Characterization of cytomegalovirus disease in solid organ transplant recipients by markers of inflammation in plasma

Human Cytomegalovirus Infection Induces Long-Term Changes in the Cytokine Milieu of Kidney Transplant Recipients

The impact of human cytomegalovirus (HCMV) infection on the mid- and long-term balance between pro-inflammatory and anti-inflammatory cytokines among kidney transplant recipients (KTRs) remains unclear. We measured plasma levels of 12 Th1/Th2-type cytokines (granulocyte-macrophage colony-stimulating factor, interferon-γ, interleukin [IL]-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-18 and tumor necrosis factor-α) in a cohort of 290 KTRs at four time points through month 12 after transplantation. Cytokine levels at each point were compared according to the previous documentation of HCMV replication by two approaches: "cumulative exposure" from the time of transplantation and "recent exposure" within the 2-3 months preceding cytokine assessment. Significance levels were Bonferroni-corrected for multiple pairwise comparisons. Plasma levels of IL-6, IL-10, and IL-12p70 at month 1 were significantly increased in KTRs that had experienced HCMV infection during the first 30 days. By month 3, IL-6 and IL-10 remained increased in KTRs with cumulative exposure through day 90. Cumulative exposure to HCMV replication through day 180 was also associated to increased IL-10 levels at month 6. In addition, KTRs with recent HCMV exposure had increased IL-10 levels at months 3 and 6. After multivariable adjustment, cumulative exposure to HCMV infection and/or the area under curve of HCMV DNAemia during the corresponding period were associated to IL-10 levels within the highest quartile at months 1, 3, and 6. Preceding HCMV infection induces sustained changes in the plasma cytokine milieu of KTRs, with elevated IL-6 and IL-10 levels throughout the first 6 months after transplantation.

An exploratory analysis of C-X-C motif chemokine ligand 10 as a new biomarker of asymptomatic Leishmania infantum infection in Solid-Organ Transplant Recipients

OBJECTIVE

Sensitive and less laborious assays are needed to detect asymptomatic Leishmania among solid organ transplant (SOT) recipients. Using SLA-stimulated plasma from SOT recipients living where an outbreak of Leishmania infantum occurred, we examined potential biomarkers to identify asymptomatic Leishmania infections.

METHODS

Concentrations of cytokines/chemokines in plasma from whole blood stimulated with specific Leishmania antigen (SLA) were compared against infection status as determined by a currently used cell proliferation assay.

RESULTS

Twenty-six percent (13/50) of the SOT recipients had a cell proliferation assay (CPA) indicating asymptomatic infection, and showed higher processed plasma C-X-C motif chemokine ligand 10 (CXCL10 or IP-10) concentrations than did non-infected subjects (median 2272.0 pg/ml [IQR-1570-2772] vs. 18.2 pg/ml [IQR 1-150.1]; p<0.0001). CXCL10 showed a sensitivity of 93% and a specificity of 95% compared to CPA. In addition, we demonstrated that the number of asymptomatic infections detected using CXCL10, decreased with distance from a park at the centre of the mentioned outbreak.

CONCLUSION

CXCL10 in plasma from SLA-stimulated blood could be a robust biomarker of asymptomatic L. infantum infection in solid organ transplant recipients.

Approaches for monitoring of non virus-specific and virus-specific T-cell response in solid organ transplantation and their clinical applications

Opportunistic viral infections are still a major complication following solid organ transplantation. Immune monitoring may allow the identification of patients at risk of infection and, eventually, the modulation of immunosuppressive strategies. Immune monitoring can be performed using virus-specific and non virus-specific assays. This article describes and summarizes the pros and cons of the different technical approaches. Among the assays based on non virus-specific antigens, the enumeration of T-cell subsets, the quantification of cytokines and chemokines and the quantification of intracellular adenosine triphosphate following mitogen stimulation are described and their clinical applications to determine the risk for viral infection are discussed. In addition, current specific methods available for monitoring viral-specific T-cell responses are summarized, such as peptide-MHC multimer staining, intracellular cytokine staining, enzyme-linked immunospot and virus-specific IFN-γ ELISA assays, and their clinical applications to determine the individual risk for opportunistic viral infections with human cytomegalovirus, Epstein-Barr virus and polyoma BK virus are discussed. The standardization of the procedure, the choice of the antigen(s) and the criteria to define cut-off values for positive responses are needed for some of these approaches before their implementation in the clinic. Nevertheless, immune monitoring combined with virological monitoring in transplant recipients is increasingly regarded as a helpful tool to identify patients at risk of infection as well as to assess treatment efficacy.

Increased osteoprotegerin predicts poor virological outcome during anticytomegalovirus therapy in solid organ transplant recipients

BACKGROUND

Cytomegalovirus (CMV) infection involves interaction between endothelial cells and leukocyte subsets that may promote vascular inflammation and lead to treatment failure in infected individuals. Osteoprotegerin is a marker of vascular and systemic inflammation but has not been investigated in relation to treatment outcome during CMV infection.

METHODS

We investigated whether circulating levels of osteoprotegerin are related to features of CMV disease and treatment outcomes during CMV infection in 291 solid organ transplant recipients receiving valganciclovir or ganciclovir in an international multicenter trial of CMV disease treatment (the VICTOR study).

RESULTS

Elevated plasma osteoprotegerin was associated with (i) certain disease characteristics including presence of tissue invasive disease (P<0.05) and increased viral load at baseline (P<0.05), (ii) poor virological outcome at day 49 after anti-CMV therapy, (iii) increased plasma levels of markers of inflammation (pentraxin 3 and C-reactive protein) and endothelial cell activation (von Willebrand factor) both at baseline and during follow-up.

CONCLUSION

Our finding indicates that elevated osteoprotegerin levels in solid organ transplant recipients with CMV infection may reflect vascular inflammation and is associated with late virological outcome in these patients.

Clinical relevance of the plasma load of cytomegalovirus in patients infected with HIV--a survival analysis

To investigate whether asymptomatic cytomegalovirus (CMV) viraemia impact the course of human immunodeficiency virus (HIV) infection, this study evaluated the effect of CMV replication on progression of newly-diagnosed HIV infected individuals towards AIDS events and death. In a 3-year prospective study on co-infected patients, clinical, immunological, and virological tests were performed in a national reference hospital quarterly. CMV viraemia was quantified by RoboGene® HCMV DNA Quantification Kit (Analytik Jena, Germany), on ABI Prism® 7000 Sequence Detection System (Applied Biosystems, USA). One hundred and five patients were enrolled with a balanced sex distribution and a median age of 30.7 years. Median CD4(+) cell count at enrollment was 164/mm(3) and median HIV RNA 4.6 log10 copies/ml. Detectable CMV viraemia was found in 25.7% of the patients. Kaplan-Meier analysis showed progression of HIV infection to be significantly increased in those with active CMV replication and/or low CD4(+) cell count. Cox regression indicated the risk of developing new AIDS events was 2.6 times greater in patients with detectable CMV viraemia versus those without (CI95% 1-6.6; P = 0.04). Also in multivariate analysis, the overall risk of progression to AIDS events or death was 3-fold higher in those with detectable CMV viraemia (CI95% 1.3-6.7; P = 0.008) and 2.3-fold higher if CD4(+) cell count was below 100/mm(3) (CI95% 1-5.1; P = 0.04). In these young Romanian HIV-seropositives, active CMV replication increased morbidity, even when treated with combination antiretroviral therapy. Further studies are needed to evaluate if serial quantitative CMV-DNA levels might correlate with non-infectious inflammation-related risks in patients with HIV and active CMV infection.

Increased expression of the homeostatic chemokines CCL19 and CCL21 in clinical and experimental Rickettsia conorii infection

Background

Based on their essential role in concerting immunological and inflammatory responses we hypothesized that the homeostatic chemokines CCL19 and CCL21 may play a pathogenic role in rickettsiae infection.

Methods

Serum levels of CCL19 and CCL21 in patients with R. africae and R. conorii infection were analyzed by enzyme immunoassays. Lungs from R. conorii infected mice were examined for CCL19, CCL21 and CCR7 expression by immunohistochemistry.

Results

We found that patients with R. africae infection (n = 15) and in particular those with R. conorii infection (n = 16) had elevated serum levels of CCL19 on admission, with a decline during follow-up. While a similar pattern was seen for CCL21 in R. africae infection, patients with R. conorii infection showed persistently increased CCL21 levels during follow-up. In experimental R. conorii infection, we found strong immunostaining of CCL19 and CCL21 in the lungs, particularly in individuals that had received lethal doses. Immunofluorescence showed co-localization of CCR7 to endothelial cells, macrophages and fibroblasts within the lung tissue of R. conorii infected mice.

Conclusions

Our findings suggest that the CCL19/CCL21/CCR7 axis is up-regulated during R. africae and in particular during R. conorii infection, which may potentially contribute to the pathogenesis of these disorders.