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Biomedical subjects

F Ensoli

Publications and source records attributed to F Ensoli.

25 records · Page 2Linked to original sources
PubMed1991

Plasma viraemia in seronegative HIV-1-infected individuals.

It has been reported that the period of latency between HIV-1 infection and the production of antibodies against the virus is sometimes prolonged for greater than 6 months. However, the data supporting this are still controversial and it is not known whether these individuals are actually infectious, especially through body fluids. We have performed a prospective study of 65 high-risk HIV-1-antibody-negative individuals who were followed-up for a period of at least 1 year. Twelve of these individuals were shown by polymerase chain reaction (PCR) to be carriers of HIV-1 proviral sequences. The virus was isolated from lymphocytes in five out of 10 PCR-positive subjects and from cell-free plasma in two. Our data indicate that in some cases delayed seroconversions may be associated with productive infection, suggesting that mechanism(s) other than viral latency may be responsible for the absence of antibody responses to HIV-1 proteins.

Blood Cells↗
PubMed1990

Proviral sequences detection of human immunodeficiency virus in seronegative subjects by polymerase chain reaction.

Human immunodeficiency virus type 1 (HIV-1) can be isolated from lymphocytes and tissues of symptomatic and asymptomatic seropositive subjects. However, in some individuals, virus isolation is not always positive, especially in asymptomatics. In this paper we report the results of HIV-1 DNA detection by means of polymerase chain reaction (PCR), a new technique that permits the amplification of specific DNA sequences. PCR was carried out to amplify two highly conserved env regions on samples from 20 normal individuals used as controls, 20 seropositive patients at different stages of HIV disease and 25 seronegative individuals at high risk for infection, such as sexual partners of seropositive patients and intravenous drug addicts. Eighteen out of 20 seropositive subjects were positive by PCR while among seronegatives HIV DNA was detected in 7/25 individuals. Virus isolation was positive only in 2/7. These subjects, followed for HIV antibody production for a period of 10-12 months, remained seronegative except one case who seroconverted after a few weeks. Long latency of HIV infection without detectable antibodies seems prevalent in these subjects. PCR assay represents a useful technique for identifying proviral sequences in seronegative high-risk individuals, to confirm the infection during its early phases and during the follow-up of patients with HIV disease.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Release of natural killer cytotoxic factor in patients with lymphoproliferative disease of granular lymphocytes.

To further investigate the mechanisms accounting for defective natural killer (NK) activity observed in the majority of patients with lymphoproliferative disease of granular lymphocytes (LDGL), we have studied the generation of natural killer cytotoxic factor (NKCF) from peripheral blood lymphocytes recovered from twelve LDGL patients. On the basis of their cytotoxic activity against the K-562 target cells, cases under study were separated in two groups. Cells from five patients, referred to as NK+, were found to exhibit high levels of NK-cell mediated cytotoxicity; cells from seven patients, referred to as NK-, despite their ability to bind to the K-562 targets, displayed a defective NK function. The coculture of cells from NK+ patients with NK sensitive K-562 cells triggered a significantly higher production of NKCF with respect to NK- patients (p less than 0.001 at 1:2 dilution). Using phytohemagglutinin (PHA) as the NKCF stimulator, differences between the groups were not significant, due to a recovery of NKCF generation in NK- patients. Furthermore, a consistent lectin (PHA) dependent cellular cytotoxicity (LDCC) was exhibited by both groups of patients. The addition of gamma-interferon (IFN-gamma) or interleukin-2 (IL-2) during NKCF generation did not significantly modify the production of this factor. Our data point out that (a) NKCF is involved in the lytic activity of LDGL patients' cells, (b) a constitutional impairment in the generation of NKCF is not present in NK- patients, since recovery of lytic function occurs after PHA stimulation, and (c) IL-2 and IFN-gamma do not play a relevant role in triggering NKCF production when added during the generation of this factor. These studies help to clarify the factors involved in the cytotoxic machinery of LDGL patients' cells, suggesting that the defect of the cytotoxic function observed in some LDGL patients could lie at the level of target recognition.

Adult↗
PubMed1989

Deficiency of lymphocyte lectin-dependent cytotoxicity in myelodysplastic syndromes.

We studied a group of patients with myelodysplastic syndromes (MDS) for surface markers and cytotoxic activities of peripheral blood mononuclear cells (PBMNC). The results indicate a significant increase in the total count of CD11b+, Leu7+ and CD16+ with a percent reduction in CD4+. A reduction in PHA-induced cellular cytotoxicity (PHA-ICC) and NK activity were found. A similar phenotype was found both in refractory anemia (RA) and (RA) with excess of blasts (RAEB/RAEB-t). However, the functional activities reached the normal level only in RA patients; while in RAEB/RAEB-t patients a significant reduction was detected in PHA-ICC and NK activity.

Aged↗
PubMed1988

Natural killer activity from normal peripheral blood lymphocytes against a human T lymphotropic retrovirus type III (HTLV-III)-infected cell line.

An H9-HTLV-III-infected cell line was used as a target in a short-term (3-hr) Cr release assay to assess its sensitivity to lysis by peripheral blood lymphocytes (PBL) from normal donors. The single cell cytotoxicity assay (SCCA) on poly-L-lysine-coated coverslips was used to investigate further the mechanism of binding and killing. Uninfected H9 and K562 cell lines were studied as controls. Our results argue in favour of a natural killer (NK) mechanism being operative on an H9-HTLV-III-infected cell line owing to the following findings: (1) the cell line is sensitive to lysis in a short-term assay; (2) its sensitivity is significantly higher than K562; and (3) the kinetics of lysis, as assessed by SCCA, is similar to that of K562, with a more efficient killing being detectable against H9-HTLV-III. Furthermore, a phenotypic analysis of effector cells suggests that CD4+ lymphocytes are also involved in the lysis of this target. Our data provide evidence for an immune mechanism that may be operative in HTLV-III infection. We then studied, by this method, five groups of patients: one (n = 20) affected by acquired immunodeficiency syndrome (AIDS), one (n = 20) by AIDS-related complex (ARC), one (n = 20) by lymphadenopathy syndrome (LAS), one group (n = 40) of HTLV-III seropositive, apparently healthy people, and one (n = 40) of healthy HTLV-III seronegatives.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Complex↗
PubMed1986

Decreased NK activity in hairy cell leukemia (HCL): an analysis at the cellular level.

Peripheral blood lymphocytes (PBL) of eleven patients with Hairy Cell Leukemia were studied for surface phenotype and for NK activity against the K 562 cell line (using both the standard 51Cr Release Assay and the Single Cell Cytotoxicity Assay on poly-L-lysine coated coverslips). A significant reduction in NK activity, target binding cells (TBC) and NK active cells (NKa) was detected. In some cases however, despite a very low percentage of NKa, residual NK activity was observed, suggesting an efficient recycling capacity.

Adult↗