Successful Lung Transplantation for Pulmonary Disease Associated With Erdheim-Chester Disease

Case Report: Evolution of a Severe Vascular Refractory Form of ECD Requiring Liver Transplantation Correlated With the Change in the Monocyte Subset Analysis

Erdheim–Chester disease is a rare histiocytosis characterized by iconic features associated with compatible histology. Most patients have somatic mutations in the MAP-kinase pathway gene, and the mutations occur in CD14⁺ monocytes. Differentiation of the myeloid lineage plays a central role in the pathogenesis of histiocytosis. Monocytes are myeloid-derived white blood cells, divided into three subsets, but only the CD14⁺⁺CD16⁻ “classical monocyte” can differentiate into dendritic cells and tissue macrophages. Since most mutations occur in CD14⁺ cells and since ECD patients have a particular monocytic phenotype resembling CMML, we studied the correlation between disease activity and monocytic subset distribution during the course of a severe vascular form of ECD requiring liver transplantation. During early follow-up, increased CD14⁺⁺CD16⁻ “classical monocyte” associated with decreased CD14^lowCD16⁺⁺ “non-classical monocyte” correlated with disease activity. Further studies are needed to confirm the use of monocyte as a marker of disease activity in patients with ECD.

Kidney Transplantation for Erdheim-Chester Disease

Erdheim-Chester disease is a rare inflammatory disease that infiltrates skeletal and extra-skeletal tissue. Chronic kidney disease (CKD) in Erdheim-Chester disease is usually attributed to retroperitoneal lesions that lead to urologic obstruction and hydronephrosis. In this report, we describe a patient diagnosed with Erdheim-Chester disease who eventually developed end-stage kidney disease (ESKD). After complete remission of Erdheim-Chester disease by vemurafenib therapy and 2 years of hemodialysis, the patient underwent a deceased donor kidney transplantation with basiliximab induction and tacrolimus/mycophenolic acid maintenance. After conversion of mycophenolic acid to azathioprine due to cost, acute cellular rejection had occurred, and he was treated with steroid therapy. The patient remained in complete remission from Erdheim-Chester disease and dialysis-free 16 months after transplant. Kidney transplantation is another treatment option for those patients with Erdheim-Chester disease who suffer from renal failure in the setting of complete remission.

Clinical and Histopathologic Features of Interstitial Lung Disease in Erdheim⁻Chester Disease

Limited information is available regarding interstitial lung disease (ILD) in Erdheim⁻Chester disease (ECD), a rare multisystemic non-Langerhans cell histiocytosis. Sixty-two biopsy-confirmed ECD patients were divided into those with no ILD (19.5%), minimal ILD (32%), mild ILD (29%), and moderate/severe ILD (19.5%), based on computed tomography (CT) findings. Dyspnea affected at least half of the patients with mild or moderate/severe ILD. Diffusion capacity was significantly reduced in ECD patients with minimal ILD. Disease severity was inversely correlated with pulmonary function measurements; no correlation with BRAF V600E mutation status was seen. Reticulations and ground-glass opacities were the predominant findings on CT images. Automated CT scores were significantly higher in patients with moderate/severe ILD, compared to those in other groups. Immunostaining of lung biopsies was consistent with ECD. Histopathology findings included subpleural and septal fibrosis, with areas of interspersed normal lung, diffuse interstitial fibrosis, histiocytes with foamy cytoplasm embedded in fibrosis, lymphoid aggregates, and focal type II alveolar cell hyperplasia. In conclusion, ILD of varying severity may affect a high proportion of ECD patients. Histopathology features of ILD in ECD can mimic interstitial fibrosis patterns observed in idiopathic ILD.

Potential of Bioactive Glasses for Cardiac and Pulmonary Tissue Engineering

Repair and regeneration of disorders affecting cardiac and pulmonary tissues through tissue-engineering-based approaches is currently of particular interest. On this matter, different families of bioactive glasses (BGs) have recently been given much consideration with respect to treating refractory diseases of these tissues, such as myocardial infarction. The inherent properties of BGs, including their ability to bond to hard and soft tissues, to stimulate angiogenesis, and to elicit antimicrobial effects, along with their excellent biocompatibility, support these newly proposed strategies. Moreover, BGs can also act as a bioactive reinforcing phase to finely tune the mechanical properties of polymer-based constructs used to repair the damaged cardiac and pulmonary tissues. In the present study, we evaluated the potential of different forms of BGs, alone or in combination with other materials (e.g., polymers), in regards to repair and regenerate injured tissues of cardiac and pulmonary systems.