Histopathological features of gastrointestinal mucosal biopsies in children with juvenile idiopathic arthritis

Faecal Bacteriome and Metabolome Profiles Associated with Decreased Mucosal Inflammatory Activity Upon Anti-TNF Therapy in Paediatric Crohn's Disease

BACKGROUND AND AIMS

Treatment with anti-tumour necrosis factor α antibodies [anti-TNF] changes the dysbiotic faecal bacteriome in Crohn's disease [CD]. However, it is not known whether these changes are due to decreasing mucosal inflammatory activity or whether similar bacteriome reactions might be observed in gut-healthy subjects. Therefore, we explored changes in the faecal bacteriome and metabolome upon anti-TNF administration [and therapeutic response] in children with CD and contrasted those to anti-TNF-treated children with juvenile idiopathic arthritis [JIA].

METHODS

Faecal samples collected longitudinally before and during anti-TNF therapy were analysed with regard to the bacteriome by massively parallel sequencing of the 16S rDNA [V4 region] and the faecal metabolome by 1H nuclear magnetic resonance imaging. The response to treatment by mucosal healing was assessed by the MINI index at 3 months after the treatment started. We also tested several representative gut bacterial strains for in vitro growth inhibition by infliximab.

RESULTS

We analysed 530 stool samples from 121 children [CD 54, JIA 18, healthy 49]. Bacterial community composition changed on anti-TNF in CD: three members of the class Clostridia increased on anti-TNF, whereas the class Bacteroidia decreased. Among faecal metabolites, glucose and glycerol increased, whereas isoleucine and uracil decreased. Some of these changes differed by treatment response [mucosal healing] after anti-TNF. No significant changes in the bacteriome or metabolome were noted upon anti-TNF in JIA. Bacterial growth was not affected by infliximab in a disc diffusion test.

CONCLUSIONS

Our findings suggest that gut mucosal healing is responsible for the bacteriome and metabolome changes observed in CD, rather than any general effect of anti-TNF.

Nutritional Aspects of Juvenile Idiopathic Arthritis: An A to Z for Dietitians

Juvenile idiopathic arthritis (JIA) represents a chronic, autoimmune, rheumatic musculoskeletal disease with a diagnosis before 16 years of age. Chronic arthritis is a common manifestation in all JIA subtypes. The nature of JIA, in combination to its therapy often results in the development of nutrition-, gastrointestinal (GI)- or metabolic-related issues. The most-common therapy-related nutritional issues involve methotrexate (MTX) and glucocorticosteroids (GCC) adverse events. MTX is a folic acid antagonist, thus supplementation with folic acid in required for improving GI side effects and correcting low serum levels. On the other hand, long-term GCC administration is often associated with hyperglycemia, insulin resistance and growth delay. This relationship is further aggravated when more joints are affected and greater doses of GCC are being administered. Apart from stature, body mass index z-scores are also suboptimal in JIA. Other signs of malnutrition include decreased phase angle and muscle mass, especially among patients with polyarthritis JIA. Evidence also points to the existence of an inverse relationship between disease activity and overweight/obesity. Specific dietary patterns, including the anti-inflammatory diet, might confer improvements in selected JIA outcomes, but the level of available research is yet insufficient to draw safe conclusions. The majority of patients exhibit suboptimal vitamin D status; hence, supplementation is recommended. Collectively, the evidence indicates that, due to the age of onset and the complexity of the disease, along with its pharmacotherapy, children with JIA are prone to the development of several nutritional problems, warranting expert monitoring. Vitamin deficiencies, oral and GI-problems limiting dietary intake, faltering growth, overweight and obesity, physical inactivity, or impaired bone health are among the many nutritional issues in JIA requiring dietitian support.

Abdominal pain in Finnish young adults with juvenile idiopathic arthritis

OBJECTIVES

Abdominal pain (AP) is a common feature in the general population. However, in patients with juvenile idiopathic arthritis (JIA) AP has scantily been studied. Among other reasons, gastrointestinal symptoms may present as side effects due to the medical treatment of JIA. The aim of the study was to explore the frequency of AP and its relationship to disease components and health-related quality of life (HRQoL) among young adults with JIA.

METHODS

This study included a cohort of 97 Finnish patients belonging to the population-based Nordic JIA cohort at their 17-year follow-up study visit. Mean age of the patients was 23 years. AP, functional status, fatigue, HRQoL, disease characteristics of JIA, and comorbidities were evaluated. AP was classified into three categories according to frequency: (1) never, (2) seldom (one to three times a month) and (3) frequent (at least once a week).

RESULTS

About 48 (50%) young adults with JIA reported AP. Seldom AP was reported by 37 (38%), and frequent AP by 11 (11%) patients. AP was significantly associated with fatigue, female gender, functional status and arthritis-related pain. Patients having frequent AP reported lower HRQoL. AP was associated with the use of methotrexate and sulfasalazine, but not with nonsteroidal anti-inflammatory drugs (NSAIDs).

CONCLUSION

AP is an important complaint in young adults with JIA and is associated with fatigue, female gender, methotrexate and sulfasalazine use. Patients with JIA reporting frequent AP with lower functional status and higher arthritis-related pain values have lower HRQoL.

The Increased Levels of Fecal Calprotectin in Children With Active Enthesitis Related Arthritis and MRI Signs of Sacroiliitis: The Results of a Single Center Cross-Sectional Exploratory Study in Juvenile Idiopathic Arthritis Patients

Enthesitis related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA), often regarded as an undifferentiated form of juvenile spondyloarthritis (jSpA). While gut is increasingly recognized as origin and/or target of inflammation in adult onset spondyloarthritis (SpA), the incidence of gut involvement in ERA patients is largely unknown. The aim of this study was to measure the concentration of fecal calprotectin (fCAL), a surrogate marker of gut inflammation, in patients with different subtypes of JIA, as well as to correlate the results with various demographic, clinical, laboratory, imaging, and treatment characteristics. The cross-sectional exploratory study involving 71 patients with ERA, other forms of JIA and children complaining musculoskeletal symptoms was therefore conducted. Along with fCAL assessment, a detailed clinical and laboratory examination was performed, including the calculation of a composite disease activity scores. Moreover, MRI of the sacroiliac joints was performed in all ERA and other patients complaining of low back pain. The median concentration of fCAL was highest in ERA patients (33.2 mg/kg, p = 0.02), with a significant difference between those with inactive and active disease (20.0 vs. 57.4, p = 0.01), as well as those with and without MRI signs of sacroiliitis (22.6 vs. 54.3, p = 0.04). The fCAL did not differ depending on the NSAID use (23 vs. 20, p = 0.18), although weak correlation was observed with the treatment duration (r = 0.25, p = 0.03). In conclusion, our findings indicate that a parallel inflammation in musculoskeletal system and gut can occur not just in adults with SpA, but in children with ERA as well.

Enthesitis-related arthritis: current perspectives

In this narrative review, we overview the recent literature on enthesitis-related arthritis (ERA). For the purpose of our review, we searched Scopus for recent articles on this subject from 2013 onward, including some classic older articles for perspective. ERA is a juvenile idiopathic arthritis (JIA) subtype more common in males, associated in a majority with human leucocyte antigen B27. Such children generally present with asymmetric oligoarthritis or polyarthritis, predominantly of lower limb joints, associated with enthesitis or sacroiliitis. While diagnosis remains clinical, ultrasound is being increasingly used to detect subclinical enthesitis and for guiding entheseal site injections. Spine MRI can help detect sacroiliitis, inflammatory spinal changes, and pelvic sites of enthesitis in such patients. The recent juvenile spondyloarthropathy disease activity index recognizes the key clinical features of ERA, viz enthesitis and inflammatory back pain, which other disease activity indices used in JIA did not include. Management includes NSAIDs with physical therapy. Conventional disease-modifying agents like sulfasalazine and methotrexate may be used to minimize duration of NSAID use and in those with high inflammatory burden. In patients refractory to these drugs, biologics such as antitumor necrosis factor alpha agents have proven useful, based on evidences from randomized controlled trials and retrospective registry analyses. Factors predicting a poorer outcome in such children include hip or ankle involvement or restricted spinal mobility. Considering that children with ERA have overall poorer long-term outcomes than other subtypes of JIA, there is a need to further optimize therapeutic strategies for such patients.

Serologic Evidence of Gut-driven Systemic Inflammation in Juvenile Idiopathic Arthritis

OBJECTIVE

Accumulating evidence links juvenile idiopathic arthritis (JIA) to nonhost factors such as gut microbes. We hypothesize that children with new-onset JIA have increased intestinal bacterial translocation and circulating lipopolysaccharide (LPS).

METHODS

We studied systemic treatment-naive patients with JIA [polyarticular JIA, n = 22, oligoarticular JIA, n = 31, and spondyloarthropathies (SpA), n = 16], patients with established inflammatory bowel disease-related arthritis (IBD-RA, n = 11), and 34 healthy controls. We determined circulating IgG reactivity against LPS, LPS-binding protein (LBP), α-1-acid glycoprotein (α-1AGP), and C-reactive protein (CRP) in plasma or serum from these patients and controls. Juvenile Arthritis Disease Activity Score (JADAS-27) was calculated for patients with JIA.

RESULTS

Circulating anticore LPS antibody concentrations in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.024), and SpA (p = 0.001) were significantly greater than in controls, but there were no significant intergroup differences. Circulating LBP concentrations were also significantly greater in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.002), and SpA (p = 0.006) than controls, as were α-1AGP concentrations (p = 0.001, 0.001, and 0.003, respectively). No differences were observed between controls and patients with IBD-RA in any of the assays. Circulating concentrations of LBP and α-1AGP correlated strongly with CRP concentrations (r = 0.78 and r = 0.66, respectively). Anticore LPS antibody levels and CRP (r = 0.26), LBP (r = 0.24), and α-AGP (r = 0.22) concentrations had weaker correlations. JADAS-27 scores correlated with LBP (r = 0.66) and α-1AGP concentrations (r = 0.58).

CONCLUSION

Children with polyarticular JIA, oligoarticular JIA, and SpA have evidence of increased exposure to gut bacterial products. These data reinforce the concept that the intestine is a source of immune stimulation in JIA.

Cow's Milk Allergy in Infancy and Later Development of Juvenile Idiopathic Arthritis: A Register-Based Case-Control Study

We examined the association between cow's milk allergy (CMA) and juvenile idiopathic arthritis (JIA). The material for this case-control study was collected from national registers of all children born in Finland between 2000 and 2010 and diagnosed with JIA (n = 1,298) and age-, sex-, and place-matched controls (n = 5,179). We identified 235 children with CMA; 66 of these children also had JIA. A conditional logistic regression analysis was performed to evaluate the association between CMA and JIA and to test whether exposure to antibiotics would be a covariate for this association. In boys (but not in girls), a diagnosis of CMA and the use of hypoallergenic formula in infancy were associated with the later development of JIA (odds ratio = 2.4, 95% confidence interval: 1.6, 3.6). The association was most evident in boys who were diagnosed with JIA before age 3 years or diagnosed with CMA with predominantly gastrointestinal symptoms. There was no statistically significant additive interaction between CMA and antibiotic exposure in the later development of JIA. These associations may reflect impaired maturation of intestinal immunity and integrity in boys with a risk of JIA. Predisposing factors related to JIA pathogenesis seem to display a sex-linked disparity.

Inflammatory bowel disease following anti-interleukin-1-treatment in systemic juvenile idiopathic arthritis

BACKGROUND

Inflammatory bowel disease can develop in the context of some rheumatic diseases in childhood, including juvenile idiopathic arthritis (JIA). Inflammatory bowel disease (IBD) is frequently associated with other immune-mediated diseases; however, systemic onset JIA (sJIA) has not previously been connected to IBD. Treatment of sJIA has significantly changed in recent years, possibly causing changes in inflammatory patterns. Therefore, data from the German Center for Pediatric and Adolescent Rheumtology from 2010 until 2015 were analyzed by retrospective chart review.

FINDINGS

Eighty-two patients with confirmed diagosis of sJIA were found. Of these, three were identified with a diagnosis of IBD confirmed by colonoscopy (two cases of Crohn's disease, one case of ulcerative colitis) 0.8 - 4.3 years after diagnosis. All three were treated with IL-1 antagonists (anakinra in two cases, canakinumab in one case) and were well controlled for sJIA symptoms at time of diagnosis of IBD CONCLUSIONS: IBD seems to be a rare, but possible complication of sJIA. Treatment with IL-1 antagonists might be a relevant factor for a switch in the clinical phenotype of the underlying inflammatory process.

CD161+ Tconv and CD161+ Treg Share a Transcriptional and Functional Phenotype despite Limited Overlap in TCRβ Repertoire

Human regulatory T cells (Treg) are important in immune regulation, but can also show plasticity in specific settings. CD161 is a lectin-like receptor and its expression identifies an effector-like Treg population. Here, we determined how CD161⁺ Treg relate to CD161⁺ conventional T cells (Tconv). Transcriptional profiling identified a shared transcriptional signature between CD161⁺ Tconv and CD161⁺ Treg, which is associated with T helper (Th)1 and Th17 cells, and tissue homing, including high expression of gut-homing receptors. Upon retinoic acid (RA) exposure, CD161⁺ T cells were more enriched for CCR9⁺ and integrin α4⁺β7⁺ cells than CD161^- T cells. In addition, CD161⁺ Tconv and CD161⁺ Treg were enriched at the inflamed site in autoimmune arthritis, and both CD161⁺ and CD161^- Treg from the inflamed site were suppressive in vitro. CD161⁺ T cells from the site of autoimmune arthritis showed a diminished gut-homing phenotype and blunted response to RA suggesting prior imprinting by RA in the gut or at peripheral sites rather than during synovial inflammation. TCRβ repertoires of CD161⁺ and CD161^- Tconv and Treg from blood showed limited overlap whereas there was clear overlap between CD161⁺ and CD161^- Tconv, and CD161⁺ and CD161^- Treg from the inflamed site suggesting that the inflamed environment may alter CD161 levels, potentially contributing to disease pathogenesis.

Gut microbiota-host interactions and juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis is the most common form of chronic arthritis in children. There is mounting evidence that the microbiota may influence the disease.

MAIN BODY

Recent observations in several systemic inflammatory diseases including JIA have indicated that abnormalities in the contents of the microbiota may be factors in disease pathogenesis, while other studies in turn have shown that environmental factors impacting the composition of the microbiota, such as delivery mode and early exposure to antibiotics, affect the risk of chronic inflammatory diseases including JIA. Microbial alterations may predispose to JIA through a variety of mechanisms, including impaired immunologic development, alterations in the balances of pro- versus anti-inflammatory bacteria, and low-grade mucosal inflammation. Additional confirmatory studies of microbiota aberrations and their risk factors are needed, as well as additional mechanistic studies linking these alterations to the disease itself.

CONCLUSIONS

The microbiota may influence the risk of JIA and other systemic inflammatory conditions through a variety of mechanisms. Additional research is required to improve our understanding of the links between the microbiota and arthritis, and the treatment implications thereof.