COVID-19-related headache and innate immune response - a narrative review.

Headache is one of the most prevalent, although often underreported, symptoms of coronavirus disease 2019 (COVID-19). It is generally accepted that this symptom is a form of secondary headache due to systemic viral infection. There are several hypotheses that try to explain its aetiopathogenesis. One of the most compelling is related to innate immune response to viral infection. This rationale is supported by similarities to other viral infections and the temporal overlap between immunological reactions and headache. Moreover, several key factors in innate immunity have been shown to facilitate headache e.g. interferons, interleukin (IL) -1-ß, IL-6, and tumour necrosis factor. There is also a possibility that the virus causes headache by the direct activation of afferents through pattern recognition receptors (i.e. Toll-like receptor 7). Moreover, some data on post-COVID-19 headache and after vaccination against SARS-CoV-2 infection suggests a similar cytokine-mediated pathomechanism in these clinical situations. Future research should look for evidence of causality between particular immune response factors and headache. Identifying key molecules responsible for headache during acute viral infection would be an important step towards managing one of the most prevalent secondary headache disorders.

Impact of Adipose-Derived Mesenchymal Stem Cells (ASCs) of Rheumatic Disease Patients on T Helper Cell Differentiation.

Complex pathogenesis of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is associated with an imbalance of various Th-cell subpopulations. Mesenchymal stem cells (MSCs) have the ability to restore this balance. However, bone marrow-derived MSCs of SLE and SSc patients exhibit many abnormalities, whereas the properties of adipose derived mesenchymal stem cells (ASCS) are much less known. Therefore, we examined the effect of ASCs obtained from SLE (SLE/ASCs) and SSc (SSc/ASCs) patients on Th subset differentiation, using cells from healthy donors (HD/ASCs) as controls. ASCs were co-cultured with activated CD4+ T cells or peripheral blood mononuclear cells. Expression of transcription factors defining Th1, Th2, Th17, and regulatory T cell (Tregs) subsets, i.e., T-bet, GATA3, RORc, and FoxP3, were analysed by quantitative RT-PCR, the concentrations of subset-specific cytokines were measured by ELISA, and Tregs formation by flow cytometry. Compared with HD/ASCs, SLE/ASCs and especially SSc/ASCs triggered Th differentiation which was disturbed at the transcription levels of genes encoding Th1- and Tregs-related transcription factors. However, we failed to find functional consequences of this abnormality, because all tested ASCs similarly switched differentiation from Th1 to Th2 direction with accompanying IFNγ/IL-4 ratio decrease, up-regulated Th17 formation and IL-17 secretion, and up-regulated classical Tregs generation.

Direct anti-proliferative effect of adipose-derived mesenchymal stem cells of ankylosing spondylitis patients on allogenic CD4+ cells.

OBJECTIVES: T-cell-mediated adaptive immunity contributes to the development and persistence of ankylosing spondylitis (AS). Mesenchymal stromal/stem cells (MSCs) have immunomodulatory potential and are able to inhibit T-cell proliferation, but their functionality in AS patients is relatively unknown. The aim of the study was to assess the direct anti-proliferative effects of MSCs isolated from subcutaneous abdominal adipose tissue of AS patients (AS/ASCs) on allogeneic T lymphocytes, using commercially available ASC lines from healthy donors (HD/ASCs) as a control. MATERIAL AND METHODS: CD3+CD4+ T-cells were isolated from peripheral blood of healthy blood donors, activated with anti-CD3/CD28 beads, and co-cultured for 5 days with untreated and TNF+IFN-γ pre-stimulated HD/ASCs (5 cell lines) and AS/ASCs, obtained from 11 patients (6F/5M). The proliferative response of T-cells was analysed by flow cytometry, while the concentrations of kynurenines, prostaglandin E2 (PGE-2), interleukin 10 (IL-10), and interleukin 1 receptor antagonist (IL-1Ra) were measured spectrophotometrically or using a specific enzyme-linked immunosorbent assay (ELISA). RESULTS: HD/ASCs and AS/ASCs similarly reduced the T-cell proliferation response, i.e. the percentage of proliferating cells, the proliferation, and replication indices, and these effects were dependent mostly on soluble factors. In the co-cultures of activated CD4+ T-cells with HD/ASCs and AS/ASCs significant increases of kynurenines, PGE-2, and IL-1Ra, but not IL-10, production were observed. The release of these factors was dependent either on cell-to-cell contact (IL-10, IL-1Ra) or soluble factors (kynurenines, PGE-2). There was a moderate to strong negative correlation between T-cell proliferative response, and the concentrations of kynurenines, PGE-2, and IL-10, but not IL-1Ra. This association was more evident in the case of TI-treated AS/ASCs than HD/ASCs. CONCLUSIONS: AS/ASCs, similar to HD/ASCs, exert a direct effective anti-proliferative impact on CD4+ T cells, acting via soluble factors that are released in cell contact-dependent (IL-10) and independent (kynurenines, PGE-2) pathways. Thus, our results suggest that AS/ASCs are potentially useful for therapeutic application.

The Interplay between Transcriptional Factors and MicroRNAs as an Important Factor for Th17/Treg Balance in RA Patients.

MicroRNAs regulate gene expression of transcriptional factors, which influence Th17/Treg (regulatory T cells) balance, establishing the molecular mechanism of genetic and epigenetic regulation of Treg and Th17 cells is crucial for understanding rheumatoid arthritis (RA) pathogenesis. The study goal was to understand the potential impact of the selected microRNAs expression profiles on Treg/Th17 cells frequency, RA phenotype, the expression profile of selected microRNAs, and their correlation with the expression profiles of selected transcriptional factors: SOCS1, SMAD3, SMAD4, STAT3, STAT5 in RA; we used osteoarthritis (OA) and healthy controls (HCs) as controls. The study was conducted on 14 RA and 11 OA patients, and 15 HCs. Treg/Th17 frequency was established by flow cytometry. Gene expression analysis was estimated by qPCR. We noticed correlations in RA Th17 cells between miR-26 and SMAD3, STAT3, SOCS1; and miR-155 and STAT3-and in RA Treg cells between miR-26 and SOCS1; miR-31, -155 and SMAD3; and miR-155 and SMAD4. In RA Tregs, we found a negative correlation between miR-26, -126 and STAT5a. The expression level of miR-31 in Th17 cells from RA patients with DAS28 ≤ 5.1 is higher and that for miR-24 is greater in Tregs from patients with DAS28 > 5.1. MiR-146a in Tregs is higher in rheumatoid factor (RF) positive RA patients.

Survival of lymphocytes is not restricted by IDO-expressing fibroblast from rheumatoid arthritis patients.

Objective: Rheumatoid arthritis (RA) is characterized by expansion of fibroblast-like synoviocytes (FLS) in inflamed joints and activation of lymphocytes. Tryptophan (trp) is an essential amino acid indispensable for the biosynthesis of proteins and critical for survival of lymphocytes. Indoleamine 2,3-dioxygenase (IDO) that initiates the degradation of trp and tryptophanyl-tRNA synthetase (TTS) essential for tryptophan synthesis, regulate trp bioavailability. Here, we tested the hypothesis that triggered by cytokines, enhanced IDO activity modulate regulatory function of otherwise non-tolerogenic FLS isolated from RA patients. Materials and methods: IDO and TTS mRNA expression were evaluated by RT-PCR. IDO enzymatic activity was confirmed using HPLC. Resting or PHA-activated PBMC from healthy volunteers and RA patients were co-cultured with IDO expressing untreated (FLSC) or IFNγ-treated (FLSIFNγ) RA FLS. Lymphocyte survival and proliferation were evaluated by flow cytometry analysis and tritiated thymidine incorporation, respectively. Results: RA FLSIFNγ produce functionally active IDO and constitutively express TTS. RA FLSC and FLSIFNγ increased survival of resting lymphocytes in both studied groups, and decreased proliferation of healthy, but not RA, PBMC. Only FLSIFNγ diminished survival of activated CD3+CD4-, but not CD3+CD4+, healthy T cells and similar tendency was observed in rheumatoid cells. Importantly, IDO inhibitor, 1-methyl-DL-tryptophan (1-MT), failed to reverse this effect. PBMC, irrespective of their state (resting versus activated) or origin (healthy or RA), expressed high level of TTS mRNA. Conclusions: We suggest that RA FLS express functionally active IDO but control survival and expansion of healthy cells in IDO-independent mechanism and exert weaker, if any, suppressive effect on rheumatoid cells.

Monocyte alterations in rheumatoid arthritis are dominated by preterm release from bone marrow and prominent triggering in the joint.

OBJECTIVE: Rheumatoid arthritis (RA) accompanies infiltration and activation of monocytes in inflamed joints. We investigated dominant alterations of RA monocytes in bone marrow (BM), blood and inflamed joints. METHODS: CD14+ cells from BM and peripheral blood (PB) of patients with RA and osteoarthritis (OA) were profiled with GeneChip microarrays. Detailed functional analysis was performed with reference transcriptomes of BM precursors, monocyte blood subsets, monocyte activation and mobilisation. Cytometric profiling determined monocyte subsets of CD14++CD16-, CD14++CD16+ and CD14+CD16+ cells in BM, PB and synovial fluid (SF) and ELISAs quantified the release of activation markers into SF and serum. RESULTS: Investigation of genes differentially expressed between RA and OA monocytes with reference transcriptomes revealed gene patterns of early myeloid precursors in RA-BM and late myeloid precursors along with reduced terminal differentiation to CD14+CD16+monocytes in RA-PB. Patterns associated with tumor necrosis factor/lipopolysaccharide (TNF/LPS) stimulation were weak and more pronounced in RA-PB than RA-BM. Cytometric phenotyping of cells in BM, blood and SF disclosed differences related to monocyte subsets and confirmed the reduced frequency of terminally differentiated CD14+CD16+monocytes in RA-PB. Monocyte activation in SF was characterised by the predominance of CD14++CD16++CD163+HLA-DR+ cells and elevated concentrations of sCD14, sCD163 and S100P. CONCLUSION: Patterns of less mature and less differentiated RA-BM and RA-PB monocytes suggest increased turnover with accelerated monocytopoiesis, BM egress and migration into inflamed joints. Predominant activation in the joint indicates the action of local and primary stimuli, which may also promote adaptive immune triggering through monocytes, potentially leading to new diagnostic and therapeutic strategies.

Monocyte-related biomarkers of rheumatoid arthritis development in undifferentiated arthritis patients - a pilot study.

OBJECTIVES: Enhanced/disturbed activities of monocytes are crucial for perpetuation and for development of rheumatoid arthritis (RA). Therefore, knowledge about monocyte activities and regulation of molecular pathways operating within monocytes early in the course of RA development may help to predict the progression to the full-blown disease. We aimed to investigate the profile of miRNAs expression in circulating monocytes and monocyte-related cytokines in sera of individuals at undifferentiated arthritis (UA) stage, wich could serve as new biomarkers for RA development. MATERIAL AND METHODS: Magnetically sorted monocytes from peripheral blood of 20 UA patients served for total RNA isolation. RNA samples were used for microRNA profiling. Concentrations of CCL3/MIP-1α, M-CSF, CCL2/MCP-1, IL-6, TNF-α and IL-15 in sera of UA patients were measured using ELISA assays. Verification of diagnosis after 4 years of follow-up led to the identification of patients who developed RA (UA→RA patients) and patients who remained still in UA phase (UA → UA patients). Comparisons between patients groups were performed using two-tailed Mann-Whitney U test. RESULTS: We identified 50 miRNAs in monocytes with the largest variation of expression across all patients samples. From these selected miRNAs, expression of miR-642b-5p, miR-483-3p, miR-371b-5p were significantly up-regulated and miR-25-3p and miR-378d were significantly down-regulated in UA → RA vs. UA → UA patients. This specific pattern of miRNAs expression in circulating monocytes paralleled elevated IL-15 and M-CSF concentrations in sera of UA patients who progressed to RA. CONCLUSIONS: Results of our pilot study indicate that altered activity of monocytes can be detected at early stages of RA. We found new miRNA candidates differentially expressed in peripheral blood monocytes and elevated concentrations of IL-15 and M-CSF involved in monocyte activity and differentiation in patients with UA who subsequently developed RA, in comparison to UA patients who did not progress to RA after 4 years follow-up.

The role of anti-citrullinated protein antibodies (ACPA) in the pathogenesis of rheumatoid arthritis.

The most specific autoimmunity known for rheumatoid arthritis (RA) is reflected by generation of anti-citrullinated protein antibodies (ACPA). Presence of ACPA in established RA is associated with disease severity, while generation of ACPA at early developmental phases of RA can have a strong predictive value for progressing to the full-blown disease. Hence, development of ACPA may be of crucial importance to the pathogenesis of RA. Therefore, a lot of effort has been put recently to investigate the feature of ACPA at early developmental stages of RA (before disease onset) and functional activities of these autoantibodies. Results of these studies enlarged the knowledge about the nature of ACPA, which is essential for planning the therapeutic or preventive strategies interfering with their development and pathogenic functions. In this review we describe recent evidence for a role of ACPA in the etiopathogenesis of RA and indicate key unresolved issues regarding ACPA biology that need to be clarified in the future.

Different expression of chemokines in rheumatoid arthritis and osteoarthritis bone marrow.

OBJECTIVES: Rheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction. In addition to involvement of the joints, there is growing evidence that inflammatory/autoimmune processes take place in bone marrow, beginning the disease onset. Activated T and B cells accumulate in bone marrow, where also effective antigen presentation takes place. An increased number of activated T cells was observed in RA in comparison to osteoarthritis (OA) bone marrow. In the present study we analyzed the levels of chemokines that may be responsible for accumulation/retention of T-cells in the bone marrow of RA and OA patients. MATERIAL AND METHODS: Bone marrow samples were obtained from RA and OA patients during total hip replacement surgery, and bone marrow plasma was obtained by gradient centrifugation. Levels of the chemokines CX3CL1, CCL5, CCL2, CXCL12 and CXCL1 were measured in bone marrow plasma by specific ELISAs. Comparison between the groups of patients and statistical significance were analyzed by the two-tailed Mann-Whitney U test. RESULTS: Increased levels of CX3CL1 (818 ±431 pg/ml vs. 502 ±131 pg/ml, p < 0.0007) and CCL5 (5967 ±1680 pg/ml vs. 4878 ±2360 pg/ml, p < 0.05) respectively in bone marrow plasma from RA in comparison with OA patients were observed. In contrast, similar levels of CCL2, CXCL12 and CXCL1 in RA and OA bone marrow suggest that these cytokines do not play a significant role in the observed T cell accumulation in RA bone marrow. CONCLUSIONS: CX3CL1 and CCL5 overproduced in RA bone marrow may contribute to the accumulation of T cells observed in RA bone marrow.

Impact of methotrexate treatment on vaccines immunogenicity in adult rheumatological patients - Lessons learned from the COVID-19 pandemic.

Despite the development of new biological and synthetic targeted therapies, methotrexate remains one of the most commonly used immunomodulatory drugs in rheumatology. However, its effect on the immunogenicity of vaccines has been studied only to a limited extent until recently, resulting in the lack of clear guidelines on the use of methotrexate during vaccination. Significant progress was made during the COVID-19 pandemic due to the dynamic development of research on vaccines, including patients with autoimmune inflammatory rheumatic diseases. In the following literature review, we present a summary of what we know so far on the impact of methotrexate on post-vaccination response in adult rheumatology patients, taking into account the lessons learned from the COVID-19 pandemic. Studies on the effect of methotrexate on the immunogenicity of influenza, pneumococcal, herpes zoster, tetanus/diphtheria/pertussis, hepatitis A, yellow fever, and COVID-19 vaccines are described in detail, including the effect of methotrexate on the humoral and cellular response of individual vaccines. The available evidence for recommendations for withholding methotrexate in the post-vaccination period is presented. Lastly, an overview of potential immunological mechanisms through which MTX modulates the immunogenicity of vaccinations is also provided.

Basic Properties of Adipose-Derived Mesenchymal Stem Cells of Rheumatoid Arthritis and Osteoarthritis Patients.

Rheumatoid arthritis (RA) and osteoarthritis (OA) are destructive joint diseases, the development of which are associated with the expansion of pathogenic T lymphocytes. Mesenchymal stem cells may be an attractive therapeutic option for patients with RA or OA due to the regenerative and immunomodulatory abilities of these cells. The infrapatellar fat pad (IFP) is a rich and easily available source of mesenchymal stem cells (adipose-derived stem cells, ASCs). However, the phenotypic, potential and immunomodulatory properties of ASCs have not been fully characterised. We aimed to evaluate the phenotype, regenerative potential and effects of IFP-derived ASCs from RA and OA patients on CD4+ T cell proliferation. The MSC phenotype was assessed using flow cytometry. The multipotency of MSCs was evaluated on the basis of their ability to differentiate into adipocytes, chondrocytes and osteoblasts. The immunomodulatory activities of MSCs were examined in co-cultures with sorted CD4+ T cells or peripheral blood mononuclear cells. The concentrations of soluble factors involved in ASC-dependent immunomodulatory activities were assessed in co-culture supernatants using ELISA. We found that ASCs with PPIs from RA and OA patients maintain the ability to differentiate into adipocytes, chondrocytes and osteoblasts. ASCs from RA and OA patients also showed a similar phenotype and comparable abilities to inhibit CD4+ T cell proliferation, which was dependent on the induction of soluble factors The results of our study constitute the basis for further research on the therapeutic potential of ASCs in the treatment of patients with RA and OA.

The Kinetics of Humoral and Cellular Responses after the Booster Dose of COVID-19 Vaccine in Inflammatory Arthritis Patients.

Impaired immunogenicity of COVID-19 vaccinations in inflammatory arthritis (IA) patients results in diminished immunity. However, optimal booster vaccination regimens are still unknown. Therefore, this study aimed to assess the kinetics of humoral and cellular responses in IA patients after the COVID-19 booster. In 29 IA patients and 16 healthy controls (HC), humoral responses (level of IgG antibodies) and cellular responses (IFN-γ production) were assessed before (T0), after 4 weeks (T1), and after more than 6 months (T2) from the booster vaccination with BNT162b2. IA patients, but not HC, showed lower anti-S-IgG concentration and IGRA fold change at T2 compared to T1 (p = 0.026 and p = 0.031). Furthermore, in IA patients the level of cellular response at T2 returned to the pre-booster level (T0). All immunomodulatory drugs, except IL-6 and IL-17 inhibitors for the humoral and IL-17 inhibitors for the cellular response, impaired the immunogenicity of the booster dose at T2. Our study showed impaired kinetics of both humoral and cellular responses after the booster dose of the COVID-19 vaccine in IA patients, which, in the case of cellular response, did not allow the vaccination effect to be maintained for more than 6 months. Repetitive vaccination with subsequent booster doses seems to be necessary for IA patients.

Immature platelet fraction in cardiovascular diagnostics and antiplatelet therapy monitoring.

Immature platelet fraction (IPF), circulating platelets still containing RNA, can be easily calculated by automated flow cytometry, this makes them an accessible biomarker. Higher IPF concentrations were reported in patients with thrombocytopenia, patients who were smokers, and also those who were diabetics. Several studies have reported their diagnostic and prognostic importance in patients presenting with acute coronary syndromes, especially ST-segment elevation myocardial infarction, where increased IPF level is an independent predictor of cardiovascular death. In addition, higher IPF were reported in patients with inadequate response to either clopidogrel or prasugrel, suggesting their potential role in antiplatelet therapy monitoring. Their prognostic significance was also observed in both coronary artery disease and postcardiac surgery status, where their higher levels correlated with the risk of major adverse cardiac events. The current review aims to present the current evidence on diagnostic, prognostic and potentially therapeutic roles of IPF in cardiovascular medicine.

Associations of IL-18 with Altered Cardiovascular Risk Profile in Psoriatic Arthritis and Ankylosing Spondylitis.

OBJECTIVE: To investigate the associations of IL-18 serum levels with serum lipids, cardiovascular risk, and disease activity in patients with ankylosing spondylitis (AS) and psoriatic arthritis (PsA) with axial (axPsA) and peripheral (perPsA) joint involvement. METHODS: 155 adult patients (PsA 61/AS 94) were enrolled in the study. Standard disease activity indices, BASDAI, and ASDAS, were calculated for AS and PsA and DAPSA for PsA. Sera from peripheral blood samples were obtained after night fasting. Serum concentrations of cytokines (IL-18, IL-17) were measured by ELISA, while lipid profile with total cholesterol (TC), triglycerides (TG), low-density cholesterol-(LDL), high-density cholesterol (HDL), and C-reactive protein (CRP) concentrations were determined using routine procedures. The atherogenic index was calculated using the standard formula AI = TC/HDL. RESULTS: Patients with PsA and peripheral joint involvement (perPsA) had significantly higher IL-18 serum levels than axial PsA and AS patients (medians 160 vs. 116 vs. 80 pg/mL). In patients with PsA and in the subgroup with PsA+ ischemic heart disease (IHD), IL-18 positively correlated with atherogenic index (AI) (rho = 0.46 and rho = 0.67, respectively) and TG serum concentrations (rho = 0.4 and rho = 0.675), while negatively with HDL levels (rho = -0.37 and rho = -0.608). In PsA + IHD subgroup IL-18 serum levels correlated positively also with disease activity (DAPSA) (rho = 0.613). Importantly, in patients with perPsA, characterized by the highest IL-18 serum levels, cardiovascular risk, and frequency of both hypertriglyceridemia and IHD, positive correlations between IL-18 and IL-17 (rho = 0.47, p = 0.002), TG (rho = 0.45 p = 0.01) levels and AI (rho = 0.63 p = 0.021) were found. Whereas linear regression models revealed that IL-17, TG concentrations and the tender joint count had an impact on IL-18 Conclusions: We confirmed that patients with perPsA are characterized by a more pronounced proinflammatory and proatherogenic cardiovascular risk profile than patients with axPsA and AS. Importantly our study indicates that in PsA, but not in AS, elevated serum concentration of IL-18 is associated with higher disease activity and proatherogenic lipid profile, leading to a higher cardiovascular risk. Thus, our results point out IL-18 as a critical contributor in these pathological processes and possible therapeutic targets.

Humoral and cellular immunogenicity of COVID-19 booster dose vaccination in inflammatory arthritis patients.

Introduction: Previous studies have shown a reduction in the effectiveness of primary COVID-19 vaccination in patients with rheumatic diseases. However, limited data is available regarding the effectiveness of the COVID-19 vaccine booster dose, especially on cellular response. The study aimed to assess the humoral and cellular immunogenicity of a booster dose in patients with inflammatory arthritis (IA). Patients and methods: 49 IA and 47 age and sex-matched healthy controls (HC) were included in a prospective cohort study. Both groups completed primary COVID-19 vaccination and after more than 180 days received a BNT162b2 booster shot. Humoral responses (level of IgG antibodies) and cellular responses (IFN-γ production) were assessed before and after 4 weeks from the booster dose of the vaccine. Results: After the booster dose, all participants showed an increased humoral response, although significantly reduced antibody levels were observed in IA patients compared to HC (p=0.004). The cellular response was significantly lower both before (p<0.001) and after (p<0.001) the booster dose in IA patients as compared to HC. Among the immunomodulatory drugs, only biological and targeted synthetic drugs lowered the humoral response after booster vaccination. However, the cellular response was decreased after all immunomodulatory drugs except IL-17 inhibitors and sulfasalazine. Conclusion: Our data indicate that patients with rheumatic diseases present lower humoral and cellular responses after the COVID-19 booster vaccine in comparison to HC. This may translate into a recommendation for subsequent booster doses of the COVID-19 vaccine for rheumatic patients.

Effectiveness of Soluble CTLA-4-Fc in the Inhibition of Bone Marrow T-Cell Activation in Context of Indoleamine 2.3-Dioxygenase (IDO) and CD4+Foxp3+ Treg Induction.

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease with systemic inflammation finally resulting in damaged joints. One of the RA development models suggests bone marrow (BM) as a place of inflammation development further leading to disease progression. We aimed to investigate the potential of CTLA-4-Fc molecule in inducing tolerogenic milieu in BM measured as indoleamine 2,3-dioxygenase (IDO) expression, CD4+Foxp3+ Treg induction, and T cell activation control. The expression of IDO-pathway genes was also examined in monocytes to estimate the tolerogenic potential in the periphery. Methods: Bone marrow mononuclear cells (BMMC) were stimulated by pro-inflammatory cytokines and CTLA-4-Fc. Next IDO expression, CD4+CD69+ and CD4+Foxp3+ percentage were estimated by PCR and FACS staining, respectively. Enzymatic activity of IDO was confirmed by HPLC in BM plasma and blood plasma. Genes expressed in IDO-pathway were analyzed by NGS in peripheral monocytes isolated from RA patients and healthy controls. Results: We found that CTLA-4-Fc and IFN-γ stimulation results in IDO production by BMMC. CTLA-4-Fc induced tryptophan catabolism can inhibit mitogen-induced CD4+ T cells activation without influencing CD8+ cells, but did not control CD25 nor Foxp3 expression in BM cells. Significantly higher expression of selected IDO-pathway genes was detected on peripheral monocytes isolated from RA as compared to healthy controls. Conclusion: This study sheds light on some immunosuppression aspects present or induced in BM. The potential of IDO-mediated pathways were confirmed in the periphery, what may represent the promising candidates for therapeutic strategies in RA.

Circulating miRNA Correlates with Lipid Profile and Disease Activity in Psoriatic Arthritis, Rheumatoid Arthritis, and Ankylosing Spondylitis Patients.

This study aimed to investigate the associations of microRNA (miRs) signatures with cytokines, serum lipids, and disease activity in patients with psoriatic arthritis (PsA), ankylosing spondylitis (AS), and rheumatoid arthritis (RA). In total, 65 patients (PsA n = 25, AS n = 25, RA n = 15) and 25 healthy controls (HC) were enrolled into the study. The expression of miR-223-5p, miR-92b-3p, miR-485-3p, miR-10b-5p, let-7d-5p, miR-26a-2-3p, miR-146b-3p, and cytokines levels were measured in sera. DIANA-mirPath analysis was used to predict pathways targeted by the dysregulated miRs. Disease activity scores were calculated. Lipid profile, uric acid, glucose level, and C-reactive protein (CRP) concentrations were determined in the blood. Based on lipid profiles, the PsA group had hypertriglyceridaemia, and RA patients revealed mixed dyslipidaemia, while in AS, no specific changes were found. miR expression analysis revealed upregulation of miR-26a-2-3p and miR-10b-5p in PsA, miR-485-3p in AS, and let-7d-5p in RA. Several correlations between disease activity indexes, metabolites levels, and expression of miRs were observed in PsA, RA, and AS patients. Finally, in ROC analysis, miR-26a-2-3p/miR-485-3p, and let-7d-5p/miR-146b-3p tandems revealed high sensitivity and specificity in distinguishing between PsA, AS, and RA. Our study illustrates the superiority of miR expressions in distinguishing between RA, PsA, and AS. In PsA, a unique regulatory pathway exists through miR-26a-2-3p, miR-223-5p, miR-10b-5p, and miR-92b-3p that converges proatherogenic metabolism and disease activity.

Elevated number of recently activated T cells in bone marrow of patients with rheumatoid arthritis: a role for interleukin 15?

OBJECTIVES: (1) To compare the absolute T-cell numbers in bone marrow (BM) isolated from patients with rheumatoid arthritis (RA) and osteoarthritis (OA); (2) to measure the levels of soluble interleukin 15 (IL-15) and IL-7; (3) to analyse the expression of activation markers on T cells; (4) to analyse influence of IL-15 stimulation on T-cell proliferation. METHODS: BM samples were obtained from patients undergoing joint replacement surgery. Concentrations of IL-15 and IL-7 were measured using specific ELISAs. The absolute number of T lymphocytes, their activation status and proliferation were evaluated by flow cytometry. RESULTS: BM from patients with RA contained double the number of CD3 T cells in comparison with OA (6.1 vs 2.7 × 10(6) cells/ml, p<0.008). Ratio CD3CD4:CD3CD8 was increased in RA BM, clearly indicating accumulation of CD3CD4 cells. T cells obtained from patients with RA expressed higher level of early activation markers than from OA. Elevated levels of IL-15 were found in BM plasma from patients with RA in comparison with patients with OA (1304.5±956.3 pg/ml and 760±238.7 pg/ml respectively, p<0.01). These data were confirmed by immunohistochemistry of RA BM from regions proximal and distal to the joint. Although both CD3CD4 and CD3CD8 cells proliferated after IL-15 stimulation in vitro, CD3CD4 cells from patients with RA proliferated more vigorously than those from patients with OA, reflecting the composition of T-cell subsets in BM. CONCLUSION: These results suggest that locally overproduced IL-15 may be responsible for the activation and proliferation of T cells in situ, reflected by significantly increased number of activated T cells in RA BM, possibly contributing to the pathogenesis of RA.

Inhibition of Allogeneic and Autologous T Cell Proliferation by Adipose-Derived Mesenchymal Stem Cells of Ankylosing Spondylitis Patients.

BACKGROUND: In ankylosing spondylitis (AS), accompanied by chronic inflammation, T cell expansion plays a pathogenic role; the immunoregulatory properties of bone marrow-derived mesenchymal stem cells (BM-MSCs) are impaired, while functional characteristics of their adipose tissue-derived counterparts are (ASCs) unknown. METHODS: We evaluated the antiproliferative activity of AS/ASCs, obtained from 20 patients, towards allogeneic and autologous T lymphocytes, using ASCs from healthy donors (HD/ASCs) as the reference cell lines. The PHA-activated peripheral blood mononuclear cells (PBMCs) were cocultured in cell-cell contact and transwell conditions with untreated or TNF + IFNγ- (TI-) licensed ASCs, then analyzed by flow cytometry to identify proliferating and nonproliferating CD4+ and CD8+ T cells. The concentrations of kynurenines, prostaglandin E2 (PGE2), and IL-10 were measured in culture supernatants. RESULTS: In an allogeneic system, HD/ASCs and AS/ASCs similarly decreased the proliferation of CD4+ and CD8+ T cells and acted mainly via soluble factors. The concentrations of kynurenines and PGE2 inversely correlated with T cell proliferation, and selective inhibitors of these factors synthesis significantly restored T cell response. AS/ASCs exerted a similar antiproliferative impact also on autologous T cells. CONCLUSION: We report for the first time that despite chronic in vivo exposure to inflammatory conditions, AS/ASCs retain the normal capability to restrain expansion of allogeneic and autologous CD4+ and CD8+ T cells, act primarily via kynurenines and PGE2, and thus may have potential therapeutic value. Some distinctions between the antiproliferative effects of AS/ASCs and HD/ASCs suggest in vivo licensing of AS/ASCs.