One Gene Links Five HLA-B27 Diseases, Study Finds

For decades, doctors have noticed that patients carrying a particular immune-system marker called HLA-B27 seem unusually prone to a cluster of seemingly unrelated conditions: painful spinal arthritis, scaly skin and joint disease, gut inflammation, and sudden eye attacks known as acute anterior uveitis. What has remained stubbornly unclear is whether these diseases share a common molecular engine or merely a genetic coincidence. A new study published in the Journal of Translational Medicine by a team at the First Affiliated Hospital of Zhengzhou University has now taken one of the most systematic looks yet at that question, combing through thousands of gene-expression profiles to find the molecular threads that tie HLA-B27-associated immune-mediated diseases together.

The research, led by Xinyue Zhu and Chunyu Liang under the senior authorship of Liping Du and Lin Li, began in the public repositories of the Gene Expression Omnibus, a vast library of raw genetic data generated by laboratories worldwide. The team pulled together transcriptomic datasets covering five distinct conditions: axial spondyloarthritis, psoriatic arthritis, ulcerative colitis, Crohn’s disease, and acute anterior uveitis. Each of these conditions has long been epidemiologically linked to HLA-B27, a human leukocyte antigen molecule that presents fragments of proteins to immune cells and is carried by a substantial fraction of people with these diagnoses. By comparing diseased tissue and blood samples against healthy controls across all five diseases simultaneously, the researchers could ask a question no single-disease study can answer: which genes behave abnormally everywhere?

The scale of the dysregulation they uncovered was striking. Differential expression analysis identified 2,485 genes altered in axial spondyloarthritis, 380 in psoriatic arthritis, 2,682 in ulcerative colitis, 2,232 in Crohn’s disease, and 481 in acute anterior uveitis. Yet when the team intersected these lists, searching for genes misregulated in every single disease, only one survivor emerged: ABCD2, a gene encoding an ATP-binding cassette transporter involved in the handling of very-long-chain fatty acids. That singular convergence is the study’s headline finding, and it suggests that lipid metabolism, rather than any single inflammatory pathway, may sit at the molecular crossroads of the entire HLA-B27 disease spectrum.

To test whether ABCD2 could actually serve as a diagnostic marker rather than a statistical curiosity, the researchers applied a machine-learning pipeline that has become standard in modern biomarker discovery. Least absolute shrinkage and selection operator regression, a technique that penalizes complexity and strips away genes that add little predictive power, was used to distill each disease’s thousands of candidate genes into compact diagnostic panels. Receiver operating characteristic analysis then measured how well each panel separated patients from healthy individuals, with the team demanding an area under the curve above 0.9, a threshold indicating near-clinical discrimination. The resulting panels contained three genes for axial spondyloarthritis, six for psoriatic arthritis, fifteen for ulcerative colitis, nine for Crohn’s disease, and four for acute anterior uveitis.

Crucially, the team did not stop at computational prediction. They obtained peripheral blood mononuclear cells, the circulating immune cells that serve as a accessible window into systemic inflammation, from patients with ankylosing spondylitis, the most severe form of axial spondyloarthritis, and from patients with ulcerative colitis. Using reverse transcription quantitative polymerase chain reaction to measure messenger RNA and Western blotting to measure protein, they confirmed that ABCD2 was indeed upregulated in both patient groups. Perforin-1, encoded by PRF1, was elevated in the ankylosing spondylitis samples, while FN1, interleukin-6, and the thrombin receptor F2R were elevated in ulcerative colitis. The experimental validation, conducted under ethical approval from Zhengzhou University’s Life Science Ethics Review Committee, transforms the study from an exercise in data mining into a hypothesis grounded in human biology.

Beyond the single shared biomarker, the analysis revealed an architecture of two distinct gene clusters that appear to divide the HLA-B27 disease spectrum along clinical lines. The first cluster, comprising LAG3, IL15, PRF1, TBX21, and IL2RB, is dominated by genes that govern cytotoxic immunity: the training of killer T cells, the activity of natural killer cells, and the molecular machinery of cellular destruction. The second cluster, containing IL6, FN1, F2R, HIF1A, and ANGPT2, tells a different story, one of inflammatory signaling, tissue remodeling, blood coagulation, and the low-oxygen stress responses that characterize chronically inflamed tissue. The researchers interpret these as an arthritis-related cluster and an extra-articular disease-related cluster, respectively, hinting that joint disease and organ-based inflammation may diverge at the transcriptional level even when they share a genetic predisposition.

Immune-cell deconvolution added another layer of nuance. Using single-sample gene set enrichment analysis, a method that estimates the composition of immune cells within bulk tissue samples, the team showed that the patterns of immune infiltration differed significantly across the five diseases. This finding matters because it challenges the notion of a single unified inflammatory signature in HLA-B27-associated disease. Instead, the same genetic risk appears to be channeled into different immune-cell armies depending on the tissue and context, which may explain why a patient with axial spondyloarthritis and a patient with Crohn’s disease can carry the same HLA-B27 allele yet experience profoundly different symptoms and treatment responses.

The study also mapped the regulatory circuitry above these genes. By constructing competing endogenous RNA networks, which describe how long noncoding RNAs sponge away microRNAs and thereby lift repression from messenger RNAs, and by layering transcription factor interactions on top, the researchers built a multi-tiered map of the molecular controls governing their candidate biomarkers. They then queried the Drug-Gene Interaction Database to identify existing pharmaceutical agents that could plausibly target nodes in these networks, generating a shortlist of candidate drugs for future testing. This translational framing, from gene to regulatory network to therapeutic hypothesis, reflects a growing trend in which computational screens are designed from the outset to feed directly into drug repurposing pipelines.

The identification of ABCD2 as the sole cross-disease biomarker is particularly intriguing because of what the gene does. ABCD2 belongs to a family of half-transporters that shuttle very-long-chain fatty acids into peroxisomes, the cellular compartments where these bulky lipid molecules are broken down. Its connection to inflammatory disease is not obvious from classical immunology, but accumulating evidence links lipid handling to immune regulation, including the composition of membranes, the production of lipid mediators, and the metabolic fitness of immune cells. If ABCD2 dysregulation proves causal rather than merely correlative, it could reframe HLA-B27-associated diseases as disorders in which lipid metabolism and immune activation are entangled, opening therapeutic avenues far removed from conventional anti-inflammatory drugs.

The authors are appropriately measured in their conclusions, describing ABCD2 and the two gene clusters as exploratory candidates for future research rather than validated clinical tools. The diagnostic panels were derived from retrospective datasets and validated in a limited set of patient samples, and the study, published open access on 29 August 2026, will need independent replication in larger and more diverse cohorts before any of these signatures reaches the clinic. Nevertheless, the work demonstrates the power of cross-disease computational biology to extract shared signals from noisy human data, and it hands researchers a concrete, experimentally supported starting point for unraveling why one immune marker predisposes carriers to diseases of the spine, the skin, the gut, and the eye all at once.

Subject of Research: Shared diagnostic biomarkers and gene signatures across HLA-B27-associated immune-mediated diseases

Article Title: Computational identification and experimental validation of shared diagnostic biomarkers and gene signatures across HLA-B27-associated immune-mediated diseases

Article References: Zhu, X., Liang, C., Xu, Z., Zhao, X., Shi, L., He, J., Liu, K., Zhou, P., Xie, K., Jin, B., Zhu, H., Du, L., & Li, L. (2026). Computational identification and experimental validation of shared diagnostic biomarkers and gene signatures across HLA-B27-associated immune-mediated diseases. Journal of Translational Medicine, 24(1), Article 1152. https://doi.org/10.1186/s12967-026-08707-9

Image Credits: AI Generated

DOI: 10.1186/s12967-026-08707-9

Keywords: HLA-B27, biomarkers, axial spondyloarthritis, psoriatic arthritis, inflammatory bowel disease, acute anterior uveitis, ABCD2, bioinformatics, gene expression, diagnostic genes, immune infiltration, Journal of Translational Medicine