Bona fide dendritic cells are pivotal precursors for osteoclasts.

OBJECTIVES: Osteoclasts (OCs) are myeloid-derived multinucleated cells uniquely able to degrade bone. However, the exact nature of their myeloid precursors is not yet defined. METHODS: CD11c-diphtheria toxin receptor (CD11cDTR) transgenic mice were treated with diphtheria toxin (DT) or phosphate buffered saline (PBS) during serum transfer arthritis (STA) and human tumour necrosis factor transgenic (hTNFtg) arthritis and scored clinically and histologically. We measured cytokines in synovitis by quantitative polymerase chain reaction (qPCR). We performed ovariectomy in CD11cDTR mice treated with PBS or DT. We analysed CD11cDTR, CD11c-Cre/CX3CR1-STOP-DTR and Zbtb46-DTR-treated mice with DT using histomorphometry and OC of CD11c and Zbtb46 fate reporter mice by fluorescent imaging. We sorted murine and human OC precursors and stimulated them with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL) to generate OCs. RESULTS: Targeting CD11c+ cells in vivo in models of inflammatory arthritis (STA and hTNFtg) ameliorates arthritis by reducing inflammatory bone destruction and OC generation. Targeting CD11c-expressing cells in unchallenged mice removes all OCs in their long bones. OCs do not seem to be derived from CD11c+ cells expressing CX3CR1+, but from Zbtb46+conventional dendritic cells (cDCs) as all OCs in Zbtb46-Tomato fate reporter mice are Tomato+. In line, administration of DT in Zbtb46-DTR mice depletes all OCs in long bones. Finally, human CD1c-expressing cDCs readily differentiated into bone resorbing OCs. CONCLUSION: Taken together, we identify DCs as important OC precursors in bone homeostasis and inflammation, which might open new avenues for therapeutic interventions in OC-mediated diseases.

Pregnancy outcomes in patients with systemic lupus erythematosus compared to a high-risk tertiary cohort and to standard population from the Austrian birth registry.

INTRODUCTION: Women with systemic lupus erythematosus (SLE) have a higher risk for fetal and maternal complications. We aimed to investigate maternal and fetal complications in pregnant women with SLE compared to a high-risk pregnancy cohort (HR) from a tertiary university center and a standard-risk general population (SR) from the Austrian Birth Registry. MATERIAL AND METHODS: In this retrospective data analysis, we compared the incidence of fetal/neonatal and maternal complications of pregnancies and deliveries of women with SLE to age, body mass index and delivery date-matched high-risk pregnancies from the same department, a progressive tertiary obstetric center and to a group of women, who represent pregnancies with standard obstetric risk from the Austrian Birth Registry. RESULTS: One hundred women with SLE were compared to 300 women with high-risk pregnancies and 207 039 women with standard-risk pregnancies. The incidence of composite maternal complications (preeclampsia, Hemolysis, Elevated Liver enzymes and Low Platelets [HELLP] syndrome, pregnancy-related hypertension, gestational diabetes mellitus, maternal death, thromboembolic events) was significantly higher in the SLE as compared to the SR group (28% vs. 6.28% SLE vs. SR, p = 0.001). There was no difference between the SLE and the HR groups (28% vs. 29.6% SLE vs. HR group, p = 0.80). The incidence of composite fetal complications (preterm birth before 37 weeks of gestation, stillbirths, birthweight less than 2500 g, fetal growth restriction, large for gestational age, admission to neonatal intensive care unit, 5-min Apgar <7) was also higher in the SLE than in the SR group (55% vs. 25.54% SLE vs. SR p < 0.001) while the higher incidence of adverse fetal outcome was detected in the HR than in the SLE group (55% vs. 75% SLE vs. HR group, p = 0.0005). CONCLUSIONS: Although composite fetal risk is higher in the SLE group than in the general population, it is still significantly lower as compared to high-risk pregnant women at a tertiary obstetric center. Prepregnancy counseling of women with SLE should put fetal and maternal risk in perspective, not only in relation to healthy, low risk cohorts, but also compared to mixed HR populations.

Safety and immunogenicity of a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases compared with healthy controls.

OBJECTIVES: A third COVID-19 vaccination is recommended for immunosuppressed patients. However, data on immunogenicity and safety of a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases (IMIDs) are sparse and therefore addressed within this clinical trial. METHODS: 60 immunosuppressed patients and 48 healthy controls (HCs) received a third vaccination with an mRNA vaccine. The primary endpoint was defined as the presence of antibody levels against the receptor-binding domain (RBD)>1500 BAU/mL in patients with IMIDs versus HCs. Further endpoints included differences in neutralising antibodies and cellular immune responses after the third vaccination. Reactogenicity was recorded for 7 days, and safety was evaluated until week 4. RESULTS: Rate of individuals with anti-RBD antibodies>1500 BAU/mL was not significantly different after the third vaccination between patients with IMIDs and HCs (91% vs 100% p=0.101). Anti-RBD and neutralising antibody levels were significantly lower in patients with IMIDs after the third vaccination than in HCs (p=0.002 and p=0.016, respectively). In contrast, fold increase in antibody levels between week 0 and 4 was higher in patients with IMIDs. Treatment with biological (b) disease-modifying anti-rheumatic drugs (DMARD) or combination of bDMARDs and conventional synthetic DMARDs was associated with reduced antibody levels. Enhanced cellular immune response to wild type and Omicron peptide stimulation was observed after the third vaccination. No serious adverse event was attributed to the third vaccination. CONCLUSION: Our clinical trial data support the immunogenicity and safety of a third COVID-19 vaccination in patients with IMIDs. However, effects of DMARD therapy on immunogenicity should be considered. TRIAL REGISTRATION NUMBER: EudraCT No: 2021-002693-10.

Vaginal microbiota in pregnant women with inflammatory rheumatic and inflammatory bowel disease: A matched case-control study.

BACKGROUND: Rheumatic diseases and vaginal infections both increase the risk of preterm birth. It is unclear whether pregnant women with rheumatic disease are more likely to experience vaginal infections, which might potentially accumulate modifiable risk factors. OBJECTIVE: In this study, we sought to evaluate the vaginal microbiota of pregnant women with inflammatory rheumatic and inflammatory bowel disease. METHODS: A total of 539 asymptomatic women with singleton pregnancy were routinely screened for an abnormal vaginal microbiota between 10 + 0 and 16 + 0 gestational weeks. Vaginal smears were Gram-stained and microscopically analysed. Those with inflammatory diseases (with or without immunomodulatory therapy) were assigned to the case group and matched in a 1:3 ratio to healthy pregnant controls. RESULTS: Overall, an abnormal vaginal microbiota occurred more frequently among women of the case group, compared with those of the control group (33.8% vs 15.6%; 95% CI: 1.78-4.27, p < .001). In particular, Candida colonisation (22.3% vs 9.2%; 95% CI: 1.69-4.75, p < .001), but also bacterial vaginosis (14.9% vs 7.2%; 95% CI: 1.25-4.1, p = .006), occurred more often in the case than in the control group. No significant difference was found with regard to the occurrence of an abnormal vaginal microbiota between subgroups with and without immunomodulatory treatment (37.0% vs 27.1%; 95% CI: 0.29-1.35, p = .232). CONCLUSION: Pregnant women with inflammatory rheumatic and inflammatory bowel disease are at risk for bacterial vaginosis and Candida colonisation, which might pose a risk for preterm birth. Prospective studies are needed to further evaluate the influence of autoimmune conditions and immunosuppressive therapy on the vaginal microbiota.

CCR6 controls autoimmune but not innate immunity-driven experimental arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease, characterized by synovial infiltration of various inflammatory cells. Chemokines are involved in controlling the recruitment of different cell types into the synovial membrane. The role of CCR6 in the development of arthritis so far remains unclear. In this study, we investigated the role of CCR6 in the pathogenesis of arthritis using three different murine arthritis models. Compared to WT animals, CCR6-/- mice developed less clinical signs of arthritis in the collagen-induced arthritis model but not in the K/BxN serum transfer arthritis model and in the human tumour necrosis factor transgenic arthritis model, suggesting a defect in adaptive effector functions but intact innate effector functions in the development of arthritis in CCR6-/- animals. In line with this, anti-collagen antibody levels were significantly reduced in CCR6-/- mice compared with WT mice. Moreover, we demonstrate enhanced osteoclastogenesis in vitro in CCR6-/- mice compared with WT mice. However, we did not detect differences in bone mass under steady state conditions in vivo between WT and CCR6-deficient mice. These data suggest that CCR6 is crucially involved in adaptive but not in innate immunity-driven arthritis. CCR6 or its chemokine ligand CCL20 might represent a possible new target for the treatment of RA.

Non-classical monocytes as mediators of tissue destruction in arthritis.

OBJECTIVES: Bone destruction in rheumatoid arthritis is mediated by osteoclasts (OC), which are derived from precursor cells of the myeloid lineage. The role of the two monocyte subsets, classical monocytes (expressing CD115, Ly6C and CCR2) and non-classical monocytes (which are CD115 positive, but low in Ly6C and CCR2), in serving as precursors for OC in arthritis is still elusive. METHODS: We investigated CCR2-/- mice, which lack circulating classical monocytes, crossed into hTNFtg mice for the extent of joint damage. We analysed monocyte subsets in hTNFtg and K/BxN serum transfer arthritis by flow cytometry. We sorted monocyte subsets and analysed their potential to differentiate into OC and their transcriptional response in response to RANKL by RNA sequencing. With these data, we performed a gene ontology enrichment analysis and gene set enrichment analysis. RESULTS: We show that in hTNFtg arthritis local bone erosion and OC generation are even enhanced in the absence of CCR2. We further show the numbers of non-classical monocytes in blood are elevated and are significantly correlated with histological signs of joint destruction. Sorted non-classical monocytes display an increased capacity to differentiate into OCs. This is associated with an increased expression of signal transduction components of RANK, most importantly TRAF6, leading to an increased responsiveness to RANKL. CONCLUSION: Therefore, non-classical monocytes are pivotal cells in arthritis tissue damage and a possible target for therapeutically intervention for the prevention of inflammatory joint damage.

MicroRNA-146a governs fibroblast activation and joint pathology in arthritis.

Synovial fibroblasts are key cells orchestrating the inflammatory response in arthritis. Here we demonstrate that loss of miR-146a, a key epigenetic regulator of the innate immune response, leads to increased joint destruction in a TNF-driven model of arthritis by specifically regulating the behavior of synovial fibroblasts. Absence of miR-146a in synovial fibroblasts display a highly deregulated gene expression pattern and enhanced proliferation in vitro and in vivo. Deficiency of miR-146a induces deregulation of tumor necrosis factor (TNF) receptor associated factor 6 (TRAF6) in synovial fibroblasts, leading to increased proliferation. In addition, loss of miR-146a shifts the metabolic state of fibroblasts towards glycolysis and augments the ability of synovial fibroblasts to support the generation of osteoclasts by controlling the balance of osteoclastogenic regulatory factors receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). Bone marrow transplantation experiments confirmed the importance of miR-146a in the radioresistant mesenchymal compartment for the control of arthritis severity, in particular for inflammatory joint destruction. This study therefore identifies microRNA-146a as an important local epigenetic regulator of the inflammatory response in arthritis. It is a central element of an anti-inflammatory feedback loop in resident synovial fibroblasts, who are orchestrating the inflammatory response in chronic arthritis. MiR-146a restricts their activation, thereby preventing excessive tissue damage during arthritis.

Which MR sequences should we use for the reliable detection and localization of bone marrow edema in spondyloarthritis?

OBJECTIVES: To assess the diagnostic confidence in detecting and localizing areas of bone marrow edema in the sacroiliac joint of patients with suspected spondyloarthritis using a single-plane method and comparing it with multiplanar unenhanced and enhanced methods. MATERIALS AND METHODS: Patients with clinical suspicion of spondyloarthritis undergoing an MRI of the sacroiliac joint were included in this retrospective study. To assess sacroiliitis, three methods were applied: single-plane (i.e., para-coronal STIR alone), multiplanar unenhanced (i.e., para-coronal STIR and para-axial PD-fs), and multiplanar enhanced method (i.e., para-coronal and para-axial post-contrast T1-fs). Two 4-point scales were used to evaluate, respectively, the diagnostic confidence in detection and localization of bone marrow edema. The distribution of certain and uncertain rating according to signal intensity and size of the lesions was also calculated. RESULTS: Seventy-four patients met the inclusion criteria. Both multiplanar methods increased the diagnostic confidence in detection (p < 0.001) and localization (p < 0.001) of sacroiliitis; no significant difference occurred between the multiplanar unenhanced and enhanced methods (p = 0.405 and p = 1.00, respectively, for detection and localization). A statistically significant difference between the distributions of certain and uncertain rating for detection based on the size and signal intensity of each lesion emerged (p = 0.006 and p < 0.001, respectively), whereas no statistically significant difference occurred for the confidence of localization (p = 0.452 and p = 0.694, respectively). CONCLUSIONS: The multiplanar methods increased the diagnostic confidence in detection and localization of sacroiliitis. The absence of a significant difference between the proposed unenhanced and enhanced methods suggests that contrast medium is not mandatory for the detection of sacroiliitis.

Optimizing the MRI protocol of the sacroiliac joints in Spondyloarthritis: which para-axial sequence should be used?

INTRODUCTION: To assess the diagnostic value of para-axial T2w-TSE (paT2) and fat-suppressed proton density (paPD-FS) MRI sequences for the evaluation of the sacroiliac joint (SIJ) of patients with axial Spondylarthritis (SpA). MATERIALS AND METHODS: One hundred and six patients with clinical findings suggestive of SpA underwent an MR protocol of the SIJ with additional paPD-FS (41 patients) and paT2 (105 patients). Acute (bone marrow oedema [BME], enthesitis, capsulitis, synovitis) and chronic findings (erosions, ankylosis) were assessed by paPD-FS and compared with the gold standard post-contrast sequences, whereas chronic features (because of the lack of fat suppression) were evaluated on paT2 and compared with pcT1. RESULTS: paPD-FS demonstrated high sensitivity (98.9 %) and specificity (99.1 %) for BME; sensitivity and specificity for synovitis and enthesitis were 100 %; 85.7 % and 100 %, respectively, for capsulitis. paPD-FS and paT2 showed 100 % sensitivity and specificity for ankylosis; for erosions, paT2 demonstrated 85.3 % sensitivity and 100 % specificity, whereas paPD-FS, respectively, 98 % and 100 %. DISCUSSION: PaT2 and paPD-FS provided precious information enabling an accurate interpretation of the heterogeneous findings of SpA. paPD-FS showed good results in detecting acute and chronic lesions and its inclusion in a routine MR examination of the SIJ could increase the diagnostic performance of a pre-contrast protocol. KEY POINTS: Para-axial sequence should be included in a routine MRI protocol for SpA. Acute and chronic findings can be evaluated on para-axial PD-FS. Para-axial PD-FS is superior to para-axial T2-W in SpA.

Loss of phosphatase and tensin homolog (PTEN) in myeloid cells controls inflammatory bone destruction by regulating the osteoclastogenic potential of myeloid cells.

OBJECTIVE: Local bone destruction in rheumatic diseases, which often leads to disability and severely reduced quality of life, is almost exclusively mediated by osteoclasts. Therefore, it is important to understand pathways regulating the generation of osteoclasts. Here, we analysed the impact of the Phosphoinositide-3-Kinase (PI3K)/Phosphatase and tensin homolog (PTEN) axis on osteoclast generation and bone biology under basal and inflammatory conditions. METHODS: We analysed osteoclastogenesis of wildtype (wt) and PTEN(-/-) cells in vitro and in vivo, pit resorption and qPCR of osteoclasts in vitro. Mice with a myeloid cell-specific deletion of PTEN and wt littermate mice were investigated by bone histomorphometry and clinical and histological assessment in the human tumour necrosis factor (TNF)-transgenic (hTNFtg) arthritis model. RESULTS: We show that myeloid-specific PTEN(-/-) mice display increased osteoclastogenesis in vitro and in vivo compared to wt mice. Loss of PTEN did not affect the generation or survival of osteoclast precursor cells. However, PTEN deficiency greatly enhanced receptor activator of nuclear factor κ-B ligand (RANKL)-induced expression of the master transcription factor of osteoclastogenesis, nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), resulting in markedly increased terminal differentiation of osteoclasts in vitro. We also observed increased osteoclastogenesis under inflammatory conditions in the hTNFtg mouse model of arthritis, where hTNFtg/myeloid-specific PTEN(-/-) mice displayed enhanced local bone destruction as well as osteoclast formation in the inflamed joints. The extent of synovial inflammation, however, as well as recruitment of osteoclast precursor cells was not different between wt and myeloid-specific PTEN(-/-) mice. CONCLUSIONS: These data demonstrate that loss of PTEN and, therefore, sustained PI3-Kinase signalling in myeloid cells especially, elevates the osteoclastogenic potential of myeloid cells, leading to enhanced inflammatory local bone destruction. Therefore, although our study allows no direct translational conclusion since we used a conditional knockout approach, the therapeutic targeting of the PI3-Kinase pathway may be of benefit in preventing structural joint damage.

IL-6 blockade in chronic inflammatory diseases.

Proinflammatory cytokines are centrally involved in the pathogenesis of various rheumatic diseases. Interleukin (IL)-6 is a prototypic representative of this family. Basic research has uncovered a multitude of functions for this cytokine, such as immune regulation, hematopoiesis, inflammation, and oncogenesis (Fig. 1). In recent years, agents blocking the actions of IL-6 have been developed for the therapy of rheumatologic inflammatory diseases. While in some diseases, most notably rheumatoid arthritis, the clinical efficacy of these drugs was excellent, the results of clinical trials in other chronic inflammatory diseases were heterogeneous. In this review, we will summarize the data currently available on IL-6 blockade in chronic inflammatory diseases and will also discuss the safety issues of blocking this cytokine.

Tumor necrosis factor-inhibiting therapy preferentially targets bone destruction but not synovial inflammation in a tumor necrosis factor-driven model of rheumatoid arthritis.

OBJECTIVE: To investigate how tumor necrosis factor (TNF)-inhibiting therapy affects bone destruction and inflammation in a TNF-driven mouse model of rheumatoid arthritis. METHODS: In order to evaluate the influence of TNF on osteoclastogenesis in vitro, different concentrations of TNF were added to spleen cell-derived monocytes in the absence or presence of different concentrations of RANKL. In addition, the effects of TNF inhibition on osteoclast precursors as well as local bone destruction in vivo were assessed by treating TNF-transgenic mice with different doses of adalimumab. RESULTS: TNF stimulated osteoclastogenesis mainly by increasing the number of osteoclast precursor cells in vitro. This TNF effect was independent of the presence of RANKL. In the hTNF-transgenic mouse model of destructive arthritis, low-dose TNF-inhibiting therapy with adalimumab had no effect on synovial inflammation but significantly inhibited local bone destruction and the generation of osteoclasts. This inhibition was accompanied by a reduction in the number of c-Fms-positive osteoclast precursor cells in the bone marrow and a reduction of the osteoclast precursor pools in the blood and inflamed synovial membrane of hTNF-transgenic mice. CONCLUSION: Low-dose TNF-inhibiting therapy significantly reduces bone erosions by reducing the number of circulating and joint-invading osteoclast precursors. This effect is uncoupled from its antiinflammatory action.

Periconceptional Counselling in Women with Autoimmune Inflammatory Rheumatic Diseases.

Systemic autoimmune rheumatic diseases (SARDs) in pregnancy represent a complex challenge for both patients and healthcare providers. Timely preparation for pregnancy enables adequate disease control, thereby reducing the risk of disease flare and pregnancy complications. Interdisciplinary care starting from the pre-pregnancy period throughout pregnancy and during breastfeeding ensures better fetal and maternal outcomes. This review provides a comprehensive guide to pre-pregnancy counselling in SARDs, an overview of medication management strategies tailored to pregnancy, disease activity and pregnancy monitoring in patients, and the promotion of shared decision making between healthcare providers and patients. Guidelines from international organizations were selected to provide a basis for this review and guidance through the quintessential discussion points of care.

Impact of TNF-blocking agents on male sperm characteristics and pregnancy outcomes in fathers exposed to TNF-blocking agents at time of conception.

OBJECTIVES: Published data were analysed to determine if the use of tumour necrosis factor (TNF) blocking agents in male patients during time of conception is associated with an increased risk of fetal abnormalities or complications during pregnancy. Moreover, we were interested in the impact of TNFblocking agents on sperm quality characteristics. METHODS: We performed a systematic literature review (Medline, online archives of Annual European Congress of Rheumatology and the American College of Rheumatology). One-hundred and thirty-nine Articles of potentially relevant reports were identified and screened for retrieval and nine articles were included in the final analysis. RESULTS: Overall, there were sixty cases, where expectant fathers used TNFblocking agents shortly before conception. The outcomes of the pregnancies are documented in twenty-eight events. We did not find any documentation of miscarriages or physical abnormities associated with TNF blocking treatment and paternity; however, we did find documentation evidence that sperm motility and vitality even may improve under TNF-blocking therapy. This improvement may be caused by a decrease in disease activity. CONCLUSIONS: Published data suggest that TNF-blocking therapy in male patients during time of conception does not increase the risk of adverse pregnancy outcome. In addition TNF-blocking therapy does not appear to reduce male fertility.

Essential role of microRNA-155 in the pathogenesis of autoimmune arthritis in mice.

OBJECTIVE: MicroRNAs (miRNA) are a new class of regulatory elements. Altered expression of miRNA has been demonstrated in the inflamed joints of patients with rheumatoid arthritis (RA). The aim of this study was to examine the role of miRNA in the pathogenesis of autoimmune arthritis, using 2 murine models. METHODS: Collagen-induced arthritis (CIA) and K/BxN serum-transfer arthritis were induced in wild-type (WT) and miR-155-deficient (miR-155(-/-) ) mice. The severity of arthritis was determined clinically and histologically. Anticollagen antibodies and cytokines were measured by enzyme-linked immunosorbent assay. The cellular composition of the draining lymph nodes after induction of CIA was measured by flow cytometry. RESULTS: The miR-155(-/-) mice did not develop CIA. Deficiency in miR-155 prevented the generation of pathogenic autoreactive B and T cells, since anticollagen antibodies and the expression levels of antigen-specific T cells were strongly reduced in miR-155(-/-) mice. Moreover, Th17 polarization of miR-155(-/-) mouse T cells was impaired, as shown by a significant decrease in the levels of interleukin-17 (IL-17) and IL-22. In the K/BxN serum-transfer arthritis model, which only depends on innate effector mechanisms, miR-155(-/-) mice showed significantly reduced local bone destruction, attributed to reduced generation of osteoclasts, although the severity of joint inflammation was similar to that in WT mice. CONCLUSION: These results demonstrate that miR-155 is essentially involved in the adaptive and innate immune reactions leading to autoimmune arthritis, and therefore miR-155 might provide a novel target for the treatment of patients with RA.

Heterologous vector versus homologous mRNA COVID-19 booster vaccination in non-seroconverted immunosuppressed patients: a randomized controlled trial.

Impaired response to COVID-19 vaccination is of particular concern in immunosuppressed patients. To determine the best vaccination strategy for this vulnerable group we performed a single center, 1:1 randomized blinded clinical trial. Patients who failed to seroconvert upon two mRNA vaccinations (BNT162b2 or mRNA-1273) are randomized to receive either a third dose of the same mRNA or the vector vaccine ChAdOx1 nCoV-19. Primary endpoint is the difference in SARS-CoV-2 spike antibody seroconversion rate between vector and mRNA vaccinated patients four weeks after the third dose. Secondary outcomes include cellular immune responses. Seroconversion rates at week four are significantly higher in the mRNA (homologous vaccination, 15/24, 63%) as compared to the vector vaccine group (heterologous vaccination, 4/22, 18%). SARS-CoV-2-specific T-cell responses are reduced but could be increased after a third dose of either vector or mRNA vaccine. In a multivariable logistic regression analysis, patient age and vaccine type are associated with seroconversion. No serious adverse event is attributed to COVID-19 booster vaccination. Efficacy and safety data underline the importance of a booster vaccination and support the use of a homologous mRNA booster vaccination in immunosuppressed patients.Trial registration: EudraCT No.: 2021-002693-10.

Immunosuppressives and biologics during pregnancy and lactation : A consensus report issued by the Austrian Societies of Gastroenterology and Hepatology and Rheumatology and Rehabilitation.

An increasing and early-onset use of immunosuppressives and biologics has become more frequently seen among patients with inflammatory bowel diseases (IBD) and rheumatic disorders. Many women in their childbearing years currently receive such medications, and some of them in an interdisciplinary setting. Many questions arise in women already pregnant or wishing to conceive with respect to continuing or discontinuing treatment, the risks borne by the newborns and their mothers and long-term safety. Together with the Austrian Society of Rheumatology and Rehabilitation, the IBD working group of the Austrian Society of Gastroenterology and Hepatology has elaborated consensus statements on the use of immunosuppressives and biologics in pregnancy and lactation. This is the first Austrian interdisciplinary consensus on this topic. It is intended to serve as a basis and support for providing advice to our patients and their treating physicians.

MicroRNA-155 Controls T Helper Cell Activation During Viral Infection.

MicroRNA (miR) 155 has been implicated in the regulation of innate and adaptive immunity as well as autoimmune processes. Importantly, it has been shown to regulate several antiviral responses, but its contribution to the immune response against cytopathic viruses such as vesicular stomatitis virus (VSV) infections is not known. Using transgenic/recombinant VSV expressing ovalbumin, we show that miR-155 is crucially involved in regulating the T helper cell response against this virus. Our experiments indicate that miR-155 in CD4+ T cells controls their activation, proliferation, and cytokine production in vitro and in vivo upon immunization with OVA as well as during VSV viral infection. Using intravital multiphoton microscopy we analyzed the interaction of antigen presenting cells (APCs) and T cells after OVA immunization and found impaired complex formation when using miR-155 deficient CD4+ T cells compared to wildtype CD4+ T cells ex vivo. In contrast, miR-155 was dispensable for the maturation of myeloid APCs and for their T cell stimulatory capacity. Our data provide the first evidence that miR-155 is required for efficient CD4+ T cell activation during anti-viral defense by allowing robust APC-T cell interaction required for activation and cytokine production of virus specific T cells.

MicroRNA 155-deficiency leads to decreased autoantibody levels and reduced severity of nephritis and pneumonitis in pristane-induced lupus.

OBJECTIVE: We herein examine the role of endogenous miR155 in the development of systemic manifestations in pristane induced lupus. MATERIALS AND METHODS: Systemic lupus in miR155-deficient and wild type mice was induced upon injection of pristane and analyzed after 8 months, PBS-injected mice served as controls. Glomerulonephritis and pneumonitis were quantified using the kidney biopsy score and a newly adapted histomorphometric image analysis system; lung tissue was further analyzed by tissue cytometry. Serum levels of anti-dsDNA, anti-histone and anti-chromatin antibodies were measured by ELISA. Frequencies of B cells, activated and regulatory CD4+ T cells as well as Th1, Th2, Th17 cells were measured by flow cytometry. RT-qPCR was used to measure expression levels of interferon-signature and T-cell subset related as well as miR155-associated genes. RESULTS: After induction of lupus, miR155-deficient mice had significant less pulmonary involvement (perivascular inflammatory area in mm2/mm2 lung area 0.00092±0.00015 vs. 0.0027±0.00075, p = 0.0347) and renal disease (glomerular activity score 1.95±0.19 vs 3±0.26, p = 0.0029) compared to wild types. MiR155-deficient mice had significantly lower serum levels of disease-associated auto-antibodies and decreased frequencies of activated CD4+CD25+ (Foxp3-) cells. Upon restimulation, CD4+ cells showed a less pronounced Th2 and Th17 and a slightly decreased Th1 response in mir155-deficient mice. Pristane-treated wild types showed significantly up-regulated expression of genes related to the INF-signature (MX1, IP10, IRF7, ISG15). CONCLUSIONS: MiR155-deficient mice had less severe organ involvement, lower serum auto-antibody levels, a less prominent T cell response and lower expressions of genes jointly responsible for disease development. Thus, antagonizing miR155 might be a future approach in treating SLE.

Therapeutic Modulation of Plasmacytoid Dendritic Cells in Experimental Arthritis.

OBJECTIVE: The role of plasmacytoid dendritic cells (PDCs) and type I interferons (IFNs) in rheumatoid arthritis (RA) remains a subject of controversy. This study was undertaken to explore the contribution of PDCs and type I IFNs to RA pathogenesis using various animal models of PDC depletion and to monitor the effect of localized PDC recruitment and activation on joint inflammation and bone damage. METHODS: Mice with K/BxN serum-induced arthritis, collagen-induced arthritis, and human tumor necrosis factor transgene insertion were studied. Symptoms were evaluated by visual scoring, quantification of paw swelling, determination of cytokine levels by enzyme-linked immunosorbent assay, and histologic analysis. Imiquimod-dependent therapeutic effects were monitored by transcriptome analysis (using quantitative reverse transcriptase-polymerase chain reaction) and flow cytometric analysis of the periarticular tissue. RESULTS: PDC-deficient mice showed exacerbation of inflammatory and arthritis symptoms after arthritogenic serum transfer. In contrast, enhancing PDC recruitment and activation to arthritic joints by topical application of the Toll-like receptor 7 (TLR-7) agonist imiquimod significantly ameliorated arthritis in various mouse models. Imiquimod induced an IFN signature and led to reduced infiltration of inflammatory cells. CONCLUSION: The therapeutic effects of imiquimod on joint inflammation and bone destruction are dependent on TLR-7 sensing by PDCs and type I IFN signaling. Our findings indicate that local recruitment and activation of PDCs represents an attractive therapeutic opportunity for RA patients.