Isabel Benet

Uncontrolled immune response in acute myocardial infarction: Unraveling the thread

Recently, the theory that hyperinflammation is the bodys primary response to potent stimulus has been challenged. Indeed, a deregulation of the immune system could be the cause of multiple organ failure. So far, clinicians have focused on the last steps of the inflammatory cascade. However, little attention has been paid to lymphocytes, which play an important role as strategists of the inflammatory response. Experimental evidence suggests a crucial role of T lymphocytes in the pathophysiology of atherosclerosis and acute myocardial infarction (AMI). In summary, from the bottom of an imaginary inverted pyramid, a few regulatory T-cells control the upper parts represented by the wide spectrum of the inflammatory cascade. In AMI, a loss of regulation of the inflammatory system occurs in patients with a decreased activity of regulatory T-cells. As a consequence, aggressive T-cells boost and anti-inflammatory T-cells drop. A pleiotropic proinflammatory imbalance with damaging effects in terms of left ventricular performance and patient outcome is the result of this uncontrolled immune response. It is needed to unravel the thread of the inflammatory cells to better understand the pathophysiology as well as to open innovative therapeutic options in AMI.

Virological and immunological features of active cytomegalovirus infection in nonimmunosuppressed patients in a surgical and trauma intensive care unit.

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‐α 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. Clearance of CMV DNAemia preceded that of CMV DNA in TA in some episodes. Peak CMV DNA levels were significantly higher in TA than in PL (P = 0.02). CMV reactivation developed in the presence of CMV‐specific T cells. Termination of CMV reactivation was associated with an expansion of functional CMV‐specific T cells. Plasma levels of TNF‐α did not allow for the prediction of the occurrence of CMV reactivation. CMV‐specific T‐cell immunity is preserved in most critically ill patients experiencing CMV reactivation. Analysis of respiratory specimens is imperative for an optimal monitoring of CMV reactivation in this setting. J. Med. Virol. 82:1384–1391, 2010.

Kinetics of cytomegalovirus (CMV) pp65 and IE-1-specific IFNγ CD8+ and CD4+ T cells during episodes of viral DNAemia in allogeneic stem cell transplant recipients: potential implications for the management of active CMV infection.

The dynamics of CMV pp65 and IE‐1‐specific IFNγ‐producing CD8+ (IFNγ CD8+) and CD4+ (IFNγ CD4+) T cells and CMV DNAemia were assessed in 19 pre‐emptively treated episodes of active CMV infection. Peripheral counts of IFNγ CD8+ and IFNγ CD4+ T cells inversely correlated with CMV DNAemia levels (P = <0.001 and P = 0.003, respectively). A threshold value of 1.3 cells/µl predicting CMV DNAemia clearance was established for IFNγ CD8+ T cells (PPV, 100%; NPV, 93%) and for IFNγ CD4+ T cells (PPV, 100%; NPV, 75%). Undetectable T‐cell responses were usually observed at the time of initiation of pre‐emptive therapy. Either a rapid (within 7 days) or a delayed (median 31 days) expansion of both T‐cell populations concomitant with CMV DNAemia clearance was observed in 5 and 8 episodes, respectively. An inconsistent or a lack of expansion of both T‐cell subsets was related to a persistent CMV DNAemia. Robust and maintained CMV‐specific T‐cell responses after CMV DNAemia clearance and cessation of antiviral therapy were associated with a null incidence of relapsing infections at least during the following month. Data obtained in the present study may be helpful in the design of therapeutic strategies for the management of active CMV infections in the allo‐SCT recipient. J. Med. Virol. 82: 1208–1215, 2010.

Performance of the QuantiFERON-Cytomegalovirus (CMV) Assay for Detection and Estimation of the Magnitude and Functionality of the CMV-Specific Gamma Interferon-Producing CD8+ T-Cell Response in Allogeneic Stem Cell Transplant Recipients

ABSTRACT The performance of the QuantiFERON-cytomegalovirus (CMV) assay was compared to that of a flow cytometry intracellular cytokine staining (ICS) method for the detection of CMV-specific gamma interferon (IFN-γ)-producing CD8+ T-cell responses in allogeneic stem cell transplant (allo-SCT) recipients and for estimations of their magnitude and functionality. A total of 90 whole-blood specimens from 23 allo-SCT recipients was analyzed by both methods. Overall, the percentage of specimens that yielded concordant results by both methods was 68.8% (κ = 0.691; 95% confidence interval [CI], 0.548 to 0.835), and the sensitivity of the QuantiFERON-CMV assay for the detection of positive IFN-γ T-cell responses (>0.2 IU/ml), taking the ICS method as the reference, was 76.3%. The magnitude of IFN-γ-producing CD8+ T-cell responses to CMV-specific peptides measured with the QuantiFERON-CMV assay correlated significantly (σ = 0.695; P = <0.001) with that of the total IFN-γ-producing CD8+ T cells and dual-functional (IFN-γ/tumor necrosis factor alpha [TNF-α] [σ = 0.652; P = <0.001] and IFN-γ/CD107a [σ = 0.690; P = <0.001]) and trifunctional (IFN-γ/TNF-α/CD107a [σ = 0.679; P = >0.001]) CMV-specific CD8+ T-cell responses, as quantitated by ICS. In summary, the data indicated that the QuantiFERON-CMV assay is less sensitive than the ICS method for the detection of CMV-specific IFN-γ-producing CD8+ T-cell responses in the allo-SCT setting. Nevertheless, it allowed the estimation of the total and polyfunctional CMV-specific IFN-γ-producing CD8+ T-cell responses in specimens that tested positive by both methods.

Cytogenetic response induced by interferon alpha in the myeloproliferative disorder with eosinophilia, T cell lymphoma and the chromosomal translocation t(8;13)(p11;q12)

Cytogenetic response induced by interferon alpha in the myeloproliferative disorder with eosinophilia, T cell lymphoma and the chromosomal translocation t(8;13)(p11;q12)

An Assessment of the Effect of Human Herpesvirus-6 Replication on Active Cytomegalovirus Infection after Allogeneic Stem Cell Transplantation

Human herpesvirus-6 (HHV-6) may enhance cytomegalovirus (CMV) replication in allogeneic stem cell transplant (allo-SCT) recipients either through direct or indirect mechanisms. Definitive evidence supporting this hypothesis are lacking. We investigated the effect of HHV-6 replication on active CMV infection in 68 allo-SCT recipients. Analysis of plasma HHV-6 and CMV DNAemia was performed by real-time PCR. Enumeration of pp65 and IE-1 CMV-specific IFNgamma CD8(+) and CD4(+)T cells was performed by intracellular cytokine staining. HHV-6 DNAemia occurred in 39.8% of patients, and was significantly associated with subsequent CMV DNAemia in univariate (P=.01), but not in multivariate analysis (P=.65). The peak of HHV-6 DNAemia was not predictive of the development of CMV DNAemia. Timing and kinetics of active CMV infection were comparable in patients either with or without a preceding episode of HHV-6 DNAemia. The occurrence of HHV-6 DNAemia had no impact on CMV-specific T cell immunity reconstitution early after transplant. The receipt of a graft from an HLA-mismatched donor was independently associated with HHV-6 (P=.009) and CMV reactivation (P=.04). The data favor the hypothesis that a state of severe immunosuppression leads to HHV-6 and CMV coactivation, but argue against a role of HHV-6 in predisposing to the development of CMV DNAemia or influencing the course of active CMV infection.

Polyethyleneimine-based immunopolyplex for targeted gene transfer in human lymphoma cell lines

Specific and efficient delivery of genes into targeted cells is a priority objective in non‐viral gene therapy. Polyethyleneimine‐based polyplexes have been reported to be good non‐viral transfection reagents. However, polyplex‐mediated DNA delivery occurs through a non‐specific mechanism. This article reports the construction of an immunopolyplex, a targeted non‐viral vector based on a polyplex backbone, and its application in gene transfer over human lymphoma cell lines.

Functional profile of cytomegalovirus (CMV)-specific CD8+ T cells and kinetics of NKG2C+ NK Cells associated with the resolution of CMV DNAemia in allogeneic stem cell transplant recipients

Immune mechanisms involved in control of cytomegalovirus (CMV) infection in the allogeneic stem cell transplantation setting have not been fully disclosed. CMV pp65 and IE‐1‐specific CD8+ T cells expressing IFN‐γ, TNF‐α, and CD107a, alone or in combination, and NKG2C+ NK cells were prospectively enumerated during 13 episodes of CMV DNAemia. The expansion of monofunctional and polyfunctional CD8+ T cells was associated with CMV DNAemia clearance. The size and functional diversity of the expanding CD8+ T‐cell population was greater in self‐resolved episodes than in episodes treated with antivirals. These differences were related to the magnitude of expansion of cognate antigen IFN‐γ CD4+ T cells. The resolution of CMV DNAemia was associated frequently with a marked expansion of both CD56dim/CD16+ NK cells and NKG2C+ CD56bright/CD16− NK cells. The data lend support to the role of polyfunctional CD8+ T cells in controlling CMV replication in the allogeneic stem cell transplantation setting, and suggest that NKG2C+ NK cells may be involved critically in the resolution of CMV DNAemia episodes. J. Med. Virol. 84:259–267, 2012.

Evaluation of cytomegalovirus (CMV)-specific t-cell immunity for the assessment of the risk of active CMV infection in non-immunosuppressed surgical and trauma intensive care unit patients

The current study was designed to assess the predictive value of the evaluation of cytomegalovirus (CMV)‐specific T‐cell immunity early following admission to the intensive care unit for inferring the risk of active CMV infection in non‐immunosuppressed surgical and trauma patients. A total of 31 CMV‐seropositive patients were included. Patients were screened for the presence of CMV DNA in plasma and in tracheal aspirates by real‐time PCR. Enumeration of CMV pp65 and IE‐1‐specific IFN‐γ CD8+ and CD4+ T cells was performed by flow cytometry for intracellular cytokine staining. Virological and immunological monitoring was conducted once or twice a week. Active CMV infection occurred in 17 out of 31 patients. Undetectable levels of pp65 and IE‐1‐specific IFN‐γ CD8+ and CD4+ T‐cell subsets cells were observed in 10 patients who developed active CMV infection and in one who did not (at a median of 2 days following ICU admission). Peak CMV DNA loads in both tracheal aspirates and plasma were substantially higher (P = 0.018 and P = 0.091, respectively) in patients with undetectable IFN‐γ T‐cell responses than in patients with detectable responses. The expansion of both CMV‐specific T‐cell subsets following detection of active CMV infection was demonstrated in 9 out of 14 patients with active CMV infection. In conclusion, the evaluation of CMV pp65 and IE‐1‐specific IFN‐γ‐producing CD8+ and CD4+ T cells early following ICU admission may allow the identification of patients most at risk of either having or developing an episode of active CMV infection, particularly those associated with high‐level virus replication. J Med. Virol. 85:1802–1810, 2013.

Bcl-6 mutation status provides clinically valuable information in early-stage B-cell chronic lymphocytic leukemia

In B-cell chronic lymphocytic leukemia (B-CLL), somatic mutation of IgVH genes defines a subgroup with favorable prognosis, whereas the absence of IgVH mutations is correlated with a worse outcome. Mutations of the BCL-6 gene are also observed in a subset of B-CLL, but the clinical significance of this molecular alteration remains uncertain. We examined the distribution of IgVH and BCL-6 gene mutations in 95 well-characterized patients with Binet stage A B-CLL, and correlated them with clinical, laboratory, cytogenetic findings and disease progression. Mutations of the BCL-6 gene were observed only in cases harboring mutated IgVH. Unexpectedly, coexistence of IgVH and BCL-6 mutations was correlated with shorter treatment-free interval (TFI) compared to cases harboring only IgVH mutation (median, 55 months vs not reached; P=0.01), resembling the clinical course of unmutated IgVH cases (median TFI, 44 months). As expected, deletions of 17p13 (P53 locus) and 11q22 (ATM locus) were observed in cases with unmutated IgVH, except one patient who showed mutations of both IgVH and BCL-6. No other statistically significant differences were observed among the genetic subgroups. Our data indicate that BCL-6 mutations identify a subgroup of Binet stage A B-CLL patients with a high risk of progression despite the presence of mutated IgVH gene.