The development of a more equitable approach to resource allocation and manpower planning for undergraduate teaching in a UK medical school

CONTEXT

Resource allocation and manpower planning in the clinical faculty of a UK medical school.

PURPOSE

To design a model, which is perceived to be fair, to determine indicative undergraduate teaching budgets to departments within the school from university resources and to specialty care groups of the main university hospital from service increment for teaching (SIFT) resources, and to aid manpower planning.

METHOD

The student load for each department is measured in full-time-equivalent student numbers (FTEs) for each specialty and compared with the total load for the whole curriculum to derive each department's percentage share of available undergraduate teaching resources. Data on staff numbers available for teaching, both from the school and NHS, are also included. Student load and teaching capacity are then compared.

RESULT

Undergraduate teaching resources relate to student load in the resource allocation process, and changes to the course are automatically reflected. Staff data, when compared with student load, facilitate rational planning of establishment levels to meet the teaching needs of the undergraduate curriculum. Of the respondents to a survey of heads of departments and the faculty's management board, 88% agreed that it was a better approach to resource allocation than the previous historical basis. PRESENT LIMITATIONS AND SCOPE FOR DEVELOPMENT: Data are currently entered manually but will be transmitted electronically in the future via the Web. Further consideration will be given to the possible inclusion in the model of weighting factors for different types of teaching and to how appropriate measures of quality may be incorporated into the resource allocation process.

CONCLUSION

The model, despite some limitations, is a cost-effective and pragmatic management tool.

Service increment for teaching (SIFT): a review of its origins, development and current role in supporting undergraduate medical education in England and Wales

OBJECTIVES

To describe the ways in which total resources available for the Service Increment for Teaching (SIFT) have been determined and related to numbers of undergraduate medical students; and the development and current arrangements for allocating SIFT to the providers of service support for teaching.

DESIGN

The derivation of SIFT from excess costs of teaching hospitals over general hospitals is described. The official principles of organizing SIFT to reimburse the service costs of teaching undergraduate medical students are explained. The crucial development that is examined is the change from SIFT being a global subsidy to being related to educational contracts. This development has facilitated both the specification of standards and innovative uses of SIFT. These are illustrated with examples.

SETTING

Hospital and Community Health Services and Primary Care in the National Health Service (NHS) in England and Wales.

SUBJECTS

Medical students.

RESULTS

There is often confusion caused by SIFT being intended to cover the service costs of teaching but not having been derived in this way. This causes problems in deciding what providers should be paid through contracts for teaching of different kinds.

CONCLUSIONS

The new contractual basis has enabled medical schools to use contracts to improve the clinical teaching of undergraduate medical students in the NHS. These developments may offer useful models for other countries.

Hepatitis C infection and autoimmunity

Since the first tests for antibodies to components of the hepatitis C virus became widely available there has been considerable interest in evidence linking HCV infection with autoimmune liver diseases and other autoimmune conditions. With respect to autoimmune hepatitis, it is now clear that the early tests were quite non-specific and that it was the abnormalities in serum globulins in autoimmune hepatitis which led to such high positivity rates in this disease. Careful surveys across Europe have now made it clear that there are true associations between HCV infection and autoimmune liver diseases, but that their frequency is much higher in the south than the north. This is particularly striking for that variety of autoimmune hepatitis positive for antibodies to the liver/kidney microsomal antigen (cytochrome P450 2D6). Here there are distinct subgroups; one a "true" autoimmune group of younger females with more active disease, and a second, containing older patients with a more even sex distribution, where the virus seems to be driving an autoimmune reaction. The mechanisms underlying these associations are not yet clear, although analysis of the amino-acid sequences of selected virus and host proteins has shown some significant homology. Interestingly, and surprisingly, the overall incidence of periportal hepatitis is lower in HCV infection than in acute or chronic HBV infection, or acute HAV hepatitis. There is a parallel distribution in the frequency and titre of antibodies to the asialoglycoprotein receptor, one of the important targets for autoimmune reactions on the liver cell membrane. There are many reports of associations between HCV infection and other immune-mediated conditions, and although the strength of such associations is always difficult to judge, HCV infection in some conditions, such as cryglobulinaemia, is clearly an important driving force. Here, treatment of the HCV infection with interferon may led to striking remission in associated vascular lesions. Clinically, it can be very difficult to distinguish between liver disease due to HCV infection and autoimmune hepatitis co-existing with HCV infection, but because the treatment for these two conditions is quite different, the distinction is important. Alpha-interferon, the current treatment of choice for HCV infection, often induces a relapse in autoimmune hepatitis, while steroids, the treatment of choice for autoimmune hepatitis, may be permissive for HCV replication, and thus, at least in theory, may militate against the success of a subsequent course of alpha-interferon. A pragmatic approach to the choice of a first therapeutic agent is recommended based on the relative local prevalence of the two conditions, the use of readily available clinical tests, and the results of appropriate specialised assays in the most difficult cases.

The major histocompatibility complex influences the development of chronic liver disease in male children and young adults with cystic fibrosis

BACKGROUND/AIMS

Chronic liver disease is a well-recognised complication of cystic fibrosis. Recent reports suggest that its development is not determined by specific mutations within the cystic fibrosis gene; however, familial clustering of portal hypertension cases and inappropriate immune responses against liver membrane antigens demonstrated in children with cystic fibrosis and chronic liver disease suggest that other genetic loci may be relevant. As the major histocompatibility complex has an important immunoregulatory role, we have investigated for associations with this complex and chronic liver disease in cystic fibrosis.

METHODS

We have determined human leucocyte antigen class I (A and B) and class II (DR) phenotypes by serological tissue typing and class II (DR and DQ) and class III (complement component C4 and 21-hydroxylase) gene polymorphisms in 274 children and young adults with cystic fibrosis, of whom 82 had evidence of chronic liver disease with portal hypertension in 49, and 146 healthy controls.

RESULTS

A marked difference in human leucocyte antigen frequency was limited to DQ6, which was found in 66.7% of cystic fibrosis patients with liver disease compared to 32.9% of patients with no liver disease (Pc < 0.03) and 28.8% of controls (Pc < 0.006). An increased frequency of the two antigens in strong linkage disequilibrium with DQ6 was also observed within this patient group, namely DR15 and B7. When the patients were stratified for the presence of portal hypertension, these observations were confirmed, but the human leucocyte antigen associations were significant only for male patients and there was no association with the age of onset of liver disease.

CONCLUSIONS

These data suggest that the haplotype B7-DR15-DQ6 may carry an increased risk of development of liver disease in male cystic fibrosis patients.

Induction of T-helper cell response to hepatitis B core antigen in chronic hepatitis B: a major factor in activation of the host immune response to the hepatitis B virus

The T helper (Th) cell response to hepatitis B core antigen (HBcAg) was analyzed in 76 chronic hepatitis B virus (HBV) carriers with varying degrees of hepatic inflammation and HBV replication. Fifty-five patients had active viral replication, 28 with minimal histological changes and normal alanine transaminase (ALT) and 27 with active hepatic inflammation and elevated ALT. The remaining 21 chronic hepatitis B surface antigen (HBsAg) carriers had undetectable HBV replication, minimal histological activity, and normal ALT. In addition, 34 chronic HBV carriers were studied prospectively during treatment with alpha-interferon. The HBcAg-specific Th cell response was evaluated by a proliferative assay using 3H-thymidine uptake and gamma-interferon production by peripheral blood mononuclear cells. The proliferative response and gamma-interferon production of patients with active hepatic inflammation were significantly higher than in patients with minimal histological changes and in controls. In the longitudinal analysis during alpha-interferon treatment, 22 of 34 patients sustained an ALT flare accompanied by a parallel, significant Th cell response, which preceded or coincided with the ALT flare. The elevation in the Th cell response and the ALT flare were followed by a significant rise in the serum immunoglobulin (Ig) M anti-HBc index. Ten of twenty-two patients with an enhanced Th cell response and an ALT flare seroconverted after alpha-interferon treatment. The Th cell activity in the 10 responders rapidly subsided after hepatitis B e antigen (HBeAg) to anti-HBe seroconversion, whereas in the 12 nonresponders it remained elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of T-helper cell response to hepatitis B core antigen in chronic hepatitis B: a major factor in activation of the host immune response to the hepatitis B virus

The T helper (Th) cell response to hepatitis B core antigen (HBcAg) was analyzed in 76 chronic hepatitis B virus (HBV) carriers with varying degrees of hepatic inflammation and HBV replication. Fifty-five patients had active viral replication, 28 with minimal histological changes and normal alanine transaminase (ALT) and 27 with active hepatic inflammation and elevated ALT. The remaining 21 chronic hepatitis B surface antigen (HBsAg) carriers had undetectable HBV replication, minimal histological activity, and normal ALT. In addition, 34 chronic HBV carriers were studied prospectively during treatment with alpha-interferon. The HBcAg-specific Th cell response was evaluated by a proliferative assay using 3H-thymidine uptake and gamma-interferon production by peripheral blood mononuclear cells. The proliferative response and gamma-interferon production of patients with active hepatic inflammation were significantly higher than in patients with minimal histological changes and in controls. In the longitudinal analysis during alpha-interferon treatment, 22 of 34 patients sustained an ALT flare accompanied by a parallel, significant Th cell response, which preceded or coincided with the ALT flare. The elevation in the Th cell response and the ALT flare were followed by a significant rise in the serum immunoglobulin (Ig) M anti-HBc index. Ten of twenty-two patients with an enhanced Th cell response and an ALT flare seroconverted after alpha-interferon treatment. The Th cell activity in the 10 responders rapidly subsided after hepatitis B e antigen (HBeAg) to anti-HBe seroconversion, whereas in the 12 nonresponders it remained elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Viral infection and cancer

Infection with specific viruses has a role in the pathogenesis of some cancers in human beings. However, the incidence of such cancers is much lower than the frequency of virus infection, suggesting either that infection alone does not result in cancer and that cellular events in addition to the presence of the virus must occur, or that cancer occurs only if viral proteins are expressed in an appropriate cell type or in an immunocompromised host. Molecular analysis of viruses found in association with cancer has revealed that they function, at least in part, by encoding proteins which can associate with and subvert the function of host cell-encoded tumour suppressor proteins which regulate pathways of growth arrest and apoptosis. Better understanding of the mechanisms underlying this association will have diagnostic, prognostic, and therapeutic implications in the near future.

Antibody-directed complement-mediated cytotoxicity to hepatocytes from patients with chronic hepatitis B

The susceptibility of hepatocytes from patients with chronic hepatitis B to complement-dependent cytotoxicity mediated by heterologous antibodies to hepatitis B virus core (anti-HBc) and surface (anti-HBs) antigens and to hepatic asialoglycoprotein receptor was examined using a microcytotoxicity assay. The anti-HBc-induced cytotoxicity was found to be markedly enhanced against hepatocytes isolated from patients with chronic active hepatitis (72.6 +/- 9.5% (mean +/- s.e.m.); n = 6) over that against hepatocytes from individuals with chronic persistent hepatitis or inactive liver cirrhosis (40.6 +/- 18.6%; n = 4) (P = 0.019). Overall, values of the anti-HBc-directed cytotoxicity were higher in patients positive for HBcAg in hepatocytes and seropositive for hepatitis B virus e antigen (HBeAg). Hepatocytotoxicity was also exerted by anti-HBs and anti-asialoglycoprotein receptor antibodies in the presence of complement, but it was not seemingly related to disease activity. These results indicate that hepatitis B virus core and surface antigens and asialoglycoprotein receptor at the hepatocyte surface can be recognized by antibodies, and raise the possibility that complement-dependent cytolysis may contribute to the injury of hepatitis B virus-infected hepatocytes. The data also suggest that liver cells of patients with severe chronic hepatitis might be more susceptible to anti-HBc antibody-directed complement-mediated cytotoxicity than those with inactive liver histology.

T-cell receptor constant beta germline gene polymorphisms and susceptibility to autoimmune hepatitis

BACKGROUND/AIMS

Susceptibility to autoimmune hepatitis is associated with HLA A1-B8-DR3 and DR4. T-Cell antigen receptors (TCR) are candidates for genetic susceptibility to autoimmune diseases because they recognize peptide antigens in the context of HLA molecules. The aim of this study was to investigate the possible role of TCR germline polymorphisms in susceptibility to autoimmune hepatitis.

METHODS

TCR constant beta (C beta) region polymorphisms were investigated using restriction fragment length polymorphism analysis in 60 unrelated northern European White patients with autoimmune hepatitis and 190 racially and geographically matched healthy controls.

RESULTS

A significant increase in the frequency of homozygous status for the 10-kilobase/Bgl II of the TCR C beta was found in the patients compared with controls (42% vs. 21%; corrected P value [Pc] < 0.0075; relative risk [RR] = 2.8). This difference was more pronounced in patients without HLA-DR3 and DR4 (50% vs. 14%; Pc < 0.015; RR = 6.1). Furthermore, heterozygosity for TCR C beta was significantly decreased in early-onset patients presenting with HLA-DR3 before 30 years of age (12% vs. 48%; Pc < 0.03; RR = 0.16).

CONCLUSIONS

The present findings provide evidence that genetic susceptibility to AIH may be determined by both the TCR C beta genes and HLA genes and that the genotype of the TCR C beta may be one of the factors in influencing the age at onset of disease.

Allelic sequence variation in the HLA class II genes and proteins in patients with autoimmune hepatitis

Susceptibility to autoimmune hepatitis in white patients is associated with the human leukocyte antigen class II antigens DR3 and DR4. To analyze the molecular basis of these associations, we used oligonucleotide probes to determine the DRB, DQA and DQB hypervariable nucleotide sequences in 119 patients with autoimmune hepatitis and 177 matched controls. DRB3*0101, which encodes DR52a, predisposed patients most strongly to the disease. It was present in 58% of patients and 25% of controls (corrected P < 0.000005), whereas DQA1*0101 and 0102 conferred protection in males only. The DR4 subtype, DRB1*0401, was raised in the DRB3*0101-negative patients; 81% possessed either DRB3*0101 or DRB1*0401, compared with 42% of controls (corrected P < 0.0000001). These alleles encode the amino acid sequence Leu-Leu-Glu-Gln-Lys-Arg at positions 67 to 72 of the DR beta polypeptide, which was present in 94% of patients and 64% of controls (corrected P < 0.000001) and in all patients who tested positive for autoantibodies to the hepatic asialoglycoprotein receptor. The patients with DRB1*0401 had less severe disease, relapsed less frequently and were first seen significantly later in life than those patients with DRB3*0101; and whereas a single copy of DRB1*0401 predisposed to autoimmune hepatitis, DRB3*0101-associated susceptibility had a dose-related effect. These data provide evidence that specific residues in the DR beta polypeptides predispose to autoimmune hepatitis in white patients and genes linked to DRB3*0101 and DRB1*0401 may determine two clinically distinct disease patterns.

Polymorphism in the human complement C4 genes and genetic susceptibility to autoimmune hepatitis

Susceptibility to autoimmune hepatitis is associated with the HLA-DR3 and DR4 haplotypes, but which genes are directly involved in the pathogenesis, has not been established. Low levels of complement component C4 and elevated frequencies of C4 null allotypes have been described in patients, suggesting that the C4 genes, which are closely linked with the HLA loci, may play a role. We therefore examined restriction fragment length polymorphisms in the C4 and 21-hydroxylase genes, and determined HLA-A and B phenotypes, and HLA-DR, DQ and DP genotypes in a large series of Caucasoid patients with autoimmune hepatitis and matched controls. A DNA deletion of the C4A gene and the 21-hydroxylase A pseudogene was found to be present in 50% of patients compared to 23% of controls (Pc < 0.005, relative risk = 3.3). This increase, however, appears to be due to linkage disequilibrium with HLA-DR52a which was most strongly associated with the disease. Complete C4A deficiency, determined by homozygosity for the deletion increased the risk to 18.1 (16% versus 1%, Pc < 0.005), suggesting an additional role for C4 in disease susceptibility. C4 deletions were associated with an increased mortality and tendency to relapse whilst on treatment but did not correlate with age of onset of disease. Our data suggest that MHC-encoded susceptibility to autoimmune hepatitis is polygenic, involving the HLA-DR genes plus other loci, and C4 deficiency may be a marker of disease susceptibility and/or severity.

Human leukocyte antigen A1-B8-DR3-DQ2-DPB1*0401 extended haplotype in autoimmune hepatitis

Genetic susceptibility to autoimmune hepatitis is associated with the human leukocyte antigen haplotype A1-B8-DR3 and DR4. To date, only one study in Japan has considered the human leukocyte antigen DP locus in this disease, and no studies have been reported in whites. In this study we used a series of sequence-specific oligonucleotide probes to determine human leukocyte antigen DPB1 genotypes in 101 unrelated white northern European patients and 105 racially and geographically matched controls. The aims of the study were twofold: first, to determine the degree of DPB-encoded susceptibility to autoimmune hepatitis, and, second, to establish whether susceptibility can be extended to include human leukocyte antigen DPB. None of 17 DPB1 alleles was significantly associated with the susceptibility to autoimmune hepatitis. Although one particular seven-locus haplotype A1-B8-DRB3*0101-DRB1*0301-DQA1*0501-DQB1*0201-++ +DPB1*0401 was significantly associated with the disease (27% vs. 7%, relative risk = 5.14, p < 0.0005), the association with this haplotype was weaker than that for the six-locus haplotype excluding DPB (40% vs. 11%, RR = 5.52, p < 0.0005). When the patients first seen at ages younger than 16 yr (pediatric patients) were considered separately, the greatest relative risk was for the seven-locus haplotype (41% vs. 7%; relative risk = 9.60, p < 0.0005). The results of this study further confirm that major histocompatibility complex-encoded susceptibility to autoimmune hepatitis is located at or close to the human leukocyte antigen DR locus; however, the A1-B8-DR3-DQ2-DPB1*0401 extended haplotype may be important in determining the age of onset and severity of disease.

Specific deletions in the hepatitis B virus core open reading frame in patients with chronic active hepatitis B

The polymerase chain reaction (PCR) and DNA sequencing were used to examine genomic variation in the pre-core/core open reading frame of the hepatitis B virus (HBV) in chronically infected patients. Gel electrophoresis of amplification products showed the presence of shortened forms of the core gene in addition to the full length product. These shortened forms were seen only in patients with chronic active hepatitis (CAH) seropositive for HBeAg and not in patients with chronic persistent hepatitis (CPH) or HBeAg minus CAH. Cloning and DNA sequencing revealed the presence of a number of overlapping deletions within the core gene, the majority being in-frame, which were clustered within aa 81-114 of the core gene product. These deletions were found in patients with CAH from different racial and geographical backgrounds, whereas PCR analysis of the surface and X open reading frames showed no shortened forms suggesting deletions to be specific to the core gene in these patients. Because the product of the core gene--the HBV core antigen--is believed to be the major target for T-cell-mediated liver damage, it seems likely that the products of core genes carrying deletions will alter immune recognition and may be of importance in the progression of inflammatory liver damage.

Identification of hepatitis B virus-DNA in the liver by in situ hybridization using a biotinylated probe. Relation to HBcAg expression and histology

The cellular localisation of hepatitis B virus (HBV)-DNA in liver tissue was studied by in situ hybridisation using biotinylated and radiolabelled probes on samples from HBsAg carriers with a spectrum of disease and related to the presence of HBV-DNA in serum and intrahepatic HBcAg expression. Sixteen of the 31 patients studied were seropositive for HBV-DNA; nine had chronic active hepatitis and seven had chronic persistent hepatitis. HBV-DNA was detected in the liver tissue in seven of these patients. In each, HBV-DNA was detected in both cytoplasm and nuclei. All seven also had nuclear and/or cytoplasmic HBcAg which in six was associated with chronic active hepatitis. HBcAg (without tissue HBV-DNA) was detected in the remaining nine patients with an exclusively nuclear pattern in two. Fifteen patients were seronegative for HBV-DNA. HBV-DNA was not detected in the tissue of any of these. Three of these were HBcAg positive but in each this was confined to occasional nuclei and each had inactive disease. The close association between the presence of detectable HBV-DNA in tissue, cytoplasmic HBV-DNA expression and chronic active hepatitis in one group and a failure to detect HBV-DNA in those with nuclear HBcAg and benign disease suggests that there may be two distinct patterns of HBV replication in chronic HBV carriers which may influence the development of liver damage.

Detection of genomic and intermediate replicative strands of hepatitis C virus in liver tissue by in situ hybridization

Nonisotopic in situ hybridization using a digoxigenin-labeled cDNA probe to the 3' nonstructural region (NS5) of hepatitis C virus (HCV) was performed on liver tissue from 33 patients. The results were compared with PCR detection of HCV RNA performed on 24 of the biopsies. Nonisotopic in situ hybridization correlated well with PCR findings. Hybridization signals were detected, within the cytoplasm and nuclei/nucleoli of hepatocytes, mononuclear, and biliary epithelial cells. In patients with clinically and histologically defined chronic active hepatitis related to active HCV infection, HCV genome was frequently detected in biliary epithelium and correlated well with biliary damage, an otherwise uncommon finding in chronic active hepatitis due to other hepatotropic viruses. Further studies using sense and antisense probes synthesized from the 5' non-coding region of the HCV genome confirmed the localization of positive strand of HCV in the above cell populations. The replicative intermediate strand was also present in all cells, although less frequently observed, apart from biliary epithelium, where negative strand of HCV was undetectable. The findings of HCV genome in liver biopsies of two patients with no significant histological abnormalities may suggest that the damage seen in chronic HCV infection is immune mediated, although the cytopathic effect of the virus may also be important.

Virus- and immune-mediated liver damage in hepatitis

It has been assumed for many years that liver damage associated with hepatitis B virus (HBV) infection is due to cytolytic immune reactions directed at viral antigens expressed on infected liver cells. Recent studies, however, suggest that in some clinical settings, changes in the HBV genome, possibly selected by immune pressure, can interfere with the export of viral proteins from hepatocytes and lead to direct virus-induced liver damage.

Comparison of pre-core/core hepatitis B virus region in liver tissue and serum from patients with chronic hepatitis B infection

We examined the relationship between HBV-DNA isolated from the liver and from the serum in patients with various serological characteristics of chronic hepatitis B infection. Amplification and direct sequencing of the HBV pre-core/core region was carried out in 9 patients who were seropositive for HBsAg and HBV-DNA--4 HBeAg positive and 5 anti-HBe positive. Complete sequence identity was observed between HBV-DNA isolated from the serum and the liver in individual patients. In addition, shortened forms of the HBV core ORF were detected in patients with chronic active hepatitis, but not in patients with chronic persistent hepatitis.

Detection of hepatitis "C" virus in formalin-fixed liver tissue by nested polymerase chain reaction

Interpretation of antibody to hepatitis C virus (HCV) in patients with liver disease is difficult due to false-positive reactivity in some conditions. To evaluate the feasibility of HCV in archival material, HCV was sought in formalin-fixed, paraffin-embedded liver biopsy specimens. Nested polymerase chain reaction was used to detect hepatitis C virus in formalin-fixed, paraffin-embedded liver biopsy specimens after total RNA was extracted from tissue by proteinase K digestion and phenol/chloroform purification. The relative efficiency of amplification of HCV RNA from formalin-fixed material was estimated semiquantitatively by serial dilution of cDNA synthesised from RNA extracted from fresh and formalin-fixed sections from the same liver. Although HCV RNA could be detected in formalin-fixed liver tissue by nested PCR in 5/5 cases in which HCV was detected in serum, amplification was approximately 5-fold less efficient than when HCV was amplified from fresh tissue. Nevertheless, nested PCR of HCV from formalin-fixed liver tissue represents a useful technique in addressing some important questions related to the pathogenesis of liver disease.

Amino acid substitutions at position 38 of the DR beta polypeptide confer susceptibility to and protection from primary sclerosing cholangitis

Previous studies based on serological HLA phenotyping have implicated genes in the HLA class II region in susceptibility to and protection from primary sclerosing cholangitis. In a recent report, the HLA DRw52a antigen was present in all 29 patients who had been referred for liver transplantation. In this study, HLA DRB, DQA and DQB genotypes were studied using gene amplification and sequence-specific oligonucleotide probing in 71 patients with primary sclerosing cholangitis and 68 healthy controls to determine the frequency among the patients of the DRB3*0101 allele that encodes DRw52a and whether other class II alleles are involved in susceptibility or protection. DRB3*0101 was the most strongly associated allele, being present in 55% of the patients and 22% of the controls. Survival among the DRB3*0101-positive patients was reduced compared with the DRB3*0101-negative patients. Both DRB3*0101 and DRB5*0101, a possible second DRB susceptibility allele, encode a leucine residue at position 38 of the DR beta molecule. The DRB4*0101 allele, which encodes DRw53 and may be protective, encodes an alanine residue at this position. Susceptibility to and protection from primary sclerosing cholangitis may result from amino acid substitutions at position 38 of the DR beta molecule because maximum relative risk was conferred by two leucine-38-containing DR beta molecules, whereas minimum relative risk was conferred by two alanine-38-containing molecules.

Hepatic interferon-alpha gene transcripts and products in liver specimens from acute and chronic hepatitis B virus infection

In this study we have examined the localization of interferon-alpha in liver tissue from acute and chronic hepatitis B virus carriers to establish whether the defect in interferon-alpha production reported in chronic hepatitis B virus infection is at a pretranscriptional or posttranscriptional level using in situ hybridization and immunohistochemical techniques. Interferon-alpha messenger RNA transcripts and the immunoreactive protein were abundant in liver tissue and in particular in hepatocytes from patients with acute hepatitis B virus infection who subsequently recovered. In contrast interferon-alpha polypeptide was present in a significantly lower number of sinusoidal cells, mononuclear cells and hepatocytes in chronic hepatitis B virus carriers. Although a high proportion of patients with chronic hepatitis B virus infection had cells that expressed interferon-alpha messenger RNA transcripts, the number of such cells was significantly less than in acute hepatitis B virus infection, indicating that the defect in the hepatic interferon-alpha synthesis is at the level of gene activation. Furthermore, using double immunohistochemical staining, the number of hepatocytes containing HBcAg correlated inversely with the proportion of neighboring sinusoidal cells expressing interferon-alpha. These data support previous observations that interferon-alpha production is reduced in chronic hepatitis B virus infection and are consistent with the view that this cytokine is important in the clearance of the virus.

Tumour necrosis factor production in fulminant hepatic failure: relation to aetiology and superimposed microbial infection

Tumour necrosis factor-alpha (TNF-alpha), a cytokine derived from macrophages, is considered to be an important endogenous mediator of endotoxic shock. Patients with fulminant hepatic failure are particularly susceptible to infection and the development of multi-organ failure and similarities to endotoxic shock suggest a possible pathogenetic role for TNF in fulminant hepatic failure. In vitro TNF production was therefore investigated serially in 21 consecutive patients with fulminant hepatic failure and in 21 healthy controls. Spontaneous and lipopolysaccharide-stimulated TNF production were elevated in viral-induced fulminant hepatic failure, compared with healthy controls (P less than 0.05 and P less than 0.01, respectively). By contrast, patients with paracetamol-induced fulminant hepatic failure had normal spontaneous and lipopolysaccharide-stimulated TNF production, while those who died had significantly reduced spontaneous TNF production compared with survivors (P less than 0.02); this difference was present throughout admission. In this group elevations in TNF production above baseline were associated with Gram-positive bacterial or fungal infection but not Gram-negative bacterial infection. There was no correlation between any of the clinical complications of fulminant microbial stimuli in fulminant hepatic failure, but do not support a direct role for TNF in the evolution of the clinical complications of fulminant hepatic failure.

Detection of hepatitis B virus antigens in liver tissue. A relation to viral replication and histology in chronic hepatitis B infection

The expression of hepatitis B virus antigens was studied by double staining liver tissue with appropriate antisera and correlated with serum hepatitis B viral DNA and histology in 28 patients with disease related to chronic hepatitis B virus infection. The cellular localization of hepatitis B core and hepatitis B e antigens generally coincided, but there were important differences at a subcellular level. Thus, hepatitis B e antigen was detected in nuclei and/or cytoplasm but strong cytoplasmic hepatitis B e antigen was associated with a high serum hepatitis B viral DNA (P = 0.0017) but not with active liver disease. Hepatitis B core antigen could also be detected in nuclei and/or cytoplasm, but strong cytoplasmic hepatitis B core antigen expression, exceeding that of hepatitis B e antigen, was associated with active liver disease (P = 0.041) and not with serum hepatitis B virus DNA. The proportion of hepatocytes expressing hepatitis B surface antigen correlated inversely with the serum titer (P = 0.0017), whereas hepatitis B surface and nucleocapsid antigens were usually expressed independently. The data support the hypothesis that cytoplasmic hepatitis B core antigen and not hepatitis B e antigen is the target for immune system-mediated cytolysis of hepatocytes. Cytoplasmic hepatitis B e antigen is not associated with liver damage but is instead associated with high levels of hepatitis B virus replication.

Patterns of cellular immune responses to thyrocyte membrane antigens and specific immunoregulatory defects in autoimmune thyroid disease

Although Graves' disease (GD), Hashimoto's thyroiditis (HT) and idiopathic myxoedema (Myx) are clinically distinct autoimmune thyroid diseases, previous studies using crude thyroid preparations as a source of antigens have failed to identify differences in cellular immune responses. In this study, we have assessed cellular immunity in patients with these disorders to two antigen preparations (derived from thyroid gland and cervical fat) enriched in cell membranes and known to share a functional TSH receptor. Using an indirect T-lymphocyte migration inhibitory factor (T-LIF) assay, T-cell immunity to thyroid membranes was demonstrated in 11/11 patients with GD, 4/5 with HT and 4/5 with Myx, but in none of 18 patients with chronic active hepatitis (another organ-specific autoimmune disease) or sixteen healthy controls. In contrast, T lymphocytes responsive to adipocyte membranes were detected only in patients with GD. TSH binding inhibiting antibodies were found exclusively in six patients with GD, and thyroid stimulating antibodies in five of these patients. In co-culture experiments designed to study the activity of antigen-specific suppressor T cells, low numbers of T cells from 6/6 normal controls, 4/4 patients with HT and 5/5 patients with myxoedema suppressed the response to adipocyte membranes of T lymphocytes from patients with Graves' disease. The results of this study demonstrate different patterns of T-cell reactivity to thyroid antigens in patients with Graves' disease, Hashimoto's thyroiditis and myxoedema and suggest that cellular immunity to the TSH receptor is restricted to patients with Graves' disease and associated with a defect in the specific immunoregulatory control of this response.

Spontaneous production of tumour necrosis factor alpha and interleukin-1 beta during interferon-alpha treatment of chronic HBV infection

Seven chronic carriers of hepatitis B virus (HBV) were studied during treatment with interferon-alpha to determine whether tumour necrosis factor alpha (TNF alpha) or interleukin-1 beta (IL-1 beta) contributed to the elimination of HBV. Four patients responded to interferon-alpha with clearance of HBeAg and permanent inhibition of HBV replication within 3-12 weeks; in each of these patients, the changes were accompanied by substantial rises in spontaneous in-vitro production of TNF alpha and IL-1 beta by peripheral blood mononuclear cells from previously undetectable levels. There was little or no change in spontaneous TNF alpha and IL-1 beta production in the three patients who did not lose HBeAg in response to interferon-alpha. These findings suggest that TNF alpha and IL-1 beta may contribute to the permanent elimination during interferon-alpha treatment of hepatocytes supporting viral infection and that the therapeutic potential of these cytokines is worthy of investigation.

The relationship between HLA-DR3 and T-cell regulation of immunoglobulin production in primary sclerosing cholangitis

Immunoglobulin production in vitro, its control by concanavalin A-activated suppressor T-cells, and the relationship between abnormalities in nonantigen-specific suppression and histocompatibility antigens have been studied in 20 patients with primary sclerosing cholangitis (PSC). Suppression of IgG, IgM, and IgA synthesis was impaired in 12 patients with PSC alone, but was normal in 8 with PSC and associated ulcerative colitis (UC). The HLA antigens B8 and DR3 were increased in frequency in both groups of patients, but an association between DR3, and to a lesser extent B8, and defective suppressor T-cell function was only observed in the patients with PSC alone. These results not only provide further evidence of an association between HLA DR3 and impaired nonantigen-specific suppression but also indicate the genetic complexity of this association and its specificity, being found in this study in only one subgroup of patients with PSC.

The natural history of hepatitis B virus infection

It was previously thought that two distinct types of chronic hepatitis B virus (HBV) infection existed. However recent evidence suggests that these are in fact phases in a continuous spectrum which evolves with time. Immediately after infection there is active viral replication. In patients infected in adult life, particularly in Europe and the USA, this is associated with varying degrees of liver damage. In those infected at birth, particularly in the Far East, there is initially much less inflammation with normal liver function. In succeeding years, viral replication decreases and liver damage increases with more deranged liver function test results. Eventually viral replication ceases and liver inflammation decreases, resulting in seroconversion with a loss of HBeAg and appearance of anti-HBe. Unfortunately, cirrhosis has already developed in some adults, with the increased risk of the later development of primary hepatocellular carcinoma. It is likely that there is a favourable window during the natural history of the infection when interferon is effective, probably in the few years immediately before spontaneous seroconversion.

Differential effect of alpha-interferons on CD4- and CD8-positive lymphocytes in chronic hepatitis B virus carriers

alpha-Interferons are an effective therapy in a proportion of chronic hepatitis B virus (HBV) carriers. The mode of action is almost certainly dependent upon immune modulation in addition to direct antiviral effects but the precise mechanism is unknown. To investigate whether the aberrant T-cell activation present in HBV carriers was responsive to interferons, we have studied the in vitro effect of alpha-interferons on Tac antigen expression and DNA synthesis as early and late markers of T-cell activation, respectively. At a concentration of 1000 U/ml the effect of alpha-interferons on Tac expression was contrasting in the two major T-cell subsets; there was enhancement of Tac expression on CD4-positive T-cells but inhibition of the CD8-positive subset. However, there was no overall effect on lymphocyte proliferation, perhaps as a consequence of the differential effect of alpha-interferons on the early T-cell activation marker. At higher concentration, however, the enhancement of T-cell activation was less clear, indicating that the concentration range that supports T-cell activation is narrow. Such subtle differential effects on T-cell activation may be accompanied by more profound effects on immune function and this may be one way in which alpha-interferons are of value in chronic HBV infection.

Enhanced tumour necrosis factor and interleukin-1 in fulminant hepatic failure

Sepsis and endotoxaemia are common in fulminant hepatic failure (FHF) and may contribute to multisystem disease in such patients. Tumour necrosis factor (TNF) is a probable mediator of endotoxic shock and infusion of this monokine into animals causes multi-organ failure that shares features with FHF. In patients with FHF, TNF production was increased and correlated closely with activity of interleukin-1, another cytokine that is released by monocytes/macrophages in response to infection and endotoxin and is produced in increased quantities in FHF. Interleukin-2 activity was impaired in FHF and correlated negatively with TNF production.

In situ hybridisation in formalin fixed, paraffin wax embedded liver specimens: method for detecting human and viral DNA using biotinylated probes

A rapid and reproducible technique for in situ hybridisation, using biotin labelled probes for the Y chromosome, human DNA, hepatitis B virus DNA and cytomegalovirus DNA on formalin fixed, paraffin embedded liver tissue, was developed. The degree of proteolytic digestion of tissue specimens is critical to ensure adequate unmasking of DNA and to avoid non-specific staining, a consequence of endogenous biotin in liver. Specific in situ hybridisation was achieved after digestion with pepsin, proteinase K, or protease, which gave optimal results. Both hepatitis B virus DNA and cytomegalovirus DNA were visualised in tissue from patients with chronic hepatitis B virus infection or in liver transplant recipients, respectively; the distribution of viral DNA was shown to be quite distinct between the two groups of patients.

An enzyme immunoassay for the measurement of HLA-DR antigen expression

A simple, sensitive, rapid and reproducible method is described for the measurement of HLA-DR expression on monocytes. The assay is based on an enzyme-linked immunostaining of the cells in suspension form followed by colour development. The non-specific binding of anti-HLA-DR to Fc receptors was taken into account by incubation of cells with an irrelevant monoclonal antibody (antirubella-G7H9). The binding of the anti-rubella monoclonal with the cells was subtracted from the binding of anti-HLA-DR to cells. Using three different cell lines (K562, CTLL and Daudi), the specificity of the assay proved to be acceptable and the assay remained sensitive even when only 10(4) cells/well were used. The assay has a number of potential applications.

Serial study of liver-directed autoantibodies and autoreactive T-lymphocytes in acute viral hepatitis B

To explore the mechanisms underlying liver-directed autoimmune reactions in acute Hepatitis B Virus (HBV) infection, we followed five subjects who were identified in the early incubation phase (30-70 days before the first elevation of transaminases). We assessed serially cellular (using a T-lymphocyte migration inhibitory factor assay) and humoral (RIA) immunity to LSP (a macromolecular, liver-derived lipoprotein complex) and hepatic lectin (HL), the liver-specific receptor for desialylated glycoproteins, which appears to be a major target antigen for autoreactions in autoimmune chronic active hepatitis. Anti-LSP and anti-HL autoantibodies were found, at some stage during acute HBV infection, in 4/5 subjects, whereas cellular immunity to the same antigens was detected in only two patients. Sustained production of anti-HL antibodies was noted only in patients showing cellular immunity to this antigen and was apparently secondary to liver damage, whereas anti-LSP antibodies were first detected at the onset of liver injury when there was no evidence of T-cell immunity to the same antigenic complex. One explanation for this apparent dichotomy between cellular and humoral responses to LSP is that a helper T-cell response to the major envelope component of HBV, HBsAg, which precedes by 10-20 days the development of anti-LSP antibodies, promotes a humoral reaction to autoantigens contained in the LSP preparation, coexpressed with HBsAg, on the surface of infected hepatocytes.

Clearance of pre-S2 antigen: a marker of successful interferon therapy in hepatitis B virus infection

The relation between viral replication, the presence of HBsAg and pre-S2 in serum and eventual clinical outcome has been investigated in fourteen patients undergoing treatment with lymphoblastoid interferon for chronic hepatitis B virus (HBV) infection. In four patients permanent loss of pre-S2 was accompanied by loss of serum HBV-DNA in association with a marked elevation of serum aspartate aminotransferase activity and in each of these cases HBsAg was subsequently cleared from serum. In contrast there was no significant fluctuation in the concentration of either pre-S2 or HBsAg in four cases not responding to therapy although substantial or complete inhibition of viral replication had been observed during treatment. In the third group, permanent loss of HBV-DNA was observed but in these cases pre-S2 and HBsAg persisted in serum, albeit at lower concentrations, while in this group loss of HBV-DNA from serum was not accompanied by a flare in disease activity. These results suggest first, that assay of pre-S2 is a further measure of the response to interferon and second that in some cases interferon enhances immune recognition of both the pre-S2 and HBsAg polypeptides.

Interleukin-1 and interleukin-2 activity in chronic hepatitis B virus infection

Abnormalities of lymphocyte proliferation in chronic hepatitis B virus infection are well documented, although the underlying mechanisms are poorly understood. To determine whether these defects may be secondary to disordered lymphokine production, we have simultaneously assayed interleukin-1 and interleukin-2 production in 31 chronic carriers of the hepatitis B virus. Supernatants from mononuclear cells cultured both in the presence and absence of lipopolysaccharide contained significantly increased quantities of interleukin-1 activity in patients compared with normal controls (p less than 0.01). Lysates of monocytes from patients also contained more interleukin-1 than those of controls (p less than 0.05) in the presence of lipopolysaccharide or silica, or both. These results indicate that interleukin-1 production is markedly elevated in patients with chronic hepatitis B virus infection, whereas in contrast, interleukin-2 production was found to be reduced in these patients (p less than 0.01). As one of the biological properties of interleukin-1 is to stimulate fibroblasts to produce collagen, the relationship between fibrosis in the liver biopsy specimen and interleukin production was examined. There was a highly significant correlation (p less than 0.001) between interleukin-1 production and the severity of fibrosis, suggesting that this lymphokine may be closely related to the development of cirrhosis in such patients.

Sequential studies of pre-S2 antigenemia and anti-pre-S2 antibodies in relation to viral replication in acute hepatitis B followed from the early incubation phase

To determine the time sequence of expression of pre-S2 peptide (120-150) during the presymptomatic phase of acute hepatitis B, we used a monoclonal antibody radioimmunoassay in five subjects followed from 30 to 70 days before the onset of liver damage. Pre-S2 peptide was present in serum at low levels from the early incubation phase and started to increase immediately after the first detection of HBV-DNA in serum, in parallel with the increase in HBsAg levels. During the symptomatic phase, levels of pre-S2 peptide declined rapidly; it was no longer detectable after recovery. Anti-pre-S2 antibodies were detected, in four patients, only in the recovery phase. These results demonstrate that expression of pre-S2 peptide occurs very early in the incubation phase of acute HBV infection and is cleared in parallel with HBsAg. Anti-pre-S2 antibodies seem to play no role in viral clearance in these patients.

In vitro effect of TP-1 (a calf thymic extract) on suppressor T-cell function of patients with autoimmune chronic active hepatitis

Concanavalin A-activated T-lymphocyte suppression of IgG production was found to be significantly impaired in patients with untreated active autoimmune chronic hepatitis when compared to normals or patients with inactive disease. When the dose-response effect of TP-1, a calf thymic extract, on in vitro suppressor cell activity was assessed, lymphocytes from six out of eight patients with previously reduced suppressor cell function showed a significant improvement, while over a similar range the suppressor cell activity of most normal controls declined. These results support the possibility that defective immunoregulation in patients with autoimmune chronic active hepatitis may be related to a deficiency in thymic hormone levels.

Cellular immunity to nucleocapsid and pre-S determinants in asymptomatic carriers of hepatitis B virus

Previous studies of cellular immunity in asymptomatic HBV carriers have been limited to evaluation of responses to plasma-derived HBsAg preparations. We have explored the specificity of cellular immune responses to HBV antigens in these subjects using an indirect T-lymphocyte migration inhibitory factor assay and three antigen preparations (recombinant nucleocapsid antigen (HBcAg), plasma-derived HBsAg with or without pre-S2, and Saccharomyces cerevisiae-synthesized HBsAg without pre-S2 region). T cells from 10 asymptomatic chronic HBV carriers with normal liver function tests were responsive to nucleocapside determinants (mean migration index = 0.55 +/- SD 0.07) and to pre-S2-positive plasma-derived HBsAg (MI = 0.62 +/- 0.05). However, none responded to HBsAg devoid of pre-S2 sequences (MI = 0.98 +/- 0.04). In further experiments, T cells from three HBV carriers, cultured with six different HBsAg preparations, exhibited responsiveness only to those preparations containing significant pre-S2 activities. Our results show that T-cell immunity to nucleocapsid determinants of the virus and HBsAg in present in asymptomatic HBV carriers; the latter is restricted to antigenic preparations containing significant pre-S2 activities. Hence, T-cell immunity to pre-S determinants may not always be associated with HBV clearance.

Immunoglobulin on the surface of isolated hepatocytes is associated with antibody-dependent cell-mediated cytotoxicity and liver damage

Hepatocytes isolated from patients with chronic liver disease are often covered by immunoglobulin. The aim of the present study was to establish whether this surface immunoglobulin (SIg) mediates liver cell damage. Freshly isolated hepatocytes from percutaneous liver biopsy of 16 patients with chronic active hepatitis (CAH) (6 HBsAg positive), 3 with HBsAg-positive chronic lobular hepatitis (CLH), 5 with HBsAg-positive chronic persistent hepatitis (CPH) and 12 with minor histological abnormalities (MHA) (5 HBsAg positive) were divided into two aliquots. One was studied for the presence of membrane-bound immunoglobulin and the third component of complement by direct immunofluorescence and the other was incubated, in an allogeneic cytotoxic assay, with peripheral blood mononuclear cells prepared from healthy volunteers as a source of effectors for antibody-dependent cell-mediated cytotoxicity (ADCC). Liver biopsies were scored for portal and parenchymal inflammatory activity. The percentage of SIg positive hepatocytes was significantly higher in patients with CAH (median 52.5%) than in patients with CLH/CPH (20.5%) or in patients with MHA (1%). Percentages of SIg-positive liver cells were significantly correlated with total liver biopsy scores and with both portal or parenchymal scores considered independently. SIg were found to belong to the IgG class in all groups of patients. When hepatocytes were cultured with normal human lymphocytes, allogeneic cytotoxicity values were significantly higher in patients with CAH (median 34%) than in patients with CLH and CPH (18%) or in those with MHA (12%). Percentage cytotoxicity was positively correlated with total biopsy scores and with portal activity but not with parenchymal activity, suggesting that ADCC might play a damaging role mainly in the portal areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of cellular immunity to hepatitis-B-virus antigens from the early incubation phase of acute hepatitis B

Cellular immunity to hepatitis-B-virus (HBV) antigens was followed prospectively in five patients who were identified in the early incubation phase of acute HBV infection, between 30 and 70 days before the onset of liver damage. Cellular immunity to pre-S antigens was the first detectable immune response, appearing 30 days before the first rise in serum aminotransferases in every case. T-cell sensitisation to HBcAg followed, with IgM anti-HBc appearing 10 days later. A cellular immune response to HBsAg was the last to appear, 10 days before the onset of liver damage. These cellular immune responses are the earliest host responses to the virus infection and could be critical in initiating and directing the processes of liver damage and viral clearance.