Serum antinuclear antibody in adult Thais

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.

False Positivity of Anti-SARS-CoV-2 Antibodies in Patients with Acute Tropical Diseases in Thailand

Serology remains a useful indirect method of diagnosing tropical diseases, especially in dengue infection. However, the current literature regarding cross-reactivity between SARS-CoV-2 and dengue serology is limited and revealed conflicting results. As a means to uncover relevant serological insight involving antibody classes against SARS-CoV-2 and cross-reactivity, anti-SARS-CoV-2 IgA, IgM, and IgG ELISA, based on spike and nucleocapsid proteins, were selected for a fever-presenting tropical disease patient investigation. The study was conducted at the Faculty of Tropical Medicine during March to December 2021. The study data source comprised (i) 170 non-COVID-19 sera from 140 adults and children presenting with acute undifferentiated febrile illness and 30 healthy volunteers, and (ii) 31 COVID-19 sera from 17 RT-PCR-confirmed COVID-19 patients. Among 170 non-COVID-19 samples, 27 were false positives (15.9%), of which IgA, IgM, and IgG cross-reactive antibody classes were detected in 18 (10.6%), 9 (5.3%), and 3 (1.8%) cases, respectively. Interestingly, one case exhibited both IgA and IgM false positivity, while two cases exhibited both IgA and IgG false positivity. The false positivity rate in anti-SARS-CoV-2 IgA and IgM was reported in adults with dengue infection (11.3% and 5%) and adults with other tropical diseases (16.7% and 13.3%). The urea dissociation method applied to mitigate false positivity resulted in significantly decreased ELISA-based false and true positives. In conclusion, the analysis of antibody against SARS-CoV-2 in sera of patients with different tropical diseases showed that high IgA and IgM false positivity thus potentially limits serological assay utility in fever-presenting patients in tropical areas.

Clinical significance of HEp-2 cell cytoplasmic patterns in anti-neutrophil cytoplasmic antibody associated vasculitis

The study was to investigate the clinical characteristics and significance of antinuclear antibody (ANA) cytoplasmic patterns in ANCA-associated vasculitis (AAV) from Southwest China.A retrospective study including 232 AAV patients from Peoples Hospital of Deyang City was performed. These included 115 patients with ANA cytoplasmic pattern as observation group and 117 patients without ANA cytoplasmic pattern as control group.Chest involvement (60.00 vs 46.15, P = .035), cardiovascular involvement (5.21 vs 29.91, P < .001), and renal involvement (37.39 vs 77.78, P = .001) were different between groups.Total protein (69.55 vs 64.01, P < .001), triglyceride (1.41 vs 1.18, P = .023), mean cell volume (89.76 vs 87.59, P = .040), and estimated glomerular filtration rate (76.67 vs 50.87, P = .035) were higher in ANA cytoplasmic patterns group. Creatinine (73.00 vs 117.50, P = .011), white blood cell (6.93 vs 8.86, P = .001), platelet (196.0 vs 239.0, P = .017), anti-myeloperoxidase (2.44 vs 3.42, P = .042), and anti-proteinase 3 (1.00 vs 4.93, P = .007) were lower in this group. In multivariate analysis, creatinine (odds ratio [OR] = 1.21, 95% confidence interval [CI]: 1.06-1.38), triglyceride (OR = 1.97, 95% CI: 1.10-3.48), and anti-myeloperoxidase (OR = 1.64, 95% CI: 1.37-1.95) were independent risk factors of AAV renal involvement. Total protein (OR = .95, 95% CI: 0.91-0.99) was an independent protective factor of AAV renal involvement. Chi-square test showed that speckled pattern was different among anti-neutrophil cytoplasmic antibody patterns (χ2 = 18.526, P < .001).In summary, HEp-2 cell cytoplasmic patterns have certain clinical significance in AAV, which is a new exploration of the clinical value of ANA.

Association of antinuclear antibody seropositivity with inhaled environmental exposures in patients with interstitial lung disease

Background

Interstitial lung diseases (ILDs) are diffuse parenchymal lung disorders that cause substantial morbidity and mortality. In patients with ILD, elevated antinuclear antibody (ANA) titres may be a sign of an autoimmune process. Inhalational exposures contribute to ILD pathogenesis and affect prognosis and may trigger autoimmune disease. The association of inhalational exposures with ANA seropositivity in ILD patients is unknown.

Methods

This was a retrospective cohort study of adult ILD patients from five centres in the United States. Exposures to tobacco, inhaled organic antigens and inhaled inorganic particles were extracted from medical records. A multivariable logistic regression model was used to analyse the effects of confounders including age, ILD diagnosis, gender and exposure type on ANA seropositivity.

Results

Among 1265 patients with ILD, there were more ANA-seropositive (58.6%, n=741) than ANA-seronegative patients (41.4%, n=524). ANA-seropositive patients had lower total lung capacity (69% versus 75%, p<0.001) and forced vital capacity (64% versus 70%, p<0.001) than patients who were ANA-seronegative. Among patients with tobacco exposure, 61.4% (n=449) were ANA-positive compared to 54.7% (n=292) of those without tobacco exposure. In multivariable analysis, tobacco exposure remained independently associated with increased ANA seropositivity (OR 1.38, 95% CI 1.12–1.71). This significant difference was similarly demonstrated among patients with and without a history of inorganic exposures (OR 1.52, 95% CI 1.12–2.07).

Conclusion

Patients with ILD and inhalational exposure had significantly higher prevalence of ANA-seropositivity than those without reported exposures across ILD diagnoses. Environmental and occupational exposures should be systematically reviewed in patients with ILD, particularly those with ANA-seropositivity.

Association of antinuclear antibody seropositivity with inhaled exposures in ILDhttps://bit.ly/3AwIPeZ

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.

The association between antinuclear antibody and response to rituximab treatment in adult patients with primary immune thrombocytopenia

Background: Antinuclear antibodies (ANAs) can be detected in about 30% of patients with primary immune thrombocytopenia (ITP), yet their relationship with treatment response to rituximab remains elusive.Methods: we retrospectively reviewed the clinical records of hospitalized adult ITP patients who were treated with rituximab from three medical centers across China. Rituximab was given intravenously at 100 mg weekly for 4 weeks, or at a single dose of 375 mg/m². All included patients had their ANAs tested before rituximab treatment.Results: A total of 287 patients fulfilled the inclusion criteria and were eligible for analysis. ANAs were positive in 98 (34.1%) of the included patients. The incidence of overall response and complete response (CR) in ANA-positive patients was significantly higher than that in ANA-negative patients (overall response: 76.5% vs. 55.0%, P < 0.001; CR: 46.9% vs. 29.1%, P = 0.003). However, sustained response (SR) rates in ANA-positive patients at 6, 12 and 24 months were all lower compared with ANA-negative patients (all P < 0.05). The overall duration of response (DOR) estimated by Kaplan-Meier analysis in ANA-negative patients was greater than that in ANA-positive patients (P < 0.001).Conclusion: ITP patients with positive ANA test were likely to achieve a better initial response to rituximab treatment, while their long-term outcome was unfavorable. Therefore, ANA test could be useful for predicting rituximab response in ITP.

Clinical characteristics of very late-onset neuromyelitis optica spectrum disorder

BACKGROUND

The typical age at onset of neuromyelitis optica spectrum disorder (NMOSD) is between 30 and 40 years. A growing awareness about the disease and advances in diagnostic techniques have led to an increase in the number of patients being diagnosed with very late-onset (VLO) NMOSD. This study compared the clinical characteristics, treatments, and prognoses between patients with VLO-NMOSD or late-onset (LO) NMOSD.

METHODS

Patients in our study were assigned to two groups based on age at onset of the disease: LO-NMOSD (50-70 years old at onset) and VLO-NMOSD (> 70 years old at onset). We compared clinical characteristics, magnetic resonance imaging of lesions, prognosis, and treatments between the two groups.

RESULTS

We collected data from 12 VLO-NMOSD patients with a median age at onset of 74.0 years (interquartile range, 72.6-75.9 years) and 104 LO-NMOSD patients with a median age at onset of 56.0 years (55.8-57.9 years). There were a high proportion of female patients in both the VLO-NMOSD group (9, 75.0%) and the LO-NMOSD group (91, 87.5%). Our study indicated that VLO-NMOSD patients had significantly higher expanded disability status scale (EDSS) scores (8.5 vs 4.0, p = 0.01), higher motor disability rates (41.7% vs 9.6%, p = 0.002), and higher mortality rates (25.0 vs 4.8%, p = 0.044) at last follow-up. However, patients with VLO-NMOSD had lower rates of immunosuppressant usage (50.0% vs 76.9%, p = 0.044). Age at onset was positively correlated with EDSS score at remission (r = 0.49, p < 0.001).

CONCLUSION

VLO-NMOSD was associated with higher EDSS score at remission, higher rates of mortality and motor disability, but lower rates of immunosuppressive treatment usage than LO-NMOSD. Future studies are needed to understand the effects of NMOSD on older patients, and to seek suitable treatment to improve their prognosis.

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.