Familial primary biliary cirrhosis and autoimmune thrombocytopenia

Familial clustering and genetic background of primary biliary cirrhosis in Japan

BACKGROUND

Primary biliary cirrhosis (PBC) is regarded as an autoimmune liver disease and familial clustering of PBC could represent some genetic predisposition to the disease.

AIMS

To elucidate the genetic background of PBC by investigating familial cases of PBC.

METHODS

Familial cases were picked out from 171 PBC patients who enrolled in this study. We analyzed them and their family members, and compared them clinically and immunogenetically to non-familial cases.

RESULTS

Out of 171 PBC patients, ten (5.8%) were identified as familial PBC in five families. The clinical features of familial PBC were almost comparable to those of non-familial PBC. The distribution of human leukocyte antigens (HLA)-A, -B and -DR in familial PBC showed no specificity. Two new PBC patients were identified in one family in addition to the two originally enrolled PBC patients, resulting in four patients with PBC within the same family. The two new PBC patients had an identical HLA haplotype. On the other hand, one HLA-identical sister of a PBC patient in another family did not develop PBC.

CONCLUSIONS

Primary biliary cirrhosis can exhibit familial clustering without any HLA predisposition, however, a survey of families for PBC could be useful for identifying new patients with PBC in the asymptomatic stage for earlier diagnosis and treatment.

Inter-relationships between platelet count, platelet IgG, serum IgG, immune complexes and severity of liver disease

Thrombocytopenia is a common finding in subjects with chronic liver diseases. A variety of mechanisms may underlie this. Immunological disturbances are commonly a feature in chronic liver disease, including hyperglobulinaemia and the presence of autoantibodies and circulating immune complexes and immune mechanisms could therefore contribute to thrombocytopenia. We have investigated the relationships between blood platelet count, serum IgG and IgG immune complexes and IgG associated with platelets in 92 subjects with chronic liver disease (27 with chronic active hepatitis, 38 with primary biliary cirrhosis and 27 with alcoholic liver disease). Severity of liver impairment was a major determinant of degree of thrombocytopenia. Also, an inverse relationship was demonstrated between platelet count and platelet-associated IgG. In subjects with chronic active hepatitis the relationships between platelet count, serum IgG immune complexes and platelet-associated IgG were consistent with a role for immune mechanisms in general and immune complexes in particular as mediators of the thrombocytopenia.

Immune thrombocytopenic purpura following liver transplantation: a case series and review of the literature

Thrombocytopenia is common among liver transplant candidates and recipients. The aim of our study was to determine the incidence and outcome of new-onset immune-mediated thrombocytopenic purpura (ITP) following liver transplantation at a single center. Among the 256 liver transplant recipients with an International Classification of Diseases, Ninth Edition code for thrombocytopenia, 8 cases of new-onset ITP were identified, leading to an overall incidence of 0.7% in 1,105 consecutive liver transplant recipients over a 15-year period. All 8 patients were Caucasian, 5 (63%) were male, and the median age at ITP onset was 54 years (range, 15-63). The median platelet count at presentation was 3,500 cells/mL (range, 1,000-12,000) and liver disease was due to hepatitis C (38%), primary sclerosing cholangitis (38%), and cryptogenic cirrhosis (25%). The median time from transplant to ITP onset was 53.5 months (range, 1.9-173). Three of the 6 patients tested (50%) had cell-bound antiplatelet antibodies, 1 patient had an underlying hematological malignancy, and none of the organ donors had a history of ITP. Corticosteroids and/or immunoglobulin infusions were effective in 4 patients. However, serial rituximab infusions were required in 4 patients with persistent thrombocytopenia, and 3 of them eventually required splenectomy to induce disease remission. At a median follow-up of 19.7 months, 7 long-term survivors remain in remission with a median platelet count of 267,000 cells/mL. In conclusion, new-onset ITP is an infrequent but important cause of severe thrombocytopenia in liver transplant recipients. Corticosteroids and immunoglobulin infusions were effective in 50% while the remainder of patients required rituximab infusions or eventual splenectomy for long-term disease remission.

Genetic and familial considerations of primary biliary cirrhosis

The genetic basis of human autoimmune diseases is receiving increasing attention. Primary biliary cirrhosis (PBC) is a model autoimmune disease reflective of other organ-specific autoimmune pathology. PBC is an enigmatic autoimmune disease that predominantly affects women and leads to destruction of intrahepatic bile ducts. The serological hallmark of this disease is characterized by antimitochondrial antibodies that specifically react with the E2 components of 2-oxodehydrogenase enzymes, including PDC-E2. There are no clear major histocompatibility complex associations with the development of PBC, despite the observation that first-degree relations of index patients with PBC have a 4-6% prevalence of development of PBC. This risk factor is comparable or higher than any other human autoimmune disease and suggests that a genome-wide approach towards dissection of genetic associations would lead to valuable new insights. In this review, we place these concepts in perspective and highlight in particular the genetic associations in PBC and the importance of studying siblings with PBC who are concordant for disease.

Familial primary biliary cirrhosis in Hiroshima

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the presence of anti-mitochondrial antibodies and chronic inflammatory destruction of septal and intrahepatic bile ducts. Although there are no obvious associations of PBC with MHC class I or class II genes, there appears to be a significant increased risk of developing disease within families. Clearly, a combination of genetic and environmental factors play a role in disease pathogenesis, although the relative contributions of each are unclear. In this study, we have taken advantage of the well-defined health-care system in Hiroshima prefecture, where PBC is a reportable disease. In the period 1988-1997, 156 new patients with PBC in a total population of 2,873,000 were diagnosed. These patients included 18 subjects that were derived from eight different families in which more than one family member had a history of PBC; this reflects a frequency of 5.1% and further shows that the prevalence of PBC is greatly increased in family members. Of interest, the median age of onset of PBC in second generation patients was much younger (33.4+/-10.8 years) compared to median disease onset in general patients with PBC in Hiroshima (55.6+/-12 years). In fact, it was striking that the onset of disease in family members often occurred within a few years of each other. We also noted that sera of affected members had similar AMA reactive profiles against recombinant PDC-E2, BCKD-E2 and OGDC-E2; the major autoantigens of PBC. Similar HLA types were found within affected members of a pedigree but the data is limited because of absence of similar typing of unaffected members. The increased family history of PBC, and the earlier onset of disease in second generation members, suggests that environmental agents are an important risk factor for the development of disease. We suggest that genomic analysis in familial PBC will be important to identify the mechanisms of genetic susceptibility.

Successful steroid treatment of idiopathic thrombocytopenic purpura after orthotopic liver transplantation for primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune disease of the liver frequently associated with extrahepatic autoimmune phenomena. Specific antibodies against platelet glycoproteins may play an important role in the pathogenesis of thrombocytopenia associated with PBC. This is the first report of life-threatening idiopathic thrombocytopenic purpura successfully treated with steroids in a 62-yr-old woman 2 yr after liver transplantation for PBC.

Idiopathic thrombocytopenic purpura in a liver transplant recipient with previous primary biliary cirrhosis

The loss of immunotolerance has been implicated in the pathogenesis of both primary biliary cirrhosis (PBC) and idiopathic, immune-mediated thrombocytopenic purpura (ITP). An association between these two autoimmune diseases has been well described. We describe a 41-year-old woman in whom ITP developed 457 days after liver transplantation for PBC while receiving immunosuppressive medications sufficient to maintain allograft function. Our case report, the first to describe post-transplant ITP in association with PBC, demonstrates the persistence of the underlying immune dysregulation of PBC after transplantation. The practice of decreasing the dosage of immunosuppressive medication to maintenance levels after transplantation may unmask the effects of this defect in immunotolerance.

Primary biliary cirrhosis associated with idiopathic thrombocytopenic purpura

A case of primary biliary cirrhosis (PBC) associated with idiopathic thrombocytopenic purpura (ITP) is reported. The patient is a 59-year-old man. When he was 49 years old, he was diagnosed with ITP and received steroid therapy that successfully increased platelet numbers. However, the steroid therapy failed to normalize the elevated gamma-glutamyl transpeptidase. Ten years after this episode, he suffered from general itching and malaise and exhibited a gradual increase of serum biliary enzyme levels. Immunologically, IgM was increased and anti-mitochondrial antibody was positive. Histological findings of liver needle biopsy showed chronic non-suppurative destructive cholangitis, confirming the diagnosis of PBC. To date, very few PBC cases associated with ITP have been reported. Our case is the second one in Japan. PBC and ITP in our patient seemed to develop simultaneously, but the effect of steroid therapy on the two conditions was different. This result suggests that the autoimmune process may have been different in PBC and ITP in the present patient.

Prevalence and pattern of familial disease in primary biliary cirrhosis

Susceptibility to primary biliary cirrhosis (PBC) may be partly inherited although instances of PBC within families are only infrequently described. The records of 736 patients with PBC seen over a 25 year period were examined to identify those with a positive family history. Ten patients originating from eight families were identified, giving a frequency of 1.33%. They comprised mother and daughter pairs; in two families both mother and daughter had been seen at our clinic. The daughters presented at an earlier age, median 36 years (range 24-54), than the mothers, 52 years (50-81). During follow up one daughter (45 years) and six mothers have died (range 53-81 years) and two mothers and one daughter have had a transplant aged 57, 57, and 30 years respectively. It is concluded that familial PBC is not rare, that it is related to maternally inherited factors, and that disease tends to present earlier in the second generation.