Chronic liver disease: differences in autoimmune serological reactions between Australians and Asians

Cancer as a disease of old age: changing mutational and microenvironmental landscapes

Why do we get cancer mostly when we are old? According to current paradigms, the answer is simple: mutations accumulate in our tissues throughout life, and some of these mutations contribute to cancers. Although mutations are necessary for cancer development, a number of studies shed light on roles for ageing and exposure-dependent changes in tissue landscapes that determine the impact of oncogenic mutations on cellular fitness, placing carcinogenesis into an evolutionary framework. Natural selection has invested in somatic maintenance to maximise reproductive success. Tissue maintenance not only ensures functional robustness but also prevents the occurrence of cancer through periods of likely reproduction by limiting selection for oncogenic events in our cells. Indeed, studies in organisms ranging from flies to humans are revealing conserved mechanisms to eliminate damaged or oncogenically initiated cells from tissues. Reports of the existence of striking numbers of oncogenically initiated clones in normal tissues and of how this clonal architecture changes with age or external exposure to noxious substances provide critical insight into the early stages of cancer development. A major challenge for cancer biology will be the integration of these studies with epidemiology data into an evolutionary theory of carcinogenesis, which could have a large impact on addressing cancer risk and treatment.

Autoimmune hepatitis in diverse ethnic populations and geographical regions

Autoimmune hepatitis has diverse clinical phenotypes and outcomes in ethnic groups within a country and between countries, and these differences may reflect genetic predispositions, indigenous etiological agents, pharmacogenomic mechanisms and socioeconomic reasons. In the USA, African-American patients have cirrhosis more commonly, treatment failure more frequently and higher mortality than white American patients. Survival is poorest in Asian-American patients. Autoimmune hepatitis in other countries is frequently associated with genetic predispositions that may favor susceptibility to indigenous etiological agents. Cholestatic features influence treatment response; acute-on-chronic liver disease increases mortality and socioeconomic and cultural factors affect prognosis. Ethnic-based deviations from classical phenotypes and the frequency of late-stage disease can complicate the diagnosis and management of autoimmune hepatitis in non-white populations.

A 50-year experience with autoimmune hepatitis: and where are we now?

BACKGROUND

Autoimmune hepatitis (AIH) as chronic active hepatitis became recognized in the 1940s as a progressive hyperglobulinemic disease affecting younger women attributed to persisting virus infection of the liver: autoimmunity then was barely on the horizon.

EARLY OBSERVATIONS

The lupus erythematosus (LE) cell reported in 1948 signified the presence of antinuclear autoantibodies, promoting perceptions of autoimmunity in certain chronic diseases. Recognition of LE cells in chronic hepatitis led to the designation of 'lupoid hepatitis', with autoimmunity further substantiated by anti-cytoplasmic autoantibodies detected by complement fixation. Next a serum reactant with smooth muscle of rodent stomach was found to have a wider distribution and became identified as an autoantibody to filamentous (F) actin. Therapy with corticosteroids proved effective, particularly combined with azathioprine. Various trials showed greatly improved survival and established modern therapy of AIH. An HLA-based predisposition (B8, DR3) was the first pointer to a genetic etiology.

RECENT ADVANCES

Recombinant or purified autoantigenic substrates have led to automated assays, which, together with improved immunofluorescence procedures, allow serological confidence in diagnosis and institution of effective immunosuppressive therapies. The liver-kidney 'microsomal' autoantigen reactive with cytochrome P450 2D6 distinguishes two serological types of AIH that appear pathogenetically distinct. Molecular characterization of antigens and epitopes remains wanting in type 1 AIH.

FUTURE PROSPECTS

The challenge remains with both types of AIH to elucidate in molecular terms the genetic and environmental basis of pathogenesis from initiation to ultimate progression and cirrhosis (when inadequately treated). Advancing technologies are bringing this goal closer to being attainable.

Overview: Liver disease and transplantation

Australia has had a proud and enviable record of seminal contributions to hepatology, with many contributors. Thus, any attempt to summarize these contributions ab initio in a brief review article is a significant challenge, primarily because it is so easy to overlook or underestimate particular aspects. In this article, I have confined my comments primarily to the areas where the contributions have had a significant global impact and have clearly been recognized internationally. This means that many worthwhile Australian additions will be omitted if there was less apparent international impact. The first significant interest in liver disease in Australia was from the Melbourne group at the Walter and Eliza Hall Institute (WEHI) and Royal Melbourne Hospital, leading to seminal contributions to the description, diagnosis, aetiopathogenesis and therapy of autoimmune hepatitis and primary biliary cirrhosis. Others from Royal Prince Alfred Hospital in Sydney contributed substantially to the effects of immunosuppression of autoimmune hepatitis and to early descriptions of primary sclerosing cholangitis. Other areas where Australians have contributed significantly include steatohepatitis, iron metabolism (and in particular hemochromatosis), viral hepatitis (both at the molecular and clinical level), portal hypertension, and transplant immunology. The remarkable contribution of Professor Dame Sheila Sherlock to Australian hepatology is also summarized.

Autoimmune hepatitis in a North American Aboriginal/First Nations population

North American Aboriginal populations are at increased risk for developing immune-mediated disorders, including autoimmune hepatitis. In the present study, the demographic, clinical, biochemical, serological, radiological and histological features of autoimmune hepatitis were compared in 33 First Nations (FN) and 150 predominantly Caucasian, non-FN patients referred to an urban tertiary care centre. FN patients were more often female (91% versus 71%; P=0.04), and more likely to have low serum albumin (69% versus 36%; P=0.0006) and elevated bilirubin (57% versus 35%; P=0.01) levels on presentation compared with non-FN patients. They also had lower hemoglobin, and complement levels, more cholestasis and higher serum immunoglobulin A levels than non-FN patients (P=0.05 respectively). Higher histological grades of inflammation and stages of fibrosis, and more clinical and radiological evidence of advanced liver disease were observed in FN patients, but the differences failed to reach statistical significance. The results of the present study suggest that in addition to being more common, autoimmune hepatitis may be more severe in FN populations, compared with predominantly Caucasian, non-FN populations.

Historical reflections on autoimmune hepatitis

Autoimmune hepatitis (AIH), initially known as chronic active or active chronic hepatitis (and by various other names), first came under clinical notice in the late 1940s. However, quite likely, chronic active hepatitis (CAH) had been observed prior to this and was attributed to a persistently destructive virus infection of the liver. An earlier (and controversial) designation in 1956 as lupoid hepatitis was derived from associated L.E. cell test positivity and emphasized accompanying multisystem features and immunological aberrations. Young women featured prominently in early descriptions of CAH. AIH was first applied in 1965 as a descriptive term. Disease-characteristic autoantibodies were defined from the early 1960s, notably antinuclear antibody (ANA), smooth muscle antibody (SMA) and liver-kidney microsomal (LKM) antibody. These are still widely used diagnostically but their relationship to pathogenesis is still not evident. A liver and disease specific autoantigen has long been searched for but unsuccessfully. Prolonged immunosuppressive therapy with predisolone and azathioprine in the 1960s proved beneficial and remains standard therapy today. AIH like many other autoimmune diseases is associated with particular HLA alleles especially with the "ancestral" B8, DR3 haplotype, and also with DR4. Looking forwards, AIH is one of the several enigmatic autoimmune diseases that, despite being (relatively) organ specific, are marked by autoimmune reactivities with non-organ-specific autoantigens. New paradigms are needed to explain the occurrence, expressions and pathogenesis of such diseases.

Autoimmune hepatitis in Singapore: a rare syndrome affecting middle-aged women

BACKGROUND AND AIM

The prevalence of autoimmune hepatitis in Singapore is unknown. Over a period of 7 years, 24 cases were diagnosed in a district general hospital in Singapore (Toa Payoh Hospital) by using the scoring system proposed by the International Autoimmune Hepatitis Group in 1993. The aims of our study were to determine the prevalence of autoimmune hepatitis in Singapore, and to investigate the characteristics and prognosis in the mainly Chinese population.

METHODS

The case records of all 24 patients were reviewed, and the following parameters were recorded: age at presentation, sex, symptoms and signs at presentation, past exposure to hepatotoxic drugs, alcohol intake, blood transfusion laboratory and histological tests used to determine autoimmune hepatitis, response to treatment, complications, and survival.

RESULTS

The mean age of patients was 57 years old. There was a female-male ratio of 11:1. Forty-two percent of the patients were cirrhotic at presentation. The prevalence of autoimmune hepatitis was four per 100 000, with no significant difference between Chinese, Malay and Indian patients (Odds ratio of 0.38 by the chi-squared test). Eighty-nine percent of the patients responded to treatment with the induction of prednisolone, but the relapse rate was 61%. Treatment failure occurred in one patient. The mortality rate during the 7 years of follow up was 21%, and all were caused by complications of cirrhosis. The survival at 5 years was 71%, with a standard error of 0.13.

CONCLUSION

Autoimmune hepatitis in Singapore is mainly a disease in older women. The response to steroid treatment is good, with a 5-year survival rate of 71%.

Auto-immune (lupoid) hepatitis: an entity in the spectrum of chronic active liver disease

The concept of auto-immune hepatitis as a disease entity evolved from the descriptions of 'chronic active hepatitis' (CAH) in the 1950s. Several types of CAH are distinguished by disease-specific features. The distinctive (but not exclusive) markers for auto-immune CAH include: a negative test for HBsAg; female; Northern European ethnic background; multisystem disease expression; histological CAH with large areas of periportal piecemeal necrosis and plasmacytosis; pronounced hypergammaglobulinaemia; serum auto-antibodies the HLA B8-DR3 phenotype; responsiveness to corticosteroid therapy; and rarity of supervening hepatocellular carcinoma. Much weight is attached to the serological marker auto-antibodies to nuclear or smooth muscle (actin) antigens (ANA, SMA). However, these auto-antibodies do not have an absolute association with auto-immune CAH: the serological reactions are not yet standardized; titres decrease with remission of disease; and other auto-antibodies mark variant forms of auto-immune hepatitis. A more confident acceptance of auto-immune hepatitis as an entity requires detection of a liver-specific antigen, a valid experimental disease model in animals, and a better understanding of immune-mediated damage to liver cells.

Histocompatibility antigens (HLA): associations with immunopathic diseases and with responses to microbial antigens

Described is the experience from a single histocompatibility typing laboratory sampling, firstly, Australian patients with various immunopathic diseases and, secondly, subjects previously classified as "responders" or "non-responders" to various microbial antigens. The diseases considered included chronic active hepatitis (CAH) and various cirrhoses, "thyrogastric" autoimmune diseases, systemic lupus erythematosus (SLE), rheumatoid arthritis, dermatitis herpetiformis (DH) with intestinal villous atrophy, and multiple sclerosis (MS). The immune responses considered included those to flagellin, candidin, mumps, trichophyton, tuberculin and streptococcal enzymes. The HLA specificities particularly associated with disease included B8 (CAH, thyrotoxicosis SLE, DH, and miscellaneous immunopathic diseases) and B7 (thyrotoxicosis, SLE, DH, and MS). The same specificities were present in excess, although not impressively so, among responders to certain of the microbial antigens, i.e. B7 with high responders to flagellin and B8 (and A1) with responders to trichophyton.

Genetic control of immune responsiveness in man

Interest in immunogenetics originated from two streams: (a) histocompatibility in mouse and man, and (b) inheritance of specific immune responses in the guinea pig and mouse. In the mouse, there are genes associated with the major histocompatibility complex (MHC) which (i) code for antigens determining allograft responses and mixed lymphocyte reactions, (ii) control responses to certain antigens (Ir genes), and (iii) code for cell-surface antigens which elicit specific antisera (anti-Ia). In man, there is genetic control, in part X-linked, over levels of immunoglobulins and immunoglobulin classes. Evidence for MHC-linked genetic control is derived from immune responses to (i) micro-organisms, (ii) pollen antigens, (iii) food antigens, (iv) vaccines, (v) inocuous test antigens, and (vi) autoantigens. Some evidence exists for allotype-linked genetic control. Practical aspects concern influences of the MHC on susceptibility to disease, within individuals and populations.

Hepatitis-B surface antigen and cirrhosis in Iraq

Hepatitis-B surface antigen was found in 58% of 64 patients with cirrhosis in Iraq using counter immunoelectrophoresis (CIE), radioimmunoassay (RIA), and three commercial haemagglutination tests--Auscell (Abbott Laboratories), Hepatest (Wellcome Reagents Ltd.), and Hepanosticon (Organon Teknika). CIE detected about half as many positives as the other methods; RIA was the most sensitive. The number of positive reactions was much higher than in any previously reported series of patients with cirrhosis and seven times higher than in a normal hospital control population.

Hepatitis B antigen and auto-antibodies in chronic liver diseases in Hong Kong

The frequency of occurrence of hepatitis B antigen (HBAg) and certain tissue autoantibodies [antinuclear antibody (ANA), smooth muscle antibody (SMA) and mitochondrial antibody (MIA)] were studied with the microtiter complement fixation and immunofluorescence techniques respectively in a group of patients suffering from chronic liver diseases. These were chronic hepatitis (30), cirrhosis of the liver (66) and hepatocellular carcinoma, mostly with underlying cirrhosis (100). A group of closely matched hospital in-patients served as controls. HBAg was found in high frequency in the patients with liver disease (60% in chronic hepatitis, 36.4% in cirrhosis and 49% in hepatocellular carcinoma) whereas tissue auto-antibodies were found in lower frequencies (16.7%, 10.6% and 13% in the three groups respectively). However, in both the frequency was significantly higher than that in the controls (9.2% for HBAg and 0.8% for auto-antibodies). There was a negative correlation between HBAg and tissue auto-antibodies in the group of patients with liver disease when taken as a whole (x2=14.3, P less than 0.001). These results suggest a possible aetiological role played by hepatitis virus B in hepatocellular carcinoma through chronic hepatitis and cirrhosis in Hong Kong while the mutual exclusion between HBAg and auto-antibodies supports the hypothesis of heterogeneity in the aetiology of chronic liver diseases. The patients with auto-antibodies may belong to the auto-immune category but no definate conclusion can be reached until the role played by hepatitis virus A in chronic liver diseases is clarified when more reliable techniques for its identification are available.