The influence of early life factors on the risk of developing rheumatoid arthritis

Deciphering the different phases of preclinical inflammatory bowel disease

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory disease (IMID) of the gastrointestinal tract and includes two subtypes: Crohn's disease and ulcerative colitis. It is well-recognized that IBD is associated with a complex multifactorial aetiology that includes genetic predisposition and environmental exposures, with downstream dysregulation of systemic immune function and host-microbial interactions in the local environment in the gut. Evidence to support the notion of a multistage development of IBD is growing, as has been observed in other IMIDs such as rheumatoid arthritis and systemic lupus erythematosus. With the rising worldwide incidence of IBD, it is increasingly important to understand the complex interplay of pathological events during the different stages of disease development to enable IBD prediction and prevention strategies. In this article, we review comprehensively the current evidence pertaining to the preclinical phase of IBD, including at-risk, initiation and expansion phases. We also discuss the framework of preclinical IBD, expanding on underlying pathways in IBD development, future research directions and IBD development in the context of other IMIDs.

Voluntary wheel running from early adolescence reduces disease progression, and anxiety- and depression-related symptoms in an adult male mouse model of rheumatoid arthritis

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease that progressively destroys synovial joints and leads to chronic systemic inflammation. This autoimmune disorder is associated with increased anxiety- and depression-related symptoms, which reduces quality of life. Clinical and experimental evidence suggests that higher physical activity from early adolescence may prevent chronic diseases and reduce the risk of mental health problems in adulthood. This study aimed to assess whether voluntary wheel running from early adolescence can decrease clinical symptoms, anxiety- and depression-related behaviors in adult mice with rheumatoid arthritis. Adolescent male mice were exposed to voluntary wheel running until adulthood and got collagen-induced arthritis. We measured body weight, the thickness of the hind paw and knee joint (clinical signs), anxiety- and depression-related behaviors, serum testosterone, and cytokines (IFN-γ IL-1β, IL-6, TNF-α, IL-10). The findings showed that collagen-induced arthritis resulted in anxious-like behavior, increased anhedonia, elevated IL-6, IL-1β, TNF-α, and IFN-γ, and decreased testosterone levels in the serum of mice. However, no change was observed in behavioral despair. We found that higher physical activity from early adolescence significantly reduced the severity of clinical signs, anxiety- and anhedonia-like behaviors, and decreased behavioral despair in RA-induced mice. In addition, the running wheel exposure normalized RA-induced abnormalities in testosterone and inflammatory cytokines in mice. Altogether, this study suggests that higher physical activity from early adolescence may make mice less vulnerable or resistant to RA-induced clinical symptoms and anxiety- and depression-related behaviors by changing testosterone and inflammatory cytokines productions in adulthood.

Epidemiology and Risk Factors for Rheumatoid Arthritis Development

Rheumatoid arthritis (RA) is a prevalent chronic inflammatory arthritis worldwide, significantly impacting patients and population health. The disease affects women primarily, with a female-to-male ratio of three to one. Its pathogenesis is multifactorial, including genetic and environmental risk factors. Epidemiological studies highlight the link between the environment and genetic susceptibility to RA. The so-called shared epitope is the most significant risk factor that seems to act synergetic with other environmental factors in the disease occurrence. In addition, recent findings suggest a potential role of new substantial environmental factors, such as the observed pollution of the planet's natural resources, on the susceptibility and progression of the disease. This review summarises the most decisive evidence on epidemiology and genetic, environmental, and lifestyle risk factors for RA. It shows that studying genetic and environmental factors in correlation could lead to prevention strategies that may impact the natural history of the disease.

Perinatal events and development of juvenile idiopathic arthritis-associated uveitis

Uveitis is one of the most common manifestations of juvenile idiopathic arthritis (JIA). Currently, JIA is associated with decreased gut microbiota diversity. Studies confirm that perinatal events can cause aberrant microbial colonization. The objective of this study is to determine if JIA is associated with perinatal events with a secondary focus on these variables to the development of JIA-uveitis. 369 patients with strabismus (n = 200) or JIA (n = 196) were included in the study. Completed surveys (JIA 37; strabismus 18) collected data about birth route, pregnancy and labor complications, JIA medications, and the presence of eye disorders. Analysis indicates that there is no relationship between JIA development and the perinatal events investigated. Similarly, no significance was found between JIA-uveitis and birth route or labor complications. Pregnancy complications, namely gestational diabetes (GD), were statistically higher in the JIA group with uveitis compared to JIA without uveitis. The data from this survey study showed that JIA-uveitis was highly associated with pregnancy complications, particularly with GD. However, no statistically significant association was found between JIA and route of delivery, labor complications, or pregnancy complications. Further studies are needed to understand the ways that GD interrelates with the development of uveitis in JIA patients.

The co-occurrence and cumulative prevalence of hypertension, rheumatoid arthritis, and hypothyroidism in preterm-born women in the Women's Health Initiative

Emerging evidence suggests that preterm-born individuals (<37 weeks gestation) are at increased risk of developing chronic health conditions in adulthood. This study compared the prevalence, co-occurrence, and cumulative prevalence of three female predominant chronic health conditions - hypertension, rheumatoid arthritis [RA], and hypothyroidism - alone and concurrently. Of 82,514 U.S. women aged 50-79 years enrolled in the Women's Health Initiative, 2,303 self-reported being born preterm. Logistic regression was used to analyze the prevalence of each condition at enrollment with birth status (preterm, full term). Multinomial logistic regression models analyzed the association between birth status and each condition alone and concurrently. Outcome variables using the 3 conditions were created to give 8 categories ranging from no disease, each condition alone, two-way combinations, to having all three conditions. The models adjusted for age, race/ethnicity, and sociodemographic, lifestyle, and other health-related risk factors. Women born preterm were significantly more likely to have any one or a combination of the selected conditions. In fully adjusted models for individual conditions, the adjusted odds ratios (aORs) were 1.14 (95% CI, 1.04, 1.26) for hypertension, 1.28 (1.12, 1.47) for RA, and 1.12 (1.01, 1.24) for hypothyroidism. Hypothyroidism and RA were the strongest coexisting conditions [aOR 1.69, 95% CI (1.14, 2.51)], followed by hypertension and RA [aOR 1.48, 95% CI (1.20, 1.82)]. The aOR for all three conditions was 1.69 (1.22, 2.35). Perinatal history is pertinent across the life course. Preventive measures and early identification of risk factors and disease in preterm-born individuals are essential to mitigating adverse health outcomes in adulthood.

Vitamin D Concentrations at Birth and the Risk of Rheumatoid Arthritis in Early Adulthood: A Danish Population-Based Case-Cohort Study

Background: Low vitamin D in pregnancy may impair the development of the fetal immune system and influence the risk of later development of rheumatoid arthritis (RA) in the offspring. The aim was to examine whether lower 25-hydroxyvitamin D3 (25(OH)D) concentrations at birth were associated with the risk of developing RA in early adulthood. Methods: This case-cohort study obtained data from Danish registers and biobanks. Cases included all individuals born during 1981−1996 and recorded in the Danish National Patient Register with a diagnosis of RA with age >18 years at first admission. The random comparison consisted of a subset of Danish children. Vitamin D concentrations were measured in newborn dried blood. In total, 805 RA cases and 2416 individuals from the subcohort were included in the final analysis. Weighted Cox regression was used to calculate hazard ratio (HR). Results: The median (interquartile rage (IQR)) 25(OH)D concentrations among cases were 24.9 nmol/L (IQR:15.4;36.9) and 23.9 nmol/L (IQR:13.6;36.4) among the subcohort. There was no indication of a lower risk of RA among individuals in the highest vitamin D quintile compared with the lowest (HRadj.:1.21 (0.90;1.63)). Conclusion: The risk of RA in early adulthood was not associated with vitamin D concentrations at birth.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

Birthweight, body size, and growth during childhood and risks of rheumatoid arthritis: a large Danish cohort study

Objectives: Adult obesity may be positively associated with risks of rheumatoid arthritis (RA), but associations with early life body size are unknown. We examined whether birthweight, childhood body mass index (BMI), height, and changes in BMI and height were associated with risks of adult RA.Method: A cohort of 346 602 children (171 127 girls) from the Copenhagen School Health Records Register, born in 1930-1996, with measured weights and heights from 7 to 13 years of age, were included. Information on RA, including serological status, came from national registers from 1977 to 2017. Cox regressions were performed.Results: During a median of 35.1 years of observation time per person, 4991 individuals (3565 women) were registered with RA. Among girls, per BMI z-score, risks of RA and seropositive RA increased by 4-9% and 6-10%, respectively. Girls with overweight had higher risks of RA than girls without overweight. Girls who became overweight by 13 years of age had increased risks of RA compared to girls without overweight at 7 or 13 years (hazard ratio = 1.40, 95% confidence interval 1.19-1.66). For boys, associations between BMI and RA (including seropositive RA) were not statistically significant. Height was not associated with RA (any type) in girls. Taller boys had higher risks of RA, especially seropositive RA. Birthweight was not associated with RA.Conclusions: Among women, childhood adiposity was associated with increased risks of RA. Among men, childhood height was positively associated with risks of RA. These findings support the hypothesis that early life factors may be important in the aetiology of RA.

When Problems Only Get Bigger: The Impact of Adverse Childhood Experience on Adult Health

Introduction: Previous studies have shown that adverse childhood experiences negatively impact child development, with consequences throughout the lifespan. Some of these consequences include the exacerbation or onset of several pathologies and risk behaviors. Materials and Methods: A convenience sample of 398 individuals aged 20 years or older from the Porto metropolitan area, with quotas, was collected. The evaluation was conducted using an anonymous questionnaire that included sociodemographic questions about exposure to adverse childhood experiences, a list of current health conditions, questions about risk behaviors, the AUDIT-C test, the Fagerström test and the Childhood Trauma Questionnaire-brief form. Variables were quantified to measure adverse childhood experiences, pathologies, and risk behaviors in adult individuals for comparison purposes. Results: Individuals with different forms of adverse childhood experiences present higher rates of smoking dependence, self-harm behaviors, victimization of/aggression toward intimate partners, early onset of sexual life, sexually transmitted infections, multiple sexual partners, abortions, anxiety, depression, diabetes, arthritis, high cholesterol, hypertension, and stroke. Different associations are analyzed and presented. Discussion and Conclusions: The results show that individuals with adverse childhood experiences have higher total scores for more risk behaviors and health conditions than individuals without traumatic backgrounds. These results are relevant for health purposes and indicate the need for further research to promote preventive and protective measures.

Adiposity and the risk of rheumatoid arthritis: a systematic review and meta-analysis of cohort studies

Several studies have investigated associations between overweight/obesity and risk of developing rheumatoid arthritis, however, the evidence is not entirely consistent, and previous meta-analyses mainly included case–control studies, which can be affected by various biases. We therefore conducted a systematic review and meta-analysis of cohort studies on adiposity and risk of rheumatoid arthritis. Relevant studies were identified by searching PubMed and Embase databases. Random effects models were used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs) for rheumatoid arthritis in relation to different measures of adiposity. Thirteen cohort studies (10 publications) were included. The summary RR per 5 kg/m² increase in body mass index (BMI) was 1.11 (95% CI 1.05–1.18, I² = 50%), but the association was restricted to women (1.15, 95% CI 1.08–1.21, I² = 17%) and not observed in men (0.89, 95% CI 0.73–1.09, I² = 58%). The summary RR per 5 kg/m² increment in BMI at age 18 years was 1.17 (95% CI 1.01–1.36, I² = 26%, n = 3), and per 10 cm increase in waist circumference was 1.13 (95% CI 1.02–1.25, I² = 44%, n = 2). Higher BMI in middle age, BMI at age 18 years, and waist circumference were associated with increased rheumatoid arthritis risk, suggesting adiposity could be targeted for primary prevention.

Continuous Developmental and Early Life Trichloroethylene Exposure Promoted DNA Methylation Alterations in Polycomb Protein Binding Sites in Effector/Memory CD4+ T Cells

Trichloroethylene (TCE) is an industrial solvent and drinking water pollutant associated with CD4⁺ T cell-mediated autoimmunity. In our mouse model, discontinuation of TCE exposure during adulthood after developmental exposure did not prevent immunotoxicity. To determine whether persistent effects were linked to epigenetic changes we conducted whole genome reduced representation bisulfite sequencing (RRBS) to evaluate methylation of CpG sites in autosomal chromosomes in activated effector/memory CD4⁺ T cells. Female MRL+/+ mice were exposed to vehicle control or TCE in the drinking water from gestation until ~37 weeks of age [postnatal day (PND) 259]. In a subset of mice, TCE exposure was discontinued at ~22 weeks of age (PND 154). At PND 259, RRBS assessment revealed more global methylation changes in the continuous exposure group vs. the discontinuous exposure group. A majority of the differentially methylated CpG regions (DMRs) across promoters, islands, and regulatory elements were hypermethylated (~90%). However, continuous developmental TCE exposure altered the methylation of 274 CpG sites in promoters and CpG islands. In contrast, only 4 CpG island regions were differentially methylated (hypermethylated) in the discontinuous group. Interestingly, 2 of these 4 sites were also hypermethylated in the continuous exposure group, and both of these island regions are associated with lysine 27 on histone H3 (H3K27) involved in polycomb complex-dependent transcriptional repression via H3K27 tri-methylation. CpG sites were overlapped with the Open Regulatory Annotation database. Unlike the discontinuous group, continuous TCE treatment resulted in 129 DMRs including 12 unique transcription factors and regulatory elements; 80% of which were enriched for one or more polycomb group (PcG) protein binding regions (i.e., SUZ12, EZH2, JARID2, and MTF2). Pathway analysis of the DMRs indicated that TCE primarily altered the methylation of genes associated with regulation of cellular metabolism and cell signaling. The results demonstrated that continuous developmental exposure to TCE differentially methylated binding sites of PcG proteins in effector/memory CD4⁺ cells. There were minimal yet potentially biologically significant effects that occurred when exposure was discontinued. These results point toward a novel mechanism by which chronic developmental TCE exposure may alter terminally differentiated CD4⁺ T cell function in adulthood.

Developmental Immunotoxicity (DIT) Testing: Current Recommendations and the Future of DIT Testing

Immune-based childhood diseases and conditions, including allergic diseases and asthma, recurrent otitis media, pediatric celiac disease, and type 1 diabetes have been on the rise over the past decades. As a result, the use of developmental immunotoxicity (DIT) testing to identify potential environmental risk factors contributing to these and other diseases has become a priority for scientists across sectors. This chapter serves to provide insight into the scientific basis for DIT and determining the necessity of DIT testing and offers recommendations for DIT testing parameters to optimize sensitivity, power, and concordance among DIT assays.

Temporomandibular Disorders and Oral Features in Early Rheumatoid Arthritis Patients: An Observational Study

Aims: Temporomandibular disorders (TMD) represent a heterogeneous group of inflammatory or degenerative diseases of the stomatognatic system, with algic and/or dysfunctional clinical features involving temporomandibular joint (TMJ) and related masticatory muscles. Rheumatoid Arthritis (RA) is an autoimmune polyarthritis characterized by the chronic inflammation of synovial joints and oral implications such as hyposalivation, difficulty in swallowing and phoning, feeling of burning mouth, increased thirst, loss of taste or unpleasant taste and smell, dental sensitivity. The aim of this observational study was to investigate the prevalence of TMD symptoms and signs as well as oral implications in patients with Early Rheumatoid Arthritis (ERA), that is a RA diagnosed within 12 months, compared with a control group. Methods: The study group included 52 ERA patients (11 men, 41 women) diagnosed according to the 2010 ACR/EULAR Classification Criteria for Rheumatoid Arthritis. A randomly selected group of 52 patients not affected by this disease, matched by sex and age, served as the control group. The examination for TMD signs and symptoms was based on the standardized Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) by means of a questionnaire and through clinical examination. Results: Regarding the oral kinematics, the left lateral excursion of the mandible was restricted in statistically significant way in ERA patients (p=0.017). The endfeel values were significantly increased in ERA group (p=0.0017), thus showing the presence of a higher muscle contracture. On the other side, the study group complained less frequently (67.3%) of TDM symptoms (muscle pain on chewing, pain in the neck and shoulders muscles, difficulty in mouth opening, arthralgia of TMJ, tinnitus) than controls (90.4%) (χ²= 8.301 p=0.0039). The presence of TMJ noises was significantly lower in the study group (χ²= 3.869 p=0.0049), as well as presence of opening derangement (χ²= 14.014 p=0.0002). The salivary flow was significantly decreased in the study group respect to the control one (p<0.0001). Conclusions: The data collected show a weak TMJ kinematic impairment, a paucisymptomatic muscle contracture (positive endfeel) and a remarkable reduction of salivary flow in ERA patients. Myofacial pain (MP) evoked by palpation was more frequent and severe in the control group than in the study one, this result being highly significant.

Epigenetic underpinnings of developmental immunotoxicity and autoimmune disease

The concordance rate for developing autoimmune disease in identical twins is around 50% demonstrating that gene and environmental interactions contribute to disease etiology. The environmental contribution to autoimmune disease is a wide-ranging concept including exposure to immunotoxic environmental chemicals. Because the immune system is immature during development suggests that adult-onset autoimmunity may originate when the immune system is particularly sensitive. Among the pollutants most closely associated with inflammation and/or autoimmunity include Bisphenol-A, mercury, TCDD, and trichloroethylene. These toxicants have been shown to impart epigenetic changes (e.g., DNA methylation) that may alter immune function and promote autoreactivity. Here we review these autoimmune-promoting toxicants and their relation to immune cell epigenetics both in terms of adult and developmental exposure.

Breastfeeding and autoimmunity: Programing health from the beginning

Breast milk is not only a completely adapted nutrition source for the newborn but also an impressive array of immune-active molecules that afford protection against infections and shape mucosal immune responses. Decisive imprinting events might be modulated during the first months of life with potential health long-term effects, enhancing the importance of breastfeeding as a major influence on the immune system correct development and modifying disease susceptibility. The aim of this review was to clarify the link between breastfeeding and autoimmune diseases, inquiring the related mechanisms, based on data available in the literature. Being breastfed was associated with a lower incidence of diabetes, celiac disease, multiple sclerosis and asthma, explained by the protection against early infections, anti-inflammatory properties, antigen-specific tolerance induction, and regulation of infant's microbiome. The protective role of human milk in idiopathic juvenile arthritis, rheumatoid arthritis, and inflammatory bowel diseases remains controversial. On the other hand, the breastfeeding mother faces a health-challenging period in life. High levels of prolactin may lead either to the development of autoimmune diseases in susceptible mothers or exacerbations of current immune-mediated disorders. These features raise the question if mothers with autoimmune diseases, mainly systemic lupus erythematosus, should avoid breastfeeding.

Exposure Cessation During Adulthood Did Not Prevent Immunotoxicity Caused by Developmental Exposure to Low-Level Trichloroethylene in Drinking Water

Exposure to the water pollutant trichloroethylene (TCE) can promote autoimmunity in both humans and rodents. Using a mouse model we have shown that chronic adult exposure to TCE at 500 μg/ml in drinking water generates autoimmune hepatitis in female MRL+/+ mice. There is increasing evidence that developmental exposure to certain chemicals can be more toxic than adult exposure. This study was designed to test whether exposure to a much lower level of TCE (0.05 μg/ml) during gestation, lactation, and early life generated autoimmunity similar to that found following adult exposure to higher concentrations of TCE. When female MRL+/+ mice were examined at postnatal day (PND) 259 we found that developmental/early life exposure [gestational day 0 to PND 154] to TCE at a concentration 10 000 fold lower than that shown to be effective for adult exposure triggered autoimmune hepatitis. This effect was observed despite exposure cessation at PND 154. In concordance with the liver pathology, female MRL+/+ exposed during development and early life to TCE (0.05 or 500 μg/ml) generated a range of antiliver antibodies detected by Western blotting. Expression of proinflammatory cytokines by CD4+ T cells was also similarly observed at PND 259 in the TCE-exposed mice regardless of concentration. Thus, exposure to TCE at approximately environmental levels from gestational day 0 to PND 154 generated tissue pathology and CD4+ T cell alterations that required higher concentrations if exposure was limited to adulthood. TCE exposure cessation at PND 154 did not prevent the immunotoxicity.

Juvenile idiopathic arthritis in relation to perinatal and maternal characteristics: a case control study

BACKGROUND

Existing data on associations between maternal and early childhood exposures and juvenile idiopathic arthritis (JIA) risk is scant and inconsistent with previous studies showing potential role for prematurity, number of siblings and infections. We explored JIA and International League of Associations for Rheumatology (ILAR) JIA categories in relation to selected infant (birthweight, size-for-gestational-age, gestational age), and maternal (parity, delivery type, prior fetal loss) characteristics that may be markers for exposures related to two pathways (hygiene hypothesis, microchimerism) potentially associated with autoimmune disorder occurrence.

METHODS

A case-control analysis with 1,234 JIA cases and 5,993 birth year-matched controls was conducted. Exposure information was obtained from WA state birth certificates. Multivariable logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) for associations with maternal and early life exposures for JIA and JIA categories.

RESULTS

Greater maternal parity was associated with a decreased OR for JIA (most marked for persistent oligoarticular JIA, OR 0.32, 95% CI 0.15; 0.71, p for trend = 0.0001). Prior fetal loss (except for oligoarticular JIA) was associated with an increased OR for JIA. Prematurity was associated with increased risk of enthesitis related arthritis (OR 1.9, 95% CI: 1.3-2.9) and rheumatoid factor positive polyarticular JIA (OR 2.2, 95% CI: 1.0-4.8).

CONCLUSIONS

We observed associations of selected maternal factors with JIA, some of which varied across JIA categories. The findings of decreased ORs for JIA in relation to greater maternal parity may be consistent with the hygiene and microchimerism hypotheses. Future studies with biomarkers relevant to these hypotheses will help elucidate any associations.

Low birthweight is associated with an increased risk of LADA and type 2 diabetes: results from a Swedish case-control study

AIMS/HYPOTHESIS

Our aim was to investigate the association between birthweight and latent autoimmune diabetes in adults (LADA), a common diabetes form with features of both type 1 and type 2 diabetes.

METHODS

We used data from the Epidemiological Study of Risk Factors for LADA and Type 2 Diabetes (ESTRID), a Swedish population-based study. Eligible for the analysis were 134 incident LADA cases (glutamic acid decarboxylase antibody [GADA] positive), 350 incident type 2 diabetes cases (GADA negative) and 603 randomly selected controls. We present ORs and 95% CIs for LADA and type 2 diabetes in relation to birthweight, adjusted for sex, age, BMI and family history of diabetes.

RESULTS

Low birthweight increased the risk of LADA as well as the risk of type 2 diabetes; OR per kg reduction was estimated as 1.52 (95% CI 1.12, 2.08) and 1.58 (1.23, 2.04), respectively. The OR for participants weighing <3 kg compared with ≥4 kg at birth was estimated as 2.38 (1.23, 4.60) for LADA and 2.37 (1.37, 4.10) for type 2 diabetes. A combination of low birthweight (<3 kg) and current overweight (BMI ≥ 25) further augmented the risk: LADA, OR 3.26 (1.69, 6.29); and type 2 diabetes, OR 39.93 (19.27, 82.71). Family history of diabetes had little impact on these estimates.

CONCLUSIONS/INTERPRETATION

Our results suggest that low birthweight may be a risk factor for LADA of the same strength as for type 2 diabetes. These findings support LADA, despite its autoimmune component, having an aetiology that includes factors related to type 2 diabetes.

Rheumatoid factor mediates excess serum lipoprotein(a) for independent association with type 2 diabetes in men

OBJECTIVE

The potential association of rheumatoid factor (RF) and lipoprotein (Lp)(a) levels, as well as with the likelihood of type 2 diabetes and hypertension, needs exploring.

METHODS

Cross-sectional associations were sought in this unselected and population-based 1539-adult cohort (age 58.8±10.6 years). RF was assayed nephelometrically. Multiple logistic regression analyses were used for covariates of RF positivity and for the latter's association with diabetes and hypertension.

RESULTS

RF-positive individuals were older, fewer current smokers, had significantly lower fasting triglycerides (by 13%), higher fibrinogen, and tended to higher sex hormone-binding globulin (SHBG) levels. Whereas, women had a similar risk profile irrespective of RF status, RF-positive men had significantly higher Lp(a). In contrast to Lp(a) being positively correlated with SHBG in RF-negative subjects (r=0.08; p=0.007), an inverse correlation existed in seropositive individuals (r=-0.32, p=0.011), suggesting the interplay of an immune complex. In regression analyses, RF positivity was associated with Lp(a) in men but not in women, [OR 1.53 (1.19; 1.96)], independent of age, SHBG, and C-reactive protein (CRP). RF positivity was further associated with diabetes [OR 1.98 (95% CI 1.11; 3.52)] in the whole sample, additively to waist circumference and CRP, major determinants of diabetes. RF-positive subjects were not significantly associated independently with hypertension.

CONCLUSION

Autoimmune activation linked to Lp(a) is mediated by the autoantibody RF in contributing to the development of type 2 diabetes.

The gut microbiome in autoimmunity: Sex matters

Autoimmune diseases like rheumatoid arthritis are multifactorial in nature, requiring both genetic and environmental factors for onset. Increased predisposition of females to a wide range of autoimmune diseases points to a gender bias in the multifactorial etiology of these disorders. However, the existing evidence to date has not provided any conclusive mechanism of gender-bias beyond the role of hormones and sex chromosomes. The gut microbiome, which impacts the innate and adaptive branches of immunity, not only influences the development of autoimmune disorders but may interact with sex-hormones to modulate disease progression and sex-bias. Here, we review the current information on gender bias in autoimmunity and discuss the potential of microbiome-derived biomarkers to help unravel the complex interplay between genes, environment and hormones in rheumatoid arthritis.

Lactation and the use of biologic immunosuppressive medications

Biologic medications are effective therapeutic options for treating autoimmune diseases, but information on their safety in lactation is still scarce. Autoimmune conditions occur frequently in women of childbearing age, creating difficult decisions regarding optimizing maternal health and supporting breastfeeding. Available data, in addition to the favorable pharmacokinetic properties of biologics, suggest that these medications are compatible with breastfeeding. A review of the available evidence and information is presented, as well as recommendations on counseling the nursing mother and her healthcare team to make informed decisions about maternal and infant care.

Protective environmental factors for neuromyelitis optica

OBJECTIVE

To determine whether early environmental factors, such as cesarean delivery, breastfeeding, and exposure to smoking or herpes viruses, are associated with neuromyelitis optica (NMO) risk in children.

METHODS

This is a case-control study of pediatric NMO, multiple sclerosis (MS), and healthy subjects. Early-life exposures were obtained by standardized questionnaire. Epstein-Barr virus, cytomegalovirus, and herpes simplex virus 1 antibody responses were determined by ELISA. Multivariate logistic regression models were used to adjust for age at sampling, sex, race, and ethnicity.

RESULTS

Early-life exposures were obtained from 36 pediatric subjects with NMO, 491 with MS, and 224 healthy controls. Daycare (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.14, 0.78; p < 0.01) and breastfeeding (OR 0.42, 95% CI 0.18, 0.99; p = 0.05) were associated with lower odds of having NMO compared with healthy subjects. Cesarean delivery tended to be associated with 2-fold-higher odds of NMO compared with having MS/clinically isolated syndrome (OR 1.98, 95% CI 0.88, 4.59; p = 0.12) or with being healthy (OR 1.95, 95% CI 0.81, 4.71; p = 0.14). Sera and DNA were available for 31 subjects with NMO, 189 with MS, and 94 healthy controls. Epstein-Barr virus, herpes simplex virus 1, cytomegalovirus exposure, and being HLA-DRB1*15 positive were not associated with odds of having NMO compared with healthy subjects.

CONCLUSIONS

Exposure to other young children may be an early protective factor against the development of NMO, as previously reported for MS, consistent with the hypothesis that infections contribute to disease risk modification. Unlike MS, pediatric NMO does not appear to be associated with exposures to common herpes viruses.

Prediction of future rheumatoid arthritis

Rheumatoid arthritis (RA) results from an interaction between genetic susceptibility and environmental factors. Several of these factors are known, such as family history of RA, high birth weight, smoking, silica exposure, alcohol nonuse, obesity, diabetes mellitus, rheumatoid factor, anti-citrullinated protein antibody, and genetic variants such as the shared epitope and protein tyrosine phosphatase nonreceptor type 22. The impact of these factors can be modeled in the 2 main groups at risk of RA: family members of patients with RA and seropositive persons with or without arthralgia. Current models have the potential to select individuals for preventive strategies.

Differential immunotoxicity induced by two different windows of developmental trichloroethylene exposure

Developmental exposure to environmental toxicants may induce immune system alterations that contribute to adult stage autoimmune disease. We have shown that continuous exposure of MRL+/+ mice to trichloroethylene (TCE) from gestational day (GD) 0 to postnatal day (PND) 49 alters several aspects of CD4(+) T cell function. This window of exposure corresponds to conception-adolescence/young adulthood in humans. More narrowly defining the window of TCE developmental exposure causes immunotoxicity that would establish the stage at which avoidance and/or intervention would be most effective. The current study divided continuous TCE exposure into two separate windows, namely, gestation only (GD0 to birth (PND0)) and early-life only (PND0-PND49). The mice were examined for specific alterations in CD4(+) T cell function at PND49. One potentially long-lasting effect of developmental exposure, alterations in retrotransposon expression indicative of epigenetic alterations, was found in peripheral CD4(+) T cells from both sets of developmentally exposed mice. Interestingly, certain other effects, such as alterations in thymus cellularity, were only found in mice exposed to TCE during gestation. In contrast, expansion of memory/activation cell subset of peripheral CD4(+) T cells were only found in mice exposed to TCE during early life. Different windows of developmental TCE exposure can have different functional consequences.

Broadening the translational immunology landscape

It is just over 5 years sinceClinical and Experimental Immunology came under the direction of a new team of Editors and made a concerted effort to refresh its approach to promoting clinical and applied immunology through its pages. There were two major objectives: to foster papers in a field which, at the time, we loosely termed ‘translational immunology’; and to create a forum for the presentation and discussion of immunology that is relevant to clinicians operating in this space. So, how are we doing with these endeavours? This brief paper aims to summarize some of the key learning points and successes and highlight areas in which translational gaps remain.

Childhood socioeconomic factors and perinatal characteristics influence development of rheumatoid arthritis in adulthood

BACKGROUND

Rheumatoid arthritis (RA) has been associated with lower socioeconomic status (SES), but the reasons for this are not known.

OBJECTIVE

To examine childhood SES measures, SES trajectory and other perinatal factors in relation to RA.

METHODS

The sample included 50 884 women, aged 35-74 (84% non-Hispanic white) enrolled 2004-9 in a US national cohort study. In baseline questionnaires, cases (N=424, 0.8%) reported RA diagnosis after age 16, ever use of disease-modifying antirheumatic drugs or steroids for RA and ≥6 weeks bilateral joint swelling. Childhood SES measures are presented as OR and 95% CI adjusted for age and race/ethnicity. Analyses of perinatal factors also adjusted for childhood SES, and joint effects of childhood and adult SES and smoking exposures were evaluated.

RESULTS

Patients with RA reported lower childhood household education (<12 years vs college degree; OR=1.7; 95% CI 1.1 to 2.5), food insecurity (OR=1.5, 95% CI 1.1 to 2.0) and young maternal age (<20 vs 20-34 years; OR=1.7, 95% CI 1.2 to 2.5), with a trend (p<0.0001) for increasing number of adverse factors (OR=3.0; 95% CI 1.3 to 7.0; 4 vs 0 factors) compared with non-cases. Low birth weight (<2500 g) [corrected] and preconception paternal smoking were independently associated with RA. Together, lower childhood SES and adult education (<college degree) were associated with RA (interaction p=0.03), with a joint effect magnitude similar to a history of paternal and adult smoking.

CONCLUSIONS

RA was associated with low childhood SES sustained into adulthood, with cumulative effects across multiple measures, suggesting the importance of other unmeasured factors linking SES and RA.

Prenatal alcohol exposure alters the course and severity of adjuvant-induced arthritis in female rats

Prenatal alcohol exposure (PAE) has adverse effects on the development of numerous physiological systems, including the hypothalamic-pituitary-adrenal (HPA) axis and the immune system. HPA hyper-responsiveness and impairments in immune competence have been demonstrated. The present study investigated immune function in PAE females utilizing an adjuvant-induced arthritis (AA) model, widely used as a model of human rheumatoid arthritis. Given the effects of PAE on HPA and immune function, and the known interaction between HPA and immune systems in arthritis, we hypothesized that PAE females would have heightened autoimmune responses, resulting in increased severity of arthritis, compared to controls, and that altered HPA activity might play a role in the immune system changes observed. The data demonstrate, for the first time, an adverse effect of PAE on the course and severity of AA in adulthood, indicating an important long-term alteration in functional immune status. Although overall, across prenatal treatments, adjuvant-injected animals gained less weight, and exhibited decreased thymus and increased adrenal weights, and increased basal levels of corticosterone and adrenocorticotropin, PAE females had a more prolonged course of disease and greater severity of inflammation compared to controls. In addition, PAE females exhibited blunted lymphocyte proliferative responses to concanavalin A and a greater increase in basal ACTH levels compared to controls during the induction phase, before any clinical signs of disease were apparent. These data suggest that prenatal alcohol exposure has both direct and indirect effects on inflammatory processes, altering both immune and HPA function, and likely, the normal interactions between these systems.