Bone marrow fibrosis (pseudo-myelofibrosis) in human kala-azar

Prevalence, severity, and pathogeneses of anemia in visceral leishmaniasis

Anemia is a typical symptom during visceral leishmaniasis (VL). We performed a systematic analysis of the literature on anemia in VL to understand the prevalence, severity, and possible mechanisms. Anemia is very common in VL patients with an overall prevalence higher than 90 %. The degree of anemia in VL is moderate to severe (hemoglobin level ∼7.5 g/dl), and the status can be recovered by treatment with antileishmanial drugs within a certain period of time. Possible pathogeneses of anemia in VL based on clinical observations included anti-RBC antibodies, dysfunction in erythropoiesis, and hemophagocytosis in the bone marrow or spleen, while hemolysis is a more likely cause than dyserythropoiesis. In hamsters with experimental VL, hemophagocytosis induced by immune complex and changes on erythrocyte membrane is speculated as the pathogenesis for anemia. In contrast, our recent study on murine VL indicated that hemophagocytosis contributes to anemia in contrast to lower contribution of anti-RBC antibodies or dysfunction in erythropoiesis. Together, hemophagocytosis is most likely associated with anemia in VL, and elucidation of the immunological mechanisms may lead to development of novel interventions to manage the symptom.

Fibrogenesis in Primary Myelofibrosis: Diagnostic, Clinical, and Therapeutic Implications

Primary myelofibrosis is a stem cell-derived clonal malignancy characterized by unchecked proliferation of myeloid cells, resulting in bone marrow fibrosis, osteosclerosis, and pathologic angiogenesis. Bone marrow fibrosis (BMF) plays a central role in the pathophysiology of the disease. This review describes current issues regarding BMF in primary myelofibrosis, including the pathophysiology and impact of abnormal deposition of excess collagen and reticulin fibers in bone marrow spaces, the modified Bauermeister and the European Consensus grading systems of BMF, and the prognostic impact of BMF on the overall outcome of patients with primary myelofibrosis. The impact of novel therapeutic strategies, including JAK-STAT inhibitors and allogeneic stem cell transplant, on BMF is discussed.

Brucellosis presenting as myelofibrosis: first case report

We describe the case of a 29-year-old woman who presented with pancytopenia and myelofibrosis. Brucella melitensis was identified in her blood. The patient recovered completely with doxycycline and rifampin. A repeat bone marrow biopsy showed hypercellularity without myelofibrosis. Bone marrow findings in cases of pancytopenia due to brucellosis reveal normocellularity, hypercellularity, hemophagocytosis, or granuloma. To our knowledge this is the first report of brucellosis causing myelofibrosis. Brucellosis should be considered as a possible cause of myelofibrosis in endemic areas.

Bone marrow fibrosis: pathophysiology and clinical significance of increased bone marrow stromal fibres

In bone marrow biopsies, stromal structural fibres are detected by reticulin and trichrome stains, routine stains performed on bone marrow biopsy specimens in diagnostic laboratories. Increased reticulin staining (reticulin fibrosis) is associated with many benign and malignant conditions while increased trichrome staining (collagen fibrosis) is particularly prominent in late stages of severe myeloproliferative diseases or following tumour metastasis to the bone marrow. Recent evidence has shown that the amount of bone marrow reticulin staining often exhibits no correlation to disease severity, while the presence of type 1 collagen, as detected by trichrome staining, is often associated with more severe disease and a poorer prognosis. It was originally thought that increases in bone marrow stromal fibres themselves contributed to the haematopoietic abnormalities seen in certain diseases, but recent studies suggest that these increases are a result of underlying cellular abnormalities rather than a cause. A growing body of evidence suggests that increased deposition of bone marrow stromal fibres is mediated by transforming growth factor-beta and other factors elaborated by megakaryocytes, but it is likely that other cells, cytokines and growth factors are also involved. This suggests new avenues for investigation into the pathogenesis of various disorders associated with increased bone marrow stromal fibres.

Visceral leishmaniasis: bone marrow biopsy findings

Visceral leishmaniasis (VL) or Kala-azar is a common parasitic infection among children in Iran. The records of 249 children with VL were evaluated retrospectively. The clinical, hematologic, and bone marrow biopsy findings were studied. In particular, we assessed whether there was an association between bone marrow biopsy findings and prognosis. Five major groups were identified: (1) hypercellular marrow with many Leishman Donovan (LD) bodies, (2) multiple noncaseating granulomas with a few LD bodies, (3) diffuse fibrosis with rare LD bodies, (4) benign lymphoid nodules with many LD bodies, and (5) marrow necrosis with many LD bodies. The patients with hypercellular marrow and benign lymphoid nodules were alive and responded well to glucantime therapy. The patients with marrow fibrosis and marrow necrosis died and were resistant to any type of therapy. Patients with granulomas did not respond to glucantime therapy but responded to amphotericin B. However, less than half of the patients died owing to malnutrition and misdiagnosis. We correlated the bone marrow biopsy findings with the treatment outcomes and prognosis. The outcome was excellent in cases of hypercellular marrow, very poor in cases of fibrosis and necrosis, and intermediate in cases of granulomas. As a result, we believe that bone marrow biopsy findings can be helpful for assessing the prognosis of VL patients.

bcr/abl-negative, classic myeloproliferative disorders: diagnosis and treatment

Essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia constitute the "classic" bcr/abl-negative myeloproliferative disorders (MPDs). Each of these MPDs represents a stem cell-derived clonal myeloproliferation with the respective features of thrombocytosis, erythrocytosis, and bone marrow fibrosis. Unlike with cases of chronic myeloid leukemia, in which the bcr/abl mutation is invariably detected, current diagnosis of essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia is based on a consensus-driven set of clinical and laboratory criteria that have undergone substantial modification in recent times. The recent discovery of a recurrent activating Janus tyrosine kinase (JAK2) mutation (JAK2VG17F) in all 3 classic MPDs offers another opportunity for refining current diagnoses and disease classifications. In this article, we outline contemporary diagnostic algorithms for each of these disorders and provide an evidence-based approach to management.