[Prevalence and diagnostic value of antinuclear antibodies without identified antigenic target: a retrospective study of 90 patients]

Epidemiology of Sjögren Syndrome in Africa: A Scoping Review

BACKGROUND

The epidemiology of Sjögren syndrome (SS) has been extensively studied in America, Europe, and Asia.

OBJECTIVE

To summarize available data on the epidemiology of SS in Africa.

METHODS

MEDLINE, EMBASE, and African Journals Online were searched from inception up to May 17, 2020, to identify relevant articles. Data gleaned from these reports have been summarized narratively in this review.

RESULTS

Twenty-one hospital-based studies were included. These studies reported 744 cases of SS. The mean age at diagnosis varied between 28 and 73.6 years, and the female proportion ranged from 83.3% to 100%. There was no population-based incidence or prevalence. Among people with autoimmune and other rheumatic conditions, the frequency of primary SS was in the range 1.9% to 47.6%, whereas that of rheumatoid arthritis-associated secondary SS was in the range 4.3% to 100%. Sicca symptoms were the commonest features, with most frequently involved organs being joints, lungs, and neurological structures. Main autoantibodies were anti-Ro/SS antigen A, anti-La/SS antigen B, and antinuclear antibodies.

CONCLUSIONS

The epidemiology of SS is poorly characterized in Africa. Available data are broadly consistent with those from other populations. Extensive and high-quality research is urgently needed.

Antinuclear antibodies in children: clinical signification and diagnosis utility

Background: Antinuclear antibodies (ANA) test is used to screen adults as well as children for connective tissue diseases (CTD) and autoimmune hepatitis. However, interpretation of ANA positivity can be delicate.

Aim: to determine clinical significance and diagnosis utility of ANA positivity in children.

Methods: Patients from a general pediatric department with ANA positive results were included (follow-up period of 2 years). ANA screening was performed by indirect immunofluorescence (IIF) on HEp-2 cells substrate (BioSystems^®). In case of ANA positivity (cut-off: 1:80), the specificity was determined by IIF on Crithidia luciliea substrate (BioSystems^®) and immunodot (Euroimmun^®).

Results: Among 102 ANA tests, 55 (53,9%) were positive. We recorded the data of 38 patients (age average: 9,5 years - sex ratio: 0.72). The most frequent signs were join pain (55,3%). ANA titer varied between 1:80 (39,5% of cases) and 1:1280 (2,6% of cases). Typing was negative in 89,5% of cases. The majority (42,1%) of children with positive ANA test had musculoskeletal diseases. The others (57,9%) had systemic lupus erythematosus(n=2), overlap syndrome(n=1), rheumatoid purpura(n=2), idiopathic thrombocytopenic purpura(n=1), coeliac disease(n=1) or non-autoimmune diseases/no confirmed diagnosis(n=15).

Conclusions: ANA prevalence in children was relatively high. When the pretest probability is low, the positive predictive value for CTD or autoimmune hepatitis is low. However, depending on the clinical context, ANA detection can represent a supplement diagnostic tool for these diseases and/or can lead to a clinico-biological monitoring.

Prevalence of autoimmune diseases and clinical significance of autoantibody profile: Data from National Institute of Hygiene in Rabat, Morocco

AIM

The objective of this study was to explore the prevalence of various autoimmune diseases (AIDs) in a large cohort of patients and to characterize the autoantibody profile in the patients with and without AIDs to confirm the diagnosis and to refine the Moroccan databases.

PATIENTS AND METHOD

Retrospective study was conducted in the Laboratory of autoimmunity National Institute of Hygiene (NIH) of Rabat in Morocco. A total of 3182 consecutive Moroccan patients (2183 females and 999 males) whose sera were tested for 14 autoantibody profile between 2010 and 2016.

RESULTS

Only 944 (29.7%) patients were diagnosed with AIDs of those suspected. The prevalence of systemic lupus erythematosus (SLE), intestinal malabsorption (IM) and arthritis polyarthralgia (AP) were the highest (4.2, 4.1 and 4%), subsequently followed by rheumatoid arthritis (RA) (2.8%), cholestatic syndrome (CS) (1.8%), interstitial lung disease (ILD) (1.6%).In females IM, AP and SLE also showed the highest prevalence (5.4%, 5.3% and 4.9% respectively), while of male, SLE showed the highest prevalence (1.9%). The prevalence of ANA was increased in most patients with systemic especially in neuropathy (NP), hemolytic anemia (HA), primary Sjogren's syndrome (pSS), dermatomyositis (DM), thrombocytopenia (Tb), systemic sclerosis (SSc), ANCA-associated vasculitis (AAV), AP, Renal impairment (RI), SLE, and mixed connective tissue disease (MCTD). Anti-dsDNA antibodies were higher in SLE and ENA showed the highest titers in MCTD. Others are relatively specific for certain disease, such as anti β2GP1 for thrombosis syndrome, anti ANCA for primary sclerosing cholangitis (PSC), AAV, ILD and RI, anti CCP2 for RA, ILD and AP. the prevalence of anti AMA was higher in primary biliary cirrhosis (PBC), followed in CS, also, ANA have been identified in up to 25% of patients with primary biliary cirrhosis. The prevalence of anti-SMA was higher in PBC, treated patients for Chronic hepatitis C (HCV), and autoimmune hepatitis (AIH) and anti-PCA was higher in biermer anemia patients with vitamin B12 deficiency (BA/Def vit B12). The prevalence of IgA EMA, IgA tTG and IgA AGA were higher in patients IM and celiac disease (CD). The prevalence of anti thyroperoxidase (TPO) was significantly increased in the autoimmune thyroiditis (AIT).

CONCLUSION

Our study shows the diagnostic value of auto antibodies in AIDs. It would be interesting to carry out prospective studies on each pathology separately, in order to fill the classic vagaries of the retrospective study and objectively estimate the prevalence in different AIDs. These data on the prevalence of each autoimmune disease are valuable for the public health system.

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.

How should a district general hospital immunology service screen for anti-nuclear antibodies? An 'in-the-field' audit

Anti-nuclear antibody (ANA) testing assists in the diagnosis of several immune-mediated disorders. The gold standard method for detection of these antibodies is by indirect immunofluorescence testing on human epidermoid laryngeal carcinoma (HEp-2) cells. However, many laboratories test for these antibodies using solid-phase assays such as enzyme-linked immunosorbent assay (ELISA), which allows for higher throughput testing at reduced cost. In this study, we have audited the performance of a previously established ELISA assay to screen for ANA, making comparison with the gold standard HEp-2 immunofluorescence test. A prospective and unselected sample of 89 consecutive ANA test requests by consultant rheumatologists were evaluated in parallel over a period of 10 months using both tests. ELISA and HEp-2 screening assays yielded 40 (45%) and 72 (81%) positive test results, respectively, demonstrating lack of concordance between test methods. Using standard and clinical samples, it was demonstrated that the ELISA method did not detect several ANA with nucleolar, homogeneous and speckled immunofluorescence patterns. None of these ELISA(NEG) HEp-2(POS) ANA were reactive with a panel of six extractable nuclear antigens or with double-stranded DNA. Nonetheless, 13 of these samples (15%) originated from patients with recognized ANA-associated disease (n = 7) or Raynaud's phenomenon (n = 6). We conclude that ELISA screening may fail to detect clinically relevant ANA that lack defined specificity for antigen.