Synovial fluid (SF)-derived monocyte-macrophage (MON-Mφ)-lineage cells in knee osteoarthritis (KOA) remain poorly understood. We analyzed SF samples from 420 patients with KOA with effusion. The MON-Mφ cells accounted for 47.4% (median; range 7.1%-94.4%) of CD45+ cells and consisted of four subpopulations that correlated with the distribution and activation of other immune cells. The most abundant subpopulation was that of inactive CD11b+CD14-CD16- myeloid dendritic cells (mDCs; cDC2), which exhibited low cytokine production, low T lymphocyte stimulation, and high migratory ability. Other major subpopulations included CD11b+CD14+CD16- monocyte-like cells and CD11b+CD14+CD16+ macrophages, which share a similar transcriptomic profile. A subpopulation of CD11b-CD14-CD16- mDCs (cDC1) was less common. A higher proportion of CD11b+CD14-CD16- mDCs was linked to early-stage KOA and mild joint pain. Dendritic cells were rarely present in KOA synovium. This study revealed the considerable complexity of SF-derived MON-Mφ subpopulations and highlighted the role of inactive mDCs in KOA.

• MeSH
• Osteoarthritis, Knee * pathology   metabolism   immunology   MeSH
• Cell Lineage MeSH
• Dendritic Cells * metabolism   immunology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Macrophages * metabolism   immunology   MeSH
• Monocytes * metabolism   immunology   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Synovial Fluid * metabolism   immunology   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Antiphospholipid syndrome (APS) is an autoimmune thrombophilia that is characterised by thrombosis and obstetric complications in the presence of antiphospholipid antibodies (aPL). Pregnancy complications remain a challenging problem for patients with APS, especially during the first trimester. Although natural killer (NK) cells constitute up to 70% of decidual lymphocytes during the first trimester, their contribution to early pregnancy loss in APS is largely unknown. We aimed to analyse whether aPL are able to recruit antibody-dependent cellular cytotoxicity (ADCC) of NK cells, with special emphasis on the differences in the effects of aPL containing anti-β2GPI domain 1 (anti-β2GPI-D1) antibodies (aPL+/D1+) and those that do not (aPL+/D1-). Our findings revealed a differential distribution of NK subsets in the presence of different aPL. Namely, aPL+/D1- IgGs increased CD56dim/CD16dim cells, while aPL+/D1 + IgGs increased the number of CD56bright/CD16dim cells. ADCC NK cell cytotoxicity was found to be higher in the presence of aPL+/D1- IgGs, as defined by an increased target cell death, degranulation and increased expression of CD11b, CD69 and NKG2D. Overall, our evidence showed that aPL are able to recruit ADCC, suggesting NK cells as candidate cells for APS-related obstetric complications.

• MeSH
• Antibodies, Antiphospholipid * MeSH
• Antiphospholipid Syndrome * complications   pathology   MeSH
• beta 2-Glycoprotein I MeSH
• Killer Cells, Natural * metabolism   MeSH
• Humans MeSH
• Pregnancy Trimester, First MeSH
• Pregnancy MeSH
• Check Tag
• Humans MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The fungal pathogen Candida albicans is linked to chronic brain diseases such as Alzheimer's disease (AD), but the molecular basis of brain anti-Candida immunity remains unknown. We show that C. albicans enters the mouse brain from the blood and induces two neuroimmune sensing mechanisms involving secreted aspartic proteinases (Saps) and candidalysin. Saps disrupt tight junction proteins of the blood-brain barrier (BBB) to permit fungal brain invasion. Saps also hydrolyze amyloid precursor protein (APP) into amyloid β (Aβ)-like peptides that bind to Toll-like receptor 4 (TLR4) and promote fungal killing in vitro while candidalysin engages the integrin CD11b (Mac-1) on microglia. Recognition of Aβ-like peptides and candidalysin promotes fungal clearance from the brain, and disruption of candidalysin recognition through CD11b markedly prolongs C. albicans cerebral mycosis. Thus, C. albicans is cleared from the brain through innate immune mechanisms involving Saps, Aβ, candidalysin, and CD11b.

• MeSH
• Alzheimer Disease metabolism   microbiology   MeSH
• Amyloid beta-Peptides metabolism   MeSH
• CD11b Antigen * metabolism   MeSH
• Candida albicans metabolism   MeSH
• Fungal Proteins metabolism   MeSH
• Microglia * metabolism   microbiology   MeSH
• Mycoses * genetics   metabolism   MeSH
• Mice MeSH
• Toll-Like Receptor 4 * metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

INTRODUCTION: Juvenile idiopathic arthritis (JIA), a clinically variable disease characterized by autoimmune arthritis, affects children, and its immunopathology remains elusive. Alterations in neutrophil biology play an important role in this disease. In the present study, we aimed to explore the features of low-density neutrophils (LDNs) in patients with JIA. METHODS: Gene expression of peripheral blood mononuclear cells (PBMCs) from children with distinct subtypes of JIA was analyzed by NanoString Immunology panel. Presence of LDNs was ascertained by flow cytometry and the release of neutrophil-associated products were analyzed by LUMINEX. RESULTS: LDNs were detected in patients' peripheral blood mononuclear cells (PBMCs) after density gradient centrifugation. Transcriptomic analysis of JIA PBMCs revealed that genes related to neutrophil degranulation were markedly upregulated. The number of LDNs and level of their degranulation products increased in patients' PBMCs and correlated with serum calprotectin, but not with disease activity, sedimentation rate and C-reactive protein (CRP) levels. The phenotypes of LDNs varied from those of normal-density neutrophils and healthy donor LDNs. Phenotypical analysis revealed LDNs are immature and primed population with decreased suppressive capacity. A negative correlation between surface proteins CD62L, CD66b, and CD11b and the number of inflamed joints/JADAS was established. CONCLUSION: Our results describe LDNs as primed, degranulated, immature cells with impaired suppressive activities. This work thus contributes to the increasing body of evidence that LDNs in JIA are altered and their role in the disease immunopathogenesis and possible clinical associations should be investigated further.

• MeSH
• Neutrophil Activation MeSH
• Child MeSH
• Arthritis, Juvenile * MeSH
• Leukocytes, Mononuclear MeSH
• Humans MeSH
• Neutrophils * MeSH
• Flow Cytometry MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

OBJECTIVE: An increase in the number of neutrophils (NEUs) has long been associated with infections in the knee joints; however, their impact on knee osteoarthritis (KOA) pathophysiology remains largely unexplored. DESIGN: This study compared the phenotypic and functional characteristics of synovial fluid (SF)-derived NEUs in KOA and knee infection (INF). RESULTS: KOA NEUs were characterised by a lower expression of CD11b, CD54, and CD64 and higher expression of CD62L, TLR2, and TLR4 compared with INF NEUs. Except for CCL2, lower levels of inflammatory mediators and proteases were detected in KOA SF than in INF SF. Functionally, KOA NEUs displayed increased reactive oxygen species production and phagocytic activity compared with INF NEUs. Moreover, KOA and INF NEUs differed in cell sizes, histological characteristics of the surrounding synovial tissues, and their effects on the endothelial cells assessed by human umbilical vein endothelial cells. When KOA patients were subdivided based on the SF NEU abundance, patients with high NEUs (10%-60%) were characterised by i) elevated SF protein levels of TNF-α, IL-1RA, MMP-9, sTREM-1, VILIP-1 and ii) lower CD54, CD64, TLR2 and TLR4 expression compared to patients with low NEUs (<10%). Analysis of paired SF samples suggests that low or high NEU percentages, respectively, persist throughout the course of disease. CONCLUSIONS: Our findings suggest that NEU may play a significant role in KOA pathophysiology. Further studies should explore the mechanisms that contribute to the increased number of NEUs in SF and the clinical consequences of neutrophilic phenotype in KOA.

• MeSH
• Osteoarthritis, Knee * MeSH
• Endothelial Cells metabolism   MeSH
• Phenotype MeSH
• Knee Joint pathology   MeSH
• Humans MeSH
• Neutrophils MeSH
• Synovial Fluid * metabolism   MeSH
• Toll-Like Receptor 2 metabolism   MeSH
• Toll-Like Receptor 4 metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Fractured bones can regenerate and restore their biological and mechanical properties to the state prior to the damage. In some cases, however, the treatment of fractures requires the use of supportive implants. For bone healing, three processes are essential: the inflammatory phase, the repair phase and the remodelling phase. A proper course of the first - inflammatory - stage is important to ensure a successful fracture healing process. In our study, we evaluated tissue samples immunohistochemically from the area surrounding the fractures of upper and lower limbs (bone tissue, soft tissue, and the implant-adhering tissue) for markers: CD11b, CD15, CD34, CD44, CD68, Cathepsin K, and TRAcP that are linked to the aforementioned phases. In soft tissue, higher expressions of CD68, CD34, CD15 and CD11b markers were observed than in other locations. TRAcP and Cathepsin K markers were more expressed in the bone tissue, while pigmentation, necrosis and calcification were more observed in the implant-adhering tissue. Since even the implant materials commonly perceived as inert elicit the observed inflammatory responses, new surface treatments and materials need to be developed.

• MeSH
• Lower Extremity MeSH
• Fracture Healing * MeSH
• Cathepsin K MeSH
• Bone and Bones * MeSH
• Tartrate-Resistant Acid Phosphatase MeSH
• Publication type
• Journal Article MeSH

The pertussis agent Bordetella pertussis produces a number of virulence factors, of which the filamentous hemagglutinin (FhaB) plays a role in B. pertussis adhesion to epithelial and phagocytic cells. Moreover, FhaB was recently found to play a crucial role in nasal cavity infection and B. pertussis transmission to new hosts. The 367 kDa FhaB protein translocates through an FhaC pore to the outer bacterial surface and is eventually processed to a ~220 kDa N-terminal FHA fragment by the SphB1 protease. A fraction of the mature FHA then remains associated with bacterial cell surface, while most of FHA is shed into the bacterial environment. Previously reported indirect evidence suggested that FHA, or its precursor FhaB, may bind the β2 integrin CD11b/CD18 of human macrophages. Therefore, we assessed FHA binding to various cells producing or lacking the integrin and show that purified mature FHA does not bind CD11b/CD18. Further results then revealed that the adhesion of B. pertussis to cells does not involve an interaction between the bacterial surface-associated FhaB and/or mature FHA and the β2 integrin CD11b/CD18. In contrast, FHA binding was strongly inhibited at micromolar concentrations of heparin, corroborating that the cell binding of FHA is ruled by the interaction of its heparin-binding domain with sulfated glycosaminoglycans on the cell surface.

• MeSH
• CD18 Antigens MeSH
• Bacterial Adhesion MeSH
• Adhesins, Bacterial metabolism   MeSH
• Bordetella pertussis * metabolism   MeSH
• Virulence Factors, Bordetella MeSH
• Glycosaminoglycans MeSH
• Hemagglutinins metabolism   MeSH
• Heparin MeSH
• Integrins MeSH
• Humans MeSH
• Macrophage-1 Antigen MeSH
• Whooping Cough * MeSH
• Peptide Hydrolases MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

OBJECTIVE: CD11b is an integrin molecule located on the surface of leukocytes. CD11b is involved in the processes of cell adhesion and migration. Expression of CD11b increases during inflammation. Therefore, this study was aimed at the evaluation of concentrations of CD11b in the amniotic fluid from pregnancies complicated by preterm prelabor rupture of the membranes (PPROM), with respect to the presence of microbial invasion of the amniotic cavity (MIAC), intra-amniotic inflammation (IAI), and microbial-associated IAI (the presence of both MIAC and IAI). METHODS: Eighty women with singleton pregnancies complicated by PPROM were included. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid CD11b concentrations were determined by enzyme-linked immunosorbent assay. MIAC was determined by a non-cultivation approach. IAI was defined by a bedside amniotic fluid interleukin-6 concentration ≥745 pg/mL. RESULT: Women with MIAC or microbial-associated IAI had higher CD11b concentrations in the amniotic fluid than women without these complications (with MIAC: median 0.31 ng/mL versus without MIAC: median 0.17 ng/mL, p = .001; with microbial associated-IAI: median 0.35 ng/mL versus without microbial-associated IAI: median 0.16 ng/mL; p =.02). The presence of IAI was not associated with elevated CD11b concentrations. A weak negative correlation was found between amniotic fluid CD11b concentrations and interleukin-6 concentrations (rho = 0.26; p = .02). CONCLUSIONS: MIAC and microbial-associated IAI are characterized by higher amniotic fluid CD11b concentrations in pregnancies complicated by PPROM.

• MeSH
• Amniocentesis MeSH
• Chorioamnionitis * metabolism   MeSH
• Gestational Age MeSH
• Humans MeSH
• Infant, Newborn MeSH
• Amniotic Fluid metabolism   MeSH
• Fetal Membranes, Premature Rupture * metabolism   MeSH
• Pregnancy MeSH
• Check Tag
• Humans MeSH
• Infant, Newborn MeSH
• Pregnancy MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

Acute megakaryoblastic leukemia (AMKL) is a rare and heterogeneous subtype of acute myeloid leukemia (AML). We evaluated the immunophenotypic profile of 72 AMKL and 114 non-AMKL AML patients using the EuroFlow AML panel. Univariate and multivariate/multidimensional analyses were performed to identify most relevant markers contributing to the diagnosis of AMKL. AMKL patients were subdivided into transient abnormal myelopoiesis (TAM), myeloid leukemia associated with Down syndrome (ML-DS), AML-not otherwise specified with megakaryocytic differentiation (NOS-AMKL), and AMKL-other patients (AML patients with other WHO classification but with flowcytometric features of megakaryocytic differentiation). Flowcytometric analysis showed good discrimination between AMKL and non-AMKL patients based on differential expression of, in particular, CD42a.CD61, CD41, CD42b, HLADR, CD15 and CD13. Combining CD42a.CD61 (positive) and CD13 (negative) resulted in a sensitivity of 71% and a specificity of 99%. Within AMKL patients, TAM and ML-DS patients showed higher frequencies of immature CD34+/CD117+ leukemic cells as compared to NOS-AMKL and AMKL-Other patients. In addition, ML-DS patients showed a significantly higher expression of CD33, CD11b, CD38 and CD7 as compared to the other three subgroups, allowing for good distinction of these patients. Overall, our data show that the EuroFlow AML panel allows for straightforward diagnosis of AMKL and that ML-DS is associated with a unique immunophenotypic profile.

• Publication type
• Journal Article MeSH

In health, commensal bacteria from oral biofilms stimulate polymorphonuclear neutrophil (PMN) recruitment in gingival sulci and the oral cavity. Oral PMN (oPMN) is short-lived cells with low prosurvival gene expression. In periodontitis, oPMN accumulates in higher numbers, has extended lifespan, and sustains nonresolving inflammation. We hypothesize that short- and long-chain free fatty acids (SCFAs and LCFAs) and lipid mediator resolvin E1 (RvE1) modulate host ability to control biofilms and resolve inflammation. Our objective was to measure oPMN surface expression of receptors FFAR2 (binds bacteria-derived SCFA), FFAR4 (binds LCFA, EPA, and DHA), and ERV1 (binds RvE1) in health and to assess sex differences. We included 20 periodontally healthy individuals aged 20-80 years (10 males, 10 females), who were asked to (1) answer a targeted health nutritional questionnaire and (2) provide an oral saline rinse. oPMN isolated by sequential filtration was labeled with fluorophore-conjugated antibodies against CD11b, CD14, CD16, CD66b, ERV1, FFAR2, and FFAR4 and analyzed by flow cytometry. Statistical analyses were the following: two-way ANOVA, Tukey's test, and Pearson's correlation. Oral rinses contained 80% oPMN of which 60% were ERV1+ and FFAR2+, and 10% FFAR4+, with no sex differences. Females had more oPMN ERV1 compared to males. Both sexes had higher ERV1 compared to FFAR2 and FFAR4. CD66b+CD16high oPMN expressed less ERV1 and FFAR2 compared to CD66b+CD16low. There were positive correlations between oPMN ERV1 and FFAR2 expression and between ERV1+ and FFAR2+ oPMN and fish intake. These findings will help to better understand how oral host and microbiome interactions maintain periodontal health.

• Publication type
• Journal Article MeSH