Background and aims: Primary biliary cirrhosis (PBC) has been reported in up to 4-6% of first degree relatives of patients with the disease. In addition, immune abnormalities, including hypergammaglobulinemia, autoantibodies and increased frequency of autoimmune disorders, were reported in family members of PBC patients. The aim of the present study was to investigate the prevalence of PBC in relatives of patients with PBC, and to investigate the occurrence of chronic liver disease (CLD) and immune abnormalities in these subjects.
Methods: One-hundred first degree relatives of 26 patients with PBC were interviewed and submitted to physical examination and determination of liver enzymes, gamma-globulin, bilirubin and auto-antibodies, including antinuclear (ANA), antismooth muscle (SMA), antimitochondrial antibodies (AMA) by indirect immunofluorescence (IIF) and anti-M2 antibody by immunoblotting (IB).
Results: Immune disturbances were rarely observed in relatives of PBC patients. Higher gamma-globulin levels, SMA and ANA were detected in four, eight and two family members, respectively. In most subjects, these autoantibodies were either in low titers or associated with concurrent diseases. Only four relatives had extrahepatic autoimmune diseases and another eight exhibited other CLD. Primary biliary cirrhosis was detected in a sister of one patient. Additionally, two other relatives of PBC patients who tested negative for AMA by IIF showed reactivity for anti-M2 by IB.
Conclusions: Immune disturbances, including ANA and SMA, are uncommon in family members of PBC patients. Conversely, anti-M2 antibodies and overt PBC do occur in relatives of PBC patients, even in Brazil where the disease is quite rare.