Search results for "Cytomegalovirus infections"
showing 10 items of 153 documents
Impact of CMV and EBV seropositivity on CD8 T lymphocytes in an old population from West-Sicily.
2007
Abstract Herpes viruses (particularly CMV and to some extent EBV) might play a role in accelerating the deterioration of immune functions with age. Indeed, it has been demonstrated that chronic infection with CMV causes an expansion of specific CD8 T lymphocytes and that this is related to a shrinkage of the T cell repertoire in very elderly people, predicting mortality. We have analysed CD8 T cells in young and old healthy Sicilians who were both CMV- and EBV-seropositive. Our data confirm expansions of T cells specific for the HLA-A2-restricted pp65 (495–503) CMV epitope up to nearly 14% of total peripheral CD8 cells in certain elderly individuals (range 0–14%). However, the mean percenta…
Virological and immunological features of active cytomegalovirus infection in nonimmunosuppressed patients in a surgical and trauma intensive care un…
2010
Cytomegalovirus (CMV) reactivation occurs frequently in critically ill patients. The natural course of CMV infection and the interaction between CMV and the adaptive immune system in this setting remain poorly defined. Fifty-three CMV-seropositive patients in a surgical and trauma intensive care unit were included in this study. The CMV DNA load in tracheal aspirates (TA) and plasma (PL) was monitored by qPCR. CMV-specific T-cell immunity was assessed by intracellular cytokine staining. Plasma TNF-alpha levels were determined by ELISA. CMV reactivation occurred in 39.7% of patients (23% had CMV DNA detected only in TA). The analysis of TA allowed an earlier diagnosis in 28% of patients. Cle…
Toxic megacolon and human Cytomegalovirus in a series of severe ulcerative colitis patients
2015
Abstract Background Human Cytomegalovirus (HCMV) infection has been reported to be a cause of refractory ulcerative colitis (UC). Toxic megacolon (TM) is a rare but severe complication of an acute attack of UC. Objectives Aim of this study is to evaluate in a case-control study the association between HCMV and TM. Study design All patients who were admitted at Medicine Department of V. Cervello Hospital in Palermo (tertiary referral center) for a severe UC flare-up complicated by the onset of TM (diameter of the transverse colon > 6 cm) between January 1990 and November 2011 were identified through the electronic database. A total of 24 consecutive patients (16 male/8 female) with TM were i…
The role of the human cytomegalovirus UL111A gene in down-regulating CD4+ T-cell recognition of latently infected cells: implications for virus elimi…
2009
AbstractThe capacity of human cytomegalovirus (HCMV) to establish and maintain a latent infection from which it can later reactivate ensures its widespread distribution in the population, but the mechanisms enabling maintenance of latency in the face of a robust immune system are poorly understood. We examined the role of the HCMV UL111A gene, which encodes homologs of the immunosuppressive cytokine interleukin-10 in the context of latent infection of myeloid progenitor cells. A UL111A deletion virus was able to establish, maintain, and reactivate from experimental latency in a manner comparable with parental virus, but major histocompatibility complex class II levels increased significantl…
Optimized recombinant dense bodies of human cytomegalovirus efficiently prime virus specific lymphocytes and neutralizing antibodies without the addi…
2010
Control of human cytomegalovirus (HCMV) infection correlates with the reconstitution of antiviral T lymphocytes in haematopoietic stem cell transplant recipients. A vaccine to foster this reconstitution and to ameliorate the severe consequences of HCMV reactivation is yet unavailable. This work focused on providing a rationale for the amendment of the yields and the antigenic composition of a vaccine, based on subviral dense bodies (DB) of HCMV. Modified DB were generated that contained the HLA-A2 presented IE1 model peptide TMYGGISLL, integrated at different positions in the major DB protein pp65. Insertion at position W175 of pp65 allowed efficient formation of recDB in the cytoplasm of i…
Human cytomegalovirus pp71 stimulates major histocompatibility complex class i presentation of IE1-derived peptides at immediate early times of infec…
2013
ABSTRACT Suppression of major histocompatibility complex (MHC) class I-mediated presentation of human cytomegalovirus (HCMV) peptides is an important mechanism to avoid CD8 T lymphocyte recognition and killing of infected cells. Of particular interest is how MHC class I presentation of essential regulatory immediate early (IE) proteins of HCMV can be effectively compromised at times when known viral immunoevasins are not abundantly expressed. The tegument protein pp71 had been suggested to be involved in MHC class I downregulation. Intriguingly, this polypeptide is also critically engaged in the initial derepression of the major IE gene locus, leading to enhanced expression of IE proteins I…
Cytomegalovirus and varicella–zoster virus vaccines in hematopoietic stem cell transplantation
2009
Impairment of cellular immunity upon hematopoietic stem cell transplantation (HSCT) may lead to serious clinical manifestations induced by human cytomegalovirus (HCMV) and varicella-zoster virus (VZV) infections. Although the clinical presentations, preferential organ involvement and clinical courses are different, infections with both herpesviruses are similar with respect to many pathophysiological aspects and the therapeutic strategies that are employed to combat them. Antiviral drug prophylaxis and therapy are successfully used to limit the risk of reactivated HCMV and VZV infections, but are unable to absolutely prevent episodes of virus disease in long-term follow-up after HSCT. Contr…
Application of a 5-bromo-2′-deoxyuridine ELISA for measuring the lymphoproliferative response to human cytomegalovirus in HIV-1-infected patients
2002
Assessment of the lymphoproliferative response to human cytomegalovirus (HCMV) may help to identify human immunodeficiency virus (HIV)-1-infected patients at high risk of developing HCMV end-organ disease. The tritiated thymidine ([3H]-TdR)-incorporation assay is the gold standard for measuring lymphoproliferative responses, though it is unsuitable as a routine laboratory procedure. An alternative non-radioactive technique, a 5-bromo-2'-deoxyuridine (BrdU) enzyme-linked immunosorbent assay, was applied for measuring T-cell proliferation in response to HCMV. Stimulation of either 1 x 10(5) or 5 x 10(4) peripheral blood mononuclear cells (PBMCs)/well with 10 PFU/well (before inactivation) of …
Are human Vδ2(pos) T cells really resistant to aging and Human Cytomegalovirus infection?()
2019
In their recent paper, Weili Xu et al. [1] described the different behaviors of Vδ1pos and Vδ2pos T cell subsets in response to lifelong stress and claimed that Vδ2pos T cells are not affected by aging and Human Cytomegalovirus (HCMV) infection. While we agree that these two γδ T cell subsets diverge both in phenotype/function and in tissue distribution, we are somewhat surprised that authors did not take into account the several previously published and contradictory experimental evidence in regards to senescence of Vδ2pos T cells [2,3]. These latter studies reported that HCMV infection not only induces a clonal expansion of a distinct Vγ9neg/Vδ2pos T cell subset, but also determines a con…
Development of novel vaccine strategies against human cytomegalovirus infection based on subviral particles.
2002
Abstract Background: Pre- and perinatal human cytomegalovirus (HCMV) infection remains one of the major causes of mental defects and sensineural hearing loss in children. In addition, it is a prominent infectious complication in immunosuppressed individuals such as AIDS patients or transplant recipients. Therefore, the development of an HCMV vaccine has been given top priority by health care institutions. Study design: Defective subviral particles of HCMV, termed Dense Bodies (DB) contain the dominant target antigens for humoral and cellular immune responses elicited during natural infection. These enveloped particles are released from infected culture cells and can be purified by gradient …