It is well recognized that macrophages in many contexts in vitro and in vivo display a spectrum of inflammatory features and functional properties. A convenient system to group together different subsets of macrophages has been the M1 (inflammatory)/M2 (anti-inflammatory) classification. In addition to other sites of inflammation, it is now established that atherosclerotic plaques contain both M1 and M2 macrophages. We review results made possible by a number of recent mouse models of atherosclerotic regression that, taken with other literature, have shown the M1/M2 balance in plaques to be dynamic, with M1 predominating in disease progression and M2 in regression. The regulation of the macrophage phenotype in plaques and the functional consequences of the M1 and M2 states in atherosclerosis will also be discussed.

Programmed cell death-1 (PD-1) is an essential inhibitory receptor in T cells. Antibodies targeting PD-1 elicit durable clinical responses in patients with multiple tumor indications. Nevertheless, a significant proportion of patients do not respond to anti-PD-1 treatment, and a better understanding of the signaling pathways downstream of PD-1 could provide biomarkers for those whose tumors respond and new therapeutic approaches for those whose tumors do not. We used affinity purification mass spectrometry to uncover multiple proteins associated with PD-1. Among these proteins, signaling lymphocytic activation molecule-associated protein (SAP) was functionally and mechanistically analyzed for its contribution to PD-1 inhibitory responses. Silencing of SAP augmented and overexpression blocked PD-1 function. T cells from patients with X-linked lymphoproliferative disease (XLP), who lack functional SAP, were hyperresponsive to PD-1 signaling, confirming its inhibitory role downstream of PD-1. Strikingly, signaling downstream of PD-1 in purified T cell subsets did not correlate with PD-1 surface expression but was inversely correlated with intracellular SAP levels. Mechanistically, SAP opposed PD-1 function by acting as a molecular shield of key tyrosine residues that are targets for the tyrosine phosphatase SHP2, which mediates PD-1 inhibitory properties. Our results identify SAP as an inhibitor of PD-1 function and SHP2 as a potential therapeutic target in patients with XLP.

PurposeWeight loss is a well-recognized prognostic parameter for survival of lung cancer patients. Computerized-tomography (CT)-based analysis of body composition and blood-based metabolic evaluation are promising prognostic tools. We aimed to assess the correlation between albumin, body mass index (BMI), skeletal muscle mass index (SMI), fat-free mass index (FFMI), fat mass index (FMI) and weight change, as well as their correlation with survival of lung cancer patients on nivolumab treatment.MethodsData were retrospectively collected. Weight was measured at a diagnosis of stage 4 disease and before start of nivolumab. Albumin levels were measured before starting nivolumab. BMI, SMI, FFMI, and FMI were evaluated from CT scans performed at start of nivolumab. Overall survival (OS) was from starting of nivolumab to death or censured at last follow-up. Statistical analysis was done to identify correlation between the various factors and between those factors and survival.ResultsForty-six patients with advanced non-small cell lung cancer (NSCLC) were included. Median follow-up was 22 months. Pathology was Adenocarcinoma/Squamous/non-other specified in 25/15/6 respectively. All patients received nivolumab as an advanced-line treatment for stage IV NSCLC. We observed a significant correlation of weight loss (P=0.01, HR=2.85) and albumin (P=0.043, HR=0.34) with OS in multivariate analysis. A significant correlation was found between BMI to SMI, FFMI, FMI, and weight change.ConclusionWeight loss and low albumin levels are significant negative prognostic factors for NSCLC patients on immunotherapy. CT-based parameters of body composition remain to be proven as more reliable than standard clinical parameters.

8534 Background: Resected NSCLC clinical stage I or II harbor a 5 year survival of only 30-50%. Immunotherapy might be more effective in low-burden disease. We hypothesized that neo-adjuvant immunotherapy is a feasible, safe and effective treatment (Tx) for early stage NSCLC. Methods: MK3475-223 is an ongoing phase I study of neoadjuvant pembrolizumab in stage I-II NSCLC. All Pembro Txs are 200mg q 3 weeks (wks). Objectives: determine safety; recommended phase 2 dose/schedule; pathological & radiological response. Doses-schedule limiting toxicities (DLT) were defined as significant surgical complications (bleeding, delayed wound healing, ARDS, prolonged air-leak) or a significant delay of surgery. The doses-schedule escalation cohorts were (i) single pembro dose 3 wk prior to surgery; (ii) 2 pembro doses, 2 wks later surgery; (iii) 2 pembro doses, 1 wk later surgery. Expansion cohort received the doses-schedule of cohort (iii). Percentages of remaining viable tumor in the post-Tx were assessed, 10% or less was considered amajor pathological response (MPR). IHC for pre-Tx PDL1 was done. Efficacy was evaluated for the patients who had received 2 doses of pembrolizumab. Results: No DLT occurred in the dose-schedule escalation cohorts. 10 patients received 2 cycles of neo-adjuvant pembrolizumab. 4 patients achieved a MPR (4/10 who received 2 cycles of pembro; 40%; 95% C.I. 16.7-68.8%). No correlation is seen between the levels of PDL1 pre-Tx and the pathologic response. Size of the tumor and N status was also not in any apparent correlation with MPR (data not shown). Interestingly, all of the MPR cases had a relatively long interval from 1st Tx till surgery. Clinical trial information: NCT02938624. Conclusions: Neo-adjuvant pembro is safe and feasible. A promising sign of efficacy is seen. Achieving MPR might require a longer 1st-Tx-surgery interval. Predictive biomarkers for response might be different from those in advanced disease. Recruitment and correlative studies are ongoing.[Table: see text]

Atherosclerosis can be induced by the injection of a gain-of-function mutant of proprotein convertase subtilisin/kexin type 9 (PCSK9)–encoding adeno-associated viral vector (AAVmPCSK9), avoiding the need for knockout mice models, such as low-density lipoprotein receptor deficient mice. As regression of atherosclerosis is a crucial therapeutic goal, we aimed to establish a regression model based on AAVmPCSK9, which will eliminate the need for germ-line genetic modifications. C57BL6/J mice were injected with AAVmPCSK9 and were fed with Western diet for 16 weeks, followed by reversal of hyperlipidemia by a diet switch to chow and treatment with a microsomal triglyceride transfer protein inhibitor (MTPi). Sixteen weeks following AAVmPCSK9 injection, mice had advanced atherosclerotic lesions in the aortic root. Surprisingly, diet switch to chow alone reversed hyperlipidemia to near normal levels, and the addition of MTPi completely normalized hyperlipidemia. A six week reversal of hyperlipidemia, either by diet switch alone or by diet switch and MTPi treatment, was accompanied by regression of atherosclerosis as defined by a significant decrease of macrophages in the atherosclerotic plaques, compared to baseline. Thus, we have established an atherosclerosis regression model that is independent of the genetic background.