A case of transposition of the great arteries in a female infant of a HIV-1-infected woman. Potential teratogenic effects of antiretroviral drugs.
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Adult↗
Biomedical subjects
Francesco Indiveri
Publications and source records attributed to Francesco Indiveri.
Endocrine regulation of suppressor lymphocytes: role of the glucocorticoid-induced TNF-like receptor.
Mechanisms responsible for peripheral immune tolerance are currently under investigation in several laboratories, in order to define the role of immune homeostasis in physiological processes and pathologic conditions, such as autoimmunity and cancer. In this context, recent studies attributed a relevant role to the glucocorticoid-induced TNFR-related gene (GITR). GITR is expressed at high levels on CD4(+)CD25(+). T regulatory (Treg) cells, but only at low levels on resting responder T lymphocytes, and is upregulated after activation. GITR triggering induces both pro- and anti-apoptotic effects through different intracellular pathways, abrogates the suppressive activity of Treg cells, and co-stimulates responder T cells. These data hint that GITR triggering overstimulates the immune system. Indeed, in vivo studies demonstrated that GITR stimulation may both induce autoimmune diseases and strengthen anti-virus and anti-tumor immune responses. Therefore, the GITR-GITRL system appears crucial in regulating immunity. Currently, the majority of studies about GITR's role on regulatory cells are focused on CD4(+)CD25(+) Treg cells, while very little is known about the importance of this molecule in other Treg subtypes. We have recently characterized a subpopulation of CD8+ T suppressor lymphocytes able to inhibit both T cell proliferation and cytotoxicity. Preliminary data show that GITR is expressed on such CD8+ T suppressor cells and that its activation by a specific antibody inhibits generation, but not function, of these cells. These early results suggest the importance of GITR in human T suppressor lymphocytes other than CD4(+)CD25(+) Treg cells.
Animals↗
Migraine during systemic lupus erythematosus: findings from brain single photon emission computed tomography.
OBJECTIVE: Headache in systemic lupus erythematosus (SLE) is controversial, as is evidence of brain impairment in patients with SLE and headache. Perfusion single photon emission computed tomography (SPECT) was performed to investigate brain impairment in SLE patients with migraine-like headache either from the period of diagnosis or later in the course of disease. METHODS: Eighteen patients with SLE (mean age 40.8 +/- 13.6 yrs) matching these characteristics underwent brain SPECT with 99mTc-HMPAO in the interictal period. Electroencephalography (EEG) and magnetic resonance imaging (MRI) were performed in 12 and 10 patients, respectively. SPECT was analyzed through visual and asymmetry combined analysis as well as by voxel-based statistical analysis compared to a control group of matched healthy subjects (statistical threshold: p = 0.01). RESULTS: Focal hypoperfusion was evidenced in 15 (83%) patients, often matching the main side of pain location, whereas EEG and MRI each gave a positive result in 50% of cases. Using voxel-based analysis, significant hypoperfusion was found in 8 (44%) patients, either lateralized to one side or localized to the anterior cingulate cortex, independent of pain location. CONCLUSION: Brain perfusion SPECT is a sensitive tool for identifying brain impairment in SLE-related migraine, although the mechanisms of brain damage remain to be elucidated. Besides confirming focal hypoperfusion in some patients, in 4 patients statistical analysis revealed interictal hypofunction of the anterior cingulate cortex, a key structure for cortical elaboration of pain in the midline network.
Adult↗
Apoptosis of antigen-specific T lymphocytes upon the engagement of CD8 by soluble HLA class I molecules is Fas ligand/Fas mediated: evidence for the involvement of p56lck, calcium calmodulin kinase II, and Calcium-independent protein kinase C signaling pathways and for NF-kappaB and NF-AT nuclear translocation.
The binding of soluble HLA class I (sHLA-I) molecules to CD8 on EBV-specific CTL induced up-regulation of Fas ligand (FasL) mRNA and consequent sFasL protein secretion. This, in turn, triggered CTL apoptosis by FasL/Fas interaction. Molecular analysis of the biochemical pathways responsible for FasL up-regulation showed that sHLA-I/CD8 interaction firstly induced the recruitment of src-like p56(lck) and syk-like Zap-70 protein tyrosine kinases (PTK). Interestingly, p59(fyn) was activated upon the engagement of CD3/TCR complex but not upon the interaction of sHLA-I with CD8. In addition, sHLA-I/CD8 interaction, which is different from signaling through the CD3/TCR complex, did not induce nuclear translocation of AP-1 protein complex. These findings suggest that CD8- and CD3/TCR-mediated activating stimuli can recruit different PTK and transcription factors. Indeed, the engagement of CD8 by sHLA-I led to the activation of Ca2+ calmodulin kinase II pathway, which eventually was responsible for the NF-AT nuclear translocation. In addition, we found that the ligation of sHLA-I to CD8 recruited protein kinase C, leading to NF-kappaB activation. Both NF-AT and NF-kappaB were responsible for the induction of FasL mRNA and consequent CTL apoptosis. Moreover, FasL up-regulation and CTL apoptotic death were down-regulated by pharmacological specific inhibitors of Ca2+/calmodulin/calcineurin and Ca2+-independent protein kinase C signaling pathways. These findings clarify the intracellular signaling pathways triggering FasL up-regulation and apoptosis in CTL upon sHLA-I/CD8 ligation and suggest that sHLA-I molecules can be proposed as therapeutic tools to modulate immune responses.
Apoptosis↗
Frequency of telomerase-specific CD8+ T lymphocytes in patients with cancer.
Telomerase is considered a universal tumor-associated antigen (TAA) due to its high rate of expression by cancers (approximately 90%), and clinical trials are in progress to test the immunotherapeutical efficacy of antitelomerase immunization in patients with cancer. However, the data concerning frequency and functional activity of telomerase-specific cytotoxic T lymphocytes (CTLs) in patients with cancer are few and conflicting, although their knowledge would be mandatory to predict the efficacy of telomerase-specific immunotherapy in selected patients. We performed this study to analyze frequency and cytolytic function of circulating CD8+ T lymphocytes specific for the p540 telomerase peptide in a series of human leukocyte antigen (HLA)-A2+ cancer patients. The results show that most patients with cancer have circulating telomerase-specific CD8+ T lymphocytes, but a high frequency of telomerase-specific CTLs are present only in a fraction of them. Furthermore, CTL lines able to kill telomerase-positive tumor cells, including autologous cancer cells, can be expanded ex vivo from some, but not all, patients with cancer. In conclusion, the results of the study support the development of clinical protocols using telomerase peptides as an immunizing agent. However, they underline the necessity to study single patients immunologically before undergoing vaccination, to select the patients adequately, and to eventually adapt the immunization schedule to the patient's immunologic status.
CD8-Positive T-Lymphocytes↗
Bone marrow mesenchymal progenitor cells inhibit lymphocyte proliferation by activation of the programmed death 1 pathway.
Bone marrow mesenchymal progenitor cells (BMSC) are used for regenerating tissues of mesodermal origin, as well as tissues of different embryological derivation. Experimental evidence shows that BMSC are able to suppress the activation of the immune response by mechanisms that are still not completely understood. Thus far, in vitro studies carried using human or mouse cells indicate that autologous or allogeneic BMSC strongly suppress proliferation of T lymphocytes, triggered by cellular stimuli, nonspecific mitogenic stimuli, or antigenic peptides. Using cell proliferation and blocking assays, we demonstrated that BMSC inhibited the activation of murine splenocytes, T, and B lymphocytes. Direct contact of BMSC and target cells in a cognate fashion determined the inhibition of cell proliferation via engagement of the inhibitory molecule programmed death 1 (PD-1) to its ligands PD-L1 and PD-L2, leading the target cells to modulate the expression of different cytokine receptors and transduction molecules for cytokine signaling. Soluble factors present on supernatants of BMSC cultures were effective in suppressing proliferation of B cells to a mitogenic stimulus. Taken together, these results highlight the complexity of the role of BMSC in regulating the immune response, asserting the possibility of their therapeutic application in transplantation and autoimmune diseases.
Animals↗
Emerging biologic drugs for the treatment of rheumatoid arthritis.
This article reviews the role of emerging biologic drugs for the treatment of rheumatoid arthritis (RA). Besides anti-tumor necrosis factor (TNF)-alpha and anti-interleukin (IL)-1 agents (Infliximab, Adalimumab, Etanercept and Anakinra) whose clinical efficacy is now established, new drugs have been proposed for the therapy of rheumatoid arthritis patients not responding to conventional treatments. These approaches include the blockade of B-cell activity with anti-CD20 monoclonal antibody (Rituximab) and the inhibition of T-cell activation with fusion protein CTLA4Ig. Moreover, promising results have been obtained in animal models utilizing suppressors of cytokine signaling (SOCS) and dominant-negative TNF variants to inactivate TNF signaling.
Anti-Inflammatory Agents, Non-Steroidal↗
Decay of human immunodeficiency virus type 1 unintegrated DNA containing two long terminal repeats in infected individuals after 3 to 8 years of sustained control of viremia.
Covert human immunodeficiency virus (HIV) replication was ongoing during the first 3 years of aviremia in 22 patients, as determined by detection of DNA containing two long terminal repeats (2 LTR DNA). Although total HIV DNA was detected in 60 2 LTR DNA-negative samples, the absence of 2 LTR DNA in 90% of patients following 7 to 8 years of highly active antiretroviral therapy suggests suppression of cryptic viral replication.
Antiretroviral Therapy, Highly Active↗
Nonantigen specific CD8+ T suppressor lymphocytes originate from CD8+CD28- T cells and inhibit both T-cell proliferation and CTL function.
Nonantigen specific CD8+ suppressor T lymphocytes (CD8+ Ts) inhibit T-cell proliferation of antigen-specific T lymphocytes. The impossibility to generate in vitro these cells has been correlated with the appearance of relapses in patients affected by autoimmune diseases, suggesting the involvement of these cells in immune regulation. This study was aimed to identify circulating precursors and to characterize the phenotype and mechanism of action of CD8+ Ts. We found that CD8+ Ts can be generated in vitro from CD8+CD28- T lymphocytes, but not from CD8+CD28+ T cells. A key role in their generation is played by monocytes that secrete interleukin-10 (IL-10) after granulocyte macrophage-colony-stimulating factor (GM-CSF) stimulation. Cell-to-cell direct interaction between CD8+CD28- T cells and monocytes does not play a role in the generation of CD8+ Ts. CD8+ Ts have a CD45RA+, CD27-, CCR7-, IL-10Ralpha+ phenotype and a TCR Vbeta chain repertoire overlapping that of autologous circulating CD8+ T cells. This phenotype is typical of T lymphocytes previously expanded due to antigen stimulation. Their suppressive effect on T-cell proliferation targets both antigen presenting cells, such as dendritic cells, and antigen-specific T lymphocytes, and is mediated by IL-10. CD8+ Ts suppress also the antigen-specific cytotoxic activity of CTL decreasing the expression of HLA class I molecules on target cells through IL-10 secretion. These findings can be helpful for the better understanding of immune regulatory circuits and for the definition of new pathogenic aspects in autoimmunity and tumor immunology.
Antibodies, Monoclonal↗
Migration of V delta 1 and V delta 2 T cells in response to CXCR3 and CXCR4 ligands in healthy donors and HIV-1-infected patients: competition by HIV-1 Tat.
We show that HIV-1-infected patients have increased concentrations of circulating V delta 1 T cells (2.2%-9.0% of T lymphocytes; healthy donors, 1.0%-2%) and, in some instances, V delta 2 T cells (3.5%-4.8% vs 2.0%-3.3%). In these patients, both V delta 1 and V delta 2 T cells are CXCR3+CXCR4+, whereas in healthy donors CXCR4 was preferentially expressed on V delta 1 T lymphocytes. gamma delta T cells transmigrated across endothelial monolayers, in response to interferon-gamma-inducing protein-10 (IP-10/CXCL10), stromal cell-derived factor-1 (SDF-1/CXCL12), or both, according to the expression of the specific receptors CXCR3 and CXCR4. Interestingly, 6Ckine/SLC/CCL21 was more effective than IP-10/CXCL10 on V delta 1 CXCR3+ cells, whereas V delta 2 CXCR3+ cells were driven more efficiently by IP-10/CXCL10. IP-10/CXCL10- and SDF-1/CXCL12-induced transmigration was dependent on phosphoinositide-3 kinase (PI-3K), as demonstrated by the use of the specific blockers wortmannin and LY294002 and by the activation of the downstream serine kinase Akt/PKB on ligation of CXCR3 and CXCR4. Occupancy of CXCR3, but not of CXCR4, led to CAMKII activation; accordingly, the CAMKII inhibitors KN62 and KN93 decreased IP-10/CXCL10- but not SDF-1/CXCL12-driven transmigration. Finally, HIV-1 Tat, which is present in the serum of HIV-1-infected patients, interferes with the chemotactic activity of these chemokines because of the cysteine-rich domain of the protein, which contains CXC and CC chemokine-like sequences.
Adult↗
Transforming growth factor-beta1 in supernatants from stored red blood cells inhibits neutrophil locomotion.
Studies comparing transfusion and nontransfusion patients suggest an increased risk of postoperative infections in transfusion groups. Supernatants of blood components have been shown to affect the function of T lymphocytes and natural killer cells. Here, we found that supernatants from stored red blood cells (RBCs) inhibit human neutrophil migration in response to formyl peptides and stimulate neutrophil locomotion. These effects can be observed with high dilutions of RBC supernatants, such as 1:5 x 106 (vol/vol), able to trigger locomotion as well as desensitization of the cells to alternative chemoattractants. The phenomenon might be mediated by chemoattractants present in the supernatants. As RBC supernatants failed to mobilize intracellular free calcium, the chemoattractants should belong to the group of pure chemoattractants, that is, soluble Fas ligand (sFasL) and transforming growth factor-beta1 (TGF-beta1), known to act without increasing calcium levels. Recombinant TGF-beta1, but not sFasL, was found to reproduce the ability of RBC supernatants to both inhibit neutrophil response to formyl peptides and stimulate neutrophil locomotion. Moreover, TGF-beta1-immunodepleted supernatants did not display neutrophil-directed activities. Finally, RBC supernatants from RBCs stored after depletion of leukocytes were incapable of affecting neutrophil function. With neutrophils acting as a first-line antimicrobial defense, the ability, shown here, of high dilutions of RBC supernatants to inhibit neutrophil chemotaxis through TGF-beta1 may be a relevant determinant of infections in the postoperative period for transfusion patients. Consistently, the neutrophil chemotactic response to formyl peptide was inhibited by the plasma obtained from 5 transfusion patients.
Blood Preservation↗
IFN-gamma production in human NK cells through the engagement of CD8 by soluble or surface HLA class I molecules.
The engagement of CD8 on NK cell surface by either surface or soluble HLA class I (sHLA-I) molecules induces synthesis and secretion of IFN-gamma. HLA-I-mediated effects were inhibited by the covering of CD8 with specific anti-CD8 monoclonal antibodies, indicating a direct interaction of HLA-I and CD8. That CD8 ligation induces IFN-gamma production was further supported by the finding that cross-linking of CD8 led to release of IFN-gamma at similar levels to those obtained with HLA-I. The sHLA-I-induced IFN-gamma production via CD8 was strongly down-regulated by the engagement of the inhibitory isoforms of either CD94/NKG2 complex by sHLA-I-non-(A,B,C,G) (putative sHLA-E) or CD158b by sHLA-I-Cw3 allele. Ligation of CD8 did not elicit, different from other activating NK cell surface molecules such as CD16 or CD69, triggering of NK cell-mediated cytolysis. Cyclosporin A, but not concanamycin A, an H+-ATPase vacuolar inhibitor which affects perforin and granzyme release, strongly reduced the sHLA-I-mediated CD8-dependent IFN-gamma production but did not affect cytolytic activity of NK cells, suggesting that different biochemical pathways are involved. Altogether, these findings indicate that CD8 engagement by sHLA-I activates a cyclosporin A-dependent pathway leading to production and secretion of IFN-gamma which may play a role in the regulation of innate immune responses in humans.
CD8 Antigens↗
Soluble HLA-A,-B,-C and -G molecules induce apoptosis in T and NK CD8+ cells and inhibit cytotoxic T cell activity through CD8 ligation.
There is convincing evidence that soluble HLA-A,-B,-C (sHLA-A,-B,-C) and soluble HLA-G (sHLA-G) antigens can induce apoptosis in CD8(+) activated T cells although there is scanty and conflicting information about the mechanism(s) by which sHLA-A,-B,-C antigens and sHLA-G antigens induce apoptosis. In this study we have compared the apoptosis-inducing ability of sHLA-A,-B,-C antigens with that of sHLA-G1 antigens in CD8(+) T lymphocytes and CD8(+) NK cells. Furthermore we have compared the inhibitory effect of sHLA-A,-B,-C antigens and of sHLA-G1 antigens on the activity of EBV-specific CD8(+) cytotoxic T lymphocytes (CTL). sHLA molecules were purified from serum and from the supernatant of HLA class I-negative cells transfected with one gene encoding either classical or non-classical HLA class I antigens. Both classical and non-classical sHLA class I molecules trigger apoptosis in CD8(+) T lymphocytes and in CD8(+) NK cells, which lack the T cell receptor, and their apoptotic potency is comparable. The binding of sHLA-A,-B,-C and sHLA-G1 molecules to CD8 leads to Fas ligand (FasL) up-regulation, soluble FasL (sFasL) secretion and CD8(+) cell apoptosis by Fas/sFasL interaction. Moreover, classical and non-classical sHLA class I molecules inhibit the cytotoxic activity of EBV-specific CD8(+) CTL. As the amount ofsHLA-G molecules detectable in normal serum is significantly lower than that of sHLA-A,-B,-C molecules, the immunomodulatory effects of sHLA class I molecules purified from serum are likely to be mainly attributable to classical HLA class I antigens. As far as the potential in vivo relevance of these findings is concerned, we suggest that classical sHLA class I molecules may play a major immunoregulatory role in clinical situations characterized by activation of the immune system and elevated sHLA-A,-B,-C serum levels. In contrast, non-classical HLA class I molecules may exert immunomodulatory effects in particular conditions characterized by elevated sHLA-G levels such as pregnancy and some neoplastic diseases.
Antibodies, Monoclonal↗
Apoptotic DNA binds to HLA class II molecules inhibiting antigen presentation and participating in the development of anti-inflammatory functional behavior of phagocytic macrophages.
Resident macrophages are mainly responsible for the clearance of apoptotic cells from tissue by phagocytosis. Phagocytosis of apoptotic cells is not accompanied by activation of inflammatory mechanisms, unlike what happens when necrotic phenomena occur. We analyzed the effect of phagocytosis of apoptotic bodies on macrophage cell functions. After phagocytosis of apoptotic cells macrophages were unable to present an exogenous antigen to autologous antigen-specific T-cell lines. The inhibition was mediated by different mechanisms including binding of apoptotic DNA to human leukocyte antigen (HLA) class II molecules of macrophages, decreased expression of co-stimulatory molecules and increased secretion of tumor growth factor beta (TGFbeta). When dendritic cells were cultured with macrophages phagocytosing apoptotic cells, or with their supernatant, impaired dendritic cell antigen presenting activity and reduced tumor necrosis factor alpha (TNFalpha) secretion were found. Our results suggest that: (1) the phagocytosis of apoptotic bodies inhibits macrophage antigen presentation; (2) such inhibition is mediated by the binding of apoptotic DNA to macrophage HLA class II molecules as well as by the activation of biological mechanisms that induce an anti-inflammatory functional behavior in macrophages; and (3) macrophages phagocytosing apoptotic cells inhibit antigen presentation of neighboring dendritic cells via TGFbeta secretion. These events are likely related to the preservation of healthy tissues from the onset of inflammation.
Antigen Presentation↗
Autoimmune hepatitis revealed by atorvastatin.
Cases of acute hepatitis induced by statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) have been reported. A 65-year-old woman was admitted to our hospital because of fatigue, jaundice and altered liver function tests while on treatment with atorvastatin. On the basis of clinical, serological and histological findings, a score leading to a diagnosis of autoimmune hepatitis was reached. We suggest that atorvastatin may have revealed an underlying autoimmune hepatitis.
Aged↗
Effect of clotting factors concentrates on lymphocyte and neutrophil function in vitro.
Immunological abnormalities have been reported in haemophiliacs. Although infections with HIV, hepatitis and other viruses may contribute to these abnormalities, immune defects are detectable also in HIV seronegative haemophiliacs. It is likely that chronic exposure to extraneous proteins in clotting factor concentrates (CFCs) may play a role in immunomodulation, but the underlying mechanisms remain unclear. The results of the present paper show that: a) soluble HLA class I (sHLA-I), soluble Fas-ligand (sFas-L) and transforming growth factor beta 1 (TGF-beta1) are detectable in plasma derived but not in recombinant CFCs; b) the level of sHLA-I and sFas-L is proportional to the grade of CFCs purity whereas TGF-beta1 showed very variable levels; c) soluble molecules detected in CFCs exert immunomodulatory effects in vitro like apoptosis induction in Jurkat cells and inhibition of mixed lymphocyte reaction response, antigen-specific lymphocyte cytotoxic activity and neutrophil chemotaxis.
Apoptosis↗
Soluble HLA class I induces NK cell apoptosis upon the engagement of killer-activating HLA class I receptors through FasL-Fas interaction.
The engagement of the activating isoforms of C-type lectin inhibitory receptor (CLIR) or killer Ig-like receptor (KIR) by their natural ligands, represented by soluble HLA-I (sHLA-I) molecules, induced programmed cell death of natural killer (NK) cells. Indeed, NK cell apoptosis elicited by either putative HLA-E and HLA-F (sHLA-I non-A, -B, -C, and -G) or sHLA-I-Cw4 or -Cw3 from untransfected or -Cw4 or -Cw3 alleles transfected HLA-A(-), B(-), C(-), G(-), E(+), F(+) 721.221 lymphoblastoid cell line, respectively, was blocked by covering the corresponding activating receptor with either anti-CLIR- or anti-KIR-specific monoclonal antibodies (mAbs). After sHLA-I-activating receptor interaction, NK cells produced and released Fas ligand (FasL), which in turn led to NK cell apoptosis by interacting with Fas at the NK cell surface. Blocking anti-Fas mAb, or anti-FasL mAb, inhibited sHLA-I-mediated apoptosis via activating receptor in NK cell clones. This apoptosis was inhibited by NK cell treatment with cyclosporin A, whereas this drug had no effect on activating receptor-mediated activation of cytolysis. Conversely, concanamycin A, an inhibitor of vacuolar type H(+)-adenosine triphosphatase (H(+)-ATPase) of granules, inhibited activating receptor-induced NK cell cytolysis, suggesting that activating receptor-mediated apoptosis and cytolysis can use different intracellular pathways. Furthermore, a large amount of interferon-gamma (IFN-gamma) was detectable in culture supernatant of activating receptor(+) NK cells incubated with the appropriate sHLA-I ligand. Again, cyclosporin A, but not concanamycin A, strongly reduced activating receptor-mediated IFN-gamma production. This suggests that activating receptor-induced apoptosis of NK cells could play a role in eliminating potentially harmful NK cell clones and, at the same time, it leads to production of IFN-gamma, an antiviral cytokine able to amplify immune responses.
Antigens, CD↗
Soluble HLA class I molecules induce natural killer cell apoptosis through the engagement of CD8: evidence for a negative regulation exerted by members of the inhibitory receptor superfamily.
Herein, we show that CD8(dull), CD8(intermediate), and CD8(bright) natural killer (NK) cell clones can be identified. Triggering of CD8 with its natural ligand(s), represented by soluble HLA class I (sHLA-I), isolated either from serum of healthy donors or from HLA-I(-) 721.221 lymphoblastoid cell line transfected with HLA-A2, -Cw4, and -Bw46 alleles, or HLA-G1 leads to NK cell apoptosis. The magnitude of this effect directly correlated with the level of CD8 expression. sHLA-I-induced apoptosis depends on the interaction with CD8, as it was inhibited by masking this molecule with specific monoclonal antibodies (mAbs). Moreover, sHLA-I or CD8 cross-linking with specific mAbs elicited intracellular calcium increases, Fas ligand (FasL) messenger RNA transcription, and FasL secretion, which were needed for delivering the death signal. Indeed, this apoptosis was inhibited by preincubation of NK cell clones with Fas or FasL antagonist mAbs, indicating that the Fas/FasL pathway is involved. Furthermore, members of the inhibitory receptor superfamily, such as CD94/NKG2 complex or killer inhibitory receptors, were shown to exert an inhibitory effect on sHLA-I-mediated apoptosis and secretion of FasL. These findings suggest that interaction between sHLA-I and CD8 evokes an apoptotic signal that is down-regulated by inhibitory receptor superfamily that function as survival receptors in NK cells.
Apoptosis↗