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Biomedical subjects

G Gasparotto

Publications and source records attributed to G Gasparotto.

At least 19 recordsLinked to original sources

Phenotypic and functional characterization of cytotoxic cells derived from endomyocardial biopsies in human cardiac allografts.

This study was undertaken to characterize the phenotype and function of lymphocytes derived from endomyocardial biopsies in heart transplant patients. To this aim, tissue infiltrating lymphocytes were derived from seven heart transplant patients and were analyzed for the expression of a panel of markers, including CD3, CD4, CD8, CD16, CD56, CD45RA, CD45RO, alpha/beta and gamma/delta T cell receptor, and for their ability to lyse a series of targets, including NK-sensitive K-562 targets, NK-resistant Raji targets, donor related, and unrelated normal splenocytes. Our data show that the majority of cultured lymphocytes expressed the CD3+ phenotype and the alpha/beta T cell receptor. The CD4 and CD8 molecules were heterogeneously expressed among T cell lines tested. Concerning cytotoxic related markers, a significant percentage of cells were CD56+. The evaluation of CD45 isoforms showed that both "naive" and "memory" cells were present among heart TIL. Cytotoxic in vitro studies demonstrated that all our T cell lines showed an efficient cytotoxic machinery when tested against NK-sensitive targets. A marked lysis of donor-related splenocytes was demonstrated in all patients tested. To investigate the role of CD3 and HLA class I molecules in the cytotoxic mechanisms taking place in human heart allograft rejection mechanisms, TIL were assessed for their lytic activity against different targets in the presence of anti-CD3 and anti-HLA class I monoclonal antibodies (mAbs). Although donor-specific cytotoxicity was considerably inhibited by the anti-CD3 mAb, no inhibitory effect was displayed by this antibody on TIL-mediated cytotoxicity against donor-unrelated splenocytes. Anti-HLA class I mAb was able to inhibit both allospecific and nonallospecific cytotoxicity. These data suggest that different types of cytotoxic cells may be propagated from biopsy specimens of heart transplant patients.

Adult

Cytotoxic in vitro function in the lymphoproliferative disease of granular lymphocytes.

In 20 patients with lymphoproliferative disease of granular lymphocytes (LDGL) the cytotoxic in vitro function of peripheral blood mononuclear cells was studied against both NK sensitive (K-562) and NK resistant target cells (Daudi). Cytotoxicity was analysed at resting conditions and after in vitro pre-incubation with recombinant alpha 2-interferon, gamma-interferon and interleukin 2. At resting conditions, a heterogeneous cytotoxic picture was observed against the K-562 targets, with 11 of the 20 patients showing a normal or increased NK activity, and nine an impaired function. Against the Daudi targets, unstimulated cells from all patients displayed a normal cytotoxic activity. Following in vitro stimulation, an increased lytic function against K-562 cells was demonstrated in six of the nine patients with low basal values, in three after boosting with all lymphokines tested and in three with interleukin 2. In three of these six patients incubation with interleukin 2 also produced an increased cytotoxic function against Daudi target cells; this phenomenon may be associated to the lymphokine-activated killer (LAK) system. The importance of investigating the cytotoxic in vitro function in LDGL patients to further characterize the biological features of GL and its relevance to better define the nature of this disease are discussed.

Adult

The acquired immunodeficiency syndrome (AIDS): insights into the immunopathogenesis of the pulmonary involvement.

The lung is involved in more than 50 per cent of patients with the acquired immune deficiency syndrome (AIDS), and pulmonary abnormalities can be easily investigated using the bronchoalveolar lavage (BAL). Besides providing information on the type of infecting microorganism, BAL has been used to characterize immunocompetent cells from the lower respiratory tract in these patients. This allows new insights into the immunopathogenetic mechanism involved in the persistence of opportunistic pulmonary infections and in the uncontrolled viral replication. This paper emphasizes the value of BAL evaluation as a simple and useful method for investigating the involvement of the distal respiratory tract in AIDS patients. A particular attention is payed on the immunological pulmonary abnormalities of this epidemic immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome

Bronchoalveolar lavage and lung histology. Comparative analysis of inflammatory and immunocompetent cells in patients with sarcoidosis and hypersensitivity pneumonitis.

To determine whether bronchoalveolar lavage reflects the histologic aspects of the lung histology in patients with sarcoidosis and hypersensitivity pneumonitis, cells recovered from lavage fluid were compared with tissue sections from transbronchial lung biopsies in 33 patients. The evaluation of cellular types and their topographic distribution in situ was determined by using monoclonal antibodies in combination with immunohistochemical techniques. Cell counts in bronchoalveolar lavage and lung biopsies were significantly correlated both in sarcoidosis and hypersensitivity pneumonitis. In fact, the relative proportions of inflammatory and immunocompetent cells recovered from lavage fluid accurately overlapped those observed in lung tissue sections. However, in patients with more pronounced alveolitis, the frequency of macrophages in tissue sections was higher than that observed in the bronchoalveolar lavage, and the degree of lymphocytes in the lavage was higher than that observed in the corresponding biopsy. Specifically, in these patients the lavage underestimated the amount of macrophages in the lung biopsies and overestimated the number of lymphocytes that were present in the lung parenchyma. This was more evident in patients with hypersensitivity pneumonitis, where the intensity of alveolitis was higher than in sarcoidosis. Our data support the idea that, at least in patients with sarcoidosis and hypersensitivity pneumonitis, bronchoalveolar lavage correctly samples the alveolitis. Discrepancies in patients with very high intensity alveolitis could be due to a more pronounced recirculation of lymphocytes from the parenchyma to the alveolar spaces.

Adolescent

Impaired production of interleukin-2 in peripheral blood of patients with sarcoidosis.

In twelve patients with active sarcoidosis we attempted to explain the nature of reduced release on interleukin-2 (IL-2) and the consequent impairment in lymphoproliferative in vitro responses. The addition of exogenous IL-2 containing supernatants was unable to completely restore the defective uptake of 3H-Thymidine suggesting that an impairment of IL-2 producer cells is not enough to explain the in vitro hyporesponsiveness of sarcoid lymphocytes. We also found a reduced number of precursors of IL-2 responder cells, as defined by peripheral blood lymphocytes bearing Tac determinant following in vitro stimulation with mitogens. The abnormalities of both IL-2 producer cells and precursors of IL-2 responder cells in peripheral blood of patients with sarcoidosis are discussed, stressing the importance of the concept of compartmentalization of T lymphocytes in this disease.

Adult

alpha-Mercaptopropionyl-glycine influence on the in vitro proliferative response of human lymphocytes.

The effect of alpha-mercaptopropinyl-glycine on the in vitro proliferative response of healthy subjects' lymphocytes was studied. Low doses of the drug enhanced spontaneous lymphocyte blastigenesis but had no effect on the PHA-induced blastic response. With increasing concentrations of alpha-mercaptopropionyl-glycine inhibition of 3H-thymidine incorporation was found in unstimulated as well as in PHA stimulated lymphocytes.

Amino Acids, Sulfur

Immunobiology of paediatric intracranial tumours. A preliminary report.

Preliminary findings in the evaluation of the immune response of children with primary neoplasms of the CNS, mainly medulloblastomas, are reported and discussed. A broad scheme for the monitoring of B- and T-cell-dependent immunity and of delayed hypersensitivity reactions in this type of patient is presented. The most important immunobiological findings are discussed. Special attention is given to the striking failure of the T-cell-dependent pool (currently identified by "active" RFC and blastigenesis tests) and to the remarkable decrease of hypersensitivity reactions (depressed skin-test response), both of which seem to be related to the degree of malignancy of the tumour. A very peculiar feature, i.e., the appearance of cells with natural cytotoxic activity, is dealt with in some detail. Our present knowledge concerning the immunobiology of primary CNS neoplasms is still very incomplete, but seems to suggest a possible role for immunotherapy in paediatric neurosurgery.

B-Lymphocytes

Immunological features in chronic lymphocytic leukaemia (CLL) of T cell origin.

Peripheral blood lymphocytes from a patient with chronic lymphocytic leukaemia of T cell origin were studied. The thymus derived nature of these lymphocytes was confirmed by surface markers, mitogen cultures, mixed lymphocyte reaction, cytotoxicity studies, and cytochemical stains. This case is notable for several clinical and laboratory findings. Among these, the benign clinical course, the reduced rate of serum immunoglobulins, the elevated number of active E rosettes, the increased PHA-induced response to low mitogen doses, the absence of PHA mediated cellular cytotoxicity, and the thy-like positivity to ANAE should be pointed out. Emphasis should be placed, however, on the loss of stimulatory ability in MLR. This last feature supports the hypothesis that these cells proliferate as a clone.

Aged

T mediated immunity in patients undergoing periodic hemodialysis.

Seventeen patients with well compensated chronic renal failure undergoing periodic hemodialysis were studied with regard to absolute number of T and B lymphocytes, spontaneous and PHA induced lymphocyte blastogenesis both with autologous and homologous compatible plasma. A normal lymphocyte count as well as a normal relative and absolute number of T and B lymphocytes was found in most cases. Spontaneous blastogenesis was normal. Lymphocyte response to PHA was reduced both with autologous and homologous plasma, but the depression was more relevant when autologous plasma was used in culture. The authors discuss these findings with respect to available data, particularly concerning inhibitory factors in uraemic plasma.

Adult

[Possible influence of plasma factors on lymphocyte blastigenesis and E rosette forming in rheumatoid arthritis (author's transl)].

The lymphocytes blastigenesis to PHA in culture with autologous or normal plasma, the formation of E rosettes and the presence of immunoglob-lins on the lymphocytes surface were evaluated in 51 patients with chronic primary polyarthritis. While the percentage of T and B cells was almost normal (52.1 +/- 2.1% and 18.1 +/- 2.1%, N.V. 55.6 +/- 2.0% and 16.2 +/- 0.8%), the blastigenesis was significantly reduced in cultures with a 25% autologous plasma (5399 +/- 709 cpm compared to 13,182 +/- 920 cpm of the normal standard) and returned towards normal values when it was replaced by the plasma of a normal subject (12,189 +/- 1081 cpm). The rheumatoid plasma was capable of reducing the blastigenesis in 11 normal subjects (7395 +/- 750 cpm). The preincubation for 90' of the lymphocytes of 14 controls in rheumatoid or autologous plasma induced a significant reduction in the formation of spontaneous rosettes (40.8 +/- 1.4 % and 56.2 +/- 1.7%). These results suggest that the reduced function of the T lymphocytes in this disease is due to plasma factors.

Arthritis, Rheumatoid

Active E rosette formation by human lymphoblasts.

The percentage of active and total E rosettes for lymphocytes cultured for 72 h both with and without phytohaemagglutinin (PHA) was evaluated in 20 normal subjects. A clear increase in the formation of active E rosettes by PHA-stimulated lymphocytes was demonstrated with respect to unstimulated lymphocytes. Our data gives further proof that the active E rosettes constitute a specific subpopulation of lymphocytes which represent functionally active T cells in the blood.

Adult