Anti-CD207 Monoclonal antibody, clone SNVM.3 [eFluor® 660]

Pulmonary Langerhans' cell histiocytosis (PLCH) is a rare disorder of unknown cause characterised by the infiltration of the lungs and other organs by the bone marrow derived Langerhans' cells, which carry mutations of BRAF gene and/or NRAS, KRAS and MAP2K1 genes. It occurs predominantly in young smokers, without gender predominance. The disease is characterised by formation of eosinophilic granulomas with the presence of Langerhans' cells infiltrating and destroying distal airways. High-resolution computed tomography of the chest (HRCT) plays an outstanding role in PLCH diagnosis. The typical radiological picture of PLCH is the presence of small intralobular nodules, often forming 'tree in bud' lesions, cavitated nodules, thin-and thick-walled cystic lesions frequently confluent. Definite diagnosis requires the finding of characteristic lesions in histological examination and demonstration of antigen CD1a or CD207 presenting cells in immunohistochemistry. Smoking cessation is the most important recommendation for PLCH patients. There are no evidence based data regarding systemic steroid therapy. The treatment of progressive PLCH is based on cladribine or cytarabine as salvage therapy. The prognosis is good, and over 85% of patients survive 10 years.

Erdheim-Chester disease (ECD), one type of systemic non-Langerhans cell histiocytosis, has been rarely seen and is characterized by the accumulation of foamy CD68CCD1a- histiocytes. We reported a case of ECD and reviewed the clinical features of 13 cases of ECD reported so far in China. A 53-year-old male was diagnosed with central diabetes insipidus in March 2014, followed by fever, splenomegaly and anemia in July 2014. His initial pituitary magnetic resonance imaging (MRI) revealed the absence of high signal at T1-weighted image in posterior pituitary without any lesion. A further positron emission tomography/computer tomography (PET/CT) images showed elevated metabolic activity of 18 F-2-fluro-D-deoxyglucose (FDG) and low N-13-NH3 uptake in the posterior pituitary, and multi-organ involvement. Biopsy at right femur lesion revealed that granulomatous infiltration of foamy histiocytes and Touton giant cells surrounded by fibrosis tissues. Immunohistochemistry stain was positive for CD68, negative for CD207/Langerin and S-100. The diagnosis of ECD was confirmed and the treatment with pegylated interferon was effective. ECD was a possible immune-related disorder concluding from the IgG4 immunohistochemistry results. We summarized the pathological manifestations for ECD and its differential diagnosis from Langerhans cell histiocytosis (LCH) and Rosai-Dorfman disease (RDD). ECD should be considered by both pathologists and clinicians in the differential diagnosis when central diabetes insipidus is accompanied with multi-organ involvement, especially skeletal system involvement, or recurrent fever.