Antinuclear antibody positive autoimmune disorders in North India: an appraisal

Incidence and prevalence of systemic sclerosis in Thailand in year 2017-2020: a database from the Ministry of Public Health

BACKGROUND

A better understanding of the epidemiological profile of systemic sclerosis (SSc) in Thais could improve care, human resource deployment, and public health budgeting.

OBJECTIVES

We aimed to determine the incidence and prevalence of SSc in Thailand between 2017 and 2020.

METHODS

A descriptive epidemiological study was performed using the Information and Communication Technology Center, Ministry of Public Health database, comprising all types of healthcare providers during the study period. Demographic data of patients having a primary diagnosis of M34 systemic sclerosis and over 18 years of age between 2017 and 2020 were reviewed. The incidence and prevalence of SSc were calculated as well as their respective 95% confidence intervals (CIs).

RESULTS

The number of SSc cases in 2017 was 15,920 from a total Thai population of 65,204,797. The prevalence of SSc in 2017 was 24.4 per 100,000 populations (95% CI 24.0-24.8). The prevalence of SSc among women was 2 times greater than among men (32.7 vs. 15.8 per 100,000). The incidence of SSc was stable from 2018 to 2019 but dropped slightly in 2020 (7.2, 7.6, and 6.8 per 100,000 person-years, respectively). Most SSc cases were in northeastern Thailand (11.6, 12.1, and 11.1 per 100,000 person-years from 2018 to 2020, respectively) and the peak was between 60 and 69 years of age (24.6, 23.8, and 20.9 per 100,000 person-years from 2018 to 2020, respectively).

CONCLUSION

SSc is a rare disease among Thais. The disease was commonly revealed in late middle-aged women with a peak at age 60-69 years, mainly from the northeast regions. The incidence remained stable during the study period, albeit during the emergence of the coronavirus pandemic a slight decline was recorded. Key Points • The incidence and prevalence of systemic sclerosis (SSc) vary across ethnic populations. • There is a lack of epidemiology research of SSc since the 2013 ACR/EULAR Classification Criteria for Scleroderma was adopted among Thais included Asia-Pacific population as the population has some different clinical features than those reported among Caucasians. • SSc is a rare connective disease among Thais and commonly presents in late middle-aged group of both genders, mainly in Thailand's northern and northeastern regions. • When compare to the epidemiology of SSc in Asia-Pacific, the prevalence of SSc in Thais was higher than among East Asians and the Indian population and the incidence of SSc among Thais was greater than the other Asia-Pacific population including Australian.

Clinical and autoantibody profiles of systemic sclerosis patients: A cross-sectional study from North India

Objectives This cross-sectional study was designed to assess the clinical profile and frequency of associated autoantibodies in all consecutive patients classified as systemic sclerosis (SSc) at Medanta-the Medicity Hospital, Gurgaon, India. Methods Between August 2017 and July 2019, we identified a total of 119 consecutive patients meeting the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) 2013 criteria for SSc and 106 patients consented to this study. Their clinical and serological data at the time of enrolment were analysed. Results Our cohort had a mean age at symptom onset of 40 ± 13 years with a median symptom duration of 6 years. We had 76 patients (71.7%) with interstitial lung disease (ILD), which was a higher proportion compared to European cohorts. 62 patients (58.5%) had diffuse cutaneous involvement which was significantly associated with anti-Scl70 antibodies (p < 0.001), digital ulcers (p = 0.039) and the presence of ILD (p = 0.004). 65 patients (61.3%) had anti-Scl70 and 15 patients (14.2%) had anti-centromere (anti-CENP) antibodies. Scl70 positivity was associated with the presence of ILD (p < 0.001) and digital ulcers (p = 0.01). Centromere antibodies had a negative association with ILD (p < 0.001), but was a risk factor for calcinosis (p < 0.001) and pulmonary arterial hypertension (PAH) (p = 0.01). The combination of diffuse cutaneous disease and Scl70 antibodies was the strongest predictor of ILD and digital ulcers (p = 0.015). sm/RMP, RNP68 and Ku antibodies correlated with musculoskeletal involvement (p < 0.01), while all seven of the patients with Pm/Scl antibodies had ILD. Renal involvement was noted in only two patients. Limitations A single-centre study may not capture the true prevalence of disease characteristics in the population. Referral bias for patients with diffuse cutaneous disease has been noted. Data on RNA-Polymerase antibodies have not been provided. Conclusion North Indian patients have some characteristic differences in disease phenotype as compared to their Caucasian counterparts with a larger proportion of patients presenting with ILD and Scl70 antibodies. Antibodies against Ku, RNP and Pm/Scl occur in a minority of patients, but may be associated with musculoskeletal features.

The Frequency of Immunofluorescence Antinuclear Antibody Patterns and Extractable Nuclear Antigen: Experience From a Large Laboratory in Pakistan

Background Autoimmune disorders have shown an increasing incidence in the last few years. The systemic response to the disorder is characterized by the expression of antinuclear antibody (ANA), which serves as the serological hallmark of autoimmunity. Its presence may indicate either a systemic autoimmune disease such as systemic lupus erythematosus (SLE), scleroderma, and polymyositis/dermatomyositis or an organ-specific condition such as autoimmune thyroiditis and hepatitis. The systemic response may vary from one individual to another in each population. Several specific autoantibodies are also found to be associated with specific rheumatic diseases. Aim We aim to report the frequency of ANA positivity, ANA immunofluorescence patterns, and the presence of extractable nuclear antigen (ENA) among the general Pakistani population from one of the largest laboratories in Pakistan. Material and methods A total of 1,966 blood samples from a random Pakistani population were included, who were referred by their physicians with suspicion of autoimmune disease. These blood samples were subjected to ANA testing by indirect immunofluorescence method, and subsequently, positive samples were further analyzed for ENA detection in the Section of Chemical Pathology, Department of Pathology at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. An ANA titer of ≥1:80 was taken as positive. ANA was divided into subgroups based on titer: negative, weakly positive (titer of 1:80 or 1:160), moderately positive (titer of 1:320 or 1:640), and strongly positive (titer of ≥1:1280). Further, the frequency of ANA in male and female participants was studied in different age groups (2 to <10, 10 to <20, 20 to <30, 30 to <40, 40 to <50, 50 to <60, 60 to <70, 70 to <80, and 80+ years). Results This study included 1,966 participants, out of which 1,100 (55%) were ANA-positive at a titer of ≥1:80. Out of these ANA positives, the proportion of weakly positive (titer of 1:80 or 1:160), moderately positive (titer of 1:320 or 1:640), and strongly positive (titer of ≥1:1280) were 48.7%, 2.6%, and 4.2%, respectively. The ages ranged from two to 91 years, with a mean age of 43.64 ± 17.4 years. Females (75.5%) showed predominance over males (24.5%) in all age groups, with a ratio of 3:1. The age group in which most ANA positivity was found was 30 to <40 years. Among 1,100 ANA-positive sera, 383 (34.8%) participants tested positive for at least one out of 15 ENA. The most frequent autoantibodies noticed were anti-recombinant Ro52 (Ro52) (19.8%), anti-Sjogren's syndrome type A (SSA) (17.2%), and anti-ribonucleoprotein (RNP) (13.3%). The most prevalent ANA patterns were nuclear homogeneous (27.7%), followed by nuclear speckled (26.5%). Conclusion The frequency of ANA positivity is high in the Pakistani population and differs in different sex and age groups.

The influence of demography and referral medical specialty on the detection of autoantibodies to HEP-2 cells in a large sample of patients

Background

The prevalence of anti-cell autoantibodies detected by indirect immunofluorescence assay on HEp-2 cells (HEp-2-IIFA) increases with age and is higher in female sex. The number of medical specialties that use HEp-2-IIFA in the investigation of autoimmune diseases has increased lately. This study aimed to determine the prevalence and patterns of autoantibodies on HEp-2-IIFA according to demographics variables and referring medical specialties.

Methods

A retrospective analysis of the HEp-2-IIFA carried out between January and June of 2017 was performed. The International Consensus on Antinuclear Antibodies Patterns (ICAP) and the Brazilian Consensus on Autoantibodies were used for patterns definition on visual reading of the slides. Anti-cell (AC) codes from ICAP and Brazilian AC codes (BAC) were used for patterns classification.

Results

From 54,990 samples referred for HEp-2-IIF testing, 20.9% were positive at titer ≥ 1/80. HEp-2-IIFA positivity in females and males was 24% and 12%, respectively (p < 0.0001). The proportion of positive results in the 4 age groups analyzed: 0–19, 20–39, 40–59, and ≥ 60 years was 23.3, 20.2, 20.1, and 22.8%, respectively (p < 0.0001). Considering all positive sera (n = 11,478), AC-4 nuclear fine speckled (37.7%), AC-2 nuclear dense fine speckled (21.3%), BAC-3 nuclear quasi-homogeneous (10%) and mixed/composite patterns (8.8%) were the most prevalent patterns. The specialties that most requested HEp-2-IIFA were general practitioner (20.1%), dermatology (15%), gynecology (9.9%), rheumatology (8.5%), and cardiology (5.8%). HEp-2-IIFA positivity was higher in patients referred by rheumatologists (35.7% vs. 19.6%) (p < 0.0001). Moderate (46.4%) and high (10.8%) titers were more observed in patients referred by rheumatologists (p < 0.0001). We observed a high proportion of mixed and cytoplasmic patterns in samples referred by oncologists and a high proportion of BAC-3 (nuclear quasi-homogeneous) pattern in samples referred by pneumologists.

Conclusions

One-fifth of the patients studied were HEp-2-IIFA-positive. The age groups with more positive results were 0–19 and ≥ 60 years. AC-4, AC-2, BAC-3 and mixed/composite patterns were the most frequent patterns observed. Rheumatologists requested only 8.5% of HEp-2-IIFA. Positive results and moderate to high titers of autoantibodies were more frequent in patients referred by rheumatologists.

Assessment of ideal serum dilution for screening of antinuclear antibodies by an indirect immunofluorescence method in diagnosis of autoimmune disorders

BACKGROUND

Time and cost constraints lead to majority of clinical laboratories deviating away from an ideal practice of checking for antinuclear antibodies (ANAs) by indirect immunofluorescence (IIF) at multiple dilutions. Usage of screening dilution of 1:40 recommended by most manufacturers of commercial ANA kits results in numerous false positive-tests and misdiagnosis of connective tissue disorders (CTDs). We sought to study the ideal screening dilution for ANA by IIF for a diagnosis of ANA-related CTDs.

METHODS

Serum samples of patients with ANA-related conditions (n = 233) and healthy controls (n = 154) were evaluated by IIF using Immuno Concepts Hep-2000 ® ANA kits at dilutions from 1:40 to 1:640. Accuracy for diagnosis of CTDs for each serum dilution was assessed by receiver operating curve (ROC) analysis.

RESULTS

Antinuclear antibodies (ANA) positivity was observed in 19.5%, 10.4%, 4.55%, 0.65%, and 0% of healthy controls at dilutions of 1:40, 1:80, 1:160, 1:320, and 1:640, respectively. ANA positivity at 1:40 dilution was observed among 26.4% cases with mimics of CTDs. Prevalence of ANA positivity in ANA-related CTDs was 97.3%, 96.4%, 89.3%, 83.9%, and 71.4% at dilutions of 1:40, 1:80, 1:160, 1:320, and 1:640, respectively. ROC analysis revealed best test performance for distinction between healthy and ANA-related CTD populations at a serum dilution of 1 in 80.

CONCLUSIONS

Antinuclear antibodies (ANA) positivity at low titers (1:40) is highly prevalent in healthy population (19.5%) as well as amongst mimics of CTD (26.4%). Our study suggests a higher screening dilution of 1:80 for ANA by IIF for diagnosis of CTD maybe better. Combination of 1:80 and 1:160 dilutions provides optimum sensitivity and specificity for diagnosis of ANA-related disorders.

Antinuclear Antibody Profiling in Patients of a Tertiary Care Centre in Central India

The incidence of autoimmune disorders that includes the connective tissue diseases has seen a rise in India in recent times. Antinuclear antibodies, the telltale sign of systemic autoimmune response, thus can be used as a screening tool and also to support the diagnosis of systemic autoimmune disease. The present retrospective cross- sectional analysis aimed to study the antinuclear antibodies profile (patterns and specific antibody reactivity) amongst suspected cases of auto-immune disorders at a tertiary care teaching hospital. The study retrieved and reviewed reports of 644 patients sent for ANA testing by indirect immunofluorescence assay over a period of 1 year by different specialty departments. Positive samples were further processed for anti-ds-DNA antibody and antibodies to extractable nuclear antigen. Data collected was statistically analysed. ANA pattern positivity was observed in 31% of cases and a positive antibody reactivity was seen in 66% of them. Female predominance (82%) was noted in both pattern positivity and antibody reactivity. High levels of pattern positivity and antibody reactivity was found in the young adults (45.9%). Amongst the ANA patterns, the nuclear homogenous pattern was found the commonest. The common antibodies associated with this pattern were anti-dsDNA and U1 Sm/RNP antibodies. A stronger fluorescence intensity on initial screening showed a higher confirmation rate for specific antibodies on immunoassay. High occurrence of positive ANA patterns in autoimmune disorders suggests its utilization as a screening tool for them and would also play an adjuvant to the diagnosis. Early knowledge about future autoimmunity will earn better prognostic achievements through better treatment interventions.

A Hospital-Based Insight into the Antinuclear Antibody Patterns in Autoimmune Disorders

Background  The incidence of autoimmune disorders has seen a rise in India in recent times. The symptoms and signs of these conditions are caused by a systemic autoimmune response, essentially characterized by the expression of the antinuclear antibodies (ANA). Presence of ANA in serum of patient could be the prime evidence of an autoimmune disorder.

Aim  This study aimed to determine the antibody patterns and assess the clinical significance of ANA in patients of a teaching tertiary care hospital of central India.

Material and Methods  This retrospective cross-sectional data analysis study retrieved 538 reports of individuals, who were prescribed the ANA test by indirect immunofluorescence assay over a period of 11 months, from the archives of the Department of Biochemistry. For continuous data, student t -test was used while Chi-square and Fisher exact was conducted for categorical data. A p value less than 0.05 were taken as significant.

Results  Out of the 538 patients investigated for ANA testing by indirect immunofluorescence assay, 33% were positive, among which 74% were female, and majority belonged to the young adult age group. The most common pattern identified was nuclear, subpattern nuclear speckled.

Conclusion  A high-ANA pattern positivity could be related to a high-autoimmunity prevalence in this region, and also promotes its use as a tool of evidence of suspected autoimmune disorders.

Autoantibodies Associated With Connective Tissue Diseases: What Meaning for Clinicians?

Connective tissue diseases (CTDs) such as systemic lupus erythematosus, systemic sclerosis, myositis, Sjögren's syndrome, and rheumatoid arthritis are systemic diseases which are often associated with a challenge in diagnosis. Autoantibodies (AAbs) can be detected in these diseases and help clinicians in their diagnosis. Actually, pathophysiology of these diseases is associated with the presence of antinuclear antibodies. In the last decades, many new antibodies were discovered, but their implication in pathogenesis of CTDs remains unclear. Furthermore, the classification of these AAbs is nowadays misused, as their targets can be localized outside of the nuclear compartment. Interestingly, in most cases, each antibody is associated with a specific phenotype in CTDs and therefore help in better defining either the disease subtypes or diseases activity and outcome. Because of recent progresses in their detection and in the comprehension of their pathogenesis implication in CTD-associated antibodies, clinicians should pay attention to the presence of these different AAbs to improve patient's management. In this review, we propose to focus on the different phenotypes and features associated with each autoantibody used in clinical practice in those CTDs.

Use of panel testing for detection of antinuclear antibody in a resource-limited setting: an appraisal

OBJECTIVES

Despite an increase in the incidence of systemic connective tissue diseases (CTD), panel testing for detection of antinuclear antibodies (ANA) is not a routine practice in many health centers of the Indian subcontinent. Consequently, the data on its significance is scanty.

METHODS

To evaluate utility of panel testing, line immunoassay (LIA) and indirect immunofluorescence antinuclear antibody test (IIF-ANA) were performed in 321 cases of CTD.

RESULTS

Out of 321 serum samples screened by the above tests, 227 were positive and 18 were negative by both LIA and IIF-ANA. Additional 11/321 (3.4%) cases were picked up by LIA. SSA was most common specificity in these cases followed by SSA/SSB, SSB, Ro-52, Jo-1, dsDNA and nRNP/Sm.

CONCLUSION

Use of LIA along with IF-ANA and ELISA improves sensitivity of CTD screening.

Prevalence of antinuclear antibodies in healthy Lebanese subjects, 2008-2015: a cross-sectional study involving 10,814 subjects

Antinuclear antibodies (ANA) are found at varying frequencies in healthy populations, depending on geographical location and ethnic background of participants. The main objective of this study was to determine the prevalence of ANA in healthy Lebanese population in the period 2008-2015. Study subjects comprised 10,851 individuals (3311 males and 7503 females). ANA positivity was determined using immunofluorescence on HEp-2 cells. The prevalence of positive ANA test at a titer of ≥1:100 was 26.4 %, with 696 individuals (6.4 %) having titers exceeding 1:100. Most ANA-positive cases were recorded between 2013 and 2015, which reflected increased assay sensitivity. ANA positivity was associated with increased age and with female gender. Significant increases in ANA positivity were seen with advanced age, with steady increases from the 30- to 40-year age group through the >70-year age group, with significantly higher prevalence noted in female participants. There was a steady and significant reduction in the number of ANA-positive cases with higher ANA titers, which ranged from 20.0 % (1/100) to 3.7 % (1/320), 1.7 % (1/640), and 1.1 % (1/1000). While 45 % of low ANA titer was seen in 31-60-year age category, compared with 19.8 % for 61+ year category, the distribution of high ANA titer was more uniform between 31+ year age categories, which ranged from 11.4 % (31-40 years) to 12.4 % (>70 years). This was consistently and significantly higher in female participants. The prevalence and distribution of ANA among Lebanese individuals were comparable to the rates established for Western countries and confirm the contribution of female gender and advanced age to ANA positivity.

Prevalence of systemic autoimmune rheumatic diseases and clinical significance of ANA profile: data from a tertiary hospital in Shanghai, China

It is necessary and useful to explore prevalence of various systemic autoimmune rheumatic diseases (SARDs) in patients with suspicion of having SARDs and to characterize antinuclear antibodies (ANA) profile for identifying different populations (SARDs and non-SARDs). A total of 5024 consecutive patients with available medical records were investigated, whose sera had been tested for ANA profile, including ANA, anti-dsDNA and anti-extractable nuclear antigen (ENA) antibodies, between 31 January 2012 and 26 March 2014. Only 594 (11.8%) patients were diagnosed with SARDs of those suspected with SARDs. The prevalence of systemic lupus erythematosus (SLE) was highest (3.2%), followed by rheumatoid arthritis (RA) (2.5%), primary Sjögren's syndrome (pSS) (1.7%), ankylosing spondylitis (AS) (1.5%), etc. Of females, SLE also showed the highest prevalence (6%), while of males, AS showed the highest prevalence (1.9%). The prevalence of most SARDs was closely associated with age, except mixed connective tissue disease (MCTD), and the variation characteristics among different age groups were different among various SARDs. The prevalence of ANA was significantly increased in most SARD patients [especially in SLE, systemic sclerosis (SSc) and MCTD]. For anti-ENA antibodies, in contrast to some autoantibodies associated with multiple SARDs (e.g. anti-SSA, SSB, nRNP), others were relatively specific for certain diseases, such as anti-dsDNA, Sm, histone, nucleosome and Rib-P for SLE, anti-SCL-70 for SSc and anti-Jo-1 for polymyositis/dermatomyositis (PM/DM). Of note, ANA profile appeared to be of little significance for AS, ANCA-associated vasculitis (AAV), polymyalgia rheumatic (PMR), adult-onset Still's disease (ASD) and Behcet's disease (BD). The younger were more likely to have the presence of anti-dsDNA, Sm, histone or Rib-P for SLE, and anti-SSA for RA or MCTD. No significant differences for frequencies of ANA and anti-ENA autoantibodies were found between sexes in most SARDs, with the exception of RA and AS. The present study suggests that, of patients with SARDs-like clinical manifestations, the proportion of those with true SARDS is small, for most of whom tests for autoantibodies are necessary and useful to help make a prompt and precise diagnosis.

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.

50 years of pediatric immunology: progress and future, a clinical perspective

Rapidly evolving advances in the field of immunology over the last few decades have impacted the practice of clinical medicine in many ways. In fact, understanding the immunological basis of disease has been pivotal in deciphering the pathogenesis of several disease processes, infective or otherwise. As of today, there is hardly any specialty of medicine which is not influenced by immunology. Pediatric rheumatological disorders, vasculitides, Human Immunodeficiency Virus (HIV) infection, Primary Immunodeficiency Diseases (PIDs) and autoimmune disorders fall under the domain of clinical immunology. This specialty is poised to emerge as a major clinical specialty in our country. The gulf between bench and bedside is narrowing down as our understanding of the complex immunological mechanisms gets better. However, a lot still needs to be done in this field as the morbidity and mortality of some of these conditions is unacceptably high in the Indian setup. A number of medical schools and institutes in the country now have the resources and the wherewithal to develop into specialized centres of clinical immunology. We need to concentrate on training more physicians and pediatricians in this field. The future is bright and the prospects exciting.