The P2X7 receptor antagonist Brilliant Blue G reduces serum human interferon-γ in a humanized mouse model of graft-versus-host disease.

Graft-versus-host disease (GVHD) remains a major problem after allogeneic haematopoietic stem cell transplantation, a curative therapy for haematological malignancies. Previous studies have demonstrated a role for the adenosine triphosphate (ATP)-gated P2X7 receptor channel in allogeneic mouse models of GVHD. In this study, injection of human peripheral blood mononuclear cells (PBMCs) into immunodeficient non-obese diabetic-severe combined immunodeficiency-interleukin (NOD-SCID-IL)-2Rγnull (NSG) mice established a humanized mouse model of GVHD. This model was used to study the effect of P2X7 blockade in this disease. From five weeks post-PBMC injection, humanized mice exhibited clinical signs and histopathology characteristic of GVHD. The P2X7 antagonist, Brilliant Blue G (BBG), blocked ATP-induced cation uptake into both murine and human cells in vitro. Injection of BBG (50 mg/kg) into NSG mice did not affect engraftment of human leucocytes (predominantly T cells), or the clinical score and survival of mice. In contrast, BBG injection reduced circulating human interferon (IFN)-γ significantly, which was produced by human CD4+ and CD8+ T cells. BBG also reduced human T cell infiltration and apoptosis in target organs of GVHD. In conclusion, the P2X7 antagonist BBG reduced circulating IFN-γ in a humanized mouse model of GVHD supporting a potential role for P2X7 to alter the pathology of this disease in humans.

Does the BRAF(V600E) mutation herald a new treatment era for Erdheim-Chester disease? A case-based review of a rare and difficult to diagnose disorder.

Erdheim-Chester disease is a multi-system histiocyte disorder characterised by histological xanthogranulomatous inflammation. We report a 67-year-old man who had fatal multi-systemic Erdheim-Chester disease involvement, including retroperitoneal fibrosis, dilated cardiomyopathy and bone pain that was diagnosed late in its course and was refractory to interferon-alfa. A pathogenic BRAF(V600E) mutation, identified after death in this patient, provides insights into pathogenesis and opens potential lines of treatment.

Extra-pancreatic manifestations of IgG4-related systemic disease: a single-centre experience of treatment with combined immunosuppression.

BACKGROUND/AIM: IgG4-related systemic disease (IgG4-RSD) is a systemic inflammatory disease distinguished by tissue infiltrates of IgG4(+) plasma cells and elevated serum IgG4 levels. While IgG4-RSD often involves the pancreas, extra-pancreatic organs are also frequently affected. Here, we review the presentation and management of patients with extra-pancreatic IgG4-RSD. METHODS: A retrospective analysis was performed on patients diagnosed with extra-pancreatic IgG4-RSD identified from a single centre. RESULTS: Six patients with extra-pancreatic IgG4-RSD were identified. The median age of the patients was 64 years. The range of involved organs included lymph nodes (three patients), ocular adnexa, lung, kidneys, meninges and exocrine glands. The median delay in diagnosis was 13.5 months (4-60 months). Four patients had elevated serum IgG4 levels at diagnosis. Five symptomatic patients were commenced on combination immunosuppression, which included corticosteroids. Maintenance therapy with azathioprine was used in one patient, methotrexate and mycophenolate were each used in two patients, and cyclophosphamide in one patient. Four treated patients went into remission, while two patients had persistent radiological disease. One patient experienced two relapses. CONCLUSION: IgG4-RSD can manifest in a variety of organs. Lack of awareness regarding this entity may delay diagnosis. Combination treatment of corticosteroids and conventional immunosuppression is effective.

Adult B-cell acute lymphoblastic leukemia with two unrelated abnormal cytogenetic clones.

The presence of two different abnormal cell lines at diagnosis in hematologic malignancies is rare and raises the question of etiology and pathogenesis--two separate malignant lineages occurring together or a common stem cell malignancy? We present a 64-year-old woman who was evaluated for low platelet count and peripheral blasts. On the basis of the morphology, flow cytometry, and lack of myeloid-associated markers, a diagnosis of precursor B-cell acute lymphoblastic leukemia (B-ALL) was made. Cytogenetic analysis of the diagnostic bone marrow (BM) specimen revealed two unrelated abnormal clones--one had a dicentric (7;9)(p11;p11), resulting in the deletion of 7p and 9p, and the other had only trisomy 8. The dic(7;9) is a rare but recurrent abnormality in B-ALL, while trisomy 8 as a sole abnormality is most commonly associated with myeloid malignancies. After standard treatment for B-ALL, BM cytogenetic analysis showed disappearance of the dic(7;9) cell line but persistence of cells with trisomy 8. The presence of two unrelated clones suggestive of concomitant malignancies, possibly B-ALL with an underlying MDS, may have arisen by different mechanisms.

Late onset Rasmussen's encephalitis with triple pathology.

Rasmussen's encephalitis is a devastating illness characterized by intractable focal seizures due to chronic localised encephalitis. We report on a rare variant of delayed onset Rasmussen's encephalitis with triple pathology. A 27-year-old male, who was initially diagnosed with seizures when he was 16 years old, presented with focal seizures that became refractory to multiple anticonvulsants. Multiple investigations, including subdural electrode monitoring, revealed foci of onset in the right frontotemporal region. The patient underwent right front-temporal lobectomy. Post-operatively, the seizures became more severe and he developed new epilepsia partialis continua. Treatment with intravenous immunoglobulin was unsuccessful. He subsequently underwent a right hemispherectomy that rendered him seizure free. The three pathologies identified were old ischemic changes, type II cortical dysplasia and stage II Rasmussen's encephalitis.

Somatostatinoma: collision with neurofibroma and ultrastructural features.

The clinical presentation, histopathology and immunoelectron microscopic features of two cases of duodenal somatostatinoma are described, one of which is a hitherto unreported example of a collision tumour with a neurofibroma. Ultrastructural morphometric immunoelectron microscopy studies revealed the presence of four types of cells in both tumours, but there was no difference in the proportions of these cells between the collision tumour and the non-collision tumour. Neurosecretory granules ranging in size from 255-815 nm were generally larger than those previously reported for somatostatinomas and somatostatin was identified in granules of all sizes across this range. Neither tumour was associated with the somatostatinoma syndrome comprising associated diabetes mellitis, steatorrhoea and cholelithiasis.