No abstract

The combined occurrence of hereditary nephritis with nerve deafness (Alport's syndrome) and macrothrombocytopathic thrombocytopenia is very rare. The authors have had the opportunity to study such a case in a 20-year-old man who had been followed since birth. The clinical history, renal biopsy, platelet studies, and autopsy findings are presented. The renal pathologic findings are well defined; however, the hemostatic abnormalities and the hearing loss are not well characterized. In this paper, an attept is made to clarify the diverse platelet functional and morphologic abnormalties.

Six patients with Hodgkin's disease (HD) and demonstrable serum antibodies to human immunodeficiency virus (HIV) and two additional patients with HD belonging to HIV-associated high-risk groups but with negative HIV serology were studied. All patients were men and ranged in age from 21 to 45 years. The HIV risk factors included homosexuality (6), intravenous drug abuse (2), and hemophilia A (1). All patients had high pathologically determined stage (one Stage III and seven Stage IV), and bone marrow involvement was observed in five patients with the initial diagnosis of HD based on marrow biopsy in two cases. Four cases were histologically subclassified as mixed cellularity (MC) and three as nodular sclerosis (NS); one patient underwent only bone marrow biopsy and was not subclassified. Histologically all cases were characterized by numerous Reed-Sternberg cells and variants, and with the exception of one case, all had a distinctive decrease in the proportion of reactive background lymphocytes compared with what is usually expected in MC or NS Hodgkin's disease (relative lymphocyte depletion). Flow-cytometric immunophenotypic studies done on cell suspensions from diagnostic lymph node biopsies in four cases showed decreased CD4:CD8 ratios (mean = 1.4) compared with expected values of 4 to 6. The relative lymphocyte depletion observed histologically is probably a reflection of the decreased tissue CD4:CD8 ratios, and this impairment of host immune response may be related to the observed high stage in all eight cases. Patients with high stage HD and the described histologic and immunologic features should be evaluated for the presence of HIV infection.

No abstract

Chromosome analysis with giemsa-trypsin banding was performed on circulating myeloblasts and cultured bone marrow fibroblasts from a patient with acute myelofibrosis. Major karyotypic abnormalities were found in the myeloblasts involving chromosomes #1, 3, 5, 13, and 16; no chromosome abnormalities were detected in the fibroblasts. In addition, a pericentric inversion of number 7 was present in the circulating blasts but not the fibroblasts. Pericentric inversions have not previously been associated with acquired abnormalities of malignant cells. These findings support the concept that acute myelofibrosis is a primary malignancy of hematopoietic cells associated with secondary marrow fibrosis. The entity of acute myelofibrosis is discussed and the results of cytogenetic studies of previous reports are reviewed.

No abstract

The role of hematopoietic growth factors in lineage commitment and differentiation is unclear. We present evidence that heterologous expression of an erythroid specific receptor allows granulocytic differentiation of a myeloid cell line. We have previously characterized a truncation mutant of the erythropoietin receptor (EpoR), which is associated with familial erythrocytosis (Blood89:4628, 1997). This truncated EpoR lacks the distal 70 amino acids of the cytoplasmic domain. To study the functional role of this distal receptor domain, 32D cells, a murine interleukin-3 (IL-3)–dependent myeloid line, were transfected with the wild-type EpoR (32D/EpoR WT) or the truncated EpoR (32D/EpoR FE). 32D cells expressing either the full-length or truncated EpoR display equivalent proliferative rates in saturating concentrations of Epo. There is a dramatic difference in maturational phenotype between the two cell lines, however. The 32D/EpoR FE cells and mock transfected 32D cells have an immature, monoblastic morphology and do not express the primary granule protein myeloperoxidase. The 32D/EpoR WT cells, on the other hand, demonstrate granulocytic differentiation with profuse granulation, mature, clumped chromatin, and myeloperoxidase expression. There is no evidence of erythroid differentiation in 32D cells transfected with either the full-length or truncated EpoR. Treatment of the cells with the specific Jak2 inhibitor tyrphostin AG 490 inhibits myeloid differentiation driven by the distal EpoR. We conclude that: (1) the distal cytoplasmic domain of the EpoR is able to induce a specific myeloid differentiation signal distinct from mitogenic signaling, and (2) these data extend to myelopoiesis the growing body of evidence that the cellular milieu, not the specific cytokine receptor, determines the specificity of differentiation after cytokine receptor activation. © 1998 by The American Society of Hematology.

No abstract