Multiple phosphorylation sites are important for RUNX1 activity in early hematopoiesis and T-cell differentiation.

RUNX1 is essential for definitive hematopoiesis and T-cell differentiation. It has been shown that RUNX1 is phosphorylated at specific serine and threonine residues by several kinase families. However, it remains unclear whether RUNX1 phosphorylation is absolutely required for its biological functions. Here, we evaluated hematopoietic activities of RUNX1 mutants with serine (S)/threonine (T) to alanine (A), aspartic acid (D), or glutamic acid (E) mutations at phosphorylation sites using primary culture systems. Consistent with the results of knockin mice, RUNX1-2A, carrying two phospho-deficient mutations at S276 and S293, retained hematopoietic activity. RUNX1-4A, carrying four mutations at S276, S293, T300, and S303, showed impaired T-cell differentiation activity, but retained the ability to rescue the defective early hematopoiesis of Runx1-deficient cells. Notably, RUNX1-5A, carrying five mutations at S276, S293, T300, S303, and S462, completely lost its hematopoietic activity. In contrast, the phospho-mimic proteins RUNX1-4D/E and RUNX1-5D/E exhibited normal function. Our study identifies multiple phosphorylation sites that are indispensable for RUNX1 activity in hematopoiesis.

[Myeloid/natural killer cell precursor acute leukemia diagnosed by cell marker analysis].

We report a case of myeloid/natural killer cell precursor acute leukemia. A 68-year-old man was diagnosed as having lymphoma in his neck, and was referred to our department for further examination and treatment. After admission, blastoid-cells appeared and increased rapidly in his peripheral blood. Cell marker analysis revealed that the blastoid-cells expressed CD7, CD56, CD33, and CD34. He was then diagnosed with myeloid/natural killer cell precursor leukemia. This form of leukemia was recently established as a distinct disease entity. Further clinicopathological evaluation and the establishment of treatment are necessary.

Evi-1 promotes para-aortic splanchnopleural hematopoiesis through up-regulation of GATA-2 and repression of TGF-b signaling.

Evi-1 is a zinc-finger transcriptional factor whose inappropriate expression leads to leukemic transformation in mice and humans. Recently, it has been shown that Evi-1 regulates proliferation of hematopoietic stem/progenitor cells at embryonic stage via GATA-2 up-regulation; however, detailed mechanisms underlying Evi-1-mediated early hematopoiesis are not fully understood. We therefore evaluated hematopoietic potential of Evi-1 mutants using a cultivation system of murine para-aortic splanchnopleural (P-Sp) regions, and found that both the first zinc finger domain and the acidic domain were required for Evi-1-mediated hematopoiesis. The hematopoietic potential of Evi-1 mutants was likely to be related to its ability to up-regulate GATA-2 expression. We also showed that the decreased colony forming capacity of Evi-1-deficient P-Sp cells was successfully recovered by inhibition of TGF-b signaling, using ALK5 inhibitor or retroviral transfer of dominant-negative-type Smad3. Our findings suggest that Evi-1 promotes hematopoietic stem/progenitor expansion at the embryonic stage through up-regulation of GATA-2 and repression of TGF-beta signaling.

Diffusion-weighted imaging characteristics of methotrexate-induced acute encephalopathy.

Methotrexate (MTX)-induced encephalopathy is a grave complication in patients with malignancies. The early diagnosis of acute encephalopathy was difficult by conventional computed tomography (CT), and T1- or T2-weighted magnet resonance (MR) imaging. We report that the diffusion-weighted (DW) imaging is useful for early detection of acute leukoencephalopathy.

A case of herpes simplex virus pneumonia detected by sputum cytodiagnosis.

A sputum test is noninvasive and simple. It contributed to correct diagnosis of a patient with severe acute respiratory failure. We again point out the usefulness of sputum cytodiagnosis for differentiating severe pneumonia.

Coombs-negative Autoimmune Hemolytic Anemia Followed by Anti-erythropoetin Receptor Antibody-associated Pure Red Cell Aplasia: A Case Report and Review of Literature.

A 76-year-old woman was referred to our hospital because of anemia. The laboratory findings revealed hemolysis. Although a direct Coombs test was negative, a high titer of RBC-bound IgG was detected, and a diagnosis of Coombs-negative autoimmune hemolytic anemia was made. She was successfully treated with prednisolone. One year and five months later, she again presented anemia and was diagnosed with pure red cell aplasia. Anti-erythropoietin receptor antibody was detected in the serum. She was treated with cyclosporine and obtained prompt recovery. We herein report this rare case and review the pertinent literature.

Spermatic cord lymphoma: a case report and literature review.

Spermatic cord lymphoma is a rare lethal disease. It has a poor prognosis even in stage I or II disease when treated locally, therefore, multidisciplinary treatment for early stage is recommended. On the other hand, the treatment of choice for stage III or IV spermatic cord lymphoma remains to be determined. It is said that spermatic cord lymphoma is clinicopathologically similar to primary testicular lymphoma, therefore the treatment of spermatic cord lymphoma has often been determined by reference to the recommended treatment for primary testicular lymphoma. Here we report a new case of spermatic cord lymphoma, which was found in stage IV disease. We also review thirty-three cases which have been reported as spermatic cord lymphoma to date, and discuss treatment options.

Vascular endothelial growth factor-C and its receptor type-3 expressed in acute lymphocytic leukemia cases with t(1;19).

The vascular endothelial growth factor (VEGF)-C system was analyzed in two cases of acute lymphocytic leukemia (ALL) with TCF3/PBX1 fusion to determine whether the VEGF-C system influences the growth of these ALL blasts. Bone marrow non-adherent mononuclear cells were prepared from the patients, and expressions of VEGFs and VEGF receptors (VEGFRs) were analyzed based on RNA and protein levels. Cell proliferation was also assayed with or without neutralizing antibodies to VEGFs. The patients' leukemic blasts expressed a significant amount of VEGF-C and VEGFR type-3. When anti-VEGF-C antibody was added to the blast cell cultures, cell proliferation was suppressed. These observations indicate that, in our ALL cases with TCF3/PBX1 fusion, VEGF-C autocrine stimulation plays an important role in the proliferation of ALL.

Acute eosinophilic pneumonia is a non-infectious lung complication after allogeneic hematopoietic stem cell transplantation.

Acute eosinophilic pneumonia (AEP) is an acute febrile illness with respiratory impairment, diffuse pulmonary infiltrates, and eosinophilia in bronchoalveolar lavage (BAL) fluid. We report an adult male who developed severe cough and dyspnea with slight fever on day 78 after allogeneic hematopoietic stem transplantation. The symptoms coexisted with skin and gut GVHD. The imaging test demonstrated interstitial infiltrates and BAL analysis revealed marked increase of eosinophils and no sign of infection. We made a diagnosis of AEP and steroid was started. AEP remitted with other GVHD symptoms but exacerbated partially when steroid was decreased. This case suggests a potential link between AEP and GVHD.

Expression profiling of immature thymocytes revealed a novel homeobox gene that regulates double-negative thymocyte development.

Intrathymic development of CD4/CD8 double-negative (DN) thymocytes can be tracked by well-defined chronological subsets of thymocytes, and is an ideal target of gene expression profiling analysis to clarify the genetic basis of mature T cell production, by which differentiation of immature thymocytes is investigated in terms of gene expression profiles. In this study, we show that development of murine DN thymocytes is predominantly regulated by largely repressive rather than inductive activities of transcriptions, where lineage-promiscuous gene expression in immature thymocytes is down-regulated during their differentiation. Functional mapping of genes showing common temporal expression profiles implicates previously uncharacterized gene regulations that may be relevant to early thymocytes development. A small minority of genes is transiently expressed in the CD44(low)CD25(+) subset of DN thymocytes, from which we identified a novel homeobox gene, Duxl, whose expression is up-regulated by Runx1. Duxl promotes the transition from CD44(high)CD25(+) to CD44(low)CD25(+) in DN thymocytes, while constitutive expression of Duxl inhibits expression of TCR beta-chains and leads to impaired beta selection and greatly reduced production of CD4/CD8 double-positive thymocytes, indicating its critical roles in DN thymocyte development.