In Vitro Immunological Effects of CXCR3 Inhibitor AMG487 on Dendritic Cells.

AMG 487 is the targeted blocker of chemokine receptor CXCR3 and improves inflammatory symptoms by blocking the inflammatory cycle. Here we investigated whether AMG 487 affects dendritic cell (DC) biology and function. The expression of co-stimulatory markers on DCs was reduced, indicating the semi-mature state of DC when AMG 487 was added throughout the in vitro differentiation period. Additionally, when added solely during the final lipopolysaccharide-induced activation step, AMG 487 inhibited DC activation, as demonstrated by a decreased expression of activation markers. AMG487 also promoted the expression of PD-L2 and impaired the ability to induce antigen-specific T cell responses. Our results demonstrated that AMG 487 significantly affects DC maturity in vitro and function leading to impaired T cell activation, inducing DCs to have characteristics similar to tolerogenic DCs. AMG 487 may directly play an immunomodulatory role during DC development and functional shaping.

A patient with melanoma that became sensitized to immunotherapy after treatment with a CDK4/6 inhibitor.

Background: Despite the profound effect that checkpoint inhibitors and BRAF/MEK inhibitors have had on survival in patients with metastatic melanoma, treatment options remain limited for those who demonstrate poor response or develop resistance to these modalities. The prospect of tumor sensitization to these treatments is therefore an attractive one. Results: We describe the case of a patient who developed a sustained response to trametinib and pembrolizumab, despite prior resistance to both these therapies, after receiving treatment with a CDK4/6 inhibitor. Discussion: We further outline the preclinical data supporting a possible role for the use of CDK4/6 inhibitors in tumor sensitization to immunotherapy.

Decrease in LDL size in HIV-positive adults before and after lopinavir/ritonavir-containing regimen: an index of atherogenicity?

BACKGROUND: Hypertriglyceridemia (HTG) is frequently observed during highly active antiretroviral therapy (HAART) including protease inhibitor. Apolipoprotein (apo) CIII could be involved in this HTG by inhibition of triglyceride (TG) hydrolysis, which leads to the occurrence of small dense low density lipoprotein (sdLDL), a recognized cardiovascular risk factor. OBJECTIVE: To characterize the influence of lopinavir/ritonavir-containing regimen on lipoprotein profile. DESIGN AND METHODS: 24 antiretroviral-experienced HIV infected adults (including 14 patients in therapeutic interruption of at least 2 months) and 14 HIV uninfected healthy controls were enrolled. Serum lipid parameters (total cholesterol (TC), HDL-C, LDL-C, TG, apoA1, apoB, apoCIII), lipoprotein composition and LDL size were determined before initiation of lopinavir/ritonavir-containing regimen, and at 1 and 3 months thereafter. RESULTS: At baseline an atherogenic lipid profile was evidenced, characterized by a moderate HTG associated to a smaller mean LDL size (25.16 vs 25.93 nm, P<0.001), an enrichment in TG of LDL (11.4 vs 6.0%, P<0.01) and a high prevalence of sdLDL (75 vs 7%, P<0.01) when compared to controls. After 1 month of lopinavir/ritonavir-containing regimen, a significant reduction of LDL size (24.81 vs 25.16 nm, P<0.05) and a significant increase in cholesterol total (5.53 vs 4.49 mmol/l, P<0.001), in TG (4.20 vs 2.01 mmol/l, P<0.001), in apoA1 (1.28 vs 1.11 g/l, P<0.001), in apoB (1.08 vs 0.94 g/l, P<0.01), in apoCIII (0.16 vs 0.10 g/l, P<0.001), in TG percentage in LDL (14.4 vs 11.4, P<0.05) and in TG percentage in HDL (10.2 vs 8.3, P<0.05) were observed. CONCLUSIONS: Advanced stage of HIV infection is associated with an atherogenic lipid profile including a high prevalence of sdLDL. Lopinavir/ritonavir-containing regimen accentuates the reduction of LDL size. Since fibrates decrease TG and increase LDL size, they appear as a logical option to manage HAART-induced HTG.

Fetal membranes exhibit selective leukocyte chemotaxic activity during human labor.

One of the characteristics of the labor process in women is leukocyte recruitment into reproductive tissues. These migrating cells may play a role in the induction of functional and biochemical changes associated with the rupture of fetal membranes during labor. This study was undertaken to assess whether human fetal membranes induce leukocyte chemotaxis during labor as well as to identify and characterize leukocyte chemoattractants secreted by these tissues. Leukocyte chemotactic activity of fetal membrane extracts obtained from women with full-term pregnancies and spontaneous active labor was compared with extracts from women without labor. The number and phenotype of attracted leukocytes were analyzed by flow cytometry. Chemokines were quantified using a Multiplex system and were identified by immunofluorescence histochemistry. Although all tested extracts induced chemotaxis of leukocytes, those prepared from women undergoing labor induced higher responses. Polymorphonuclear leukocyte chemotaxis increased approximately three-fold in response to extract from fetal membranes with labor. The same extracts elicited a significant increase in attracted monocytes (36-fold) as well as T and B lymphocytes, and NK cells (all five-fold) when compared to extracts from women without labor. This enhanced chemotactic activity was associated with the presence of IL-8, MCP-1, IP-10 and MIP-1alpha. We conclude that fetal membrane extracts obtained from women during labor exhibit selective chemotaxis for specific leukocyte subpopulations in vitro. This process may contribute to a microenvironment composed of specific leukocytes that promotes and amplifies biochemical changes in the fetal membranes during labor.

Clinical ritonavir and lopinavir hypersensitivity confirmed by a specific in vitro cellular allergen stimulation test.

A HIV-infected patient treated since eight years with all antiretroviral classes save boosted protease inhibitors, at the time of changing therapy due to an emerging genotyping resistance to non-nucleoside reverse transcriptase inhibitors, experienced repeated episodes of hypersensitivity reactions to all available boosted protease inhibitors. After documenting a combined ritonavir and lopinavir hypersensitivity by means of a specific in vitro cellular antigen stimulation test (CAST), antiretroviral therapy was safely continued with unboosted atazanavir. According to our knowledge, we report the first case of application of the in vitro CAST assay to antiretroviral intolerance, and the subsequent, specific regimen selection in a HIV-infected subject who showed multiple allergy to all boosted protease inhibitors. Further, controlled investigation is strongly needed to implement in vitro allergometric testing in patients with HIV infection and related diseases, who are prone to show unpredictable drug intolerance reactions. In fact, HIV-infected patients may suffer from frequent allergic drug reactions which may be difficult to be systematically recognized (due to the frequent, multiple concurrent pharmacotherapy), while eventual drug rechallenges are expected to be potentially dangerous.