Elevated CD4+/CD25+ T cell frequency and function during acute hepatitis C presage chronic evolution.
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Acute Disease↗
Biomedical subjects
L Racioppi
Publications and source records attributed to L Racioppi.
B-cell lymphopenia and hypogammaglobulinemia in thymoma patients.
Thymic tumors represent a unique neoplastic disease associated with various immune-mediated syndromes. Immune impairment is generically recognized to be associated with thymoma. Hypogammaglobulinemia and recurrent pulmonary infections in thymoma patients define Good's syndrome. Apart from sporadic reports focusing on this topic, there is still a lack of knowledge on immune assessment and clinical sequelae in thymoma patients. The present study was performed to evaluate immunoglobulin levels, CD19(+) B lymphocytes, and CD3(+) T lymphocytes in a large series of thymoma patients from a single institution. The occurrence of recurrent severe infections was related to immunological findings to identify the possible correlation with the immunodeficiency status. Eighteen patients (eight males, ten females, mean age: 56 years, range: 19-75) with a pathological diagnosis of thymic tumor were studied. Six patients suffered from clinical recurrent pulmonary infections. Blood samples were collected to measure serum immunoglobulins and analyze immunophenotype. Low T lymphocyte number was found in 22% of the patients. T lymphocytosis was present in one patient. Panhypogammaglobulinemia was found in 4 of 18 patients (22%). Conversely B lymphopenia was a frequent finding in this series of thymoma patients (9 of 18, 50%). Five of six patients (83%) with recurrent infections had B lymphopenia, while only two (33%) had panhypogammaglobulinemia. B lymphopenia often occurred in this series of thymoma patients and was related to susceptibility to recurrent infections more than hypogammaglobulinemia. Therefore, immunophenotype has to be monitored in follow-up of thymoma patients because it may reveal significant abnormalities.
Adult↗
Induction of neutralizing antibodies and cytotoxic T lymphocytes in Balb/c mice immunized with virus-like particles presenting a gp120 molecule from a HIV-1 isolate of clade A.
We have recently developed a candidate HIV-1 vaccine based on virus-like particles (VLPs) expressing a gp120 from an Ugandan HIV-1 isolate of the clade A (HIV-VLP(A)s). In vivo immunogenicity experiments were performed in Balb/c mice, with an immunization schedule based on a multiple-dose regimen of HIV-VLP(A)s without adjuvants, showing a significant induction of both humoral and cellular immunity. The Env-specific cellular response was investigated in vitro, scoring for both the proliferative response of T helper cells and the cytolytic activity of cytotoxic T lymphocytes (CTLs). Furthermore, immune sera showed >50% neutralization activity against both the autologous field isolate and the heterologous T cell adapted B-clade HIV-1(IIIB) viral strain. This is one of the first examples of HIV-1 vaccines based on antigens derived from the A clade, which represents >25% of all isolates identified world wide. In particular, the A clade is predominant in sub-Saharan countries, where 70% of the global HIV-1 infections occur, and where vaccination is the only rational strategy for an affordable prevention against HIV-1 infection.
AIDS Vaccines↗
Serum leptin and CD4+ T lymphocytes in HIV+ children during highly active antiretroviral therapy.
OBJECTIVE: Because leptin, the adipocyte-derived hormone, affects thymocyte survival, proliferation of naïve T lymphocytes and the production of proinflammatory cytokines, we aimed to investigate the role of this molecule in immunoreconstitution during highly active antiretroviral therapy (HAART). DESIGN: Prospective longitudinal cohort study. A series of 20 HIV+ children were studied. The subjects were grouped by their increase in serum leptin levels after HAART. METHODS: All participants were weight-stable, free of endocrine disorders and opportunistic infections and equally distributed for sex (males, n=10; females, n=10). Body mass index (BMI), serum lipids, leptin, CD4+ T cells and HIV-1 RNA were measured before initiation of HAART and after a 2-year follow-up. RESULTS: Serum leptin concentration positively correlated with CD4+ lymphocyte number before treatment. HAART significantly reduced viraemia and increased serum levels of lipids in all patients, whereas a significant increase in CD4+ cells and serum leptin was observed in the majority of patients. Notably, in children where HAART was not effective in increasing CD4+ lymphocyte counts, serum leptin did not increase. CONCLUSION: To our knowledge, these findings reveal for the first time a novel link among CD4+ T lymphocytes, serum leptin and highly active anteretroviral theraphy.
Antiretroviral Therapy, Highly Active↗
Restriction in T-cell receptor repertoire in a patient affected by trichothiodystrophy and CD4+ lymphopenia.
Molecular analysis of T-cell receptor (TCR) repertoire, by measuring the CDR3 heterogeneity length of beta-variable regions (spectratyping), is useful for acquiring novel information on the status of immune system in primary immunodeficiency. Here, we evaluate TCR repertoire in a child with trichothiodystrophy (TTD) and combined immunodeficiency (CID). Spectratyping revealed marked alterations of TCR repertoire distribution: 21 and 10 out of 27 TCR Vbeta (TCRBV) families and subfamilies were skewed in CD8+ and CD4+ subsets, respectively. These findings revealed, for the first time in a TTD patient with CID, a marked reduction in the TCR repertoire complexity, which may reflect alterations in the mechanisms regulating the generation and homeostasis of T cells.
ATP-Binding Cassette Transporters↗
Human equivalent of the mouse Nude/SCID phenotype: long-term evaluation of immunologic reconstitution after bone marrow transplantation.
Human Nude/SCID (severe combined immunodeficiency) is the first severe combined immunodeficiency caused by mutation of the winged-helix-nude (WHN) gene, which is expressed in the thymus but not in the hematopoietic lineage. The disease is characterized by a T-cell defect, congenital alopecia, and nail dystrophy. A Nude/SCID patient who underwent bone marrow transplantation from the human leukocyte antigen-identical heterozygote brother was studied to investigate, in this unique model, the role of the thymus in immunologic reconstitution. Despite an increase in CD3(+), CD4(+), and CD8(+) cells, CD4(+) CD45 RA naive lymphocytes were not regenerated. Conversely, naive CD8(+) cells were normal. After an initial recovery, lymphocyte proliferation to mitogens progressively declined compared with controls and genotypically identical donor cells grown in the WHN(+/-) environment. Analysis of the T-cell receptor (TCR) repertoire of CD4(+) cells revealed that only 3 of 18 Vbeta families had an altered CDR3 heterogeneity length profile. Conversely, CD8(+) lymphocytes showed an abnormal distribution in most Vbeta families. These data indicate that the thymus is differentially required in the reconstitution of CD4(+) and CD8(+) naive subsets and in the maintenance of their TCR repertoire complexity. Taken together, these findings suggest that bone marrow transplantation is ineffective in the long-term cure of this form of SCID.
Alopecia↗
Modulation of CD45 tyrosine phosphatase activity by antigen.
CD45 is a widely distributed phosphatase which modulates the activity of Lck by controlling the phosphorylation status of two tyrosine residues localized in the catalytic activation loop and in the negative regulatory domain. Little is known about the regulation of CD45 activity upon T cell activation. In the present study, we found that, in resting lymphocytes, an enzymatically active fraction of CD45 molecules is associated to the CD4 coreceptor. TCR engagement by an agonist ligand markedly inhibited this pool of CD45 phosphatase without affecting the CD4 / CD45 association. These results reveal that the modulation of the CD4-associated CD45 phosphatase activity is a very early biochemical event triggered by TCR stimulation. Since the recruitment of CD4 is an initial step in the activation process, the inhibition of this pool of CD45 molecules would be crucial to prevent dephosphorylation of relevant substrates which promote the activation process.
Animals↗
The fine specificity of human T cell lines towards myelin basic protein peptides in southern Italian multiple sclerosis patients.
We studied the relationship between the HLA specificities associated with multiple sclerosis (MS) susceptibility in southern Italy and the reactivity of the human myelin basic protein (hMBP) immunogenic peptides 84-98 and 143-168, using short-term T-cell lines established from 9 MS patients and from 8 healthy individuals. In our population, DR15 was significantly associated with MS (34.9% in MS versus 13.7% in healthy controls, P < 0.05). This result is in agreement with the association found in northern Europe, but not with data obtained in a population from the island of Sardinia (Italy). In MS patients the frequency of reactive T-cell lines (TCL), tested for fine specificity against the immunodominant hMBP peptides 84-98 and 143-168, was increased for the hMBP 143-168 peptide (P < 0.05) but not for the 84-98 peptide. Although this reactivity was higher in DR15+ MS patients than in DR 15- MS patients, it seemed not to be associated with DR15 specificity in the MS population. Furthermore, there were no significant differences in frequency of reactive TCL to hMBP peptide 84-98 in DR15-positive or DR15-negative MS patients. Consequently, it appears that peptide 84-98, considered as a relevant autoantigen, is not implicated in the pathogenesis of MS in our population from southern Italy.
Autoantigens↗
Defective dendritic cell maturation in a child with nucleotide excision repair deficiency and CD4 lymphopenia.
We report a case of a combined immunodeficiency (CID) in a child affected by trichothiodystrophy (TTD) characterized by an altered response to ultraviolet (UV) light due to a defect in the XPD gene. The XPD gene encodes a subunit of the transcription factor II H (TFIIH), a complex involved in nucleotide-excision repair (NER) and basal transcription. Our patient showed neurological and immune system abnormalities, including CD4 + lymphopenia never previously reported in TTD patients. In vitro immunological studies revealed a marked reduction in T-cell proliferation in response to mitogens and CD3 cross-linking which was partially recovered by the addition of anti-CD28 antibody or exogenous interleukin-2. The patient's T cells displayed alterations in T-cell receptor (TCR/CD3) proximal signalling characterized by marked reduction in Lck kinase activity coupled with a constitutive hyperactivation of Fyn kinase. Despite these alterations, normal levels of Lck and Fyn proteins were detected. The role of antigen-presenting cells (APCs) in the pathogenesis of the T-cell defect was investigated by analysing dendritic cells (DCs) generated from the patient's blood monocytes. In these cells, flow cytometry revealed significantly reduced expression of the CD86 co-stimulatory molecules and HLA glycoproteins. In addition, the patient's DCs showed a decreased ability to stimulate naive T lymphocytes. Overall, the results of our study suggest that a defective TFIIH complex might result in alterations in T cells and DC functions leading to a severe immunodeficiency.
CD4-Positive T-Lymphocytes↗
Hydroxytyrosol, a natural molecule occurring in olive oil, induces cytochrome c-dependent apoptosis.
2-(3,4-Dihydroxyphenyl)ethanol (DPE), a naturally occurring phenolic antioxidant molecule found in olive oil, has been reported to exert several biological and pharmacological activities. We studied the effect of this compound on the proliferation and survival of HL60 cell line. Concentrations from 50 to 100 microM DPE, comparable to its olive oil content, caused a complete arrest of HL60 cell proliferation and the induction of apoptosis. This was demonstrated by flow cytometric analyses, poly(ADP-ribose) polymerase cleavage, and caspase 3 activation. The apoptotic effect requires the presence of two ortho-hydroxyl groups on the phenyl ring, since tyrosol, 2-(4-hydroxyphenyl)ethanol, did not induce either cell growth arrest or apoptosis. DPE-dependent apoptosis is associated with an early release of cytochrome c from mitochondria which precedes caspase 8 activation, thus ruling out the engagement of cell death receptors in the apoptotic process. 2-(3,4-Dihydroxyphenyl)ethanol induced cell death in quiescent and differentiated HL60 cells, as well as in resting and activated peripheral blood lymphocytes, while did not cause cell death in two colorectal cell lines (HT-29 and CaCo2). These results suggest that DPE down-regulates the immunological response, thus explaining the well-known antinflammatory and chemopreventive effects of olive oil at the intestinal level.
Annexin A5↗
Mucosal and systemic immune activation is present in human immunodeficiency virus-exposed seronegative women.
Immune parameters were analyzed in peripheral blood mononuclear cells (PBMC) and cervical mucosa biopsy specimens of human immunodeficiency virus (HIV)-seronegative women sexually exposed to HIV (exposed seronegative [ESN]), HIV-infected women, and healthy women without HIV exposure. HIV was not detected in PBMC or cervical mucosa biopsy specimens of ESN women. However, interleukin (IL)-6, IL-10, IL-12, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha and -beta mRNA were elevated in PBMC and cervical mucosa biopsy specimens of ESN and HIV-infected women; CCR5 and CXCR4 mRNA were augmented in cervical mucosa biopsy specimens, but not in PBMC, of ESN and HIV-infected women; HIV-specific IFN-gamma-secreting cells were detected in vaginal washes of ESN and HIV-infected women; and phenotypic alterations were present in PBMC of ESN women. These results suggest that active HIV infection is not required for T cell activation; immune alterations occur in women in whom HIV infection cannot be detected virologically or clinically.
Cytokines↗
Brain migration disorder and T-cell activation deficiency associated with abnormal signaling through TCR/CD3 complex and hyperactivity of Fyn tyrosine kinase.
In this study we report on a patient affected by a brain migration disorder and a T-cell activation deficiency presumably inherited as an autosomal recessive trait. The immunological evaluation revealed that the mitogen stimulation failed to induce a proper up-regulation of membrane expression of T-cell activation markers, and cell proliferation. This functional impairment was associated with abnormalities of the signal transduction process that follows T-cell receptor stimulation. A constitutive hyperphosphorylation of the Fyn tyrosine kinase was documented. This is the first report on a T-cell signaling abnormality associated with a developmental brain disorder. Whether the alteration of Fyn, which plays a role in both neurological and immunological systems, is responsible for either disorder remains to be elucidated.
Brain Diseases, Metabolic, Inborn↗
Effects of human immunodeficiency virus type 1 on CD4 lymphocyte subset activation.
The pathogenesis of the decline of CD4 lymphocyte counts accompanying the typical course of HIV-1 infection is not completely defined and might be related to a differential susceptibility of naive and memory cells to HIV-1 exposure. Here, we examined the effects induced by heat-inactivated HIV-1 virions on these lymphocyte populations. Exposure of CD45RA naive T cells to inactivated viral particles induced a marked decrease of both mitogenic responses and activation-induced apoptosis. Conversely, the growth of CD45RO cells was less severely restrained. Analysis of intracellular levels of cell cycle regulatory proteins revealed an arrest at the G1/S restriction point of the naive but not memory subset. This effect was associated with alterations in phosphotyrosine profile and with a marked decrease of ERK and NJK kinase activation. Finally, up-regulation of the cAMP-dependent protein kinase A (PKA) activity induced by mitogens was not affected by virus. Altogether, these findings show that interaction of HIV-1 with the T cell surface is sufficient to inhibit the proliferative response of the CD4CD45RA subset by disturbing proximal TCR signaling. This mechanism would affect renewal of naive lymphocytes, contributing in such a way to the impairment of T cell turnover during the course of HIV-1 infection.
Apoptosis↗
Immunological findings in thymoma and thymoma-related syndromes.
Human thymoma is a neoplasm of thymic epithelial cells associated with several clinical syndromes ranging from autoimmune disease to immunodeficiency. The aim of our research was to investigate T cell-mediated immune response in patients with thymoma. Initially eight patients were enrolled in this study. Four patients underwent surgical removal of the thymus, while four were submitted to diagnostic procedures only. Inversion of the CD4:CD8 ratio was found in three patients. Only one subject displayed a normal CD19 count in peripheral blood. The mean value (+/-SD) of the CD19 percentage in the patient group was 2 +/- 2.2. Notably, the patients with thymoma had fewer mature B lymphocytes than the thymectomized patients. The T-cell receptor (TCR) repertoire was investigated in three individuals affected by thymoma: one underwent thymectomy, while the two others, one of which presented with lymphocytosis, were submitted to diagnostic biopsies only. The preliminary results showed a marked alteration in the CD8 repertoire of the thymectomized patient but not in that of the lymphocytotic patient. However, alterations in the TCR repertoire were also found in one patient with thymoma. Altogether, these preliminary findings reveal that loss of CD19+ lymphocytes in peripheral blood is a frequent phenomena in thymoma patients. In this article we discuss this aspect in the context of alterations of the TCR repertoire.
Adult↗
Resveratrol arrests the cell division cycle at S/G2 phase transition.
Resveratrol (3,5,4'-trihydroxystilbene) is a naturally occurring phytoalexin, found in grapes and wine, which has been reported to exert a variety of important pharmacological effects. We have investigated the activity of resveratrol on proliferation and differentiation of the promyelocitic cell line HL-60. A concentration as low as 30 microM causes a complete arrest of proliferation and a rapid induction of differentiation towards a myelo-monocytic phenotype. Analyses by flow cytometry showed the absence of the G2/M peak and the accumulation of cells in G1 and S phases. Moreover, at the concentrations employed, a very low amount of apoptotic cells was evidenced. A detailed biochemical analysis demonstrated that the G1 phase of the cell division cycle engine was completely unmodified by resveratrol addition, thus indicating that the G1 --> S transition occurs normally. Conversely, after only 24 h treatment, a significant increase of cyclins A and E could be observed along with the accumulation of cdc2 in the inactive phosphorylated form. These data demonstrate that resveratrol causes a complete and reversible cell cycle arrest at the S phase checkpoint.
Anticarcinogenic Agents↗
Serum concentrations of soluble human leukocyte class I antigens and of the soluble intercellular adhesion molecule-1 in endometriosis: relationship with stage and non-pigmented peritoneal lesions.
Serum concentrations of soluble human leukocyte class I antigens (sHLA-I) and of the intercellular adhesion molecule-1 (sICAM-1) are increased in the early inflammatory stages of several immune-related diseases. These soluble molecules also exert immunomodulatory activity, including regulation of natural killer (NK) cell cytotoxicity. The aim of this study was to verify whether sHLA-I and sICAM-1 serum concentrations are related to the various stages of pelvic endometriosis, which is an immune-related disorder associated with impaired in-vitro NK cell activity. Serum sHLA-I and sICAM-1 concentrations were similar in patients and in healthy donors. However, when evaluated according to disease stage, sHLA-I and sICAM-1 concentrations were higher in patients with endometriosis stage I-II (revised American Fertility Society classification), or with non-pigmented peritoneal lesions. In conclusion, studies on sHLA-I and sICAM-1 may help to clarify the pathogenic mechanisms of endometriosis, and their serum concentrations may serve as additional markers for the early detection of recurrence of the disease during the monitoring of treatment outcome.
Adult↗
T cell activation deficiency associated with an aberrant pattern of protein tyrosine phosphorylation after CD3 perturbation in Down's syndrome.
Children affected by Down's syndrome (DS) have an increased susceptibility to viral or bacterial infections and leukemia, associated with several abnormalities of the immune system. We investigated whether the T cell defect was qualitative in nature and associated with abnormalities of the early events occurring during cell activation. The proliferative response of lymphocytes from DS individuals after CD3 cross-linking was clearly depressed, as already reported. In contrast, phorbol ester and ionomycin were able to induce cell cycle progression in DS, suggesting a defect in the early stages of the signal transduction through a T cell receptor/CD3 (TCR/CD3) complex upstream of protein kinase C activation. The functional impairment in DS was not related either to a decrease of circulating mature-type CD3+ cells, which express high levels of surface of CD3 molecules, or to a decrease of the CD4+ subpopulation. The analysis of phosphotyrosine-containing proteins after the cross-linking of CD3 molecules in DS lymphocytes revealed a partial signaling, characterized by increased phosphorylation of proteins of 42-44 kD, comparable to that observed in control subjects, but not of proteins of 70 and 21 kD. Moreover, although the "anti-anergic" gamma element of IL-2, IL-4, IL-7, and IL-15 receptors was normally tyrosine-phosphorylated during cell activation, the CD3 zeta-associated protein kinase (ZAP-70) was not. Our results indicate that in DS there is a T cell activation defect, characterized by partial signal transduction through a TCR/CD3 complex, and associated with a selective failure of ZAP-70 tyrosine phosphorylation.
Adolescent↗
The role of CD4-Lck in T-cell receptor antagonism: evidence for negative signaling.
Small changes in the complex between a peptide and a molecule of the major histocompatibility complex generate ligands able to partially activate (partial agonist) or even inhibit (antagonist) T-cell functions. T-cell receptor engagement of antagonist complex results in a partial zeta chain phosphorylation without activation of the associated ZAP-70 kinase. Herein we show that, despite a strong inhibition of both inositol phospholipid hydrolysis and extracellular increasing antagonist concentrations increased the activity of the CD4-Lck kinase. Addition of anti-CD4 antibody to culture medium prevented inhibitory effects induced by antagonist ligand. We propose that CD4-Lck activation triggered by antagonist complexes may act in a dominant negative mode, thus overriding stimulatory signals coming from agonist ligand. These findings identify a new T-cell signaling profile that may explain the ability of some T-cell receptor variant ligands to inhibit specific biological activities or trigger alternative activation programs.
Amino Acid Sequence↗