A retrospective study of prevalence and pattern of international consensus on ANA patterns among patients with hepatitis C virus infection

Background

A previous study reported a 30% prevalence of various autoantibodies among patients with hepatitis C virus (HCV) infection. The International Consensus on Anti-Nuclear Antibody (ANA) Patterns was recently introduced to classify ANA patterns based on immunoassay on HEp-2 cells. There is no previous report with this newly developed classification to evaluate patients with HCV infection. The study aims to study the prevalence and pattern of ANA patterns among HCV-infected patients.

Methods

We retrospectively analyzed the medical records of patients with HCV infection from September 2020 to June 2021 at our institution. A positive ANA is defined as a titer of more than 1:320. We compared patient features among the positive and negative groups.

Results

Overall, 258 patients were enrolled-184 patients with negative ANA and 74 patients (28.7%) with positive ANA. The mean age was 67.3 in ANA positive group and 61.2 ANA negative group. Female was prominent with ANA positive and accounted for 63.5%. The most detected ANA pattern was AC-1(homogeneous) (25.9%), followed by AC-4(fine speckled) (25.2%) and AC-21(anti-mitochondrial antibody) (9.6%). In ANA positive group, we found a trend of lower HCV viral load (5.72 log₁₀ IU/ML vs. 6.02 log₁₀ IU/ML), lower alanine aminotransferase level (39.5 U/L vs. 44 U/L), and higher advanced fibrosis (F3 and F4) (38.5% vs. 26.1%). In addition, higher positive ANA (more than 1:640) is significantly associated with lower estimated glomerular filtration rate (eGFR) (77.76 vs. 87.94 mL/min/1.73 m², P = 0.044).

Conclusions

A high prevalence (28.7%) of ANA was found in patients with chronic hepatitis C. The presence of positive ANA is not related to the severity of their hepatic manifestation. However, higher positive ANA was significantly associated with lower eGFR.

Concordance between myositis autoantibodies and anti-nuclear antibody patterns in a real-world, Australian cohort

OBJECTIVES

Myositis autoantibodies (MAs) were traditionally used as diagnostic biomarker for idiopathic inflammatory myopathy (IIM). Its clinical utility had recently expanded to include interstitial lung disease (ILD) diagnosis. Depending on the patient cohort, MAs false positives can be common. Correlation between anti-nuclear antibody (ANA) indirect immunofluorescent (IIF) pattern and MAs may improve its positive predictive value (PPV). The aim of our study was to determine the PPV of MAs in IIM and ILD in a real-world patient cohort. We also assessed whether concordance between MAs and ANA IIF pattern can improve the PPV of positive MA results.

METHODS

Patients with positive MAs and corresponding ANA IIF pattern were identified from Sutherland Centre of Immunology, New South Wales Health Pathology, Australia. The corresponding health records were reviewed to identify each patient's primary diagnosis. Chi-square test was used to compare the PPV between MA-ANA concordant and discordant groups.

RESULTS

Between January 2016 and July 2019, 118 patients were positive for at least one MA (mean age 66.7 years, 55% female). The most frequently detected autoantibodies were Ro52, anti-synthetase antibodies, and PM-Scl. The PPV of MAs for IIM or ILD was 47.4%. The overall concordance rate of MAs and ANA IIF pattern was 70.2%. Patients with concordant MA-ANA results were more likely to have true clinical disease (64.1% vs 17.8%, p< 0.001).

CONCLUSION

Myositis autoantibodies have a low PPV for IIM and ILD in a real-world patient cohort. A positive concordance with ANA IIF pattern can improve MA test accuracy.