Amyloid-β aggregates activate peripheral monocytes in mild cognitive impairment

The peripheral immune system is important in neurodegenerative diseases, both in protecting and inflaming the brain, but the underlying mechanisms remain elusive. Alzheimer's Disease is commonly preceded by a prodromal period. Here, we report the presence of large Aβ aggregates in plasma from patients with mild cognitive impairment (n = 38). The aggregates are associated with low level Alzheimer's Disease-like brain pathology as observed by 11C-PiB PET and 18F-FTP PET and lowered CD18-rich monocytes. We characterize complement receptor 4 as a strong binder of amyloids and show Aβ aggregates are preferentially phagocytosed and stimulate lysosomal activity through this receptor in stem cell-derived microglia. KIM127 integrin activation in monocytes promotes size selective phagocytosis of Aβ. Hydrodynamic calculations suggest Aβ aggregates associate with vessel walls of the cortical capillaries. In turn, we hypothesize aggregates may provide an adhesion substrate for recruiting CD18-rich monocytes into the cortex. Our results support a role for complement receptor 4 in regulating amyloid homeostasis.

Monocyte phenotype and extracellular vesicles in HIV-1, HIV-2, and HIV-1/2 dual infection

OBJECTIVE

AIDS-defining illness develops at higher CD4 + T-cell counts in individuals infected with HIV-2 compared with HIV-1-infected, which suggests that the two types of HIV may have different effects on other compartments of the immune system. We here investigate monocyte phenotype, activation and macrophage-derived extracellular vesicles in individuals with different HIV types.

DESIGN

Cross-sectional.

METHODS

ART-naive HIV-1 ( n  = 83), HIV-2 ( n  = 63), and HIV-1/2 dually positive ( n  = 27) participants were recruited in Bissau, Guinea-Bissau, together with HIV-negative controls ( n  = 26). Peripheral blood mononuclear cells (PBMCs) were isolated and analyzed by flow cytometry for monocyte phenotype and activation, and plasma was analyzed for extracellular vesicle forms of CD163 and CD206.

RESULTS

Compared with HIV-negative controls, all groups of HIV-positive participants had a skewed monocyte phenotype with a higher proportion of intermediate monocytes, increased CD163 expression and elevated serum levels of the inflammatory biomarkers soluble (s)CD163 and sCD206. HIV-2-positive participants had lower CD163 monocyte expression than HIV-1-positive participants, regardless of HIV RNA or CD4 + cell count. Levels of sCD206 extracellular vesicles were increased in all HIV groups, and higher in HIV-1 compared with HIV-2-positive participants.

CONCLUSION

The monocyte phenotype of HIV-2-positive participants deviated less from healthy controls than did HIV-1 participants. HIV-2-positive participants also had a lower concentration of extracellular CD206 vesicles compared with HIV-1-positive participants. This does not explain the difference in AIDS development.

STAT3 is over-activated within CD163pos bone marrow macrophages in both Multiple Myeloma and the benign pre-condition MGUS

Tumour-associated macrophages (TAMs) support cancer cell survival and suppress anti-tumour immunity. Tumour infiltration by CD163^pos TAMs is associated with poor outcome in several human malignancies, including multiple myeloma (MM). Signal transducer and activator of transcription 3 (STAT3) is over-activated in human cancers, and specifically within TAMs activation of STAT3 may induce an immunosuppressive (M2-like) phenotype. Therefore, STAT3-inhibition in TAMs may be a future therapeutic strategy.We investigated TAM markers CD163, CD206, and activated STAT3 (pSTAT3) in patients with MGUS (n = 32) and MM (n = 45), as well as healthy controls (HCs, n = 13).Blood levels of the macrophage biomarkers sCD163 and sCD206, and circulating cytokines, as well as bone marrow mRNA expression of CD163 and CD206, were generally increased in MGUS and MM patients, compared to HCs, but to highly similar levels. By immunohistochemistry, bone marrow levels of pSTAT3 were increased specifically within CD163^pos cells in both MGUS and MM patients.In conclusion, macrophage-related inflammatory changes, including activation of STAT3, were present already at the MGUS stage, at similar levels as in MM. Specific increase in pSTAT3 levels within CD163^pos cells supports that the CD163 scavenger receptor may be a useful target for future delivery of STAT3-inhibitory drugs to TAMs in MM patients.

Expression of NK cell receptor ligands in primary colorectal cancer tissue in relation to the phenotype of circulating NK- and NKT cells, and clinical outcome

INTRODUCTION

Natural killer (NK) cells and natural killer T (NKT) cells are implicated in the development and progression of colorectal cancer (CRC). Tumor cells express NK cell receptor ligands that modulate their function. This study aimed to investigate the expression of such ligands in CRC in relation to the phenotype of circulating NK- and NKT cells, and clinical outcome.

METHODS

Primary tumor tissues were analyzed for protein expression of NK cell ligands using immunohistochemistry with automated image analysis in a cohort of 78 CRC patients. For 24 of the 78 patients, RNA expression of NK cell ligands was analyzed in primary tumor tissue using RNA sequencing. Receptor expression on circulating NK- and NKT cells was previously measured by us in 71 of the 78 patients using flow cytometry.

RESULTS

High Proliferating Cell Nuclear Antigen (PCNA) protein expression in the primary tumor associated with shorter disease-free survival (DFS) of CRC patients (P = 0.026). A trend was observed towards shorter DFS in CRC patients with above-median galectin-3 protein expression in the primary tumor (P = 0.055). High protein expression of galectin-3, CD1d, and human leukocyte antigen (HLA) class I, and high RNA expression of UL16-binding protein (ULBP)-1, -2, and -5, and HLA-E in the tumor tissue correlated with low expression of the corresponding receptors on circulating NK- or NKT cells (P < 0.05).

CONCLUSIONS

Galectin-3 and PCNA expression in the primary tumor may be prognostic biomarkers in CRC patients. Furthermore, our results suggest that NK cell receptor ligands expressed by tumor cells may modulate the phenotype of circulating NK- and NKT cells, and facilitate immune escape of metastasizing cells.

CD163 as a Biomarker in Colorectal Cancer: The Expression on Circulating Monocytes and Tumor-Associated Macrophages, and the Soluble Form in the Blood

The macrophage-associated molecule CD163 has been reported as a prognostic biomarker in different cancer types, but its role in colorectal cancer (CRC) is unclear. We studied CD163 in the tumor microenvironment and circulation of patients with CRC in relation to clinicopathological parameters. An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum sCD163 levels and multiparameter flow cytometry was used to study the peripheral blood monocytes and their CD163 expression in CRC patients (N = 78) and healthy donors (N = 50). The distribution of tumor-associated macrophages (TAMs) was studied in primary colorectal tumors with multiplex immunofluorescence. We showed that CRC patients with above-median sCD163 level had a shorter overall survival (OS, p = 0.035) as well as disease-free survival (DFS, p = 0.005). The above-median sCD163 remained significantly associated with a shorter DFS in the multivariate analysis (p = 0.049). Moreover, a shorter OS was observed in CRC patients with an above-median total monocyte percentage (p = 0.007). The number and phenotype of the stromal and intraepithelial TAMs in colorectal tumors were not associated with clinical outcome. In conclusion, sCD163 and monocytes in the circulation may be potential prognostic biomarkers in CRC patients, whereas TAMs in the tumor showed no association with clinical outcome. Thus, our results emphasize the importance of the innate systemic immune response in CRC disease progression.

The effects of tumor resection and adjuvant therapy on the peripheral blood immune cell profile in patients with colon carcinoma

OBJECTIVE

The subset distribution and immunophenotype of circulating immune cells ("peripheral blood immune cell profile") may reflect tumor development and response to cancer treatment. In order to use the peripheral blood immune cell profile as biomarker to monitor patients over time, it is crucial to know how immune cell subsets respond to therapeutic interventions. In this study, we investigated the effects of tumor resection and adjuvant therapy on the peripheral blood immune cell profile in patients with colon carcinoma (CC).

METHODS

The subset distribution and immunophenotype of T cells (CD3⁺CD56^-), CD56^dim NK cells (CD3^-CD56^dim), CD56^bright NK cells (CD3^-CD56^bright) and NKT-like cells (CD3⁺CD56⁺) were studied in preoperative and postoperative peripheral blood mononuclear cell (PBMC) samples of 24 patients with CC by multiparameter flow cytometry. Changes in immunophenotype of circulating immune cells after tumor resection were studied in patients treated with and without (capecitabine-based) adjuvant therapy.

RESULTS

The NKT-like cell (% of total PBMCs) and CD8⁺ T cell (% of total T cells) populations expanded in the peripheral blood of non-adjuvant-treated CC patients after surgery. NK- and NKT-like cells showed upregulation of activating receptors and downregulation of inhibitory receptors in non-adjuvant-treated CC patients after surgery. These changes were not observed in the peripheral blood of adjuvant-treated CC patients.

CONCLUSIONS

Our results suggest tumor-induced suppression of NK- and NKT-like cells in CC patients, an effect that could not be detected after tumor resection. In contrast, adjuvant therapy maintained tumor-induced immunosuppression of NK- and NKT-like cells in CC patients.

Circulating extracellular vesicle-associated CD163 and CD206 in multiple myeloma

OBJECTIVES

Extracellular vesicles (EVs) are important for intercellular signalling in cancer. Tumour-associated macrophages, expressing the haemoglobin-haptoglobin and mannose receptors CD163 and CD206, are crucial for cancer progression. We recently identified CD163 on EVs in the circulation as a fraction of total soluble CD163 (sCD163). Here, we investigated the presence of CD163 and CD206-positive EVs (EV-CD163, EV-CD206) in patients with multiple myeloma (MM).

METHODS

We enrolled patients with MM (n = 32), monoclonal gammopathy of undetermined significance (MGUS) (n = 8) and healthy donors (n = 16). Plasma protein levels were determined by ELISA before and after vesicle precipitation. Monocytes were examined by flow cytometry, and leucocyte CD163 mRNA by qPCR.

RESULTS

Fractions of EV-CD163 and EV-CD206 were significantly elevated in patients with newly diagnosed MM (median = 39.8%, 76.5%, respectively) compared to patients with relapse (15.6%, P = .02, 42.5%, P = .003), remission (16.9%, P < .0001, 25.2%, P < .0001), MGUS (17.8%, P < .01, 33.1%, P = .0005) and healthy donors (14.8%, P < .0001, 35.5%, P < .0001). Whole blood CD163 mRNA did not vary between the groups. The intermediate monocyte subset showed a higher CD163 expression in newly diagnosed patients.

CONCLUSIONS

Our results indicate that macrophage-derived EVs may play a role in the late phase of malignant progression of MM, and encourage further EV investigations in functional experiments.

Monocyte isolation techniques significantly impact the phenotype of both isolated monocytes and derived macrophages in vitro

Monocyte-derived macrophages (MDMs) generated from peripheral blood monocytes are widely used to model human macrophages for in vitro studies. However, the possible impact of different isolation methods on the resulting MDM phenotype is poorly described. We aimed to investigate the effects of three commonly used monocyte isolation techniques on the resulting MDM phenotype. Plastic adhesion, negative selection, and CD14^pos selection were compared. Monocyte-derived macrophages were generated by 5-day culture with macrophage and granulocyte-macrophage colony-stimulating factors. We investigated monocyte and MDM yields, purity, viability, and cell phenotype. CD14^pos selection resulted in highest monocyte yield (19·8 × 10⁶ cells, equivalent to 70% of total) and purity (98·7%), compared with negative selection (17·7 × 10⁶ cells, 61% of total, 85·0% purity), and plastic adhesion (6·1 × 10⁶ cells, 12·9% of total, 44·2% purity). Negatively selected monocytes were highly contaminated with platelets. Expression of CD163 and CD14 were significantly lower on CD14^pos selection and plastic adhesion monocytes, compared with untouched peripheral blood mononuclear cells. After maturation, CD14^pos selection also resulted in the highest MDM purity (98·2%) compared with negative selection (94·5%) and plastic adhesion (66·1%). Furthermore, MDMs from plastic adhesion were M1-skewed (CD80^high  HLA-DR^high  CD163^low ), whereas negative selection MDMs were M2-skewed (CD80^low  HLA-DR^low  CD163^high ). Choice of monocyte isolation method not only significantly affects yield and purity, but also impacts resulting phenotype of cultured MDMs. These differences may partly be explained by the presence of contaminating cells when using plastic adherence or negative selection. Careful considerations of monocyte isolation methods are important for designing in vitro assays on MDMs.

Responses to Cytokine Inhibitors Associated with Cellular Composition in Models of Immune-Mediated Inflammatory Arthritis

Objective

Immune‐mediated inflammatory arthritis (IMIA) is a heterogeneous group of diseases including rheumatoid arthritis (RA), psoriatic arthritis (PsA), and spondyloarthritis (SpA). Disease‐modifying antirheumatic drugs (DMARDs) target very different cellular components of the disease processes. Characterization of the pathobiological subtypes of IMIA could provide more specific treatment approaches for each disease. For example, RA has been proposed to consist of at least three synovial pathotypes (lymphoid, myeloid, and fibroid), and only a subgroup of RA patients have erosive disease. The objective of this study was to evaluate the effects of various DMARDs on different synovial cell subsets using human ex vivo models of IMIA.

Methods

Synovial fluid and blood samples were obtained from a study population consisting of patients with RA, PsA, or peripheral SpA with at least one swollen joint (n = 18). The DMARDs used in this study were methotrexate, adalimumab, etanercept, tocilizumab, anakinra, ustekinumab, secukinumab, tofacitinib, and baricitinib. Paired synovial fluid mononuclear cells (SFMCs), peripheral blood mononuclear cells (PBMCs), and fibroblast‐like synovial cells (FLSs) were used in three different previously optimized ex vivo models.

Results

In SFMCs cultured for 48 hours, all DMARDs except anakinra decreased the production of monocyte chemoattractant protein (MCP)‐1. In SFMCs cultured for 21 days, only the two tumor necrosis factor alpha (TNFα) inhibitors adalimumab and etanercept decreased the secretion of tartrate‐resistant acid phosphatase (P < 0.01, P < 0.001). In the FLS and PBMC 48‐hour co‐cultures, only tocilizumab (P < 0.001) and the two Janus kinase inhibitors tofacitinib and baricitinib (both P < 0.05) decreased the production of MCP‐1 by around 50%.

Conclusion

TNFα inhibition was effective in preventing inflammatory osteoclastogenesis, whereas tocilizumab, tofacitinib, and baricitinib had superior efficacy in cultures dominated by FLSs. Taken together, this study reveals that responses to cytokine inhibitors associate with cellular composition in models of IMIA. In particular, this study provides new evidence on the differential effect of DMARDs on leukocytes compared with stromal cells.

Soluble Macrophage Mannose Receptor (sCD206/sMR) as a Biomarker in Human Immunodeficiency Virus Infection

Macrophages play important roles during human immunodeficiency virus (HIV) infection, reflected by changes in macrophage-activation biomarker soluble CD163 (sCD163). Here, we present data on the novel macrophage-activation biomarker soluble mannose receptor/CD206 (sCD206) in HIV infection. We investigated sCD206 blood levels at baseline and follow-up with/without antiretroviral therapy (ART), in 212 patients with HIV type 1 (HIV-1), HIV type 2 (HIV-2), or dual infection. At baseline, there was no difference in sCD206 level between HIV types, and sCD206 was unchanged at follow-up without ART. However, in contrast to sCD163, sCD206 levels decreased significantly for both HIV-1 and HIV-2, but not for HIV-1/2 patients, during ART. Further investigations are needed to establish sCD206 as a biomarker in HIV infection.

Increased interleukin (IL)-20 and IL-24 target osteoblasts and synovial monocytes in spondyloarthritis

The pathogenesis of spondyloarthritis (SpA) involves activation of the innate immune system, inflammation and new bone formation. The two cytokines interleukin (IL)-20 and IL-24 have been shown to link innate immune activation and tissue homeostasis. We hypothesized that these two cytokines are secreted as part of activation of the innate immune system and affect bone homeostasis in SpA. IL-20 and IL-24 were measured in plasma from axial SpA patients (n = 83). Peripheral SpA patients (n = 16) were included for in-vitro cell culture studies. The plasma IL-20 and IL-24 levels were increased in SpA patients compared with healthy controls (HCs) by 57 and 83%, respectively (both P < 0·0001). The Toll-like receptor 4-induced secretion of the two cytokines was greater in SpA peripheral blood mononuclear cells (PBMCs) compared with HC PBMCs. IL-20 and IL-24 increased the production of monocyte chemoattractant protein-1 by activated SpA synovial fluid monocytes, decreased the production of Dickkopf-1 by SpA fibroblast-like synovial cells and induced mineralization in human osteoblasts. Taken together, our findings indicate disease-aggravating functions of IL-20 and IL-24 in SpA.

Soluble ectodomain CD163 and extracellular vesicle-associated CD163 are two differently regulated forms of 'soluble CD163' in plasma

CD163 is the macrophage receptor for uptake of hemoglobin-haptoglobin complexes. The human receptor can be shed from the macrophage surface owing to a cleavage site for the inflammation-inducible TACE/ADAM17 enzyme. Accordingly, plasma ‘soluble CD163’ (sCD163) has become a biomarker for macrophage activity and inflammation. The present study disclosed that 10% of sCD163 in healthy persons is actually extracellular vesicle (EV)-associated CD163 not being cleaved and shed. Endotoxin injection of human volunteers caused a selective increase in the ectodomain CD163, while septic patients exhibited high levels of both soluble ectodomain CD163 and extracellular vesicle (EV) CD163, the latter representing up 60% of total plasma CD163. A poor prognosis of septic patients measured as the sequential organ failure assessment (SOFA) score correlated with the increase in membrane-associated CD163. Our results show that soluble ectodomain CD163 and EV CD163 in plasma are part of separate macrophage response in the context of systemic inflammation. While that soluble ectodomain CD163 is released during the acute systemic inflammatory response, this is not the case for EV CD163 that instead may be released during a later phase of the inflammatory response. A separate measurement of the two forms of CD163 constituting ‘soluble CD163’ in plasma may therefore add to the diagnostic and prognostic value.

Monocyte/macrophage-derived soluble CD163: a novel biomarker in multiple myeloma

OBJECTIVES

Macrophages play an important role in cancer by suppression of adaptive immunity and promotion of angiogenesis and metastasis. Tumor-associated macrophages strongly express the hemoglobin scavenger receptor CD163, which can also be found as a soluble protein in serum and other body fluids (soluble CD163, sCD163). In this study, we examined serum sCD163 as a biomarker in patients with newly diagnosed multiple myeloma.

METHODS

Peripheral blood (n = 104) and bone marrow (n = 17) levels of sCD163 were measured using an enzyme-linked immunosorbent assay.

RESULTS

At diagnosis, high sCD163 was associated with higher stage according to the International Staging System (ISS) and with other known prognostic factors in multiple myeloma (creatinine, C-reactive protein, and beta-2 microglobulin). Soluble CD163 decreased upon high-dose treatment, and in a multivariate survival analysis including the covariates treatment modality and age at diagnosis, higher levels of sCD163 were associated with poor outcome (HR = 1.82; P = 0.010). The prognostic significance of sCD163 was lost when including ISS stage in the model (HR = 1.51; P = 0.085). Soluble CD163 values were significantly higher in bone marrow samples than in the matched blood samples, which indicate a localized production of sCD163 within the bone marrow microenvironment.

CONCLUSIONS

Soluble CD163 was found to be a prognostic marker in patients with multiple myeloma. This may indicate that macrophages and/or monocytes have an important role in the bone marrow microenvironment of myeloma patients, supporting myeloma cell proliferation and survival. We propose the serum sCD163 value 1.8 mg/L as a cutoff concentration for survival analysis in patients with multiple myeloma, which should be validated in future studies.

Factors that affect the outcome of peripheral arterial embolization

To find the factors that significantly affected prognosis in patients with peripheral arterial thromboembolism, we reviewed a 12-year experience at two hospitals. Sixty-one patients had 67 embolectomies. Operative treatment and management preserved the limbs in 75.8%. Mortality was 22.4%. Outcome was favorably affected when age was less than 60 years and when arteriosclerotic heart disease was absent, and was adversely affected when common femoral emboli were present and hematocrit level elevated. Duration of symptoms did not affect outcome. Our treatment of patients with peripheral embolism is based on the effect of certain intrinsic factors on the formation of distal thrombus. These factors may be more important than duration of symptoms. Immediate, complete heparinization is recommended to arrest thrombosis, and to allow both for proper emphasis on treatment on the often-associated cardiopathy and for attention to hydration and acid-base balance. This preoperative plan of therapy should produce maximal limb salvage with reduced operative mortality.

Coronary bypass in a patient with hemophilia B, or Christmas disease. Case report

A 40-year-old patient with moderate factor IX deficiency (Christmas disease) underwent quadruple saphenous vein coronary bypass grafts for angina and severe coronary atherosclerosis involving the left and right main, left anterior descending, and circumflex coronary arteries. Excessive bleeding was prevented by infusion of factor IX concentrates during and after the operation. The surgical procedure and total body perfusion were carried out in the same manner as in patients without a hemorrhagic disorder. The patient was discharged after 13 days of hospitalization. He is doing well at the time of this publication and has returned to work.

Bilateral atrial myxomas. Echocardiographic considerations

In this report we describe a patient with bilateral atrial myxomas, which were diagnosed preoperatively by echocardiography and angiography, and successfully removed. The excised tumor mass consisted of mobile right and left atrial myxomas connected by a common stalk which passed through the atrial septum, collectively resembling the shape of a dumbbell. Preoperative echocardiographic and angiographic observations were instrumental in planning the surgical approach, and correlated well with intraoperative findings and with the anatomic configuration of the intact pathologic specimen. Diagnostic aspects of echocardiography are emphasized as they relate to both isolated and bilaterally-occurring atrial myxomas.