Detection of anti-nuclear antibody by immunofluorescence assay and enzyme immunoassay in childhood systemic lupus erythematosus: experience from Bangladesh

Exosomes as biomarkers and therapeutic delivery for autoimmune diseases: Opportunities and challenges

Exosomes are spherical lipid bilayer vesicles composed of lipids, proteins and nucleic acids that deliver signaling molecules through a vesicular transport system to regulate the function and morphology of target cells, thereby involving in a variety of biological processes, such as cell apoptosis or proliferation, and cytokine production. In the past decades, there are emerging evidence that exosomes play pivotal roles in the pathological mechanisms of several autoimmune diseases (ADs), including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), type 1 diabetes mellitus (T1DM), Sjogren's syndrome (SS), multiple sclerosis (MS), inflammatory bowel disease (IBD). systemic sclerosis (SSc), etc. Several publications have shown that exosomes are involved in the pathogenesis of ADs mainly through intercellular communication and by influencing the response of immune cells. The level of exosomes and the expression of nucleic acids can reflect the degree of disease progression and are excellent biomarkers for ADs. In addition, exosomes have the potential to be used as drug carriers thanks to their biocompatibility and stability. In this review, we briefly summarized the current researches regarding the biological functions of exosomes in ADs, and provided an insight into the potential of exosomes as biomarkers and therapeutic delivery for these diseases.

Performance of Antinuclear Antibodies for Classifying Systemic Lupus Erythematosus: A Systematic Literature Review and Meta-Regression of Diagnostic Data

OBJECTIVE

To review the published literature on the performance of indirect immunofluorescence (IIF)-HEp-2 antinuclear antibody (ANA) testing for classification of systemic lupus erythematosus (SLE).

METHODS

A systematic literature search was conducted in the Medline, Embase, and Cochrane databases for articles published between January 1990 and October 2015. The research question was structured according to Population, Intervention, Comparator, Outcome (PICO) format rules, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were followed where appropriate. Meta-regression analysis for diagnostic tests was performed, using the ANA titer as independent variable, while sensitivity and specificity were dependent variables.

RESULTS

Of 4,483 publications screened, 62 matched the eligibility criteria, and another 2 articles were identified through reference analysis. The included studies comprised 13,080 SLE patients in total, of whom 12,542 (95.9%) were reported to be IIF-ANA positive at various titers. For ANA at titers of 1:40, 1:80, 1:160, and 1:320, meta-regression gave sensitivity values of 98.4% (95% confidence interval [95% CI] 97.6-99.0%), 97.8% (95% CI 96.8-98.5%), 95.8% (95% CI 94.1-97.1%), and 86.0% (95% CI 77.0-91.9%), respectively. The corresponding specificities were 66.9% (95% CI 57.8-74.9%), 74.7% (95% CI 66.7-81.3%), 86.2% (95% CI 80.4-90.5%), and 96.6% (95% CI 93.9-98.1%), respectively.

CONCLUSION

The results of this systematic literature review and meta-regression confirm that IIF-ANAs have high sensitivity for SLE. ANAs at a titer of 1:80 have sufficiently high sensitivity to be considered as an entry criterion for SLE classification criteria, i.e., formally test other classification criteria for SLE only if ANAs of at least 1:80 have been found.

Association of calreticulin expression with disease activity and organ damage in systemic lupus erythematosus patients

Measurement of disease activity in patients with systemic lupus erythematosus (SLE) is important for monitoring disease progression and evaluating the therapeutic effects. The severity of organ damage correlates with clinical status and prognosis. Therefore, it is imperative to find an effective biomarker measuring disease activity and organ damage for SLE management. The present study investigated the possibility of serum calreticulin (CRT) in the assessment of disease activity and organ damage in SLE patients. Serum CRT levels from 80 patients with SLE, 55 patients with other autoimmune diseases and 60 healthy controls (HC) were measured by ELISA. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores. Organ damage was evaluated with the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index. CRT levels in SLE were significantly higher than that in other autoimmune diseases and HC. CRT was correlated with SLEDAI-2K score (r=0.3345, P=0.0024), and with anti-double-stranded DNA (anti-dsDNA) (r=0.4483, P<0.0001). A significant negative correlation of CRT levels with complement 3 (r=-0.3635, P=0.0009) and complement 4 (r=-0.3507, P=0.0014) was observed in patients with SLE. Furthermore, the patients with SLE and a positive anti-Ro52 result had higher levels of CRT compared with those with a negative anti-Ro52 result (P<0.001). Elevated levels of CRT were also reported among patients with SLE who also indicated the presence of cumulative organ damage. In addition, increased expression of CRT correlated with the presence of lupus nephritis. In conclusion, the results of the current report provided that CRT may be used as a potential biomarker for clinical diagnosis and of prognosis, providing additional information regarding disease activity and organ damage alongside other traditional indices.

The prevalence of antinuclear antibodies in the general population of china: a cross-sectional study

BACKGROUND

The incidence of autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and primary biliary cirrhosis has increased significantly in China. Information about the susceptibility or potential of autoimmune diseases in the general population is lacking.

OBJECTIVE

To explore the prevalence of antinuclear antibody (ANA) and its specificities in the general population in China.

METHODS

Twenty thousand nine hundred seventy sera samples were taken from the physical examination center in Baoding, China. Indirect immunofluorescence and line immunoassays were used to detect ANA and its specificities, respectively.

RESULTS

Samples from females had a higher prevalence of ANA than samples from males (χ(2) = 278.55; P < 0.01). For both sexes, the prevalence of ANA positively correlated with age and there were significant differences among different age groups at 10-year intervals, except the 80 years group (P < 0.05). One thousand two hundred forty-three ANA-positive samples were further analyzed with line immunoassays. There was a significant difference among age groups and between sex groups in terms of the specific autoantibodies (P < 0.01). The autoantibodies with the top-3 positive frequencies were anti-Ro-52, anti-M2, and anti-SSA.

CONCLUSIONS

There was a high prevalence of ANA positivity in the general Chinese population that seemed to be influenced by sex and age and correlated with specific autoantibodies.

Antinuclear antibody screening by ELISA and IF techniques: discrepant results in juvenile idiopathic arthritis but consistency in childhood systemic lupus erythematous

Lately, many hospital laboratories are using for antinuclear antibody (ANA) screening the solid-phase immunoassays (ELISA-ANA) instead of the traditional immunofluorescence ANA test (IF-ANA). Results of previous studies that compare the two technologies show poor correlation between them in both juvenile idiopathic arthritis (JIA) and childhood lupus erythematous (SLE) patients. In this study, we investigated whether ELISA-ANA and traditional IF-ANA results are comparable in pediatric patients with different rheumatic diseases. A total of 156 consecutive patients were included in the study-90 children with JIA, 33 with reactive arthritis, 19 with SLE, 4 with idiopathic chronic uveitis, and 10 with other systemic rheumatic diseases. ANA determination was performed using both assays. The higher rate of discrepancies between the two methods of ANA screening appeared in the JIA population (19/90, p < 0.001). All JIA patients with false-negative results by ELISA had significant or high IF-ANA titres. The prevalence of JIA-associated uveitis was higher in the group of false-negative ELISA-ANA children than in the ELISA-positive patients but without statistical significance (p = 0.62). On the contrary, in SLE group, the consistency rate of the two assays was 100 %, and the reactivity levels of ELISA-ANA were significantly higher than in ELISA-positive JIA patients (p < 0.001). ELISA seems to be a reliable method for screening ANA in childhood SLE, but not in JIA. Limited by the few SLE patients, our findings need further consideration.