• autoantibodies
• autoanticorpi
• chronic disimmune liver disease
• epatopatie
• immunoblot

Chronic disimmune liver diseases are liver diseases whose pathogenesis is due to the attack of the immune system to liver parenchyma, either hepatocytes and/or biliary ducts. Most liver diseases are characterized by production of specific autoantibodies that can be studied with Immunoblot technique.

Methods: all «immunoblots-Liver» tested with EUROLineScan assay tests analyzed from sera of patients of Hepatology Unit from 2018 until June 2022 were recorded. All positive results, regardless of histological diagnosis, were included in the first group (n=62), while another group of patients diagnosed with disimmune chronic liver disease was recruited using specific database query (n=61). Clinical and ultrasound data of these two groups were collected, separating every group in other subgroups according to diagnosis (AIH 12 vs 41, overlap 10 vs 4, PBC 18 vs 6, PSC 0 vs 6, aspecific biliary disease 10 vs 3, and non disimmune liver disease like: NASH n = 8, DILI n=2, other n=2).
Statistical analysis was performed using Sigmaplot software.

Results: Most common type of autoantibody detected in all groups was AMA-M2 (n= 24, of which: 2 in AIH IB pos group, 2 in aspecific biliary duct disease, 2 in NASH, 8 in overlap, 10 in PBC), followed by M2-3E (n = 13) that was frequently co-expressed with AMA-M2 (1 in other biliary duct disease coexpressed with AMA-M2, 5 in overlap with coexpression of AMA-M2, 7 in PBC of which 5 coexpressed with AMA-M2). The other autoantibodies were less frequent: 5 CENP-B, 2 CENP-A (1 in AIH, 1 in other biliary duct disease, 2 in overlap, 1 in PBC), LKM (2 in AIH, 1 overlap), PGDH (3 in AIH, 1 in DILI, 1 other biliary duct disease, 2 in PBC), PML (3 in PBC, 1 in overlap, 1 in other biliary duct disease, 1 in AIH), LC-1 (1 in AIH, 2 in other biliary duct disease, 1 in portal liver sclerosis), Ro 52 (3 in PBC, 2 in overlap, 2 in NASH, 1 in DILI, 2 in other biliary duct disease, 1 in AIH), SLA/LP (2 in AIH, 1 overlap), Ro60 (3 in other biliary duct disease, 1 NASH), Scl70 (2 NASH, 1 PBC), Sp100 (1 in AIH, 1 in other biliary duct disease, 1 in overlap, 4 in PBC), Gp210 (7 in PBC, 3 in overlap, 1 in NASH, 2 in AIH).
No significant differences between autoimmune and oncological comorbidities between immunoblot positive patients and immunoblot negative patients were found (respectively: P = 0,629; P = 0,638). While, similarly with previous scientific literature, more female patients were found in the group of immunoblot positive patients (1° group f = 49; 2° group f = 36, p = 0,029), probably due to the higher prevalence of seropositive PBC diagnosis (n=18 vs n = 6), notably more common in female sex.
Regardless of autoantibodies, other analysis were performed. Liver stiffness as measured with Fibroscan was found to be correlated with:
- AST (r = 0.862, p = 0,000000200) and ALT (r = 0.802, p = 0,000000200) values at the moment of evaluation, but no correlation was found between fibroscan value and histological staging in AIH groups (r=0,448; p = 0,204), suggesting necroinflammatory activity as expressed by AST/ALT can cause overesteem of liver stiffness when measured with elastography tools. No significant differences between Fibroscan values of AIH seronegative patients and AIH IB positive patients were found (P = 0,667). A correlation between liver stiffness and levels of total IgG was found (r = 0,751 P=,00214), while no correlation was found between IgM levels and fibroscan values, suggesting IgG/fibroscan correlation could be an expression of policlonal activation in chronic liver disease.

Conclusion: immunoblot technique is a valid tool when performed by skilled technicians and interpreted by skilled clinicians and should be used when:
- the evaluation of certain autoantibodies is not available or when other assays are not sensitive enough (i.e. SLA/LP)
- to extend the sera examination to several autoantigens all at once, and therefore being able to diagnose other autoimmune comorbidities (i.e Sjogren syndrome, systemic sclerosis)
- To determine prognosis (i.e. association between Sp100, gp210 and Ro52 coexpression in PBC and SLA/LP in AIH are associated with worse outcome).
Immunoblot negativity is also another element that suggests a biliary duct disease like primary sclerosing cholangitis ("immunoblot liver" does not include in fact ANCA autoantibody neither anti-enolase autoantibodies)