Hepatosplenic alphabeta T-cell lymphomas: a report of 14 cases and comparison with hepatosplenic gammadelta T-cell lymphomas.

Hepatosplenic gammadelta T-cell lymphoma is a distinct entity, characterized by occurrence in young adult males with hepatosplenomegaly, B-symptoms, peripheral blood cytopenias, and no lymphadenopathy; lymphomatous infiltrates in the splenic red pulp, hepatic sinusoids, and bone marrow sinuses; T-cell receptor (TCR) gammadelta chains and a cytotoxic T-cell phenotype; isochromosome 7q; and an aggressive clinical course. In comparison, this study describes the clinicopathologic features of 14 hepatosplenic T-cell lymphomas expressing TCR alphabeta chains. They occurred in 11 women and 3 men with a median age of 36 years. Clinical presentation was similar to that described previously for hepatosplenic gammadelta T-cell lymphomas, except for the female preponderance and age distribution (5 patients younger than 13 years of age and 5 patients older than 50 years of age). Disease distribution was primarily in the splenic red pulp and hepatic sinusoids, although liver infiltrates were largely periportal in four cases. Bone marrow involvement, observed in eight patients, was usually interstitial and/or within the sinuses. Lymph nodes were involved in five patients, although lymphadenopathy was demonstrable in only two. Ten cases were composed of intermediate-size tumor cells with round/oval nuclei, slightly dispersed chromatin, inconspicuous nucleoli, and scant to moderate amounts of cytoplasm. Four lymphomas contained primarily large cells with irregular nuclei, dispersed chromatin, discernible nucleoli, and moderate to abundant cytoplasm. Tumor cells in all 14 lymphomas were cytotoxic alphabeta T-cells; 13 co-expressed natural killer cell-associated antigens and showed T-cell clonality. Three lymphomas were associated with Epstein-Barr virus. Two of four cases had an isochromosome 7q. Eleven patients are dead, eight within a year of diagnosis, and two patients have maintained complete remissions after combination chemotherapy. These data show that hepatosplenic T-cell lymphomas include an alphabeta-subtype. This group, along with the previously recognized gammadelta group, should be recognized as phenotypically heterogeneous subtypes of the same disease entity.

Acute myelogenous leukemia (FAB AML-M1) in the setting of HIV infection and G-CSF therapy: a case report and review of the literature.

Although hematologic dysplasia is common in HIV disease, evolution to AML is unusual. We report a case of AML in a patient with stage-C3 AIDS who had been previously treated with granulocyte colony-stimulating factor (G-CSF). This 41-year-old black man presented with pancytopenia (Hg 8.6 g/dl, Hct 24.3%, platelets 16,000/mm3, WBC 0.6 x 10(3)/mm3) and hemoptysis. His peripheral smear manifested 19% blasts. His bone marrow biopsy was hypocellular (20%) with greater than 90% blasts, which were positive for myeloperoxidase and Sudan black B. The blasts were negative for nonspecific esterase. Immunophenotypic analysis by flow cytometry showed the majority of cells to be of myeloid lineage, expressing CD13, and CD45 at low intensity. In addition, there was aberrant expression of CD2 and no expression of CD14 or CD4. The diagnosis of AML-FAB-M1 was made. The patient refused chemotherapy. Of the rare cases of AML in HIV patients previously reported in the literature, the majority were of the monocytic or myelomonocytic subtype. This case is of special interest because of prior G-CSF therapy. In this setting, the relationship between HIV, G-CSF, and subsequent AML is controversial.

Anaplastic large cell lymphoma of T-cell phenotype in acquired immunodeficiency syndrome.

Anaplastic large cell lymphoma (ALCL) is an uncommon non-Hodgkin's lymphoma in the general population as well as in HIV-infected patients. Ordinarily, ALCL expresses T-cell phenotype, but lymphoproliferative disorders derived from T cells rarely occur in acquired immunodeficiency syndrome (AIDS). We describe a white male homosexual with AIDS who had bilateral pleural effusions. Examination of the pleural fluid revealed ALCL positive for Ki-1 (CD30), LCA (CD45), UCHL-1 (CD45RO), CD43, CD3, and epithelial membrane antigen. The lymphoma was negative for the B-cell marker L26 (CD20) and for Leu-M1 (CD15). The T-cell origin was also confirmed by the monoclonal rearrangement of the T-cell receptor beta chain gene. A review of other cases of ALCL in HIV-positive individuals shows variability in clinical presentation and biologic behavior of this lymphoma type. It also points to the potential contribution of gene rearrangement studies for recognition of phenotype. In addition, the role of determination of the presence of t(2;5) and the corresponding gene product is discussed.

The alternate iron transport pathway: mobilferrin and integrin in reticulocytes.

Iron transport in reticulocytes is known to occur via the well-described transferrin-receptor-endosome pathway. An alternative pathway for iron transport independent of transferrin has been postulated in reticulocytes and other cells. Transport of iron into reticulocytes from ferric citrate solutions was shown to be saturable and independent of transferrin. During transport of iron from ferric citrate, both cell surface integrins, and a soluble protein, mobilferrin, were labelled. This demonstrated that the reticulocyte transferrin independent pathway for iron transport involved integrins and mobilferrin similar to intestinal absorptive cells. This pathway would be expected to transport iron into cells under conditions of iron overload and was capable of providing iron for haemoglobin synthesis. Mobilferrin was also radiolabelled when radioiron labelled transferrin was incubated with reticulocytes and this occurred with a different time course than was observed following reticulocyte exposure to radiolabelled ferric citrate. This suggested that mobilferrin may serve as an intermediary in both pathways.

Rapid progression of acquired amegakaryocytic thrombocytopenia to aplastic anemia.

Acquired amegakaryocytic thrombocytopenia is a rare disorder characterized by severe thrombocytopenia and selective, marked decrease or absence of megakaryocytes. Although immunosuppressive therapy (prednisone and/or antithymocyte globulin) has been shown to induce remissions in a subset of patients, most patients do not respond, and progression to aplastic anemia occurs in some cases. We report a case of acquired amegakaryocytic thrombocytopenia which, despite aggressive immunosuppressive treatment, rapidly progressed to aplastic anemia. Clinical, laboratory, and immunologic features of our patient's case are described and compared to those of the previously reported six cases that progressed from amegakaryocytic thrombocytopenia to aplastic anemia.

Autoantibodies to specific enzymes: a review.

There are two categories of autoantibodies to specific enzymes: immunoglobulin-complexed enzymes and circulating autoantibodies directed to enzymes in tissue or tissues. Immunoglobulin-complexed enzymes may result in elevated serum enzyme activity. They are found more frequently in elderly patients and have limited clinical significance. Immunoglobulin association with the enzyme must be demonstrated to distinguish this macroenzyme from other high molecular weight enzyme complexes. Autoantibodies to specific enzymes or regulators of enzyme activity do possess specific disease associations. The titers or presence of these autoantibodies may predict morbidity or response to therapy. These autoantibodies may be detected by Western blotting, enzyme-linked immunosorbent assays, tissue immunofluorescence, radioimmunoassay, immunoprecipitation flow cytometry or inhibition of enzyme activity. For example, anti-pyruvate dehydrogenase inhibits the activity of purified enzyme, but not relatively intact mitochondrial preparations. Most evidence suggests that the production of autoantibodies to specific enzymes represents an epiphenomenon secondary to tissue damage rather than a primary event in the pathogenetic pathway.

A flow cytometric method to detect anti-pyruvate dehydrogenase antibody in primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is an autoimmune disease characterized by the presence of anti-mitochondrial antibodies specifically directed against the M2 group of mitochondrial antigens. Recently, the E-1, the E-2, and protein X components of pyruvate dehydrogenase enzyme complex have been identified as the major antigens within the M2 group of autoantigens. An immunoassay using pyruvate dehydrogenase enzyme complex as a specific antigen for the diagnosis of PBC was developed. Pyruvate dehydrogenase enzyme complex was attached to polystyrene microbeads, incubated with sera from PBC patients (n = 18), normal controls (n = 50), or patients with other autoimmune diseases (n = 26), followed by incubation with a second fluorescein isothiocyanate conjugated goat anti-human immunoglobulin and then analyzed by flow cytometry. High numbers of fluorescence channels (mean, 1,693 +/- 846) were obtained for all PBC sera except for two patients. Compared to the conventional anti-mitochondrial antibody assay, the assay had a sensitivity rate of 94% and a specificity rate of 100%. The reactive antibodies are predominantly of the immunoglobulin G3 subclass. Their levels could be correlated with the histopathologic stages of PBC. These results were corroborated by immunoblotting. Sera from patients with later stages of PBC strongly reacted with pyruvate dehydrogenase enzyme complex components, E1 alpha, and protein X.

Suppression of human lymphocyte responses to specific and non-specific stimuli in human onchocerciasis.

Characterization of in vitro lymphocyte responsiveness was performed on selected groups of onchocerciasis patients from Sudan and Sierra Leone. These patients manifested a very broad range of clinical signs and showed widely divergent parasite infection intensities. Lymphocyte proliferative responses to soluble Onchocerca volvulus antigen (sAg) were poor in infected persons; mitogen and PPD responses were maintained in the normal range in one group of patients from southwestern Sudan, but were profoundly depressed in a group from N.E. Sudan. Proliferative responses and interferon-gamma (INF-gamma) secretion were very significantly depressed in the presence of live microfilariae of O. volvulus or secretions/excretions (S/E) from microfilariae (mf) or from female, but not male, adult parasites. Lymphocyte responses were maintained near normal when exogenous IL-2 was added to these cultures. The results indicate that O. volvulus infection and its clinical consequences are not consistently associated with systemic deficits in immune responsiveness. However, suppression of lymphocyte reactivity by mf and S/E in vitro suggests that direct parasite intervention in host cell responses could be taking place in vivo, perhaps at the local microenvironment level; mediated by effects on cytokine production.

Cell adherence to microfilariae of Onchocerca volvulus: a comparative study.

The conditions were examined for in vitro antibody-mediated adherence of granulocytes to microfilariae of Onchocera volvulus and Dirofilaria immitis. Reactivity in human sera from patients in endemic foci in Sudan was specific for O. volvulus and no reactions were observed with heterologous Onchocerca species or with Mansonella perstans. Microfilariae from skin, nodules or adult female worms were satisfactory targets for cell adherence, and the cells involved were almost exclusively eosinophils. The reaction was inhibited by indomethacin but not by nordihydroguaiaretic acid, an inhibitor of leukotriene production. Agents that slowed or stopped microfilarial motility (e.g. nifedipine, lidocaine, chloroquine) inhibited the reaction, probably by reducing target/cell contact. Ivermectin did not enhance the reaction, and in the absence of cells exerted only slight effects on the movement of microfilariae at higher concentrations (greater than 10 micrograms/ml). Antibody activity was labile, and did not persist well through freeze-thaw cycles. Some differences between homologous and heterologous mixtures (microfilariae/cells/serum) were seen but they could not be resolved satisfactorily. There were no apparent geographical differences between microfilariae from different foci in Sudan. In the D. immitis system neutrophils were the dominant cell type adhering to microfilariae, and the activity was stable to storage and freeze-thaw. No enhancement was detectable with diethylcarbamazine. Antibody activity was absorbable with microfilarial antigens and was reduced by agents that inhibited microfilarial motility. In dogs, adherence-mediating antibody was seen only in amicrofilaraemic animals with occult infection, and in only a minority of these sera. In humans the relationship to clinical findings was less clear, but patients with punctate keratitis were the most likely to have positive serum and were the most reactive in the assay. This system may therefore offer some insights into disease mechanisms in vivo, and its molecular mechanisms deserve further characterization.