A case of autoimmune pulmonary alveolar proteinosis during the course of treatment of rapidly progressive interstitial pneumonia associated with anti-MDA5 antibody-positive dermatomyositis.

BACKGROUND: Autoimmune pulmonary alveolar proteinosis (APAP) is a diffuse lung disease that causes abnormal accumulation of lipoproteins in the alveoli; however, its pathogenesis remains unclear. Recently, APAP cases have been reported during the course of dermatomyositis. The combination of these two diseases may be coincidental; however, it may have been overlooked because differentiating APAP from a flare-up of interstitial pneumonia associated with dermatomyositis is challenging. This didactic case demonstrates the need for early APAP scrutiny. CASE PRESENTATION: A 50-year-old woman was diagnosed with anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody-positive dermatitis and interstitial pneumonia in April 2021. The patient was treated with corticosteroids, tacrolimus, and cyclophosphamide pulse therapy for interstitial pneumonia complicated by MDA5 antibody-positive dermatitis, which improved the symptoms and interstitial pneumonia. Eight months after the start of treatment, a new interstitial shadow appeared that worsened. Therefore, three additional courses of cyclophosphamide pulse therapy were administered; however, the respiratory symptoms and interstitial shadows did not improve. Respiratory failure progressed, and 14 months after treatment initiation, bronchoscopy revealed turbid alveolar lavage fluid, numerous foamy macrophages, and numerous periodic acid-Schiff-positive unstructured materials. Blood test results revealed high anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody levels, leading to a diagnosis of APAP. The patient underwent whole-lung lavage, and the respiratory disturbance promptly improved. Anti-GM-CSF antibodies were measured from the cryopreserved serum samples collected at the time of diagnosis of anti-MDA5 antibody-positive dermatitis, and 10 months later, both values were significantly higher than normal. CONCLUSIONS: This is the first report of anti-MDA5 antibody-positive dermatomyositis complicated by interstitial pneumonia with APAP, which may develop during immunosuppressive therapy and be misdiagnosed as a re-exacerbation of interstitial pneumonia. In anti-MDA5 antibody-positive dermatomyositis, APAP comorbidity may have been overlooked, and early evaluation with bronchoalveolar lavage fluid and anti-GM-CSF antibody measurements should be considered, keeping the development of APAP in mind.

Glasgow prognostic score and body mass index predict short-term discontinuation of the antifibrotic agents pirfenidone and nintedanib.

BACKGROUND: The antifibrotic agents pirfenidone and nintedanib have been shown to be effective in patients with idiopathic pulmonary fibrosis (IPF). However, discontinuation of antifibrotic drugs is a major clinical concern because of the lack of alternative treatment options. Therefore, we identified factors that may be useful for predicting the termination of antifibrotic agents. METHODS: We retrospectively recruited 280 IPF patients treated with antifibrotic drugs between 2009 and 2018 from seven regional core hospitals in Gunma prefecture, Japan. RESULTS: At four months, the short-term discontinuation group exhibited a significantly worse prognosis in the pirfenidone group and a poorer prognosis in the nintedanib group compared to that in the continuation group. The discontinuation group of pirfenidone at 4 months exhibited lower albumin and higher C-reactive protein (CRP) levels in the sera compared to the group that continued treatment for more than 4 months. In multivariate analysis, the Glasgow prognostic score (GPS), well known as a predictor of cancer prognosis, which comprises serum CRP and albumin levels, predicted early discontinuation and prognosis in the pirfenidone group, whereas the body mass index (BMI) predicted early discontinuation of nintedanib. A high GPS, with both albumin <3.5 g/dL and CRP >1.0 mg/dL, was associated with a poorer prognosis in the pirfenidone group. CONCLUSION: GPS and BMI were significant factors for short-term pirfenidone and nintedanib discontinuation, respectively. Initial evaluation of GPS and BMI prior to antifibrotic therapy may contribute to less interrupted IPF management, thus leading to better prognostic outcomes in patients with IPF.