The "Intermediate" CD14 + CD16 + monocyte subpopulation plays a role in IVIG responsiveness of children with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute, self-limited febrile illness of unknown cause. Intravenous immunoglobulin (IVIG)-resistance are related to greater risk for permanent cardiac complications. We aimed to determine the correlation between monocytes and the phenotype of KD in relation to IVIG responsiveness in children.

MATERIALS AND METHODS

The study cohort included 62 patients who were diagnosed with KD, 20 non febrile healthy controls (NFC), and 15 other febrile controls (OFC). In all enrolled patients, blood was taken at least 4 times and laboratory tests were performed. In addition, subtypes of monocytes were characterized via flow cytometry.

RESULTS

The numbers of intermediate monocytes were significantly lower in IVIG-resistant group compared to IVIG-responsive group before IVIG infusion (p < 0.0001). After infusion, intermediate monocytes decreased in the responsive group, while a trend of increase was observed in the resistant group. Only intermediate monocytes were significant in logistic regression with adjusted OR of 0.001 and p value of 0.03.

CONCLUSIONS

CD14 + CD16 + intermediate monocyte may play an important role in IVIG responsiveness among KD children. Low starting levels of intermediate monocytes, followed by a dramatic increase post-IVIG infusion during acute phase of KD are associated with IVIG-resistance. Functional studies on intermediate monocyte may help to reveal the pathophysiology.

Early decrease in intermediate monocytes in peripheral blood is characteristic of multiple system atrophy-cerebellar type

To identify biomarkers for multiple system atrophy-cerebellar type (MSA-C), we used flow cytometry to measure surface marker expression of peripheral blood monocytes from patients with MSA-C or hereditary spinocerebellar degeneration (hSCD) and from healthy controls (HCs). The percentage of intermediate monocytes was significantly lower in MSA-C patients than in hSCD patients and HCs and showed significant positive correlations with disease duration and unified MSA rating scale scores. The percentage of CD62L⁺ intermediate monocytes was significantly lower in MSA-C patients than in hSCD patients and HCs. Early decrease of peripheral blood intermediate monocytes is characteristic of MSA-C and is a biomarker.

Longitudinal immune cell monitoring identified CD14++ CD16+ intermediate monocyte as a marker of relapse in patients with ANCA-associated vasculitis

Background

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease that affects small- to medium-sized blood vessels. Despite treatments having been improved, patients often experience disease relapses. It remains unclear how the immune cells involve in the development of vasculitis and how they fluctuate over the course of treatment. In this study, we aimed to identify the immune subsets and serum cytokines associated with disease relapse by comprehensive immuno-phenotyping in AAV patients.

Methods

We reviewed consecutive patients (n = 29) from Keio University Hospital who had been newly diagnosed with AAV from January 2015 to February 2019 and chronologically followed until 52 weeks. Numbers of circulating T cells, B cells, monocytes, and granulocytes were analyzed by flow cytometry (FACS). Serum levels of cytokines were measured by electrochemiluminescence enzyme immunoassay. Clinical information was obtained from patients’ records and association with time-course changes in immuno-phenotypes and serum levels of cytokines were assessed.

Results

Comprehensive immuno-phenotyping data from 161 samples from 29 AAV patients at diagnosis; at weeks 4, 12, 24, and 52 of treatment; and at time of major relapse were examined. FACS analysis from patients with relapse revealed that CD14⁺⁺ CD16⁺ intermediate monocytes and plasma cells concomitantly changed associated with disease relapse, which were independent from treatment regimen, ANCA status, or disease phenotype. In particular, the number of CD14⁺⁺ CD16⁺ intermediate monocytes at relapse was significantly higher than that in remission or in healthy controls. Serum cytokine measurement revealed that changes of monocyte-derived proinflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α were associated with disease status.

Conclusions

Chronological changes in CD14⁺⁺ CD16⁺ intermediate monocyte counts can be a marker of disease relapse in AAV patients.

Relationship between Circulating Inflammatory Monocytes and Cardiovascular Disease Measures of Carotid Intimal Thickness

Aims: Cardiovascular disease (CVD) remains the leading cause of death worldwide despite improvements in the treatment of atherosclerosis, an inflammatory disease and major underlying cause of CVD. Monocytes, an innate immune cell type, are linked to CVD progression; however, given their heterogeneity, the association between distinct monocyte subsets and increased risk of CVD remains unclear. This study investigated the association between peripheral monocyte subpopulation numbers and carotid intima-media thickness (cIMT), a sensitive measure of CVD risk, in a cohort of adults recruited from the general population.

Methods: We used clinical data and peripheral blood mononuclear cell (PBMC) specimens from 67 individuals. cIMT was measured by high-resolution, B-mode, ultrasound images of the right carotid artery. PBMCs were stained with conjugated monoclonal antibodies to define monocyte subpopulations based on CD14 and CD16 co-expressions into classical (CD14⁺⁺CD16⁻), intermediate/inflammatory (CD14⁺⁺CD16⁺), and non-classical/patrolling (CD14^low/+CD16⁺⁺) monocytes.

Results: We found a higher intermediate monocyte count was significantly correlated with increased right common carotid artery (RCCA) and right carotid bifurcation (RBIF) intima-media thickness (IMT) (p = 0.004 and 0.006, respectively), even after adjusting for CVD-associated clinical data (p = 0.006 and 0.004, respectively).

Conclusion: Our study demonstrated a strong correlation between inflammatory monocyte counts and cIMT. These results suggest that, in the general population, there is a relationship between intermediate monocyte expansion and elevated predictors for CVD risk, and intermediate monocytes may be involved in the development of atherosclerosis and metabolic diseases. Strategies targeting inflammatory monocytes may be needed to slow CVD progression.

High-intensity interval training reduces monocyte activation in obese adults

Alterations in the distribution and activation of monocyte subsets are frequently observed in individuals with obesity and their participation in the pathological complications of obesity is proposed. High-intensity interval training (HIIT) can be a time-efficient alternative to counteract the inflammatory outcomes of obesity, but so far, its effects on monocytes in obesity has not been fully explored. In this study, we investigated whether 8 weeks of HIIT can modify the distribution and activation of the three monocyte subsets (classical, intermediate and non-classical monocytes) in individuals with obesity. Our data show that individuals with obesity have a higher percentage of non-classical monocytes compared to control, lean individuals, and consequently an imbalance among the CD16⁺ monocyte subsets. Also, the expression of HLA-DR by intermediate monocytes is higher in insulin-resistant obese individuals, which indicates monocyte activation in obesity. After 8 weeks of HIIT, the percentage of non-classical monocytes was reduced in individuals with obesity, restoring the balance among the CD16⁺ monocytes. Also, the expression of HLA-DR by intermediate monocytes in insulin-resistant obese subjects was lower after HIIT. Both findings indicate that monocyte activation in individuals with obesity was reduced by HIIT. These modifications were observed in the absence of changes in weight and body composition, although they were accompanied by the improvement in the metabolic status (reduced insulin levels). Our findings indicate that HIIT can be considered a time-efficient strategy to manage obesity-related monocyte alterations and strengthen the immunomodulatory potential of HIIT.

Monocytes in rheumatoid arthritis: Circulating precursors of macrophages and osteoclasts and, their heterogeneity and plasticity role in RA pathogenesis

Rheumatoid arthritis (RA) is a chronic systemic, autoimmune and inflammatory disease represented as synovitis, pannus formation, adjacent bone erosions, and joint destruction. The major cells involved in the perpetuation of RA pathogenesis are CD4⁺ T-cells (mainly Th1 cells and Th17 cells), fibroblasts like synoviocytes (FLS), macrophages and B cells. Other autoimmune cells such as dendritic cells, neutrophils, mast cells, and monocytes also contribute to RA pathogenesis. Monocytes are mainly bone marrow (BM) derived cells in the circulation. The chemokine receptors CCR2 and CX3CR1 expressed by monocytes interact with chemokine ligands CCL2 (MCP-1) and CX3CL1 (fractalkine) respectively produced by FLS and this interaction promotes their migration and recruitment into RA synovium. Activated monocytes on their surface exhibit upregulated antigenic expressions such as CD14, CD16, HLA-DR, toll-like receptors (TLRs), and adhesion molecules B1 and B2 integrins. RA monocytes interconnect with other cells in a positive loop manner in the propagation of the rheumatoid process. They skew towards mainly intermediate monocyte subsets (CD14⁺⁺ CD16⁺) which produce proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. Moreover, the predominant intermediate monocytes in RA differentiate into M1-macrophages which play a major role in synovial inflammation. Demonstrations suggest monocytes with CD14⁺ and CD16^- expression (classical monocytes?) differentiate to osteoclasts which are the cells responsible for bone erosion in RA synovial joints. Th17 cells induce the production of RANKL by FLS which promotes osteoclastogenesis. Cytokines mainly TNF-α, IL-1β, and IL-6 amplify osteoclastogenesis. Hence, monocytes are the circulating precursors of macrophages and osteoclasts in RA. AIM OF THE REVIEW: To enlighten the identity of monocytes, the antigenic expression on monocyte surface and their cytokines role in RA. We also emphasize about the chemokine receptors expressed by monocytes subsets and chemotaxis of circulating monocytes into RA synovium. Additionally, we review monocytes as the circulating precursors of macrophages and osteoclasts in RA joints and their heterogeneity and plasticity role in RA.