Therapeutic strategies for the treatment of autoimmune liver disease are essentially based on corticosteroids and immunosuppressant drugs such as methotrexate and azathioprine. The exception is provided by PBC, for which ursodeoxycholic acid (UDCA) is the only established treatment [
37]. The combination of UDCA and immunosuppressants, albeit rational, failed to prove effective or sufficiently safe in most cases. Conversely, methotrexate has been shown to be virtually void from consistent adverse effects in the treatment of real-life patients with or without concomitant UDCA [
38] while being burdened by significant side effects in randomized clinical trials [
39]. A simpler scenario is provided by AIH, for which corticosteroids represent the cornerstone of currently utilized regimens [
40]. This treatment should be considered for all patients with AIH regardless of the disease activity at presentation and should be continued until 24 months to achieve normalization of liver tests and, ideally, resolution of liver inflammatory infiltrate at histology. In cases of incomplete response or relapse, a long-term maintenance regimen with azathioprine is justified. Salvage therapy includes cyclosporine or mycophenolate mofetil, although more solid data are awaited [
40] and new frontier therapeutic approaches may prove beneficial [
41].
Management of overlap syndromes between PBC and AIH is empirical and guided by the predominant manifestations of the disease. Indeed, patients with AIH and PBC with higher serum alkaline phosphatase and transaminases are candidates for treatment with corticosteroids and UDCA [
42].
Of note, potential benefits have been proposed for anti-TNFα treatments in autoimmune liver diseases although human data are scanty. In a murine model, anti-TNFα antibodies proved to be effective in reducing liver inflammation, necrosis, and fibrosis. Reports on the impact of anti-TNFα therapy in patients with inflammatory bowel diseases or other rheumatologic diseases and concomitant liver diseases [
43] demonstrated potential benefits for nonalcoholic steatohepatitis and PSC; however, AIH and hepatosplenic T-cell lymphoma have also been reported [
43].
Several are the implications of concomitant liver disease for the therapeutic intervention in rheumatologic diseases; in fact, the liver is frequently involved in the adverse events of systemic treatments utilized in rheumatology. A complete discussion goes beyond the aims of the present review article, but it is easy to foresee that hepatitis virus reactivation and drug-related liver injuries are rapidly becoming a major cause for liver involvement in rheumatology with the use of more potent immunosuppressants such as biologics [
44,
45] or hematopoietic stem cell transplantation [
46]. Detailed recommendations on the use of immunomodulatory molecules in patients with chronic liver disease were reported by the American College of Rheumatology in 2008 for RA [
47] while the American Association for the Study of Liver Diseases also presented practice guidelines in 2009 for the management of patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) chronic infection needing immunosuppressive therapy [
48,
49], and clinical guidelines are available for viral hepatitis and inflammatory bowel disease treatment [
50]. These guidelines support the view that the alanine aminotransferase (ALT) level, anti-HBsAg, anti-HBsAb, anti-HBcAb IgG and, in selected cases, HBV DNA, along with anti-HCV antibodies and HCV RNA, should be tested before an immunosuppressant treatment is initiated [
47,
50,
51]. Currently, a preventive antiviral treatment is recommended in patients with an active chronic HBV infection (HBsAg-positive, elevated ALT and serum HBV DNA levels >2,000 IU/ml) and in patients with chronic HCV infections without extrahepatic contraindications [
47,
50].
Prophylactic treatment is recommended in patients needing nonbiologic or biologic disease-modifying anti-rheumatic drugs with inactive HBV (HBsAg-positive, normal ALT and HBV DNA <2,000 IU/ml; or HBsAg-negative and anti-HBcAb-positive with or without HBsAb, normal ALT and HBV DNA <50 IU/ml), and to be considered in resolved HBV infection (HBsAg-negative, HBsAb-positive and/or anti-HBcAb-positive, normal ALT and HBV DNA <50 IU/ml) together with monitoring of ALT levels and serum HBV DNA in cases of long-term lamivudine use [
47,
50]. Disease-modifying antirheumatic drugs such as methotrexate and leflunomide are contraindicated in cirrhosis secondary to chronic HBV and HCV infections, whether treated or untreated, for all Child-Pugh stages [
47], while biologics are contraindicated in both chronic HBV and HCV, whether treated or untreated, for those with significant liver injury, defined as chronic Child-Pugh classes B or C [
47]. Immunosuppressant regimens including glucocorticoids appear to have the highest risk of HBV reactivation and HCV replication, so steroid-sparing treatment should be adopted when possible although low doses appear to be safe [
48]. Finally, the use of NSAIDs should be carefully evaluated in patients with liver cirrhosis regardless of the etiology based on the risk of renal injury secondary to tubular ischemia. Referral clinical immunology textbooks report the risk of liver injury related to the use of classical anti-inflammatory treatments such as acetaminophen, NSAIDs, or methotrexate despite the rarity of such events in clinical trials [
52].
The American College of Rheumatology guidelines indicate that when the levels of ALT are greater than twofold the upper normal limit, the initiation of disease-modifying antirheumatic drugs such as methotrexate, leflunomide, and sulfasalazine is contraindicated, while recommendations on when to discontinue the drug are not provided [
47]. Further, recent prospective data put such risk in a more accurate perspective. As an example, the risk of liver injury following acetaminophen intake is now well defined and recognizes a dose-dependent increase, with doses as high as 4 g/day proven to be safe in patients with chronic viral hepatitis or recent alcohol abuse as well as in patients with compensated liver cirrhosis [
53]. Conversely, the appearance of NSAID-induced liver injury appears to be dose independent while the new scenarios of biologic-induced autoimmune hepatitis [
54] will warrant further studies on the long-term outcomes. A most recent study on the impact of methotrexate on liver function tests demonstrated a reasonably safe profile for this medication if properly used [
55], thus suggesting that dedicated studies are necessary to detect the detrimental potential of immunomodulatory treatments. The issue of drug-induced liver injury became important with the discovery of the possible implications of occult hepatitis B infection [
56] and the subsequent impact on the widespread use of monoclonal antibodies [
57] in carriers and cases of chronic infections [
58]. Finally, we should expect that the use of hematopoietic stem cell transplantation will also impact liver biology [
59,
60].