No abstract

Neuroblastoma is the most common extracranial solid tumour in children and is histologically classified by its Schwannian stromal cells. Although having fewer Schwannian stromal cells is generally associated with more aggressive phenotypes, the exact roles of other stromal cells (mainly macrophages and fibroblasts) are unclear. Here, we examined 41 cases of neuroblastoma using immunohistochemistry for the tumour‐associated macrophage (TAM) markers CD68, CD163, and CD204, and a cancer‐associated fibroblast (CAF) marker, alpha smooth muscle actin (αSMA). Each case was assigned to low/high groups on the basis of the number of TAMs or three groups on the basis of the αSMA‐staining area for CAFs. Both the number of TAMs and the area of CAFs were significantly correlated with clinical stage, MYCN amplification, bone marrow metastasis, histological classification, histological type, and risk classification. Furthermore, TAM settled in the vicinity of the CAF area, suggesting their close interaction within the tumour microenvironment. We next determined the effects of conditioned medium of a neuroblastoma cell line (NBCM) on bone marrow‐derived mesenchymal stem cells (BM‐MSCs) and peripheral blood mononuclear cell (PBMC)‐derived macrophages in vitro. The TAM markers CD163 and CD204 were significantly up‐regulated in PBMC‐derived macrophages treated with NBCM. The expression of αSMA by BM‐MSCs was increased in NBCM‐treated cells. Co‐culturing with CAF‐like BM‐MSCs did not enhance the invasive ability but supported the proliferation of tumour cells, whereas tumour cells co‐cultured with TAM‐like macrophages had the opposite effect. Intriguingly, TAM‐like macrophages enhanced not only the invasive abilities of tumour cells and BM‐MSCs but also the proliferation of BM‐MSCs. CXCL2 secreted from TAM‐like macrophages plays an important role in tumour invasiveness. Taken together, these results indicate that PBMC‐derived macrophages and BM‐MSCs are recruited to a tumour site and activated into TAMs and CAFs, respectively, followed by the formation of favourable environments for neuroblastoma progression. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

UMIN000014214.

BackgroundTAFRO syndrome is a unique clinicopathologic variant of multicentric Castleman’s disease that has recently been identified in Japan. It is characterized by a constellation of symptoms: Thrombocytopenia, Anasarca, reticulin Fibrosis of the bone marrow, Renal dysfunction and Organomegaly (TAFRO). Previous reports have shown that affected patients usually respond to immunosuppressive therapy, but the disease sometimes has a fatal course. TAFRO syndrome occurs in the middle-aged and elderly and there are no prior reports of the disease in adolescents. Here we report the first adolescent case, successfully treated with anti-IL-6 receptor antibody (tocilizumab, TCZ) and monitored with serial cytokine profiles.Case presentationA 15-year-old Japanese boy was referred to us with fever of unknown origin. Whole body computed tomography demonstrated systemic lymphadenopathy, organomegaly and anasarca. Laboratory tests showed elevated C-reactive protein and hypoproteinemia. Bone marrow biopsy revealed a hyperplastic marrow with megakaryocytic hyperplasia and mild reticulin fibrosis. Despite methylprednisolone pulse therapy, the disease progressed markedly to respiratory distress, acute renal failure, anemia and thrombocytopenia. Serum and plasma levels of cytokines, including IL-6, vascular endothelial growth factor, neopterin and soluble tumor necrosis factor receptors I and II, were markedly elevated. Repeated weekly TCZ administration dramatically improved the patient’s symptoms and laboratory tests showed decreasing cytokine levels.ConclusionTo our knowledge, this is the first report of TAFRO syndrome in a young patient, suggesting that this disease can occur even in adolescence. The patient was successfully treated with TCZ. During our patient’s clinical course, monitoring cytokine profiles was useful to assess the disease activity of TAFRO syndrome.

Immature or reticulated platelets are known as a clinical marker of thrombopoiesis. Recently, an automatic method was established to detect reticulated platelets as immature platelet fraction (IPF) by means of hematology analyzer XE-2100. We assessed the effects of IPF detection after chemotherapy for various pediatric malignant disorders of 16 patients. Our results indicate that IPF should be considered a useful marker of imminent platelet recovery so that unnecessary platelet transfusion can be avoided.