Autoantibodies for gastrointestinal organ-specific autoimmune diseases in rheumatoid arthritis patients and their relatives

Prevalence of celiac disease in latin america: a systematic review and meta-regression

BACKGROUND

Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten in susceptible individuals, and its prevalence varies depending on the studied population. Given that information on CD in Latin America is scarce, we aimed to investigate the prevalence of CD in this region of the world through a systematic review and meta-analysis.

METHODS AND FINDINGS

This was a two-phase study. First, a cross-sectional analysis from 981 individuals of the Colombian population was made. Second, a systematic review and meta-regression analysis were performed following the Preferred Reporting Items for Systematic Meta- Analyses (PRISMA) guidelines. Our results disclosed a lack of celiac autoimmunity in the studied Colombian population (i.e., anti-tissue transglutaminase (tTG) and IgA anti-endomysium (EMA)). In the systematic review, 72 studies were considered. The estimated prevalence of CD in Latin Americans ranged between 0.46% and 0.64%. The prevalence of CD in first-degree relatives of CD probands was 5.5%. The coexistence of CD and type 1 diabetes mellitus varied from 4.6% to 8.7%, depending on the diagnosis methods (i.e., autoantibodies and/or biopsies).

CONCLUSIONS

Although CD seems to be a rare condition in Colombians; the general prevalence of the disease in Latin Americans seemingly corresponds to a similar scenario observed in Europeans.

Spectrum of autoantibodies for gastrointestinal autoimmune diseases in systemic lupus erythematosus patients

Background

Organ-specific autoimmune diseases may appear in patients with systemic lupus erythematosus (SLE). Gastrointestinal symptoms are well documented in SLE and may be similar to those related to autoimmune gastrointestinal diseases.

Objective

Our aim was to search for gastrointestinal organ-specific autoantibodies in 194 patients with systemic lupus and 103 healthy controls from Southern Brazil.

Methods

Anti-endomysium antibodies (IgA-EmA), anti-gastric parietal cells (GPC) antibodies, anti-smooth muscle antibodies (ASMA), anti-mitochondrial antibodies (AMA) and anti-LKM-1 (liver-kidney microsomal) were searched for using indirect immunofluorescence in the sera of patients and controls.

Results

The total positivity of antibodies in SLE patients was 14.4% (28/194) and differed significantly from healthy individuals (0.97%; p < 0.001). IgA-EmA was more common in lupus patients than in controls (11/194; p = 0.009), and one of these patients had dermatitis herpetiformis. Clinical association revealed that IgA-EmA was more common in SLE patients with discoid lesions. The frequency of anti-GPC ( p = 0.10), ASMA ( p = 0.16) and AMA ( p = 0.55) did not differ significantly between groups. No patient presented LKM-1 autoantibodies. One patient presenting anti-GPC was diagnosed with atrophic gastritis and pernicious anemia.

Conclusion

Only IgA-EmA was significantly associated with lupus and with the presence of discoid lesions. Until now, no obvious association with celiac disease has been found.

Factors associated with parietal cell autoantibodies in the general population

The presence in serum of parietal cell autoantibodies (PCA) is a characteristic of autoimmune gastritis. We determined the prevalence of PCA in the general population and investigate their association with type 2 diabetes, insulin resistance and lifestyle factors related with autoimmune gastritis. A cross-sectional study was performed, involving 429 individuals enrolled in a cohort study of the general population of the Canary Islands. All participants underwent physical examination, provided a blood sample and responded to a questionnaire regarding health and lifestyle factors. Serum concentrations of PCA, soluble CD40 ligand (sCD40L), C-peptide and glucose (to determine insulin resistance) were measured. The association of PCA with the other factors was determined with bivariate analysis, and logistic regression models were used to adjust the associations for age and sex. The prevalence of PCA was 7.8% (95% CI=10.3-5.3). The factors associated with PCA were female sex (p=0.032), insulin resistance (p=0.016), menopause (p=0.029) and sCD40L (p=0.019). Alcohol consumption (p=0.006) and smoking (p=0.005) were associated with low prevalences of PCA. After adjustment for age and sex, the association with PCA was confirmed for smoking (OR=0.1 [0.0-0.9]), alcohol consumption (OR=0.3 [0.1-0.9]), insulin resistance (OR=2.4 [1.1-4.9]), female sex (OR=2.4 [1.1-5.3]), sCD40L (OR=3.7 [1.2-11.4]) and menopause (OR=5.3 [1.2-23.3]). In conclusion, smoking and alcohol consumption acted as protective factors against the appearance of PCA in the general population, whereas female sex, menopause, insulin resistance and elevated serum sCD40L were risk markers for PCA. In patients who smoke or drink alcohol, clinicians should be cautious when using PCA to rule out autoimmune gastritis.