with chest HRCT scores, serum lactate dehydrogenase, serum ferritin levels, and PFTs, but not with erythrocyte sedimentation rate. During follow-up, the post-treatment serum KL-6 levels significantly reduced in the remission/stable group, but increased in the acute exacerbation group. Higher levels of ferritin and KL-6 and HRCT scores were independently associated with poor prognosis. The 1-year survival rate was significantly lower in patients with high KL-6 level than in those with low KL-6 level. The serum KL-6 levels may be a useful marker for predicting and monitoring ILD in Chinese patients with anti-MDA5+ DM, especially amyopathic DM phenotype.

Ye Y ，Fu Q ，Wang R ，Guo Q ，Bao C ... -  《-》

Clinical Significance of Serum Chitotriosidase Level in Anti-MDA5 Antibody-positive Dermatomyositis-associated Interstitial Lung Disease.

Fujisawa T ，Hozumi H ，Yasui H ，Suzuki Y ，Karayama M ，Furuhashi K ，Enomoto N ，Nakamura Y ，Inui N ，Suda T ... -  《-》

Clinical and laboratory features of fatal rapidly progressive interstitial lung disease associated with juvenile dermatomyositis.

Rapidly progressive interstitial lung disease (RP-ILD) is a rare but potentially fatal complication of JDM. The aim of this study was to establish markers for the prediction and early diagnosis of RP-ILD associated with JDM. The clinical records of 54 patients with JDM were retrospectively reviewed: 10 had RP-ILD (7 died, 3 survived), 19 had chronic ILD and 24 were without ILD. Routine tests included a high-resolution CT (HRCT) scan of the chest and measurement of serum levels of creatine phosphokinase, ferritin and Krebs von den Lungen-6 (KL-6). Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies and IL-18 levels were measured by ELISA. No differences were found in the ratio of juvenile clinically amyopathic DM between the three groups. Initial chest HRCT scan findings were variable and could not distinguish between RP-ILD and chronic ILD. Anti-MDA5 antibodies were positive in all 8 patients with RP-ILD and 10 of 14 with chronic ILD, but none of the patients without ILD. Serum levels of anti-MDA5 antibody, ferritin, KL-6 and IL-18 were significantly higher in the RP-ILD group than in the chronic ILD and non-ILD groups. Serum levels of IL-18 positively correlated with serum KL-6 (R = 0.66, P < 0.001). High serum levels of IL-18, KL-6, ferritin and anti-MDA5 antibodies (e.g. >200 units by ELISA) are associated with RP-ILD. These can be used as an indication for early intensive treatment. Both alveolar macrophages and autoimmunity to MDA5 are possibly involved in the development of RP-ILD associated with JDM.

Kobayashi N ，Takezaki S ，Kobayashi I ，Iwata N ，Mori M ，Nagai K ，Nakano N ，Miyoshi M ，Kinjo N ，Murata T ，Masunaga K ，Umebayashi H ，Imagawa T ，Agematsu K ，Sato S ，Kuwana M ，Yamada M ，Takei S ，Yokota S ，Koike K ，Ariga T ... -  《-》

Serum Krebs von den Lungen-6 concentrations reflect severity of anti-melanoma differentiation-associated protein 5 antibody positive dermatomyositis associated interstitial lung disease.

Zhu Y ，Wang L ，Sun Y ，Wang J ，Lv C ，You H ，Xu L ，Wang F ，Zhang M ，Tan W ，Ke Y ... -  《CLINICAL AND EXPERIMENTAL RHEUMATOLOGY》

Low positive titer of anti-melanoma differentiation-associated gene 5 antibody is not associated with a poor long-term outcome of interstitial lung disease in patients with dermatomyositis.

Anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5-Ab) is associated with fatal rapidly progressive interstitial lung disease (RP-ILD) in patients with dermatomyositis (DM). We attempted to clarify whether anti-MDA5-Ab is associated with long-term outcomes in patients with DM-ILD. Thirty-six patients with DM-ILD were retrospectively analyzed for their serum anti-MDA5-Ab by using an enzyme-linked immunosorbent assay. We analyzed the association between clinical parameters, including the serum levels of anti-MDA5-Ab and ferritin. Fourteen patients (39%) were positive for anti-MDA5-Ab. The serum levels of anti-MDA5-Ab and ferritin in 7 patients with acute death were higher than those in the surviving patients. An "unclassifiable pattern" on chest computed tomography and the development of RP-ILD were also prognostic markers. The serum levels of anti-MDA5-Ab and ferritin (cut-off levels, 100 IU/mL and 899 ng/mL, respectively) were markers predictive of acute death, showing good sensitivity (86% and 83%) and specificity (97% and 100%). All 7 patients with acute death developed RP-ILD and were positive for anti-MDA5-Ab, including 6 patients with a high titer (≥100 IU/mL), whereas only 2 patients (29%) developed RP-ILD among the 7 survivors with a low titer of anti-MDA5-Ab ( < 100 IU/mL). In contrast, a low positive titer of anti-MDA5-Ab was not associated with changes in pulmonary function for 2 years. Although a high serum titer of anti-MDA5-Ab (≥100 IU/mL) is associated with acute death via the development of RP-ILD, outcomes in the chronic phase for patients with a low titer of anti-MDA5-Ab ( < 100 IU/mL) were similar to those of patients without anti-MDA5-Ab.

Sakamoto S ，Okamoto M ，Kaieda S ，Fujimoto K ，Nagata S ，Tominaga M ，Nakamura M ，Zaizen Y ，Nouno T ，Koga T ，Kawayama T ，Kuwana M ，Ida H ，Hoshino T ... -  《-》