Dengue Literature Review

Antinuclear Antibodies

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Antinuclear Antibodies

Overview

Antinuclear antibodies (ANAs) are immunoglobulins directed against nuclear and cytoplasmic components of eukaryotic cells. They are the most commonly measured biomarkers of autoimmunity and are detected by indirect immunofluorescence (IIF) on HEp-2 cells as the standard method. ANA positivity is not synonymous with autoimmune disease: a substantial proportion of healthy individuals are ANA-positive, particularly at low dilutions, reflecting cross-reactive antibodies, post-infectious responses, or early/subclinical autoimmune processes.

ANA testing is clinically used as a screening test for systemic autoimmune diseases including SLE, systemic sclerosis (SSc), and Sjögren’s syndrome. The 2019 EULAR/ACR SLE classification criteria formalise ANA ≥1:80 on HEp-2 cells as a mandatory entry criterion for SLE classification (see Aringer2019 - 2019 EULAR ACR SLE Classification Criteria).

Key Points from Literature

Prevalence in Healthy Populations

Prevalence varies substantially by dilution threshold, study population, and time period:

StudyPopulationDilutionPrevalence
Tan1997 - ANA Range in Healthy IndividualsInternational multicentre; 125 healthy adults 21–60 yrs1:4031.7%
Tan1997 - ANA Range in Healthy IndividualsAs above1:8013.3%
Tan1997 - ANA Range in Healthy IndividualsAs above1:1605.0%
Tan1997 - ANA Range in Healthy IndividualsAs above1:3203.3%
Satoh2012 - ANA Prevalence in United StatesUS NHANES 1999–2004; ≥12 yrs (n=4,754)1:8013.8%
Li2019 - ANA Epidemiology in Chinese Healthy PopulationChinese health-checkup; 4 mo–93 yrs (n=25,110)>1:10014.01%
Li2019 - ANA Epidemiology in Chinese Healthy PopulationAs above>1:3205.93%
Dinse2022 - Increasing ANA Prevalence in United StatesUS NHANES 2011–2012; ≥12 yrs1:8016.1%

The convergence of ~5–6% at dilutions ≥1:160–1:320 across international populations and decades (Tan1997, Li2019) is notable. At the clinically standard 1:80 dilution, healthy-population prevalence ranges from ~11–16% in US data over 1988–2012, with a clear rising trend (see Dinse2022 - Increasing ANA Prevalence in United States).

Sociodemographic Correlates

Consistent findings across studies (see Satoh2012 - ANA Prevalence in United States, Dinse2022 - Increasing ANA Prevalence in United States, Li2019 - ANA Epidemiology in Chinese Healthy Population):

  • Female sex: consistently ~2× higher prevalence than males; female:male POR peaks at ages 40–49 years then declines
  • Age: generally increases with age, though non-linearly; most pronounced in adults ≥50 years and, paradoxically, increasingly in adolescents (see Dinse2022 temporal trend)
  • Race (US): Non-Hispanic Black individuals have modestly higher prevalence (POR ~1.3–1.75) than White; racial differences attenuated in more recent NHANES cycles
  • BMI: Inverse association — overweight and obese individuals have lower ANA prevalence than normal-weight individuals (POR ~0.74 in Satoh2012); this association shifted toward positive by 2011–2012 (Dinse2022)
  • No consistent associations with education, income, smoking, or C-reactive protein

ANA prevalence in the US has risen significantly over 25 years (see Dinse2022 - Increasing ANA Prevalence in United States): 11.0% (1988–91) → 11.4% (1999–2004) → 16.1% (2011–12; P<0.0001). The increase is most striking in:

  • Adolescents 12–19 years: 5.0% → 9.7% → 12.4% (OR 2.77 by 2011–12 vs. 1988–91)
  • Men: proportionally larger relative increase than women
  • Non-Hispanic White individuals; stable in Black and Mexican American individuals

The trend is not explained by concurrent changes in BMI, smoking, or alcohol consumption.

Clinical Threshold and SLE Classification

The 2019 EULAR/ACR criteria (see Aringer2019 - 2019 EULAR ACR SLE Classification Criteria) define ANA ≥1:80 on HEp-2 cells as the mandatory entry criterion for SLE classification. Meta-regression of 13,080 patients across 64 studies found sensitivity 97.8% (95% CI 96.8–98.5%) for SLE at this threshold. Despite this high sensitivity, specificity is limited — ~86% of individuals who test ANA-positive at 1:80 in the general population do not have SLE or another defined autoimmune disease.

At 1:160, the optimal cutoff for discriminating SLE, SSc, and Sjögren’s syndrome from healthy individuals is 95% specificity (see Tan1997 - ANA Range in Healthy Individuals).

Specific Autoantibodies

Among ANA-positive individuals in the general US population (see Satoh2012 - ANA Prevalence in United States):

  • Most common specific autoantibodies: anti-Ro (3.9% of ANA+ subjects), anti-Su (2.4%)
  • Disease-specific autoantibodies (anti-Sm, anti-topoisomerase I, anti-RNA pol I/III, anti-Jo-1) are extremely rare in healthy populations, confirming their disease specificity
  • In Chinese health-checkup population (see Li2019 - ANA Epidemiology in Chinese Healthy Population): top 3 in high-titer (>1:320) ANA+ individuals were anti-Ro-52, AMA-M2, and anti-SSA

ANA During Acute Infections

Berlin2007 - Autoantibodies in Nonautoimmune Individuals during Infections provides the only multi-infection-type cross-sectional ANA comparison in this wiki:

  • Viral infections (HAV, HBV, HCV): 21.7% ANA positive (ELISA, ANA 8 Pro 8-antigen panel, 1:100; P<0.013 vs. controls)
  • Bacterial infections: 20.0% ANA positive (P<0.006 vs. controls)
  • Healthy blood donor controls: 3.8% ANA positive

The 3.8% control rate is lower than IIF-based population estimates (13.8–16.1%), because ELISA covers only 8 specific nuclear antigens while IIF detects all antinuclear reactivities. The fold-change (~5.7×) is more informative than the absolute infection-group rate. Notably, HAV patients were positive for all 8 tested ANA specificities, including disease-associated antigens such as anti-Sm, anti-U1RNP, and anti-centromere.

These infection-triggered ANA may be transient: a study cited by Berlin2007 found ANA in 20.5% of acute viral hepatitis patients dropping to 6.4% in convalescence. See Infection-Triggered Autoimmunity for mechanistic context.

ANA in Acute Dengue — HEp-2 Gold Standard Data

Chatterjee2024 - ANA Detection in Dengue Kolkata provides the first ANA measurements from acute dengue using the HEp-2 gold standard IIFA platform:

  • ANA-IIFA (HEp-2): 54.8% of dengue-positive patients positive vs. 10.3% of dengue-negative controls (p < 0.001) — the highest ANA rate reported in any dengue context in this wiki.
  • ANA-LIA (18 specific autoantibodies): 18.5% of dengue-positive patients vs. 7.1% of controls (p = 0.009).
  • Critical gap: Only ~34% of IIFA-positive dengue patients confirmed by LIA. The remaining ~66% were IIFA-positive but LIA-negative — indicating non-specific or low-titer nuclear reactivities not corresponding to established autoimmune disease specificities.
  • Study: Kolkata, India; 135 dengue-confirmed + 126 dengue-negative controls; Feb 2021–Feb 2024; IgM ELISA-confirmed (94%) and RT-PCR (6%).

The contrast between the IIFA rate (54.8%) and the LIA rate (18.5%) is mechanistically important: it means dengue massively upregulates general antinuclear reactivity — likely through bystander activation and/or molecular mimicry — but the vast majority of these antibodies do not correspond to the specific autoantibody targets of established systemic autoimmune diseases. This is consistent with Shih2023’s population-level finding that dengue does not broadly elevate clinical autoimmune disease incidence.

ANA in Post-Dengue Context

Garcia2009 - Long-term Clinical Symptoms Post-Dengue found 23.1% ANA positivity in symptomatic Cuban adults 2 years after DENV-4 infection. This is higher than any contemporary healthy-population reference:

  • vs. 5.0% at 1:160 (Tan1997) — 4.6× higher
  • vs. 13.8% at 1:80 (Satoh2012, US population 1999–2004) — 1.7× higher
  • vs. 16.1% at 1:80 (Dinse2022, US population 2011–12) — 1.4× higher

The comparison is imperfect: Garcia2009 used rat liver tissue as the IIF substrate (older, less sensitive than HEp-2; see Indirect Immunofluorescence ANA Test), the testing dilution is not stated, the population is Cuban (not US), and no contemporaneous control group was tested. Because rat liver tissue underestimates ANA relative to HEp-2, the 23.1% figure is a conservative lower bound — HEp-2 testing would likely yield a higher rate, making the elevation above healthy-population baselines even larger than the figures above suggest. Nevertheless, the consistent elevation above all reference values supports that ANA positivity is genuinely increased in post-dengue symptomatic patients.

Comparing ANA Rates Across Dengue Contexts

A coherent timeline of ANA measurement in dengue now exists in this wiki:

StudyTimingSubstrate/MethodPlatformRate
Chatterjee2024 - ANA Detection in Dengue KolkataAcute (fever clinic)HEp-2 IIFAGold standard54.8%
Chatterjee2024 - ANA Detection in Dengue KolkataAcuteLIA (18 specificities)Confirmatory18.5%
Berlin2007 - Autoantibodies in Nonautoimmune Individuals during InfectionsAcute (non-dengue viral)ELISA (8 antigens)Narrower panel21.7%
Garcia2009 - Long-term Clinical Symptoms Post-Dengue2 years post-dengueRat liver IIFLess sensitive23.1%

The 54.8% acute dengue IIFA rate (Chatterjee2024) is not directly comparable to Garcia2009’s 23.1% at 2 years (rat liver substrate underestimates HEp-2 by an unknown factor; different time points). If the acute HEp-2 rate (~55%) eventually declines to ~23% at 2 years (rat liver equivalent), the persistence rate would still be substantial. But if the rat liver 23% corresponds to a HEp-2 equivalent of ~40–50%, then persistence may be even greater — the substrate gap makes this calculation impossible.

Contradictions & Debates

  • Dilution comparability: Studies use different thresholds (1:40, 1:80, 1:100, 1:160, 1:320), making cross-study comparisons imprecise. The international consensus coalesces on 1:80 as the clinical standard (Aringer2019), but many reference studies (including Tan1997) characterise 1:160 as the best discrimination cutoff.
  • Rising prevalence — true increase vs. methodological drift: Dinse2022 argues the rising trend is real and not explained by assay changes (single lab, identical methods). However, HEp-2 cell substrates have become more sensitive over decades as manufacturers optimise for proliferating cells — this systematic question is not fully resolved.
  • BMI paradox: The inverse BMI–ANA association (Satoh2012) shifted to positive or null in the most recent NHANES period (Dinse2022) — the mechanism and clinical significance are unclear.

Sources

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