Variants of autoimmune liver diseases: how to diagnose and treat them?

Autoimmune liver diseases (AILDs), such as autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC), are classified as rare diseases, but their incidence is increasing. In this review, we present the characteristics of AILDs in adults, and mainly focus on their variants in terms of diagnosis and management. The classic AILDs have been well defined in clinical guidelines, but a proportion of patients with a single AILD tend to show features of other AILDs. In these cases, AIH‑PSC or AIH‑PBC variants should be suspected, prompting evaluation in experienced centers. These variants are more representative of clinical categories rather than pathological diagnoses, and the leading component of the disease determines its treatment. However, treating these patients is challenging, even for experienced clinicians. Progression to end‑stage liver disease is, unfortunately, not a rare course, despite combined and second‑line therapies, particularly for AIH‑PSC variants. Thus, studies based on prospective registers are necessary to elaborate upon widely accepted guidelines, to offer better care to these patients, and to improve their prognosis.