Evolutionary analyses of polymeric immunoglobulin receptor (pIgR) in the mammals reveals an outstanding mutation rate in the lagomorphs

Enhancing liver fibrosis detection: a novel PIGR-utilizing approach in chronic hepatitis B injury assessment

BACKGROUND

Chronic Hepatitis B (CHB) is a leading cause of liver fibrosis and cirrhosis worldwide. The early detection of liver fibrosis remains challenging due to the lack of specific symptoms and noninvasive biomarkers with high sensitivity. The polymeric immunoglobulin receptor (PIGR) has recently emerged as a potential biomarker for liver fibrosis. This study aims to evaluate the utility of PIGR in CHB patients as a biomarker for liver fibrosis.

METHODS

This retrospective study analyzed 150 CHB patients from 2018 to 2023. Based on liver biopsy results, 34 patients were classified as having liver fibrosis, while 116 were categorized as non-fibrosis. Clinical data were compared to assess the relationship between PIGR expression levels and serum fibrosis indices. Logistic regression was performed to identify factors influencing liver fibrosis, and the predictive value of PIGR was evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

Significant differences were observed in collagen type IV (CIV), procollagen type III N-terminal peptide (PCIIINP), and hyaluronic acid (HA) levels between the fibrosis and non-fibrosis groups (P < 0.05). PIGR levels were significantly higher in the fibrosis group (P < 0.05) and positively correlated with HA, laminin (LN), PCIII, and CIV levels (P < 0.05). Logistic regression identified HA, LN, PCIIINP, and CIV as risk factors, with PIGR being an independent predictor (P < 0.05). At a cutoff value of 0.35, PIGR showed an area under the curve (AUC) of 0.839, with 81.90% sensitivity, 79.41% specificity, and a Youden's index of 0.613. PIGR also provided a higher net benefit than APRI.

CONCLUSION

PIGR levels are significantly elevated in CHB-related liver fibrosis and correlate closely with established fibrosis markers. As an independent predictor, PIGR demonstrates high diagnostic accuracy and holds promise as a non-invasive biomarker for detecting liver fibrosis in CHB patients, with significant potential for clinical application.

The IgA of hares (Lepus sp.) and rabbit confirms that the leporids IgA explosion is old and reveals a new case of trans-species polymorphism

Background

Immunoglobulin A (IgA) is the mammalian mucosal antibody, providing an important line of defense against pathogens. With 15 IgA subclasses, the European rabbit has an extremely complex IgA system, strikingly more complex than most other mammals, which have only one IgA or, in the case of hominoids, two IgA subclasses. Similar to the two hominoid primate IGHA genes, the expansion of the rabbit IGHA genes appears to have begun in an ancestral lagomorph since multiple IgA copies were found by Southern blot analysis for the genera Sylvilagus, Lepus, and Ochotona.

Results

To gain a better insight into the extraordinary lagomorph IgA evolution, we sequenced, for the first time, expressed IgA genes for two Lepus species, L. europaeus and L. granatensis. These were aligned with the 15 rabbit IgA isotypes, and evolutionary analyses were conducted. The obtained phylogenetic tree shows that the Lepus IgA sequences cluster with and among the rabbit IgA isotypes, and the interspecies and intraspecies nucleotide genetic distances are similar. A comparison of the amino acid sequences of the Lepus and rabbit IgA confirms that there are two trans-species polymorphisms and that the rabbit and Lepus sequences share a common genetic pool. In fact, the main differences between the studied leporids IgAs reside in the characteristics of the hinge region.

Conclusion

The Lepus IgA sequences we have obtained strongly suggest that the great expansion of the leporid IGHA genes occurred in a common ancestral species and was then maintained in the descendants. A strong selective pressure caused the extraordinary expansion of the IGHA genes but then subsided, leading to the maintenance of the acquired polymorphisms in the descendants, with little subsequent divergence. This is a unique evolutionary pattern in which an ancient gene expansion has been maintained for approximately 18 million years.