Introduction and Context
Primary biliary cholangitis–autoimmune hepatitis (PBC-AIH) is one of the most debated entities in autoimmune liver disease. In practice, patients may show both cholestatic features typical of primary biliary cholangitis (PBC) and inflammatory features suggestive of autoimmune hepatitis (AIH). Yet terminology, diagnostic thresholds, and treatment pathways have varied widely across guidelines and specialty centers.
That variability matters. Some patients are treated too conservatively, leaving inflammatory hepatitis insufficiently suppressed; others are exposed to long-term immunosuppression without enough evidence that the mixed phenotype truly warrants it. To address this gap, an international expert Delphi process, endorsed by ERN RARE-LIVER, the Global PBC Study Group, the International Autoimmune Hepatitis Group (IAIHG), and the European Society of Pathology, sought to establish a practical consensus.
The resulting Hepatology consensus is important because it does not simply refine definitions—it standardizes how clinicians should think about this entity, when biopsy is required, how often the diagnosis should be revisited, and when immunosuppression should be added to standard PBC therapy.
Why This Consensus Was Issued
The expert panel identified several major problems in current care:
- Inconsistent terminology: Some clinicians use “overlap syndrome,” while others use “variant” or “PBC with AIH features.”
- Diagnostic ambiguity: Blood tests and noninvasive findings alone often cannot reliably separate PBC, AIH, and mixed phenotypes.
- Variable biopsy use: In some settings, biopsy is considered optional; in others, it is treated as essential.
- Unclear treatment thresholds: There has been no agreed standard for when to start corticosteroids or other immunosuppressants alongside ursodeoxycholic acid (UDCA).
- Prognostic uncertainty: Clinicians have not always agreed whether PBC-AIH behaves more like PBC, AIH, or a distinct condition with its own risks.
The Delphi process was designed to fill these gaps where randomized trial evidence is sparse. This is a key example of expert consensus stepping in when hard evidence is limited but clinical decisions are still required every day.
New Guideline Highlights
The panel reached consensus on several practice-changing points:
| Topic | Consensus statement |
|---|---|
| Terminology | PBC-AIH should be defined as a variant, not an overlap syndrome. |
| Diagnosis | Liver biopsy is a prerequisite for diagnosis. |
| Diagnostic approach | The diagnosis should be re-evaluated periodically, because PBC and AIH features may appear sequentially over time. |
| Prognosis | PBC-AIH is associated with a worse prognosis than PBC alone unless appropriate immunosuppression is used. |
| Treatment | Immunosuppressive therapy should be individualized based on the severity of interface hepatitis, disease stage, age, comorbidities, and patient preference. |
| Pathology | Biopsy interpretation should ideally be reviewed by an experienced hepatopathologist. |
The most consequential shift is the move away from the term “overlap syndrome.” The panel instead favored “variant,” reflecting the idea that PBC and AIH features may coexist or emerge sequentially rather than represent two entirely separate diseases simply overlapping by chance.
Updated Recommendations and Key Changes
Because this is a Delphi consensus rather than a formal evidence-graded guideline, the update is best understood as a harmonization of expert practice rather than a strict revision of a prior numbered recommendation set.
| Clinical issue | Prior practice pattern | Consensus direction |
|---|---|---|
| Definition | “Overlap syndrome” used inconsistently | Use “PBC-AIH variant” |
| Role of biopsy | Sometimes optional if serologies are convincing | Biopsy required for diagnosis |
| Reassessment | Diagnosis often treated as fixed at presentation | Reassess over time for evolving phenotype |
| Treatment threshold | Variable use of steroids or steroid-sparing therapy | Base immunosuppression on hepatitis severity and patient factors |
| Pathology review | Local interpretation may be sufficient | Expert hepatopathology review preferred when possible |
These changes are clinically meaningful. They push the field toward a biopsy-based, pathology-informed diagnosis and away from relying solely on serology or enzyme patterns.
Topic-by-Topic Recommendations
1) Definition and nomenclature
The panel agreed that PBC-AIH should be called a variant. This language acknowledges that the disease may not behave like a neat overlap of two independent disorders. Instead, one phenotype may evolve into the other, or features of each may be present at different times.
Why this matters:
- It reduces confusion in research and clinical documentation.
- It reflects the biological uncertainty of the condition more accurately.
- It encourages clinicians to think longitudinally rather than making a one-time label at diagnosis.
2) Diagnosis: why liver biopsy is essential
The consensus is clear: liver biopsy is required to diagnose PBC-AIH. This reflects the need to document interface hepatitis and to distinguish the histologic pattern from “pure” PBC or AIH.
Biopsy is particularly important because:
- Biochemical tests can be misleading.
- Autoantibodies are not sufficient on their own to define mixed disease.
- Histology helps determine whether inflammatory hepatitis is severe enough to justify immunosuppression.
The panel also emphasized that histology should ideally be reviewed by an experienced hepatopathologist. That point is practical and important: interface hepatitis severity can be under- or over-called, and treatment decisions may hinge on the report.
3) Re-evaluation over time
A notable feature of the consensus is the recommendation to periodically re-evaluate the diagnosis. This reflects a real-world observation: patients may initially look like classic PBC and only later develop clear AIH features, or the reverse may occur.
For clinicians, this means:
- Do not assume a single biopsy or lab panel settles the diagnosis forever.
- Revisit the phenotype if liver enzymes, IgG, transaminases, cholestatic markers, or symptoms change.
- Consider repeat biopsy or expert pathology review if the clinical course becomes atypical.
4) Prognosis
The expert panel agreed that PBC-AIH generally carries a worse prognosis than PBC alone if not treated with immunosuppression when hepatitis is significant.
This is an important message for clinicians accustomed to thinking of PBC as a disease that responds well to UDCA in many patients. In PBC-AIH, untreated hepatitic inflammation may drive faster fibrosis progression and poorer outcomes. In other words, once the AIH-like component is clinically meaningful, PBC therapy alone may be insufficient.
5) Treatment strategy
The consensus supports individualized immunosuppression, not a one-size-fits-all approach. The choice to add corticosteroids and/or other immunosuppressive agents should depend on:
- Severity of interface hepatitis
- Stage of liver disease
- Age
- Comorbidities
- Patient preference
This is where the pathology report matters most. Mild interface activity may not require the same intensity of immunosuppression as severe, active hepatitis. Advanced cirrhosis, frailty, diabetes, osteoporosis risk, infection risk, and patient tolerance all influence the benefit-risk balance.
Although the abstract does not prescribe a single regimen, the practical interpretation is that treatment often combines standard PBC therapy, usually UDCA, with immunosuppressive therapy when AIH-like inflammation is substantial.
6) Special populations and real-world decision-making
The consensus highlights individualized care, which is especially relevant in:
- Older adults: Higher steroid toxicity and frailty may justify more conservative regimens.
- Patients with comorbid diabetes or osteoporosis: Corticosteroid risks are higher.
- Advanced fibrosis/cirrhosis: Treatment decisions require balancing inflammatory control against complications of immunosuppression.
- Patients with borderline histology: Expert pathology review can be decisive.
Expert Commentary and Insights
The core expert message is that PBC-AIH should be managed as a pathology-informed, longitudinal diagnosis. This is more nuanced than simply checking a box for “overlap.” The consensus reflects several important clinical realities:
- There is no single blood test that reliably identifies PBC-AIH.
- Histology remains central despite growing interest in noninvasive assessment.
- Phenotype can evolve, so clinicians must avoid premature closure.
- Treatment should be proportionate to inflammatory burden and patient risk.
A key controversy is the field’s imperfect evidence base. The Delphi panel did not create randomized-trial proof that one approach is superior; rather, it synthesized expert judgment to standardize care. That is both a strength and a limitation. The strength is immediate clinical usability. The limitation is that some recommendations—especially around the exact threshold for immunosuppression—will still need validation in prospective cohorts.
Another notable implication is the elevation of hepatopathology as a clinical partner. In mixed autoimmune liver disease, the pathologist is not just describing tissue; they are helping decide whether a patient should receive long-term immunosuppression.
Practical Implications
For day-to-day practice, this consensus suggests the following workflow:
- Suspect PBC-AIH in patients with cholestatic features plus disproportionate transaminase elevation, elevated IgG, or AIH-like serology.
- Confirm with liver biopsy before labeling the patient with PBC-AIH.
- Ask for expert pathology review when histology is uncertain or treatment decisions are high stakes.
- Treat the PBC component with standard therapy.
- Add immunosuppression when interface hepatitis is sufficiently severe and the patient’s overall risk profile supports it.
- Reassess over time if labs, symptoms, or fibrosis progression suggest disease evolution.
Brief clinical vignette
Sarah, a 52-year-old woman with fatigue and pruritus, is found to have cholestatic liver tests and antimitochondrial antibodies consistent with PBC. Her ALT is also elevated, IgG is high, and a biopsy shows moderate interface hepatitis. Under the new consensus, she would not be labeled as having a vague “overlap syndrome” based only on bloodwork. Instead, she would be diagnosed with the PBC-AIH variant, with treatment guided by biopsy severity, fibrosis stage, and her overall risk of steroid toxicity.
Bottom Line
This international Delphi consensus brings long-needed clarity to PBC-AIH. The major takeaways are straightforward: use the term PBC-AIH variant, require liver biopsy, reassess the diagnosis over time, and individualize treatment based on the severity of interface hepatitis and patient-specific factors. For clinicians, the message is not simply semantic—it is a call for more standardized, pathology-driven care in a disease where delayed or inconsistent treatment can worsen outcomes.
References
- Gerussi A, Sebode M, Nofit E, et al. Definition, diagnosis, and treatment of primary biliary cholangitis – autoimmune hepatitis (PBC-AIH) variant: An international expert delphi consensus. Hepatology. 2026 May 14. PMID: 42132745.
- EASL Clinical Practice Guidelines: The diagnosis and management of patients with primary biliary cholangitis. J Hepatol. 2017;67(1):145-172.
- EASL Clinical Practice Guidelines on the management of autoimmune hepatitis. J Hepatol. 2015;63(4):971-1004.
- European Association for the Study of the Liver (EASL). Clinical practice guidelines and consensus documents on autoimmune liver disease management. J Hepatol. 2025 updates where applicable.
- IAIHG consensus and scoring frameworks for autoimmune hepatitis diagnosis and research use.