The t(2;5)(p23;q35) translocation, associated with anaplastic large-cell lymphoma (ALCL), results in the expression of a chimeric NPM-ALK protein that can be detected by the ALK1 monoclonal antibody. This report describes the morphologic and phenotypic spectrum of 123 cases of lymphoma that all express ALK protein. The results provide strong evidence that the morphologic patterns of ALCL described in previous reports as representing possible subtypes of ALCL, eg, common type, lymphohistiocytic, or small cell patterns, are morphologic variants of the same disease entity. All of these morphologic patterns could be found within this series, and in some patients different subtypes coexisted in a single biopsy or were found in successive biopsies from a single patient. The link between these morphologic subtypes is further reinforced by the presence in all cases of a highly characteristic large cell, with an eccentric nucleus and an eosinophilic paranuclear region. We suggest that this cell can be considered as a major distinguishing feature of ALK-positive lymphomas. Another characteristic of these tumors was the perivascular pattern of neoplastic cell infiltration seen in a significant number of cases. In addition to ALK protein, all tumors expressed epithelial membrane antigen and lacked CD15, features that may be of value in differentiating ALCL from Hodgkin's disease. In the majority of cases (84%), malignant cells showed both a cytoplasmic and nuclear staining for ALK1 and thus presumably carried the 2;5 translocation, but staining was restricted to the cytoplasm in a few cases, suggesting that translocations other than t(2;5) may induce expression of ALK protein. We conclude from this study that ALK-positive neoplasms represent a distinct entity. Because their morphology is often neither anaplastic nor large cell, we suggest that they should henceforward be referred to as ALK lymphomas.

To study the incidence of, the factors associated with, and the effect on survival of anemia in human immunodeficiency virus (HIV)-infected persons, we analyzed data from the longitudinal medical record reviews of 32,867 HIV-infected persons who received medical care from January 1990 through August 1996 in clinics, hospitals, and private medical practices in nine United States cities. We calculated the 1-year incidence of anemia (a hemoglobin level of <10 g/dL or a physician diagnosis of anemia); the adjusted odds ratios showing excess risk of anemia associated with demographic factors, prescribed therapies, and concurrent diseases; the risk of death for patients who developed anemia compared with risk for patients who did not develop anemia; and, of patients who did develop anemia, the risk of death for those who did not recover from anemia compared with the risk for those who did recover. The 1-year incidence of anemia was 36.9% for persons with one or more acquired immunodeficiency syndrome (AIDS)-defining opportunistic illnesses (clinical AIDS), 12.1% for patients with a CD4 count of less than 200 cells/micron or CD4 percentage of <14 but not clinical AIDS (immunologic AIDS), and 3.2% for persons without clinical or immunologic AIDS. Of anemia diagnoses, 22% were identified by physicians as drug related. Incidence of anemia was associated with clinical AIDS, immunologic AIDS, neutropenia, thrombocytopenia, bacterial septicemia, black race, female sex, prescription of zidovudine, fluconazole, and ganciclovir, and lack of prescription of trimethoprim-sulfamethoxazole. The increased risk of death associated with anemia differed by first CD4 count: for patients with a CD4 count of >/=200 cells/microL at the beginning of the survival analysis, the risk of death was 148% (99% confidence interval [CI], 114 to 188) greater for those who developed anemia; for patients whose first CD4 count was <200 cells/microL, the risk of death was 56% (99% CI, 43 to 71) greater for those in whom anemia developed. For persons in whom anemia developed, the risk of death was 170% (99% CI, 132 to 203) greater for persons who did not recover from anemia compared with those who did recover. Anemia is a frequent complication of HIV infection, and its incidence is associated with progression of HIV disease, prescription of certain chemotherapeutics, black race, and female sex. Anemia, particularly anemia that does not resolve, is associated with shorter survival of HIV-infected patients.

Multiple Myeloma (Mm) is a clonal B-cell neoplasm that affects terminally differentiated B cells (ie, plasma cells) and may proceed through different phases: an inactive phase in which tumor cells are nonproliferating mature plasma cells, an active phase with a small percentage (<1%) of proliferating plasmablastic cells, and a fulminant phase with the frequent occurrence of extramedullary proliferation and an increase in plasmablastic cells. During the past years, considerable progress has been made in identifying some of the critical components of neoplastic transformation in MM. This review intends to propose a model of a stepwise malignant transformation during MM pathogenesis. Both diagnostic and therapeutic implications of this model will be discussed.

Since the initial observations by Kaiser and Edelman, interest in the role of calcium in ACS-induced apoptosis has wavered, in part because of the fact that extracellular calcium is only necessary for induction of apoptosis in thymocytes, but not in peripheral lymphocytes or lymphoma cells. Now, as result of molecular evidence implicating two separate ligand-gated calcium channels in ACS-induced apoptosis, interest in the role of calcium is sure to be renewed. The major challenge lies in determining the signal transduction pathway through which ACS-induced calcium fluxes mediate apoptosis.

Ribozymes are catalytic RNA molecules that recognize their target RNA in a highly sequence-specific manner. They can therefore be used to inhibit deleterious gene expression (by cleavage of the target mRNA) or even repair mutant cellular RNAs. Targets such as the mRNAs of oncogenes (resulting from base mutations or chromosome translocations, eg, ras or bcr-abl) and viral genomes and transcripts (human immunodeficiency virus-type 1 [HIV-1]) are ideal targets for such sequence-specific agents. The aim of this review is therefore to introduce the different classes of ribozymes, highlighting some of the chemistry of the reactions they catalyze, to address the specific inhibition of genes by ribozymes, the problems yet to be resolved, and how new developments in the field give hope to the future for ribozymes in the therapeutic field.