Jerome Dickstein

Methylation and silencing of miRNA-124 by EVI1 and self-renewal exhaustion of hematopoietic stem cells in murine myelodysplastic syndrome.

By expressing EVI1 in murine bone marrow (BM), we previously described a myelodysplastic syndrome (MDS) model characterized by pancytopenia, dysmegakaryopoiesis, dyserythropoiesis, and BM failure. The mice invariably died 11–14 months after BM transplantation (BMT). Here, we show that a double point mutant EVI1-(1+6Mut), unable to bind Gata1, abrogates the onset of MDS in the mouse and re-establishes normal megakaryopoiesis, erythropoiesis, BM function, and peripheral blood profiles. These normal features were maintained in the reconstituted mice until the study was ended at 21 months after BMT. We also report that EVI1 deregulates several genes that control cell division and cell self-renewal. In striking contrast, these genes are normalized in the presence of the EVI1 mutant. Moreover, EVI1, but not the EVI1 mutant, seemingly deregulates these cellular processes by altering miRNA expression. In particular, the silencing of miRNA-124 by DNA methylation is associated with EVI1 expression, but not that of the EVI1 mutant, and appears to play a key role in the up-regulation of cell division in murine BM cells and in the hematopoietic cell line 32Dcl3. The results presented here demonstrate that EVI1 induces MDS in the mouse through two major pathways, both of which require the interaction of EVI1 with other factors: one, results from EVI1–Gata1 interaction, which deregulates erythropoiesis and leads to fatal anemia, whereas the other occurs by interaction of EVI1 with unidentified factors causing perturbation of the cell cycle and self-renewal, as a consequence of silencing miRNA-124 by EVI1 and, ultimately, ensues in BM failure.

Immune-mediated red cell aplasia after anti-CTLA-4 immunotherapy for metastatic melanoma

A 55-year-old man presented in 2002 with a right lower extremity nodular melanoma, Breslow thickness 1.33 mm, without associated nevus or lymphocytic inWltrate. A sentinel lymph node biopsy was negative, and he received a wide excision and no further therapy. One year later, he presented with a subcutaneous in-transit metastasis which was resected. He began systemic adjuvant therapy on a melanoma vaccine trial containing twelve melanoma peptides in 2004, but 1 year later was found to have progressive disease with liver and subcutaneous metastases. In 2005, he participated in a clinical trial of the Wbroblast activation protein (FAP) inhibitor PT100, but developed progressive disease after 6 months, with new subcutaneous and right inguinal lymph node lesions. He continued to have excellent performance status and in late 2005 participated in a phase III trial of carboplatin and paclitaxel along with Sorafenib or placebo, but developed progressive disease after 7 months. In 2006, he began on Ipilimumab (10 mg/kg once every 3 weeks), an anti-CTLA-4 monoclonal antibody, in a phase II clinical trial approved by the Institutional Review Board at the University of Chicago. He did not have a prior personal or family history of autoimmune disease. He developed vitiligo after 3 months of therapy and had radiographic evidence of response, with decreased size of the right inguinal lymph nodes and stable liver metastases. The following month, he developed hypothyroidism, which was successfully treated with levothyroxine. He had intermittent low grade diarrhea managed with kaopectate, and fatigue, but continued to have an active lifestyle with stable disease. In 2007, after receiving four cycles of induction followed by three cycles of maintenance therapy over a total of 47 weeks, he had radiographic evidence of progressive disease of a subcutaneous mass and underwent re-induction with 10 mg/kg intravenous Ipilimumab, given once every 3 weeks. He continued to have vitiligo, hypothyroidism, and intermittent fatigue. After two cycles of re-induction, he became severely fatigued, pale and tachycardic. His hemoglobin was 7.4 g/dl and hematocrit was 20.4%, compared to a baseline of 14.4 g/dl and 42%, respectively. Ipilimumab dosing was held and he was transfused with packed red blood cells. However, he continued to have severe fatigue and persistent anemia. There was no melena or sign of active bleeding, and a stool Guaiac test was negative. Laboratory evaluation revealed hemoglobin 5.4 g/dl, hematocrit 14.9%, reticulocytes 0.1%, absolute reticulocyte count 1.72 K/ l, reticulocyte production index 0, elevated serum ferritin (839 ng/mL) and serum iron (206 mcg/dl), normal vitamin B12 and folate, and elevated serum erythropoietin (1,284 mIU/ml). Platelets were 173,000 l¡1 and white blood cells were mildly decreased at 2,900 l¡1. Although a direct antiglobulin test was positive, the levels of lactate dehydrogenase, bilirubin, and haptoglobin were normal. He was admitted to the hospital for evaluation and treatment of an apparent underproduction anemia. He was transfused with packed red blood cells and underwent a bone marrow biopsy and aspirate with review of peripheral blood smears. The diVerential diagnosis at this time included red cell aplasia, aplastic anemia, parvovirus, and I. O. Gordon · J. Dickstein (&) · T. F. Gajewski Department of Pathology, University of Chicago, 5841 S. Maryland Ave., TW055, Chicago, IL 60637, USA e-mail: jerome.dickstein@uchospitals.edu

Acute myeloid leukaemia following interferon-alfa treatment of hairy cell leukaemia.

Interferon-alfa (IFNa) has been used for the treatment of hairy cell leukaemia (HCL) since 1984 (Quesada et al, 1984). Late complications of IFNa therapy, such as second malignancies, have not been reported. We describe here a patient with HCL who developed acute myeloid leukaemia (AML) 6.5 years after initiation of IFNa therapy. Many features of this case are similar to those reported in therapy-related AML (t-AML) that follows alkylating agent therapy. A 5 7-year-old man with pancytopenia, splenomegaly and no history of chemical exposure was first seen in January 1984. A bone marrow specimen revealed HCL cells which exhibited tartrate-resistant acid phosphatase positivity. The patient underwent splenectomy with recovery of his blood counts. Three months later he was readmitted with fever: Mycobacterium kansasii was cultured from a mediastinal lymph node. He was treated with isoniazid, rifampin and ethambutol for 2 years. In February 1985 he became neutropenic and was started on IFNa-2b (1 x lo6 units/mz

Consistent Up-regulation of Stat3 Independently of Jak2 Mutations in a New Murine Model of Essential Thrombocythemia

Janus-activated kinase 2 (JAK2) mutations are common in myeloproliferative disorders; however, although they are detected in virtually all polycythemia vera patients, they are found in approximately 50% of essential thrombocythemia (ET) patients, suggesting that converging pathways/abnormalities underlie the onset of ET. Recently, the chromosomal translocation 3;21, leading to the fusion gene AML1/MDS1/EVI1 (AME), was observed in an ET patient. After we forced the expression of AME in the bone marrow (BM) of C57BL/6J mice, all the reconstituted mice died of a disease with symptoms similar to ET with a latency of 8 to 16 months. Peripheral blood smears consistently showed an elevated number of dysplastic platelets with anisocytosis, degranulation, and giant size. Although the AME-positive mice did not harbor Jak2 mutations, the BM of most of them had significantly higher levels of activated Stat3 than the controls. With combined biochemical and biological assays we found that AME binds to the Stat3 promoter leading to its up-regulation. Signal transducers and activators of transcription 3 (STAT3) analysis of a small group of ET patients shows that in about half of the patients, there is STAT3 hyperactivation independently of JAK2 mutations, suggesting that the hyperactivation of STAT3 by JAK2 mutations or promoter activation may be a critical step in development of ET.

Localization of the chromosome 22 breakpoints in two cases of acute megakaryoblastic leukemia with t(1;22)(p13;q13).

Acute megakaryoblastic leukemia with t(1;22)(p13;q13) is a rare malignancy occurring in infants and young children. The genes involved in t(1;22)(p13;q13) are unknown. In this study, dual-color fluorescence in situ hybridization (FISH) experiments with 15 probes were performed on the metaphase cells obtained from one patient to systematically narrow the region of the breakpoint on chromosome 22 and localize it to RP5-1042K10. A 22.3-kb FISH probe derived from RP5-1042K10 was used to further refine the locus of the breakpoint in this case. Southern blot analysis covering of genomic DNA from a second patient detected DNA rearrangement at a site close to the breakpoint observed with the 22.3-kb probe in the first case. A partially characterized gene, KIAA 1438, is in the vicinity of the breakpoints determined by FISH and Southern blot experiments, suggesting that this gene plays a role in this malignancy.

Cardiac tamponade mimicking tuberculous pericarditis as the initial presentation of chronic lymphocytic leukemia in a 58-year-old woman: a case report

IntroductionChronic lymphocytic leukemia is an indolent disease that often presents with complaints of lymphadenopathy or is detected as an incidental laboratory finding. It is rarely considered in the differential diagnosis of patients presenting with tamponade or a large, bloody pericardial effusion. In patients without known cancer, a large, bloody pericardial effusion raises the possibility of tuberculosis, particularly in patients from endemic areas. However, the signs, symptoms and laboratory findings of pericarditis related to chronic lymphocytic leukemia can mimic tuberculosis.Case PresentationWe report the case of a 58-year-old African American-Nigerian woman with a history of travel to Nigeria and a positive tuberculin skin test who presented with cardiac tamponade. She had a mild fever, lymphocytosis and a bloody pericardial effusion, but cultures and stains were negative for acid-fast bacteria. Assessment of blood by flow cytometry and pericardial biopsy by immunohistochemistry revealed CD5 (+) and CD20 (+) lymphocytes in both tissues, demonstrating this to be an unusual manifestation of early stage chronic lymphocytic leukemia.ConclusionAlthough most malignancies that involve the pericardium clinically manifest elsewhere before presenting with tamponade, this case illustrates the potential for early stage chronic lymphocytic leukemia to present as a large pericardial effusion with tamponade. Moreover, the presentation mimicked tuberculosis. This case also demonstrates that it is possible to treat chronic lymphocytic leukemia-related pericardial tamponade by removal of the fluid without chemotherapy.