Specific IgE positivity against inhalant allergens and development of autoimmune disease

Inhalants other than personal cigarette smoking and risk for developing rheumatoid arthritis

PURPOSE OF REVIEW

The current review summarizes the current evidence on inhalants other than personal cigarette smoking and risk for developing rheumatoid arthritis (RA).

RECENT FINDINGS

Personal cigarette smoking has been implicated as an environmental risk factor for seropositive RA, perhaps by inducing autoimmunity at pulmonary mucosa. Since many patients with RA are nonsmokers, other inhalants are being investigated as potential RA risk factors. Recent case-control and cohort studies have investigated passive cigarette smoking, air pollution, inhalant-related occupations, silica, pesticides, household environment, and allergic inhalants as inhalant exposures for RA risk. Inhalant-related occupations and silica inhalants have the most consistent evidence for associations with increased RA risk. However, most studies relied on retrospective designs and had limited ability to adjust for personal cigarette smoking or investigate associations among nonsmokers.

SUMMARY

Several inhalants other than personal cigarette smoking may be associated with increased risk for developing RA. These results support the hypothesis that inhalants, pulmonary mucosal inflammation, and RA pathogenesis may be linked. Future studies are needed to firmly establish the independence of these findings from personal cigarette smoking and to determine the specific inhalants and biologic mechanisms related to RA pathogenesis.

The Potential Role of Regulatory B Cells in Idiopathic Membranous Nephropathy

Regulatory B cells (Breg) are widely regarded as immunomodulatory cells which play an immunosuppressive role. Breg inhibits pathological autoimmune response by secreting interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and adenosine and through other ways to prevent T cells and other immune cells from expanding. Recent studies have shown that different inflammatory environments induce different types of Breg cells, and these different Breg cells have different functions. For example, Br1 cells can secrete IgG4 to block autoantigens. Idiopathic membranous nephropathy (IMN) is an autoimmune disease in which the humoral immune response is dominant and the cellular immune response is impaired. However, only a handful of studies have been done on the role of Bregs in this regard. In this review, we provide a brief overview of the types and functions of Breg found in human body, as well as the abnormal pathological and immunological phenomena in IMN, and propose the hypothesis that Breg is activated in IMN patients and the proportion of Br1 can be increased. Our review aims at highlighting the correlation between Breg and IMN and proposes potential mechanisms, which can provide a new direction for the discovery of the pathogenesis of IMN, thus providing a new strategy for the prevention and early treatment of IMN.

IgE autoantibodies and autoreactive T cells and their role in children and adults with atopic dermatitis

The pathophysiology of atopic dermatitis (AD) is highly complex and understanding of disease endotypes may improve disease management. Immunoglobulins E (IgE) against human skin epitopes (IgE autoantibodies) are thought to play a role in disease progression and prolongation. These antibodies have been described in patients with severe and chronic AD, suggesting a progression from allergic inflammation to severe autoimmune processes against the skin. This review provides a summary of the current knowledge and gaps on IgE autoreactivity and self-reactive T cells in children and adults with AD based on a systematic search. Currently, the clinical relevance and the pathomechanism of IgE autoantibodies in AD needs to be further investigated. Additionally, it is unknown whether the presence of IgE autoantibodies in patients with AD is an epiphenomenon or a disease endotype. However, increased knowledge on the clinical relevance and the pathophysiologic role of IgE autoantibodies and self-reactive T cells in AD can have consequences for diagnosis and treatment. Responses to the current available treatments can be used for better understanding of the pathways and may shed new lights on the treatment options for patients with AD and autoreactivity against skin epitopes. To conclude, IgE autoantibodies and self-reactive T cells can contribute to the pathophysiology of AD based on the body of evidence in literature. However, many questions remain open. Future studies on autoreactivity in AD should especially focus on the clinical relevance, the contribution to the disease progression and chronicity on cellular level, the onset and therapeutic strategies.

Psoriasis and IgE-mediated allergy: correlation or mutual inhibition? : A prospective cohort study in patients with mild or moderate to severe psoriasis

BACKGROUND

Psoriasis is an autoimmune disease caused by overactivation of T_H1 (Type 1 helper cells) and T_H17 (T helper 17) cells. Overactivation of T_H1 cells inhibits the activity of T_H2 cells involved in type 1 allergies, therefore, psoriasis patients might be less affected by type 1 allergies. This study tested if allergies were less frequent in patients with moderate to severe than with mild psoriasis.

METHODS

Psoriasis patients at the study site reported possible allergy symptoms and were tested for common allergens by skin prick test and IgE levels. Psoriasis was classified by PASI scores (Psoriasis Area and Severity Index) as mild (PASI <10) or moderate/severe (PASI ≥10). Patients without systemic therapy were assessed separately. Fisher's exact test was used to test for differences.

RESULTS

A total of 97 patients were included, 21 with mild and 76 with moderate to severe psoriasis. Allergies were found in 27.8%, most commonly against dust mites (23.4%) and grasses (18.1%). Allergies were found in 23.8% of the patients with mild vs. 29.0% allergic patients with moderate to severe psoriasis (P = 0.786). In patients without systemic medication, allergies were found in 21.1% vs. 35.3% (P = 0.463).

CONCLUSION

Allergy prevalence was not reduced in patients with moderate/severe psoriasis, and generally close to the prevalence in the general Austrian population (24%). The inhibiting effect of psoriasis on type 1 allergies was not confirmed.

Development of atopic sensitization in Finnish and Estonian children: A latent class analysis in a multicenter cohort

BACKGROUND

The prevalence of atopy is associated with a Western lifestyle, as shown by studies comparing neighboring regions with different socioeconomic backgrounds. Atopy might reflect various conditions differing in their susceptibility to environmental factors.

OBJECTIVE

We sought to define phenotypes of atopic sensitization in early childhood and examine their association with allergic diseases and hereditary background in Finland and Estonia.

METHODS

The analysis included 1603 Finnish and 1657 Estonian children from the DIABIMMUNE multicenter young children cohort. Specific IgE levels were measured at age 3, 4, and 5 years, respectively, and categorized into 3 CAP classes. Latent class analysis was performed with the statistical software package poLCA in R software.

RESULTS

Both populations differed in terms of socioeconomic status and environmental determinants, such as pet ownership, farm-related exposure, time spent playing outdoors, and prevalence of allergic diseases (all P < .001). Nevertheless, we found similar latent classes in both populations: an unsensitized class, a food class, 2 inhalant classes differentiating between seasonal and perennial aeroallergens, and a severe atopy class. The latter was characterized by high total and specific IgE levels and strongly associated with wheeze (odds ratio [OR], 5.64 [95% CI, 3.07-10.52] and 4.56 [95% CI, 2.35-8.52]), allergic rhinitis (OR, 22.4 [95% CI, 11.67-44.54] and 13.97 [95% CI, 7.33-26.4]), and atopic eczema (OR, 9.39 [95% CI, 4.9-19.3] and 9.5 [95% CI, 5.2-17.5] for Finland and Estonia, respectively). Environmental differences were reflected in the larger seasonal inhalant atopy class in Finland, although composition of classes was comparable between countries.

CONCLUSION

Despite profound differences in environmental exposures, there might exist genuine patterns of atopic sensitization. The distribution of these patterns might determine the contribution of atopic sensitization to disease onset.

Risk of allergic conjunctivitis in patients with type 1 diabetes mellitus: a population-based retrospective cohort study

OBJECTIVE

In accordance with the dichotomy between T helper type 1(Th1) and T helper type 2 (Th2) responses, the occurrence of allergic conjunctivitis (AC) and type 1 diabetes mellitus (T1DM) is, in theory, inversely related in the individual. However, recent studies investigating the association between the two diseases are controversial.

DESIGN

Population-based cohort study.

SETTING

We used claims data of the National Health Insurance Research Database of Taiwan.

PARTICIPANTS

We identified 4160 patients aged 1-30 years with newly diagnosed T1DM and no history of AC at baseline. For each patient with T1DM, four non-T1DM controls (n=16,640) were matched by sex. The mean follow-up time was 6 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Multivariate Cox proportional hazards regression analysis was used to evaluate the risk of AC. We additionally evaluated the association between risk of AC and T1DM progression by examining Diabetes Complications Severity Index (aDCSI) changes from the date of diagnosis until the end of follow-up.

RESULTS

The overall incidence of allergic conjunctivitis (AC) was higher in the type 1 diabetes mellitus (T1DM) cohort than in the control cohort (23.0 vs 13.5 per 1000 person-years, adjusted incidence rate ratio (aIRR): 1.59, 95% CI 1.47 to 1.71). Relative to that in patients with mildly progressive T1DM, the risk of AC increased as the adapted Diabetes Complications Severity Index (aDCSI) increased (aIRR: 1.68, 3.78 and 18.8, with yearly changes in aDCSI score: 0.51 to 1.00, 1.01 to 2.00, and >2.00 vs <0.51, respectively; for trend <0.001).

CONCLUSION

Patients with T1DM are at an elevated risk of developing AC; this risk increases with T1DM progression. The T helper type 1/T helper type 2 hypothesis is an overly simplistic explanation for this association.

Analysis of the impact of allergy and atopy on new onset of uveitis

PURPOSE

The inappropriate immune response to harmless foreign and self-antigens is a common feature of allergy, atopy and autoimmune disease. The influence of environmental factors in the initiation of autoimmunity is not well understood. It is conceivable that immune responses to allergens may also serve as a trigger of bystander immune reactions, including autoimmunity such as uveitis. Therefore, we wanted to investigate the prevalence of allergies and atopy in patients with different types of uveitis in comparison to a control cohort.

METHODS

In total, 530 consecutive patients with new-onset anterior, intermediate, posterior and panuveitis were compared to a non-uveitis control cohort consisting of 1.060 consecutive new-referral patients who attended our specialized outpatient clinics for other reasons than uveitis. Allergy and atopy status as well as demographic data (age, gender and ethnicity) were obtained by standardized interviewer-assisted questionnaires.

RESULTS

Uveitis case cohort and control cohort did not differ significantly in the allergy status (p = 0.910), such as the history of pollen allergy (p = 0.671), history of drug allergy (p = 0.920), history of food allergy (p = 0.941), history of house dust mite allergy (p = 0.197) or history of other allergens (p = 0.593), nor in the atopy status (p = 0.802), such as the history of atopic dermatitis (p = 0.365), history of asthma (p = 0.430) or history of allergic rhinitis (p = 0.115).

CONCLUSIONS

Our results argue against a substantial influence of allergies and atopy on the onset of uveitis.

Prediction of atopy via total immunoglobulin E levels andskin prick tests in patients with psoriasis

BACKGROUND/AIM

Although the etiopathogeneses of psoriasis and atopy appear to be different, psoriasis has been found to be associated with atopy and atopic dermatitis. In this study, we aimed to determine the role of atopy by examining the medical history and clinical and laboratory findings of patients with psoriasis.

MATERIALS AND METHODS

Patients with psoriasis, asthma patients, and healthy volunteers were included in the study. Serum total immunoglobulin E (IgE) levels were obtained, and prick tests were administered to all groups.

RESULTS

Psoriatic patients demonstrated percentages of atopy history (21.3%) that were higher than those of the healthy subjects (15.7%). The median total IgE level in psoriatic patients was found to be statistically higher than that in the healthy control group (P > 0.05). With respect to mite positivity, there were statistically significant differences in the psoriatic (P < 0.05) and asthmatic groups (P < 0.001) when compared to the healthy control group.

CONCLUSION

Our study is the first to use skin prick tests with psoriatic patients. Skin prick test sensitivity to mites increased in psoriatic patients, and we believe that this finding may be useful in protecting psoriatic patients from activation of psoriasis and in determining the appropriate treatment approach.

IgE sensitization to inhalant allergens and the risk of airway infection and disease: A population-based study

BACKGROUND

Immunoglobulin E (IgE) sensitization, which is the propensity to develop IgE antibodies against common environmental allergens, is associated with a lymphocyte T-helper type 2 (Th2) skewed immune response and a high risk of allergic respiratory disease. Little is known about whether IgE sensitization confers an increased risk of respiratory infections in adults. We investigated the association between IgE sensitization and the incidence of acute airway infections, other infections and chronic lower airway disease events as recorded in nation-wide registries.

METHODS

We included 14,849 persons from five population-based studies with measurements of serum specific IgE positivity against inhalant allergens. Participants were followed by linkage to Danish national registries (median follow-up time 11.3 years). The study-specific relative risks were estimated by Cox regression analysis, meta-analysed, and expressed as hazard ratios, HRs (95% confidence intervals, CIs).

RESULTS

The relative risks for IgE sensitized vs. non-sensitized were: for pneumonia (HR = 1.20, 95% CI: 1.01, 1.41), other acute airway infection (HR = 0.86, 95% CI: 0.60, 1.22), infection (HR = 1.06, 95% CI: 0.90, 1.24), asthma (HR = 2.26, 95% CI: 1.79, 2.86), and other chronic lower airway disease (HR = 1.31, 95% CI: 1.08, 1.58). In never smokers, the higher risk of pneumonia (HR = 1.73, 95% CI: 1.23, 2.44) and asthma (HR = 3.17, 95% CI: 2.10, 4.76) among IgE sensitized was more pronounced.

CONCLUSIONS

IgE sensitization was associated with a higher risk of asthma, other chronic lower airway diseases, and pneumonia. However, the association between IgE sensitization and pneumonia may be explained by undiagnosed asthma causing the pneumonia. Further studies are needed for confirmation.

Atopy and autoimmune thyroid diseases: melatonin can be useful?

Recently, there has been growing interest in the relationship between allergic and autoimmune diseases. Allergy and autoimmunity can be considered two potential outcomes of dysregulated immunity and analysis of literature data shows a strong positive association between a history of Th2-mediated allergic disorders and Th1-mediated autoimmune disorders.Autoimmune thyroid diseases are the most common of all autoimmune pathological conditions.Currently, the mechanisms explaining an association among atopy, autoimmunity, and thyroid diseases are not fully understood.There are data in literature pointing to the relationship between melatonin and thyroid activity. Several studies have suggested a paracrine role for this molecule in the regulation of thyroid activity, documenting that administration, as an antioxidant, in thyroid tissues under conditions of increased oxidative stress, could be helpful to reduce the oxidative processes involved in autoimmune thyroid diseases.Although thyroid autoimmunity has been regularly associated with atopic conditions in children, the possible protective role of melatonin has not yet been investigated.This review summarizes what is known regarding the connection between atopy and autoimmune thyroid diseases, and analyses the probable beneficial action of melatonin.

Lifestyle-Related Factors and Atopy in Seven Danish Population-Based Studies from Different Time Periods

BACKGROUND

The prevalence of allergic respiratory disease tends to increase in populations that adopt the so-called Westernized lifestyle. We investigated the association between atopy and several possible lifestyle-related factors in seven Danish population-based studies.

METHODS

A total of 20048 persons participated in the seven studies. We used logistic regression to analyse the associations between possible determinants and atopy defined as serum specific IgE or skin prick test positivity against inhalant allergens. Associations were expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs). In addition, individual participant data meta-analyses were performed.

RESULTS

Atopy was significantly associated with younger age (OR per 1 year increase in age: 0.97; 95% CI: 0.97, 0.98); male sex (OR for males versus females: 1.34; 95% CI: 1.24, 1.45), heavy drinking (OR for heavy drinkers versus light drinkers: 1.15; 95% CI: 1.04, 1.27), never smoking (OR for current versus never smokers: 0.73; 95% CI: 0.67, 0.80), and higher educational level (OR for educated versus uneducated: 1.27; 95% CI: 1.15, 1.41). Atopy was not associated with blood pressure, serum total cholesterol, physical activity or body mass except in women only, where we found a positive association (OR for obese vs. normal weight: 1.18; 95% CI: 1.00, 1.39) with ptrend = 0.032.

CONCLUSIONS

Of interest for preventive purposes, we found that atopy was associated with some of the reversible lifestyle-related factors that characterize a Westernized lifestyle.