Autoantibodies in relatives of celiac disease patients: a follow-up of 6-10 years

Autoantibodies persist in relatives to systemic lupus erythematosus patients during 12 years follow-up

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease with presence of autoantibodies and characteristic multi-organ involvement. Relatives of SLE patients have an increased risk of autoantibody production and autoimmune diseases.

Methods

In 2001, 226 first degree relatives (FDRs) of a population-based cohort of SLE patients were examined for the prevalence of autoantibodies and self-reported health complaints. In 2013, 143 FDRs were re-investigated and deceased’s medical records were examined.

Results

Participants and non-participants were comparable regarding baseline characteristics, while deceased FDRs were older than participants, but with comparable ANA status. ANA status at baseline correlated to ANA status at follow-up. At follow-up, two FDRs reported SLE and 15 FDRs other autoimmune diseases. No observation at baseline alone could predict self-reported health. During follow-up 33 died at median age 76 years. Three deceased FDRs were diagnosed with an autoimmune disease.

Conclusion

The study showed that FDRs of SLE patients have an increased prevalence of ANA compared to healthy controls. The prevalence increased during follow-up, and ANA positive FDRs at baseline were prone to be ANA positive at follow-up. ANA positive FDRs had more self-reported autoimmune diseases, including SLE and rheumatoid arthritis, than reported from other population-based investigations.

Anti-parietal cell antibodies - diagnostic significance

Anti-parietal cell antibodies (APCA) are an advantageous tool for screening for autoimmune atrophic gastritis (AAG) and pernicious anemia (PA). The target for APCA is the H+/K+ ATP-ase. It has been demonstrated, that APCA target both, the alpha, and beta subunits of the proton pump, although the major antigen is the alpha subunit. Circulating serum APCA can be detected by means of immunofluorescence, enzyme-linked immunosorbent assay - currently the most commonly used method, and radioimmunoprecipitation assay (RIA) - the 4A subunit has been optimized as a molecular-specific antigen probe. RIA is the most accurate method of antibody assessment, characterized by highest sensitivity. APCA can be found in 85-90% of patients with PA. Their presence is not sufficient for diagnosis, because they are not specific for PA as they are also found in the circulation of individuals with other diseases. APCA are more prevalent in the serum of patients with T1D, autoimmune thyroid diseases, vitiligo, celiac disease. People with autoimmune diseases should be closely screened for AAG/PA. The anemia develops longitudinally over many years in APCA-positive patients, symptomless, slowly promotes atrophy of the gastric mucosa and parietal cells. APCA are present in 7.8-19.5% of the general healthy adult population. A fraction of these sero-positive people, will never develop AAG or PA. An interesting and not fully explained question is whether APCA presence is related to Helicobacter pylori infection. APCA are found in up to 20.7% of these patients. H. pylori is implicated as one of the candidates causing AAG.

Risk of Celiac Disease in the First- and Second-Degree Relatives of Patients With Celiac Disease: A Systematic Review and Meta-Analysis

OBJECTIVES

First-degree relatives (FDRs) of patients with celiac disease (CD) are at high risk for CD and prevalence among them varies from 1.6 to 38%. The risk of having CD among FDRs if the FDR is sister, brother, mother, father, son, or daughter of index patient with CD is not known. We conducted a meta-analysis and calculated pooled prevalence of CD among FDRs, second-degree relatives (SDRs), and specific relations with index patient.

METHODS

On search of literature, 2,259 articles appeared of which 54 articles were included in this meta-analysis. Diagnosis of CD was based on standard criteria.

RESULTS

Pooled prevalence of CD was 7.5% (95% confidence interval (CI) 6.3%, 8.8%) in 10,252 FDRs and 2.3% (95% CI 1.3%, 3.8%) in 642 SDRs. Pooled prevalence of CD was highest in siblings (8.9%), followed by offsprings (7.9%) and parents (3.0%). Female FDRs had higher prevalence than male FDRs (8.4% vs. 5.2%, P=0.047). While sisters and daughters of index patient had the highest risk of having CD (1 in 7 and 1 in 8, respectively), the risk was 1 in 13 in sons, 1 in 16 in brothers, 1 in 32 in mothers, and 1 in 33 in fathers. There were also differences in the pooled prevalence of CD in FDRs according to their geographic location.

CONCLUSIONS

Pooled prevalence of CD among FDRs is 7.5% and varies considerably with their relationship with the index patient. The risk of CD in FDRs also varies according to gender and geographical location.

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.