Chlorhexidine gluconate-coated gel pad dressings for prevention of central venous catheter-related bloodstream infections in patients with hematologic diseases or autologous stem cell transplantation: A registry-based matched-pair analysis.

OBJECTIVES: Chlorhexidine gluconate (CHG)-coated gel pad dressings for central venous catheter (CVC) may prevent CVC-related bloodstream infections (CRBSI). However, real-world data showing beneficial effects in patients with hematologic malignancies are scarce. METHODS: In a matched-pair analysis with data from a multicenter CVC registry, non-tunneled jugular and subclavian vein CVC in adults with hematologic malignancies or germ cell tumors (including patients receiving autologous hematopoietic stem cell transplantation [ASCT]) with CHG were compared with non-CHG dressings. The primary endpoint was definite CRBSI rate within 14 days (dCRBSI14) of CVC insertion; secondary endpoints were combined rate of definite or probable CRBSI within 14 days (dpCRBSI14), overall (dpCRBSI), and CRBSI incidences of all estimates. RESULTS: In total, 2070 CVCs were assessed. There was no statistically significant difference in dCRBSI14 (2.3% vs. 3.5%) between patients with and without CHG gel dressings. Likewise, with regards to dpCRBSI14 (6.2% vs. 6.3%) and the overall dpCRBSI rate (9.2% vs. 10.5%), no significant difference was detected. Furthermore, dCRBSI14 incidence (2.0 vs. 3.2/1000 CVC days), dpCRBSI14 incidence (5.4 vs. 5.6/1000 CVC days), and overall CRBSI incidence (5.5 vs. 6.0/1000 CVC days) showed no significant differences. CONCLUSIONS: CRBSI rates were not reduced by the use of CHG gel dressings in patients with hematologic malignancies and/or ASCT.

Impact of the insertion site of central venous catheters on central venous catheter-related bloodstream infections in patients with cancer: results from a large prospective registry.

PURPOSE: Overall, insertion of central venous catheter (CVC) into femoral veins (FV) has been shown to be associated with a higher risk of infection compared with subclavian and internal jugular (IJV/SCV) CVC, but no data are available on the impact of the FV insertion site on the CVC-related bloodstream infections (CRBSI) risk in patients with cancer. The objective of the study is to compare CRBSI rates and incidences of FV with those of internal jugular and subclavian vein (IJV/SCV CVC) as observed in the prospective SECRECY registry. METHODS: SECRECY is an ongoing observational, prospective, clinical CRBSI registry active in six departments of hematology/oncology in Germany. Each case of FV CVC was matched at a ratio of 1:1 to a case with IJV/SCV CVC. The propensity score was estimated using a multivariable logistic regression model adjusting for age, sex, cancer type, and duration of indwelling catheter. RESULTS: Of 4268 CVCs included in this analysis, 52 (1.2%) were inserted into the FV and 4216 (98.8%) into the IJV/SCV. 52 cases of FV CVC were matched with 52 IJV/SCV CVC. There was no significant difference in the CRBSI rate (3.8% vs. 9.6%), the CRBSI incidence (5.7 vs. 14.2/1000 CVC days), and the median CVC time (5.5 vs. 5 days) between the FV and the IJV/SCV group. CONCLUSION: Based on this data, inserting FV CVCs in patients with cancer does, at least in the short-term, not appear to be associated with an increased risk of CRBSI as compared to IJV/SCV CVC.

Targeting LAG-3 and PD-1 to Enhance T Cell Activation by Antigen-Presenting Cells.

Immune checkpoint inhibition has been shown to successfully reactivate endogenous T cell responses directed against tumor-associated antigens, resulting in significantly prolonged overall survival in patients with various tumor entities. For malignancies with low endogenous immune responses, this approach has not shown a clear clinical benefit so far. Therapeutic vaccination, particularly dendritic cell (DC) vaccination, is a strategy to induce T cell responses. Interaction of DCs and T cells is dependent on receptor-ligand interactions of various immune checkpoints. In this study, we analyzed the influence of blocking antibodies targeting programmed cell death protein 1 (PD-1), HVEM, CD244, TIM-3, and lymphocyte activation gene 3 (LAG-3) on the proliferation and cytokine secretion of T cells after stimulation with autologous TLR-matured DCs. In this context, we found that LAG-3 blockade resulted in superior T cell activation compared to inhibition of other pathways, including PD-1/PD-L1. This result was consistent across different methods to measure T cell stimulation (proliferation, IFN-γ secretion), various stimulatory antigens (viral and bacterial peptide pool, specific viral antigen, specific tumor antigen), and seen for both CD4+ and CD8+ T cells. Only under conditions with a weak antigenic stimulus, particularly when combining antigen presentation by peripheral blood mononuclear cells with low concentrations of peptides, we observed the highest T cell stimulation with dual blockade of LAG-3 and PD-1 blockade. We conclude that priming of novel immune responses can be strongly enhanced by blockade of LAG-3 or dual blockade of LAG-3 and PD-1, depending on the strength of the antigenic stimulus.

T cells are functionally not impaired in AML: increased PD-1 expression is only seen at time of relapse and correlates with a shift towards the memory T cell compartment.

BACKGROUND: T cell function is crucial for the success of several novel immunotherapeutic strategies for the treatment of acute myeloid leukemia (AML). However, changes in phenotype and function of T cells have been described in various hematologic malignancies, mimicking T cell exhaustion known from chronic viral infections. Detailed knowledge about phenotype and function of T cells in AML patients at different stages of the disease is indispensable for optimal development and application of immunotherapeutic strategies for this disease. METHODS: We used flow cytometry-based assays to characterize T cell phenotype and function in peripheral blood and bone marrow of AML patients at diagnosis, at relapse after intensive chemotherapy, and at relapse after allogeneic stem cell transplantation (SCT). Surface expression of CD244, PD-1, CD160, and TIM-3 was determined, and proliferation and production of IFN-γ, TNF-α, and IL-2 were measured. RESULTS: We detected similar expression of inhibitory molecules on T cells from patients at diagnosis and from age-matched healthy controls. At relapse after SCT, however, PD-1 expression was significantly increased compared to diagnosis, both on CD4(+) and CD8(+) T cells. This pattern was not associated with age and cytomegalovirus (CMV) status but with a shift towards effector memory cells in relapsed AML patients. Proliferation and cytokine production assays did not reveal functional defects in T cells of AML patients, neither at diagnosis nor at relapse. CONCLUSION: We thus conclude that T cell exhaustion does not play a major role in AML. Immunotherapeutic strategies targeting autologous T cells thus have particularly good prospects in the setting of AML.