PAD4 Deficiency Improves Bleomycin-induced Neutrophil Extracellular Traps and Fibrosis in Mouse Lung.

Excessive release of neutrophil extracellular traps (NETs) has been implicated in several organ fibrosis, including pulmonary fibrosis. NETs constitute a phenomenon in which decorated nuclear chromatin with cytosolic proteins is released into the extracellular space. PAD4 (peptidylarginine deiminase 4) plays an important role in the formation of NETs. However, the role of NETs in the pathogenesis of pulmonary fibrosis remains undefined. Here, we identified NETs in the alveolar and interstitial lung space of mice undergoing bleomycin (BLM)-induced lung fibrosis, which was suppressed by a pan-PAD inhibitor, Cl-amidine. In vitro, BLM directly induced NETs in blood neutrophils, which was also inhibited by Cl-amidine. Furthermore, Padi4 gene knockout (PAD4-KO) in mice led to the alleviation of BLM-induced NETs and pulmonary fibrosis and to the expression of inflammatory and fibrotic genes. PAD4 deficiency prevented decreases in alveolar epithelial and pulmonary vascular endothelial cell numbers and increases in ACTA2-positive mesenchymal cells and S100A4-positive fibroblasts in the lung. Hematopoietic cell grafts from PAD4-KO mice, not wild-type mice, resolved BLM-induced lung fibrosis and fibrotic gene expression in wild-type and PAD4-KO mice, suggesting that expression of PAD4 in hematopoietic cells may be involved in the development of lung fibrosis. These data suggest that PAD4 deficiency could ameliorate BLM-induced formation of NETs and lung fibrosis, suggesting that this pathway could serve as a therapeutic target for pulmonary fibrosis treatment.

An Analysis of the Clinical Benefit of 37 Bronchoalveolar Lavage Procedures in Patients with Hematologic Disease and Pulmonary Complications.

Objective Since pulmonary complications are a major cause of mortality in patients with hematologic diseases, their rapid detection and treatment are essential. Bronchoalveolar lavage (BAL) is widely performed to diagnose pulmonary infiltrates not evident with non-invasive investigations; however, reports on its clinical benefits for patients with hematologic diseases are limited. The aim of our study was to investigate the utility of diagnostic bronchoscopy with BAL for those patients. Methods We retrospectively reviewed the clinical records of 37 consecutive BAL procedures in 33 adult patients with hematological diseases and pulmonary infiltrates with at least 6 months of follow-up between August 2013 and September 2017 (total 747 BAL procedures). The BAL results, ensuing treatment modifications, treatment outcomes, survival times, and adverse events were evaluated. Results Microbiological findings were detected in 11 (29.7%), even though wide-spectrum antibiotics and antifungal drugs had been empirically administered to most patients (>70%) prior to the bronchoscopy procedure. Overall, 25 of the 37 BAL procedures (67.6%) had some impact on the diagnosis of pulmonary diseases. Patients without specific diagnostic findings from BAL had a significantly poorer survival than those with diagnostic findings via BAL (30-day survival: 33.3% vs. 92.0%; 180-day survival: 8.3% vs. 64.0%). Four patients (12.1%) experienced complications associated with bronchoscopy; there were no procedure-related deaths. Conclusion BAL seems still important for diagnosing pulmonary infiltrates and/or excluding some of the important respiratory tract pathogens in patients with hematological diseases; furthermore, negative specific diagnostic findings from BAL may be associated with poor prognoses.

Tocilizumab-effective multicentric Castleman's disease with infiltration of eosinophil and IgG4-positive plasma cells: A case report.

A 67-year-old woman with fever and cough was diagnosed with eosinophilic pneumonia because of eosinophilia and increased eosinophil levels in the bronchoalveolar lavage fluid and transbronchial biopsy lung specimens. However, prednisolone therapy at a previous hospital was ineffective. Histological findings from thoracoscopic lung and lymph node biopsies were consistent with multicentric Castleman's disease (MCD). Since specimens also showed prominent eosinophil and IgG4-positive plasma cell infiltration, it was difficult to distinguish IgG4-related disease (IgG4-RD) from MCD. Administration of prednisolone plus tocilizumab improved the symptoms and lung lesions, and prednisolone administration was successfully reduced and then terminated. The present case highlights the difficulty in diagnosing MCD and IgG4-RD, and suggests that combined administration of tocilizumab and prednisolone might be effective in such a case.

Fetus-in-fetu: parasite or neoplasm? A study of two cases.

INTRODUCTION: Fetus-in-fetu is a rare congenital fetiform mass whose etiology is still controversial. We report two cases of fetus-in-fetu. CASE 1: A fetal retroperitoneal cystic tumor including two masses was detected by ultrasonography at 26 gestational weeks. The masses showed distinctive structures resembling a vertebral axis and were prenatally diagnosed as fetus-in-fetu. A resected specimen revealed two fetiform masses. CASE 2: An intracranial tumor with hydrocephalus was detected by ultrasonography at 19 gestational weeks. The pregnancy was terminated, and a postmortem examination revealed six fetiform masses with immature teratoma. DISCUSSION: The tumors may possibly consist of parasitic monozygotic diamniotic twins or highly differentiated teratomas.