NK cell receptor modulation in viral infections.

Natural killer (NK) cells play a crucial role in controlling viral infections. The ability to kill infected cells without prior immunization, yet being tolerant to self, healthy cells, depends on the balance of germ-line encoded surface receptors. NK cell receptors are divided to either activating, leading to activation of NK cell and its cytotoxic and pro-inflammatory activity, or inhibitory, providing tolerance for a target cell. The signals from inhibitory receptors dominate and NK cell activation requires stimulation of activating receptors. In viral infections, NK cell interaction with infected cell can result in activation, memory-like NK cell differentiation or NK cell exhaustion, which constitutes one of the viral immune evasion mechanisms. All of these states are associated with the modulation of NK cell receptor expression. In this review, we summarize the current knowledge of NK cell receptors and their role in viral infection control, as well as the alterations of their expression observed in acute or chronic infections. We present recently discovered SARS-CoV-2-mediated modulation of NK cell receptor expression and compare them with other human viral infections. Finally, since modulation of NK cell receptor activation gives promising addition to currently used antiviral therapies, we briefly discuss the clinical significance and future perspective of application of agonists or antagonists of activating and inhibitory receptors, respectively. In sum, our review shows that although much is known about NK cell receptor biology, a deeper understanding of NK cell receptors role in viral infections is still needed.

Gene Signature of Regulatory T Cells Isolated from Children with Selective IgA Deficiency and Common Variable Immunodeficiency.

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (Tregs) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of Treg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of Treg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of Treg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of Treg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of Treg dysfunctions in patients with common PIDs and associated autoimmunity.

Clinical and experimental treatment of primary humoral immunodeficiencies.

Selective IgA deficiency (sIgAD), common variable immunodeficiency (CVID), and transient hypogammaglobulinemia of infancy (THI) are the most frequent forms of primary antibody deficiencies. Difficulties in initial diagnosis, especially in the early childhood, the familiar occurrence of these diseases, as well as the possibility of progression to each other suggest common cellular and molecular patomechanism and a similar genetic background. In this review, we discuss both similarities and differences of these three humoral immunodeficiencies, focusing on current and novel therapeutic approaches. We summarize immunoglobulin substitution, antibiotic prophylaxis, treatment of autoimmune diseases, and other common complications, i.e. cytopenias, gastrointestinal complications, and granulomatous disease. We discuss novel therapeutic approaches such as allogenic stem cell transplantation and therapies targeting-specific proteins, dependent on the patient's genetic defect. The diversity of possible therapeutics models results from a great heterogeneity of the disease variants, implying the need of personalized medicine approach as a future of primary humoral immunodeficiencies treatment.

Transcriptome profiling of regulatory T cells from children with transient hypogammaglobulinemia of infancy.

Transient hypogammaglobulinemia of infancy (THI) is one of the most common forms of hypogammaglobulinemia in the early childhood. THI is usually associated with chronic, recurrent bacterial and viral infections, life-threatening in some cases, yet its pathogenesis is still largely unknown. As our previous findings indicated the possible role of Treg cells in the pathomechanism of THI, the aim of the current study was to investigate gene expression profile of Treg cells isolated from THI patients. The transcriptome-wide gene profiling was performed using microarray technology on THI patients in two time-points: during (THI-1), and in resolution phase (THI-2) of hypogammaglobulinemia. As a result, a total of 1086 genes were differentially expressed in THI-1 patients, when compared to THI-2 as well as control group. Among them, 931 were up- and 155 downregulated, and part of them encodes genes important for Treg lymphocyte biology and function, i.e. transcription factors/cofactors that regulate FOXP3 expression. Thus, we postulate that Treg cells isolated from THI patients during hypogammaglobulinemia display enhanced suppressor transcriptome signature. Treg expression profile of THI children after normalization of Ig levels largely resembles the results obtained in healthy control group, suggesting THI Treg transcriptome seems to return to that observed in healthy children. Taken together, we suggest that THI pathomechanism is associated not only with transiently elevated Treg cell numbers, but also with their enhanced regulatory/inhibitory functions. These findings expand our knowledge of human Treg cells and may be useful for the future diagnosis or management of THI.

Monocyte subpopulations display disease-specific miRNA signatures depending on the subform of Spondyloarthropathy.

Spondyloarthropathies (SpA) are a family of rheumatic disorders that could be divided into axial (axSpA) and peripheral (perSpA) sub-forms depending on the disease clinical presentation. The chronic inflammation is believed to be driven by innate immune cells such as monocytes, rather than self-reactive cells of adaptive immune system. The aim of the study was to investigate the micro-RNA (miRNA) profiles in monocyte subpopulations (classical, intermediate and non-classical subpopulations) acquired from SpA patients or healthy individuals in search for prospective disease specific and/or disease subtype differentiating miRNA markers. Several SpA-specific and axSpA/perSpA differentiating miRNAs have been identified that appear to be characteristic for specific monocyte subpopulation. For classical monocytes, upregulation of miR-567 and miR-943 was found to be SpA-specific, whereas downregulation of miR-1262 could serve as axSpA-differentiating, and the expression pattern of miR-23a, miR-34c, mi-591 and miR-630 as perSpA-differentiating markers. For intermediate monocytes, expression levels of miR-103, miR-125b, miR-140, miR-374, miR-376c and miR-1249 could be used to distinguish SpA patients from healthy donors, whereas the expression pattern of miR-155 was identified as characteristic for perSpA. For non-classical monocytes, differential expression of miR-195 was recognized as general SpA indicator, while upregulation of miR-454 and miR-487b could serve as axSpA-differentiating, and miR-1291 as perSpA-differentiating markers. Our data indicate for the first time that in different SpA subtypes, monocyte subpopulations bear disease-specific miRNA signatures that could be relevant for SpA diagnosis/differentiation process and may help to understand SpA etiopathology in the context of already known functions of monocyte subpopulations.

Transcriptional Response of Blood Mononuclear Cells from Patients with Inflammatory and Autoimmune Disorders Exposed to "Krakow Smog".

Despite the general awareness of the need to reduce air pollution, the efforts were undertaken in Poland to eliminate the pollutants and their harmful effect on human health seem to be insufficient. Moreover, the latest data indicate that the city of Krakow is at the forefront of the most polluted cities worldwide. Hence, in this report, we investigated the impact of particulate matter isolated from the air of Krakow (PM KRK) on the gene expression profile of peripheral blood mononuclear cells (PBMCs) in healthy donors (HD) and patients with atherosclerosis (AS), rheumatoid arthritis (RA) and multiple sclerosis (MS), after in vitro exposure. Blood samples were collected in two seasons, differing in the concentration of PM in the air (below or above a daily limit of 50 µg/m3 for PM 10). Data show that PBMCs exposed in vitro to PM KRK upregulated the expression of genes involved, among others, in pro-inflammatory response, cell motility, and regulation of cell metabolism. The transcriptional effects were observed predominantly in the group of patients with AS and MS. The observed changes seem to be dependent on the seasonal concentration of PM in the air of Krakow and may suggest their important role in the progression of AS, MS, and RA in the residents of Krakow.

Novel IL2RG Gene Mutation in One of Dizygotic Twins Causing Profound Changes of Receptor Structure.

In this study, we report a 4-month-old boy with T-B+NK- severe combined immunodeficiency (SCID) due to a novel mutation in exon 2 of IL2RG, the gene encoding the interleukin (IL) common gamma chain (γc) of the cytokine receptors for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. The patient was born from a twin pregnancy. He manifested recurrent infections of the gastrointestinal tract, whereas his twin brother was asymptomatic with no immune defects. In order to evaluate the effect of this unreported variant on the protein structure, a structural modeling process was performed showing prominent biochemical alterations of the protein features, including molecular weight, isoelectric charge, and possible changes to its secondary and tertiary structure.

Inflammasome function in monocyte subsets and a risk of late-onset sepsis in preterm very low birth weight neonates.

BACKGROUND: Immature immune systems predispose very low birth weight (VLBW) neonates to systemic infections in early life. Defective inflammasome function may increase a neonate's susceptibility to late-onset sepsis (LOS). METHODS: Blood samples were taken on the 5th day of life (DOL) for all VLBW neonates (non-LOS and before-LOS groups; N.=76), and within 24 hours of sepsis onset (LOS group; N.=39). Monocyte (MO) subsets and intracellular interleukin-1ß (IL-1ß) expression were analyzed using flow cytometry. Inflammasome function, defined as level of IL-1ß and interleukin-18 (IL-18) was measured with enzyme-linked immunosorbent assay. IRA B cells were reported as a fraction of all B cells. RESULTS: Stimulation of classical MO in non-LOS cells demonstrated a higher expression of intracellular IL-1ß in comparison to MO from before LOS group. Serum from the LOS group revealed a higher level of IL-18. Stimulation of mononuclear cultures from samples taken during LOS resulted in significantly increased supernatant level of IL-1ß and IL-18 in comparison to samples taken on 5th DOL. No changes in the levels of IRA B cells were detected with the onset of sepsis. CONCLUSIONS: We did not observe a difference in the functioning of the inflammasome within monocytes taken on 5th DOL from premature VLBW neonates. Furthermore, there was no observable change in the IRA B cells of the septic and non-septic groups. The decreased expression of intracellular IL-1ß within classical MO of the before-LOS group may be an independent risk factor for LOS development.

Expression of VEGFA-mRNA in classical and MSX2-mRNA in non-classical monocytes in patients with spondyloarthritis is associated with peripheral arthritis.

Spondyloarthritis (SpA) is characterized by chronic inflammation and structural damage involving spine and peripheral joints. Monocytes, as part of innate immune system, following migration into affected tissue, may play a role in the pathogenesis of SpA. Here, potential associations between osteogenesis-linked gene expression profile in particular monocyte subpopulations and clinical signs of SpA were investigated. The 20 patients with axial and 16 with peripheral SpA were enrolled in the study. Monocyte subpopulations (classical-CD14++CD16-, intermediate-CD14++CD16+ and non-classical-CD14+CD16++) were isolated from blood using flow cytometry and gene expression analysis was performed using real-time PCR method and TaqMan Array, Human Osteogenesis, Fast 96-well plates. Next, the characteristic clinical features shared by axial and peripheral SpA were analyzed in the context of the expression of selected genes in the three subpopulations of monocytes. We demonstrated that expression of VEGFA in classical and MSX2 in non-classical monocytes were associated with the number of swollen and painful peripheral joints of SpA patients. We conclude that monocytes may contribute to the development of peripheral arthritis in SpA patients. This might be possible through subpopulation specific effects, linking number of inflamed joints with expression of VEGFA in classical monocytes and MSX2 in non-classical monocytes.

Selective downregulation of natural killer activating receptors on NK cells and upregulation of PD-1 expression on T cells in children with severe and/or recurrent Herpes simplex virus infections.

Severe, recurrent or atypical Herpes simplex virus (HSV) infections are still posing clinical and diagnostic problem in clinical immunology facilities. However, the molecular background of this disorder is still unclear. The aim of this study was to investigate the expression of activating receptors on NK cells (CD16, NKp46, NKG2D, NKp80, 2B4, CD48 and NTB-A) and checkpoint molecule PD-1 on T lymphocytes and NK cells, in patients with severe and/or recurrent infections with HSV and age-matched healthy control subjects. As a result, we noticed that patients with severe and/or recurrent infection with HSV had significantly lower percentage of CD16brightCD56dim and higher percentage of CD16dimCD56bright NK cell subsets, when compared to control subjects, which may be associated with abnormal NK cell maturation during chronic HSV infection. Patients had also significantly downregulated expression of CD16 receptor on CD16bright NK cells. The expression of activating receptors was significantly reduced on patients' NK cells - either both the percentage of NK cells expressing the receptor and MFI of its expression (NKp46, NKp80 and 2B4 on CD16brightCD56dim cells and NKp46 on CD16dimCD56bright cells) or only MFI (NKG2D on both NK cell subsets). It should be noted that the reduction of receptor expression was limited to NK cells, since there was no differences in the percentage of receptor-positive cells or MFI on T cells. However, NTB-A receptor was the only one which expression was not only simultaneously changed in patients' NK and T cells, but also significantly upregulated on CD16dimCD56bright NK cell and CD8+ cell subsets. Patients had also upregulated proportion of CD4+ T cells expressing PD-1. Thus, we suggest that an increased percentage of PD-1+ cells may represent an independent indirect mechanism of downregulation of antiviral response, separate from the reduction of NK cell activating receptors expression. Altogether, our studies indicate two possible mechanisms which may promote perpetuation of HSV infection: 1) selective inhibition of activating receptors on NK cells, but not on T cells, and 2) upregulation of checkpoint molecule PD-1 on CD4+ T cells.

miRNA Regulation of NK Cells Antiviral Response in Children With Severe and/or Recurrent Herpes Simplex Virus Infections.

Severe and/or recurrent infection with Herpes simplex virus (HSV) is observed in a large group of patients treated in clinical immunology facilities. Atypical and prolonged HSV infection is the most common clinical manifestation of disturbed NK cell development and functions, yet the molecular basis of these disorders is still largely unknown. Since recent findings indicated the importance of miRNA in regulating NK cell development, maturation and functions, the aim of our study was to investigate miRNA expression pattern in NK cells in patients with severe and/or recurrent infections with HSV and analyze the role of these miRNAs in NK cell antiviral response. As a result, miRNA expression pattern analysis of human best known 754 miRNAs revealed that patients with severe and/or recurrent HSV infection had substantially upregulated expression of four miRNAs: miR-27b, miR-199b, miR-369-3p and miR-491-3p, when compared to healthy controls. Selective inhibition of miR-27b, miR-199b, miR-369-3p and miR-491-3p expression in NK-92 cells resulted in profound upregulation of 4 genes (APOBEC3G, MAP2K3, MAVS and TLR7) and downregulation of 36 genes taking part in antiviral response or associated with signaling pathways of Toll-like receptors (TLR), NOD-like receptors, the retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) and type I IFN-related response. Additionally, flow cytometry analysis revealed that miR-369-3p and miR-491-3p inhibitors downregulated NK cell intracellular perforin expression, while the expression of granzyme B and IFNγ remained unchanged. Taken together, our study suggests a novel mechanism which may promote recurrence and severity of HSV infection, based on miRNAs-dependent posttranscriptional regulation of genes taking part in antiviral response of human NK cells.

T Regulatory CD4+CD25+FoxP3+ Lymphocytes in the Peripheral Blood of Left-Sided Colorectal Cancer Patients.

Background and objectives: T regulatory lymphocytes (Treg) are one of the subsets of T-lymphocytes involved in the interaction of neoplastic tumors and the host immune system, and they may impair the immune reaction against cancer. It has been shown that Treg are increased in the peripheral blood of patients with various cancers. In colorectal cancer, the prognostic role of Treg remains controversial. Colorectal cancer is a heterogenous disease, with many variations stemming from its primary tumor location. The aim of this study is to analyse the relationship between the amount of Treg in the peripheral blood of patients with left-sided colorectal cancer in various stages of disease and long-term survival. Materials and Methods: A prospective analysis of 94 patients with left-sided colorectal cancer and a group of 21 healthy volunteers was carried out. Treg levels in peripheral blood were analysed using flow cytometry. Results: There was a statistically significant difference between the amount of Treg in the Ist and IInd TNM stages (p = 0.047). The number of Treg in the entire study group was significantly lower than in the control group (p = 0.008) and between patients in stages II and III and the control group (p = 0.003 and p = 0.018). The group of pT3+pT4 patients also had significantly lower Treg counts in their peripheral blood than the control group (p = 0.005). In the entire study group, the level of Treg cells in the peripheral blood had no influence on survival. The analysis of the TNM stage subgroups also showed no difference in survival between patients with "low" and "high" Treg counts. Conclusion: The absolute number of Treg in the peripheral blood of patients with left-sided colorectal cancer was significantly decreased in comparison to healthy controls, especially for patients with stage II+III disease. Treg presence in the peripheral blood had no impact on survival.

Sera of patients with axial spondyloarthritis (axSpA) enhance osteoclastogenic potential of monocytes isolated from healthy individuals.

BACKGROUND: Axial spondyloarthritis (axSpA) is characterized by significant bone loss caused by dysregulation of physiological bone turnover, possibly resulting from intensified differentiation of osteoclasts. The aim of this study was to reevaluate the levels of osteoclastogenesis-mediating factors: soluble RANKL, M-CSF, OPG and other cytokines in sera of untreated, with sDMARDs and/or bDMARDs, axSpA patients and to test whether these sera influence differentiation of healthy monocytes towards osteoclast lineage. METHODS: Bone remodeling molecules (RANKL, M-CSF, OPG, IL-6, OSM, IL-17A, TGFß, and TNFα) were evaluated in 27 patients with axSpA and 23 age and sex-matched controls. Disease activity (BASDAI, ASDAS) and inflammatory markers (ESR, CRP) were assessed. Monocytes obtained from healthy individuals were cultured in vitro in presence of sera from 11 randomly chosen axSpA patients and 10 controls, with addition of exogenous M-CSF and/or RANKL or without. Osteoclastic differentiation was assessed analyzing osteoclast markers (cathepsin K and RANK at mRNA level) and with osteoclast-specific staining. RESULTS: axSpA patients' sera levels of soluble RANKL were significantly lower and M-CSF, IL-6, OSM, IL-17A and TNFα significantly higher in comparison to controls, whereas of OPG and TGFß were comparable in both groups. Numbers of generated in vitro osteoclasts and cathepsin K mRNA levels did not differ between cultures supplemented with sera of healthy and axSpA patients, both in the absence and presence of M-CSF. Instead, addition of exogenous RANKL boosted osteoclastogenesis, which was significantly higher in cultures with axSpA sera. Furthermore, sera from axSpA patients induced substantially higher levels of RANK mRNA, independently of M-CSF and RANKL stimulation. CONCLUSION: We show that, paradoxically, serum levels of soluble RANKL observed in axSpA are in fact significantly lower in comparison to healthy blood donors. Our results indicate that sera of axSpA patients - in contrary to healthy subjects - contain circulating, soluble factors (presumably IL-6, OSM, IL-17A, TNFα and others) able to stimulate healthy monocytes responsiveness to even relative low RANKL serum levels, by inducing high RANK mRNA expression and - as a net effect - boosting their osteoclastogenic potential. We suggest also that locally produced RANKL in axSpA may induce overactive osteoclasts from their precursors.

Neurodegenerative changes detected by neuroimaging in a patient with contiguous X-chromosome deletion syndrome encompassing BTK and TIMM8A genes.

INTRODUCTION: In this study we describe a patient with gross deletion containing the BTK and TIMM8A genes. Mutations in these genes are responsible for X-linked agammaglobulinemia and Mohr-Tranebjaerg syndrome, respectively. X linked agammaglobulinemia is a rare primary immunodeficiency characterized by low levels of B lymphocytes and recurrent microbial infections, whereas, Mohr-Tranebjaerg syndrome is a progressive neurodegenerative disorder with early onset of sensorineural deafness. MATERIAL AND METHODS: For neuroimaging, the magnetic resonance imaging and magnetic resonance spectroscopy of the brain were performed. Microarray analysis was performed to establish the extent of deletion. RESULTS: The first clinical symptoms observed in our patient at the age of 6 months were connected with primary humoral immunodeficiency, whereas clinical signs of MTS emerged in the third year of live. Interestingly, the loss of speech ability was not accompanied by hearing failure. Neuroimaging of the brain suggested leukodystrophy. Molecular tests revealed contiguous X-chromosome deletion syndrome encompassing BTK (from exons 6 through 19) and TIMM8A genes. The loss of the patient's DNA fragment was accurately localized from 100 601 727 to 100 617 576 bp on chromosome's loci Xq22.1. CONCLUSIONS: We diagnosed XLA-MTS in the first Polish patient on the basis of particular molecular methods. We detected neurodegenerative changes in MRI and MR spectroscopy in this patient. Our results provide further insight into this rare syndrome.

The level of myeloid-derived suppressor cells positively correlates with regulatory T cells in the blood of children with transient hypogammaglobulinaemia of infancy.

INTRODUCTION: Transient hypogammaglobulinaemia of infancy (THI) is a primary immunodeficiency characterised by low levels of immunoglobulin G (often with concomitant decrease of IgA and sometimes also of IgM) with still unknown exact reason. A delayed normalisation of the immunoglobulin level in THI may be associated with a transiently elevated number of regulatory T cells (Treg). Although in cancer and chronic inflammation it was shown that the level of Treg cells can be increased by myeloid-derived suppressor cells (MDSCs), until now no studies have been performed in the context of the role of MDSCs in THI and their correlation with Treg cells. Consequently, we aimed to determine the occurrence of MDSCs in the peripheral blood of children with THI and correlate their level with the level of Treg cells. MATERIAL AND METHODS: Flow cytometry analyses of Mo-MDSCs and Gr-MDSCs, characterised as HLA-DR-CD11b+CD15-CD14+ and HLA-DR-CD11b+CD15+CD14-, respectively, and Treg (CD4+CD25+Foxp3+) cells were performed. RESULTS: The proportion of Mo-MDSCs and Gr-MDSCs was significantly higher in the group of THI patients with elevated level of Treg cells (from the 95% confidence interval level of healthy controls). The cells with Mo-MDSC and Gr-MDSC characteristics positively correlated with the level of Treg cells. Moreover, children with a higher proportion of circulating Treg cells, and thereby higher level of MDSCs, showed delayed normalisation of IgG level and recovery. CONCLUSIONS: These findings show for the first time that MDSCs may be involved in the pathomechanism of THI, probably acting through the induction of Treg cells.

Analysis of selected aspects of inflammasome function in the monocytes from neonates born extremely and very prematurely.

BACKGROUND: Inflammasomes regulate activation of caspase-1, which cleaves and activates interleukin (IL)-1ß and IL-18, the cytokines that trigger pro-inflammatory and antimicrobial responses. There is very little known about inflammasome function in the subsets of monocytes (MO) isolated from preterm neonates born extremely and very prematurely. METHODS: A group of 76 very low birth weight patients without early-onset sepsis was divided into extremely preterm (<28 gestational week) or very preterm (28-32 gestational week) neonates. The first blood sample was collected on the 5th day of life (5th DOL) to analyse MO subsets as well as the intracellular IL-1ß expression and supernatant concentration of IL-1ß and IL-18. Secondary blood samples were collected within 24h of late-onset sepsis (LOS) development and analysed as above. RESULTS: On the 5th DOL, the extremely preterm neonates were characterized by a significantly higher absolute count of MO, in particular in the classical and intermediate subsets, as compared to the very preterm group. The counts of the intermediate and non-classical MO subsets increased during LOS in all neonates. We did not observe significant differences in the intracellular IL-1ß expression between the analysed groups. Furthermore, the levels of the analysed cytokines in the MO supernatants were comparable between the extremely and very preterm neonates on the 5th DOL. Finally, a higher level of IL-18 was observed in the supernatant of the extremely preterm group during LOS. CONCLUSIONS: During LOS, extremely preterm neonates excrete a higher level of IL-18 cytokines compared to very preterm neonates. Further studies are required to determine whether this observation is a result of a higher count of the circulating MO or is a true reflection of increased inflammasome function in this particular group of newborns.

The absolute number of circulating nonclassical (CD14+CD16++) monocytes negatively correlates with DAS28 and swollen joint count in patients with peripheral spondyloarthritis.

INTRODUCTION    A different clinical course and pattern of skeletal involvement in peripheral and axial spondyloarthritis (SpA) suggests a distinct pathophysiology of these 2 phenotypic manifestations of SpA. Monocytes, as part of the innate immune system, seem to play an important role in the pathogenesis of SpA, but the exact inflammatory pathways remain to be elucidated. Regulatory T lymphocytes (Treg) and Th17 lymphocytes are also known to influence proinflammatory and anti­inflammatory reactions. OBJECTIVES    The aim of our study was to compare the absolute numbers of monocyte subpopulations, Treg, and Th17 lymphocytes with clinical measures of disease activity in patients with peripheral and axial SpA. PATIENTS AND METHODS    We enrolled 21 patients with peripheral SpA and 27 patients with axial SpA diagnosed according to the Assessment of SpondyloArthritis International Society classification criteria, as well as 23 healthy controls. Patients were under 45 years, naïve to synthetic and biological disease­modifying antirheumatic drugs and without the administration of systemic glucocorticoids. The absolute numbers of classical, intermediate, nonclassical monocytes, Treg, and Th17 in peripheral blood were analyzed. Disease activity was assessed using the Ankylosing Spondylitis Disease Activity Score (ASDAS-CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Disease Activity Score 28 (DAS28). RESULTS    In patients with SpA, the number of circulating nonclassical monocytes was decreased in comparison with controls. Only in the peripheral SpA group, a significant negative correlation was found between the concentration of nonclassical monocytes and DAS28 and the number of swollen joints. The 3 groups did not differ in terms of the concentrations of classical or intermediate monocytes and Treg or Th17 lymphocytes. CONCLUSIONS    Nonclassical monocytes may play a role in induction and perpetuation of peripheral joint inflammation, at least in peripheral SpA, as cells infiltrating the synovium.

Analysis of PD-1 expression in the monocyte subsets from non-septic and septic preterm neonates.

Programmed death-1 (PD-1) receptor system represents a part of recently reported immunoregulatory pathway. PD-1 is an immune checkpoint molecule, which plays an important role in downregulating the immune system proinflammatory activity. Until recently, PD-1 expression was not established on immune cells of the preterm infants. The study objectives were to confirm expression of the PD-1 receptors on the monocytes isolated from very low birth weight newborns (VLBW), and to analyze their expression during the first week of life and late-onset sepsis. Peripheral blood mononuclear cells were isolated from 76 VLBW patients without early-onset sepsis on their 5th day of life (DOL). PD-1 expression was determined on the monocyte subsets (classical, intermediate, non-classical) by flow cytometry. In case of late-onset sepsis (LOS), the same analysis was performed. Our results demonstrated that on the 5th DOL, PD-1 receptors were present in all the monocyte subsets. Children, whose mothers had received antenatal steroids, presented higher absolute numbers of non-classical monocytes with PD-1 expression. Infants born extremely preterm who later developed LOS, initially showed a lower percentage of PD-1 receptor-positive intermediate monocytes in comparison to neonates born very preterm. During LOS, we observed a rise in the percentage of classical monocytes with PD-1 expression. In case of septic shock or fatal outcome, there was a higher percentage and absolute count of intermediate monocytes with PD-1 expression in comparison to children without these complications. In conclusion, monocytes from VLBW children express PD-1 receptors. Antenatal steroid administration seems to induce PD-1 receptor expression in the non-classical monocytes. PD-1 might play a role in immunosuppressive phase of sepsis in the prematurely born children with septic shock and fatal outcome.

Reprint of: Alterations of TRIM21-mRNA expression during monocyte maturation.

Tripartite motif-containing protein 21 (TRIM21) play a dual role in the cytoplasm of the cells where it facilitates destruction of some antibody-coated viruses and some bacteria, and initiates synthesis of proinflammatory cytokines. Macrophages and CD16+ monocyte subset can particularly participate in a proinflammatory response caused by viral infection, however, the molecular mechanisms underlying these processes are not fully understood. The aim of this study was to determine the level of TRIM21-mRNA expression in monocyte subsets including: classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocytes, as well as during in vitro differentiation of the isolated monocytes towards dendritic cells or macrophages. Our results revealed that the level of TRIM21 mRNA expression was significantly lower in CD16- monocytes, when compared to CD16+ cells and the whole monocyte population, yet no significant differences were observed when CD16+ population was divided into intermediate and non-classical subsets. More pronounced differences were observed in the case of monocyte-derived macrophages (MDM) and dendritic cells (DCs). TRIM21-mRNA expression level was app. 6-fold higher in DCs, and app. 16-fold higher in MDM (p<0,01), when compared to freshly isolated monocytes. Our results may suggest the new mechanism of increased proinflammatory cytokine production by CD16+ (intermediate and non-classical) monocytes and macrophages, at least in patients with acute or chronic infections, caused by enveloped viruses. We suggest that TRIM21 may be one of the factors associated with the "switching on" the proinflammatory programme in CD16+ monocytes or monocyte-derived macrophages.

Connexin43high prostate cancer cells induce endothelial connexin43 up-regulation through the activation of intercellular ERK1/2-dependent signaling axis.

Connexin(Cx)43 regulates the invasive potential of prostate cancer cells and participates in their extravasation. To address the role of endothelial Cx43 in this process, we analyzed Cx43 regulation in human umbilical vein endothelial cells in the proximity of Cx43high (DU-145 and MAT-LyLu) and Cx43low prostate cancer cells (PC-3 and AT-2). Endothelial Cx43 up-regulation was observed during the diapedesis of DU-145 and MAT-LyLu cells. This process was attenuated by transient Cx43 silencing in cancer cells and by chemical inhibition of ERK1/2-dependent signaling in endothelial cells. Cx43 expression in endothelial cells was insensitive to the inhibition of gap junctional intercellular coupling between Cx43high prostate cancer and endothelial cells by 18α-glycyrrhetinic acid. Instead, endothelial Cx43 up-regulation was correlated with the local contraction of endothelial cells and with their activation in the proximity of Cx43high DU-145 and MAT-LyLu cells. It was also sensitive to pro-inflammatory factors secreted by peripheral blood monocytes, such as TNFα. In contrast to Cx43low AT-2 cells, Cx43low PC-3 cells produced angioactive factors that locally activated the endothelial cells in the absence of endothelial Cx43 up-regulation. Collectively, these data show that Cx43low and Cx43high prostate cancer cells can adapt discrete, Cx43-independent and Cx43-dependent strategies of diapedesis. Our observations identify a novel strategy of prostate cancer cell diapedesis, which depends on the activation of intercellular Cx43/ERK1/2/Cx43 signaling axis at the interfaces between Cx43high prostate cancer and endothelial cells.