Biomedical subjects
A Cafaro
Publications and source records attributed to A Cafaro.
HIV-1 infection of primary human neuroblasts.
Central nervous system (CNS) disorders are frequent in HIV-1-infected individuals, particularly in newborns and children, and are accompanied by histological alterations resulting in neuronal loss. Although several tumor-derived neuroectodermal cell lines can be infected by HIV-1, it has been reported that primary neural cells cannot be infected after they differentiate. However, pediatric AIDS is often the result of HIV-1 infection occurring during fetal development and early postnatal life, when neural cells are not yet differentiated. Here we show that primary cell cultures derived from the human fetal olfactory system which are representative of the developing CNS can be infected by both HIV-1 strains, the monocyte-macrophagotropic BaL and the lymphotropic HTLV-IIIB, although they do not express the CD4 molecule. In addition, the levels of viral replication are higher with the HIV-1 BaL than with the IIIB isolate. These results suggest that (1) during development immature neurons are susceptible to HIV-1 infection; (2) monocyte-macrophagotropic HIV-1 strains may preferentially be involved in the productive infection of the nervous system; and (3) a mechanism(s) other than the CD4-mediated viral entry is responsible for HIV-1 infection of immature neurons.
Synergy between basic fibroblast growth factor and HIV-1 Tat protein in induction of Kaposi's sarcoma.
Basic fibroblast growth factor (bFGF) and human immunodeficiency virus type 1 (HIV-1) Tat protein synergize in inducing angiogenic Kaposi's sarcoma-like lesions in mice. Synergy is due to Tat, which enhances endothelial cell growth and type-IV collagenase expression in response to bFGF mimicking extracellular matrix proteins. The bFGF, extracellular Tat and Tat receptors are present in HIV-1-associated KS, which may explain the higher frequency and aggressiveness of this form compared to classical Kaposi's sarcoma where only bFGF is present.
Viral DNA burden and decline in percentage of CD4-positive cells in the lymphoid compartment of SIV-infected macaques.
The decline in CD4+ cells and increased viral DNA and RNA burden in the blood of human immunodeficiency virus (HIV)-infected individuals have been used as closely related correlates of disease progression. However, little is known about levels of total or unintegrated viral DNA in lymphoid tissue of HIV-infected patients and how they relate to CD4+ cell decline or disease progression. Exploiting the similarities between HIV- and simian immunodeficiency virus (SIV)-induced disease, we examined lymphoid organs and peripheral blood from SIV-infected macaques for total (pol) and unintegrated 2-LTR circular viral DNA by polymerase chain reaction (PCR). Two SIV isolates (SIVmac/251 and SIVmne/E11S) that differ markedly in their biological and clinical properties were studied. The results indicate that total viral DNA burdens vary considerably between isolates. There was no strong association between total viral DNA levels and CD4% in lymphoid tissues when isolates were compared and death was not associated with any particular level of viral pol DNA. In contrast, accumulation of unintegrated viral DNA was closely associated with decline in CD4/CD8 ratios in lymphoid organs and AIDS. The appearance of both pol and unintegrated viral DNA in thymus of infected macaques also emerged as one of the single best correlates or possible predictors of advanced disease yet studied. Their roles in pathogenesis are discussed.
Abnormalities of lymphocyte subpopulations in CVI do not correlate with increased production of IL-6.
We have determined the percentages and absolute numbers of lymphocyte subpopulations in 49 patients with common variable immunodeficiency (CVI). In vitro production of IL-6 by PHA-stimulated PBMC of 28 patients was also evaluated. Our data indicate profound alterations in the lymphocyte subpopulations evaluated, including increased CD8 cells (these cells outnumbered CD4 cells in 26 cases), severe defect of CD4 cells (< 400/mm3) in 10 cases and reduction of CD19 cells (< 50/mm3) in 11/41 cases. Increased production in vitro of IL-6 by PBMC of CVI patients does not correlate with the absolute numbers of lymphocytes, lymphocyte subpopulations, or monocytes. In addition, IL-6 was unable to significantly modify the amount of PWM-driven IgM production by CVI cells.
Biologic and clinical heterogeneity of lymphoproliferative diseases of peripheral mature T lymphocytes.
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Enhancement of human immunodeficiency virus (HIV) replication in human monocytes by low titres of anti-HIV antibodies in vitro.
Low concentrations of serum obtained from a patient with acquired immunodeficiency syndrome (AIDS) enhanced the replication of human immunodeficiency virus type 1 (HIV-1) in a particular subclone of the CD-4-positive monocytoid cell line U937 clone 2. Cells of this subclone have a high expression of Fc receptors and a considerable degree of Fc-mediated phagocytic activity. IgG purified from the serum was also able to enhance the replication. These results indicate that low concentrations of human anti-HIV antibody may enhance HIV replication on human monocyte-macrophages. Furthermore, two mouse IgG1 monoclonal antibodies against gp120, the envelope glycoprotein of HIV-1, also induced enhancement at low concentrations. The binding of radiolabelled gp120 to the cells was increased at the same low concentrations. Antibodies against envelope glycoproteins may cause enhancement of HIV infection. Both normal and enhanced replication of HIV were completely inhibited by the masking of the binding site of CD4 molecules with F(ab')2 fragments of anti-CD4 antibody. Moreover, CD4-positive, Fc gamma RI-negative K562 cells and mouse macrophages failed to show any infection in the presence of antibody. These results suggest that CD4 molecules on the cell surface are necessary to cause enhancement of infection of HIV on monocyte-macrophages.
T-helper phenotype chronic lymphocytic leukemia (Thp-CLL): characterization of an Italian case with particular biological findings.
A patient with Chronic Lymphocytic Leukemia (CLL) characterized by an expansion of helper phenotype mature T lymphocytes is here described. The phenotype of these cells was OKT3+, OKT4+, Leu 9+, 5/9+, OKT8-, Tac- and functional studies showed a strong helper activity on B cell differentiation; an "in vivo" presence of an IgG-lambda paraproteinaemia has been demonstrated. Cytogenetic studies showed multiple clonal, numerical and structural rearrangements which included a tandem t(14;14) (q11;32) translocation. Hybridization showed HTLV I related specific bands indicating the presence of exogenous sequences related to prototype virus but derived from a different Retrovirus (HTLV 1c). The clinical course was aggressive and unsuccessful treatments with various polichemotherapeutic protocols, associated with multiple leukaphereses, were performed. The authors underline that despite the morphological, immunological, biological and virological heterogeneity, the common feature of T-helper CLL is the inexorable clinical course which needs a new therapeutic approach.
Phenotype of chronic lymphocytic leukemia (CLL) B-cells. B-CLL cells express the Leu-8 antigen.
In the present report we studied the phenotype of peripheral blood mononuclear cells (PBMC) from 25 patients with B-cell chronic lymphocytic leukemia (CLL). Cells from all the cases expressed monoclonal surface immunoglobulins (SmIg), formed rosettes with mouse erythrocytes (MRFC) and were positive with OKB 2 and OKIa monoclonal antibodies. In addition, CCB 1 monoclonal antibody was positive in 17 out of 20, Leu-1 in 18 out of 21 and Leu-8 in 23 out of 25 cases. Double labelling experiments confirmed that the Leu-8 antigen was co-expressed on Leu-1+, CCB2+, HLA-DR+ B-CLL cells. Thus, B-CLL cells generally express the SmIg+, MRFC+, Leu-1+, OKB2+, Leu-8+ phenotype. Since it is known that normal peripheral blood B cells may be divided into two subpopulations according to Leu-8 expression, our data indicate that B-CLL cells originate from the more immature Leu-8+ B-cell subset which will respond to anti-IgM, whereas it reacts poorly to pokeweed mitogen.
Relevance of monoclonal antibody phenotyping and of genetic studies in the classification of T-cell leukemia/lymphoma.
In this short review we discuss two clinical entities characterized by the accumulation in the blood of mature lymphocytes bearing T-cell markers (formerly T-cell chronic lymphocytic leukemia or T-CLL). The lymphoproliferative disease of granular lymphocytes (LDGL) is characterized by the expansion of granular lymphocytes (GL). Clinically most patients have a benign clinical course, while some have neutropenia. The neoplastic or reactive nature of the disease is discussed. T-CLL with a T-helper phenotype is, on the other hand, an aggressive disease with poor survival. Patients may be classified into two subgroups according to the presence of serum antibodies against HTLV-I. The possible etiological role of HTLV-I in the disease is discussed.
[Chronic T-lymphocyte lymphatic leukemia. Clinico-pathologic assessment and new epidemiologic data related to cases correlated with HTLV-I in Italy].
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The analysis of expanded cells from patients with lymphoproliferative disorders of granular lymphocytes may help to clarify the NK cell differentiation.
Surface phenotype and functional in vitro activities were studied in 2 cases of lymphoproliferative disorders of granular lymphocytes. Cells from both patients presented the same, previously unreported, surface phenotype (i.e. T3+, T8+, T4-, HNK-1-, NK-15+, M1-), were unable to display either Natural Killer (NK) activity or suppressor function in a poke-weed-driven system, and showed a defective response to phytohemagglutinin (PHA). On the basis of available schemes for NK cells ontogenesis, we will discuss the phenotype and functional activities of patients' cells suggesting that the cell population expressing the T3+, T8+, HNK-1-, NK-15+, M1- phenotype might represent a discrete stage along the NK-cell differentiation pathway.
Control of viral replication and disease onset in cynomolgus monkeys by HIV-1 TAT vaccine.
The Tat protein of HIV is produced early after infection and it is essential for viral replication and transmission. Tat is released by infected lymphocytes and is detected in the serum of HIV-infected patients. Extracellular Tat enters cells, where promotes HIV replication. Several studies suggest that humoral and cellular anti-Tat immunity have a protective role and may control disease progression. Of importance, Tat is conserved in its immunogenic regions among all viral subtypes except O subtype. Thus, the immunization with Tat cannot block virus entry but might block HIV replication and progression to disease. To test this hypothesis, monkeys (Macaca fascicularis) were immunized with a biologically active Tat protein. Tat was non toxic and induced specific humoral and cellular immune responses. High titers of anti-Tat antibodies capable of neutralizing Tat activity and the in vitro infection with the SHIV89.6P, Tat-specific proliferation, CTLs, TNFalpha production and skin tests were detected in the vaccinated monkeys. Most importantly, upon challenge with the highly pathogenic SHIV89.6P (10 MID50, i.v.), 5/7 of the vaccinated monkeys showed no signs of infection nor CD4+-T cell decline over a 19 months of follow-up, whereas 3/3 controls were highly infected. Thus, a Tat-vaccine is capable of controlling the acute phase of infection in nonhuman primates. These data open new avenues for the development of an AIDS vaccine.
Novel strategies toward the development of an effective vaccine to prevent human immunodeficiency virus infection or acquired immunodeficiency virus.
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[The oncology's rehabilitation ethical and care aspect].
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Reduction of circulating suppressor inducer T lymphocytes in the exacerbation phase of remitting-relapse multiple sclerosis.
We studied peripheral blood mononuclear cells (PBMC) from 34 multiple sclerosis (MS) patients: 8 had chronic progressive (CP) and 26 with a relapsing-remitting (RR) course. PBMC were tested with a panel of monoclonal antibodies (MoAbs) including anti-CD3, CD4, CD8, CD25 reagents. In addition, the suppressor inducer lymphocyte subset was investigated by using two color staining with anti-CD4 and G1-15 and/or anti-CD4 and anti-Leu-8 MoaAbs. A significant decrease of the suppressor inducer subset was found in the exacerbation phase of the RR form. Furthermore, a significant decrease of CD8+ (suppressor/cytotoxic) cells was shown in the remission phase of the RR group. Finally, CD25+ lymphocytes were significantly increased in both phases of RR form.
Monocytic blast cell crisis and IgG-lambda monoclonal gammopathy in a Ph1 + chronic myelogenous leukemia. Report of a case.
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