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Multiple nuclear dots and rim-like/membranous IgG isotypes in primary biliary cirrhosis
Paolo Muratori1, Alessandro Granito, Silvia Ferri
1Department of Clinical Medicine, Alma Mater Studiorum, University of Bologna, Italy. paolo.muratori3@unibo.it
Abstract:
Anti nuclear (ANA) immunomorphological patterns such as multiple nuclear dots (MND) and rim-like/membranous (RL/M) are considered highly specific but little sensitive for primary biliary cirrhosis (PBC) diagnosis. To evaluate frequency and clinical significance of MND and RL/M in PBC patients when investigated at the level of immunoglobulin G isotypes. MND and RL/M pattern have been tested in 141 PBC sera and 230 pathological controls using HEp-2 cells as substrate and anti- total IgG and individual IgG subclasses (IgG1, IgG2, IgG3, IgG4) as specific antisera. One hundred and fourteen of 141 (80%) PBC patients had RL/M or MND pattern when IgG subclasses were used as revealing reagents (vs. 34% when anti total IgG were used, p < 0.0001). The prevalent isotype was IgG1 for RL/M, and IgG2 for MND pattern. None of controls was positive. No clinical differences in terms of severity and outcome of disease have been observed in PBC patients positive for MND and RL/M when investigated with IgG isotypes. The research for RL/M and MND pattern at level of IgG isotype determines a wide gain in terms of sensitivity without a loss of specificity. In Italian PBC patients MND and RL/M pattern did not seem to characterize any subgroup of patients with a poorer prognosis.
Insights
Investigating anti-nuclear antibody (ANA) patterns like multiple nuclear dots (MND) and rim-like/membranous (RL/M) using immunoglobulin G (IgG) subclasses significantly increases sensitivity for diagnosing primary biliary cirrhosis (PBC). This enhanced detection method maintains high specificity without altering patient prognosis.
Area of Science:
- Immunology
- Hepatology
- Autoimmunity
Background:
- Anti-nuclear antibody (ANA) immunomorphological patterns, specifically multiple nuclear dots (MND) and rim-like/membranous (RL/M), are recognized for high specificity but low sensitivity in diagnosing primary biliary cirrhosis (PBC).
- The diagnostic utility of these patterns may be enhanced by investigating specific immunoglobulin G (IgG) isotypes rather than total IgG.
Purpose of the Study:
- To determine the frequency and clinical significance of MND and RL/M patterns in PBC patients.
- To evaluate these patterns when detected using individual IgG subclasses as revealing reagents.
Main Methods:
- Tested 141 PBC sera and 230 pathological controls for MND and RL/M patterns using HEp-2 cells.
- Employed anti-total IgG and individual IgG subclasses (IgG1, IgG2, IgG3, IgG4) as specific antisera.
- Analyzed the association between pattern positivity and clinical parameters including disease severity and outcome.
Main Results:
- A significantly higher detection rate of RL/M or MND patterns was observed when using IgG subclasses (80%) compared to anti-total IgG (34%, p < 0.0001).
- The prevalent isotype for RL/M was IgG1, and for MND was IgG2.
- No PBC patients tested positive for these patterns, indicating high specificity, and no correlation was found between pattern positivity and clinical disease characteristics or prognosis.
Conclusions:
- Investigating RL/M and MND patterns at the IgG isotype level substantially increases sensitivity for PBC diagnosis without compromising specificity.
- These patterns, when detected via IgG subclasses, do not appear to identify PBC patient subgroups with a poorer prognosis in the studied Italian cohort.
