The distribution of duodenal G cells in duodenal ulcer patients.

The number of G cells is evaluated in biopsy specimens of fundic, antral and duodenal mucosa from the bulb, second and third parts in 10 patients with duodenal ulcer, and compared with that observed in 6 normal controls. G cells are absent in fundic mucosa but in the antrum their number in duodenal ulcer patients does not differ from that of controls and is strictly related to the histological pattern of the mucosa. In the second and third duodenum of duodenal ulcer patients the number of G cells is significantly higher in comparison with controls, while in the bulb the two groups do not differ significantly. Moreover, when different duodenal portions are compared no differences in the number of G cells are observed in the duodenal ulcer group; while in controls the bulbar number of G cells is higher in comparison with second and third duodenum.

Serological response to the hepatitis delta virus in hepatitis D.

Sera from 74 hepatitis B surface antigen-positive individuals, who presented with acute hepatitis delta virus (HDV) infection which ran a self-limited course in 58 and progressed to chronicity in 16, were tested over time for HDV markers. In self-limited disease the serum pattern varied from early HD-antigenaemia followed by IgM and IgG anti-HD seroconversion, to the appearance of IgM and IgG anti-HD without antigenaemia, or the isolated expression of either the IgM or the IgG antibody. The typical case of IgM anti-HD was transient and appeared with a mean delay of 10-15 days from admission in the different serological subgroups. The IgG antibody usually developed several weeks later during convalescence. In contrast, patients with disease destined to become chronic had a brisk IgM antibody response and IgG anti-HD was detectable with a mean delay of 15 days; generally, the IgM and the IgG antibody persisted over the follow-up time. IgM antibody to HDV is often the only serological test positive in the clinical stage of hepatitis D and repeated testing for this marker is necessary to diagnose acute HDV co-infection. The serological follow-up provides important prognostic information: waning of IgM confirms resolution of HDV infection, persistence predicts chronicity.

Diagnostic and prognostic significance of the IgM antibody to the hepatitis delta virus.

The IgM class antibody to the hepatitis delta virus (HDV) was determined in different clinical categories of hepatitis B surface antigen carriers infected by the HDV (positive in the test for total antibody to HDV). The IgM antibody was found at high titers in each of 70 patients with inflammatory liver disease and at a low titer in one of six patients with inactive cirrhosis; it was not found in eight carriers with normal liver histology. The IgM antibody persisted in high titer over many years in patients with unremitting or progressive liver disease, but declined or disappeared before the homologous IgG antibody in the patients whose disease improved or resolved. Testing for IgM antibody to HDV distinguishes hepatitis B surface antigen carriers who have underlying inflammatory HDV liver disease from those with past HDV infection and provides prognostic information on the course of chronic HDV hepatitis.

Cell-mediated cytotoxicity to autologous hepatocytes in HBsAg positive liver disease: an analysis of the killing specificity and of the clinical use of the test.

The specificity of a system measuring cell-mediated cytotoxicity as effector-induced target cell detachment from plastic recently adopted to study autologous hepatocyte killing in liver disease, was examined in 17 HBsAg positive liver patients whose hepatocytes (after biopsy digestion with collagenase) were incubated in Terasaki plates with the corresponding blood lymphocytes over two days. The hepatocyte viability and the specificity of the effectors were evaluated as determinants of the clinical value of the test. We found that: (a) hepatocytes in all experiments showed membrane damage owing to the lytic action of collagenase on the small liver core; (b) patients' lymphocytes detached diseased autologous hepatocytes more efficiently than did normal lymphocytes with healthy hepatocytes; (c) in eight patients cytotoxicity appeared equally distributed between a population enriched in T cells and one enriched in non-T cells; yet the mean cytotoxic index of the latter subset was higher than that of the former; (d) cytotoxicity was not blocked by the addition of either aggregated IgG or purified HBsAg; (e) protein synthesis seemed required to promote hepatocyte detachment, for lymphocytes treated with Actinomycin D were no longer active. Poor target viability detracts from the specificity and the clinical value of the test, that therefore turns out to be a major problem of liver cell culture.

Microsomal autoantibodies in chronic infection with the HBsAg associated delta (delta) agent.

A cytoplasmic autoantibody is described which gives a distinct immunofluorescence pattern in tissues of man and of varied animal species. Fluorescence is maximal in human substrates; it is strong in human hepatocytes and nephron cells and weak in thyroid adrenal and pancreatic cells. Complement fixation and fluorescence absorption studies have shown that the homologous antigen is localized in the microsomal membranes of human liver. The autoantibody was found in 13% of 81 carriers of HBsAg with chronic delta infection. It was not detected in patients with acute delta infection or in HBsAg positive and HBsAg negative patients without delta infection. The apparently exclusive occurrence of this antibody in chronic delta infection suggests that its expression is induced by persistence of the viral event.

Delta hepatitis in inapparent carriers of hepatitis B surface antigen. A disease simulating acute hepatitis B progressive to chronicity.

Infection with the hepatitis B surface antigen (HBsAg)-associated delta agent (delta) was determined in a series of Italian patients with a diagnosis of acute hepatitis B (HBsAg-positive) progressive to chronicity. Twenty-two of 27 (81%) and 12 of 18 (67%) patients collected, respectively, in Naples and Cagliari, where delta is highly endemic, developed immunoglobulin M antibody to delta and/or rising titers of immunoglobulin G anti-delta during the initial acute phase of the disease. In each of them, anti-delta increased to a high-titered plateau indicative of chronic delta infection. Delta markers were found in none of the 13 patients collected in Siena, where the prevalence of delta infection is low. The great majority of the patients with anti-delta and a progressive form of HBsAg-positive hepatitis lacked the IgM antibody to hepatitis B core antigen. They were presumably unrecognized carriers of HBsAg who became infected by delta and developed hepatitis induced by this agent. In areas where delta is endemic, it may represent the true cause of seemingly type B hepatitis progressing to chronic HBsAg-positive liver disease.

Dane particle-associated hepatitis B e antigen in patients with chronic hepatitis B virus infection and hepatitis B e antibody.

A commercial radioimmunoassay was adapted to detect serum Dane particle-associated HBeAg in patients whose sera contained homologous antibody. HBeAg was released from Dane particles with guanidine HCl. Dane particles were separated from anti-HBe by gel-filtration (Sepharose 4B) and ultracentrifugation of the eluate. Dane particle-HBeAg was tested in 45 HBsAg carriers with anti-HBe and was present in 8 (18%) carriers, all of whom had chronic liver disease. By contrast, HBeAg was not found in 10 carriers with normal liver histology. Serum or liver HBcAg was found in 6 of 8 patients with Dane particle-HBeAg. None of the carriers without Dane particle-HBeAg had other markers of hepatitis B virion synthesis. We conclude that Dane particle-HBeAg provides a sensitive index of active hepatitis B virus replication, a guide to the presence of chronic hepatitis in HBsAg carriers with anti-HBe, and a noninvasive method to follow infection in these patients.

Radioimmunoassay detection of IgM antibodies to the hepatitis B core antigen in HBsAg liver disease.

A radioimmunoassay is described for detection of IgM antibody to the hepatitis B core antigen. The assay is based on the selective absorption of IgM immunoglobulins from test serum by anti-IgM fixed on a solid phase, followed by incubation with HBcAg and radiolabeled anti-HBc of IgG type. IgM anti-HBc was found in high titers in all the patients with acute hepatitis B; in two of four patients whose acute hepatitis progressed to chronicity, IgM anti- HBc disappeared in 4-6 months despite continuing HB viremia. IgM anti-HBc was also found in low titers in 19% of the patients with chronic HBV infection. No relation was noted between the presence of IgM anti-HBc and clinical or serological categories of chronic carriers of the HBsAg. The antibody was not found in carriers with hepatitis caused by superinfection with the hepatitis A virus or the HBV-associated delta agent. IgM anti-HBc is a marker of a recent HBV infection. Its absence in HBsAg-positive individuals with acute hepatitis should rise suspicion that the patients are carriers of the HBsAg experiencing disease caused by factors other than the HBV.

Radioimmunoassay detection of IgM antibodies to the HBV-associated delta (delta) antigen:" clinical significance in delta infection.

A sensitive radioimmunoassay was developed for specific detection of IgM antibodies to the hepatitis b virus-associated delta antigen. The test is based on the selective absorption of IgM by anti-IgM fixed on a solid phase. Transient primary IgM anti-delta responses with no conversion to a secondary IgG response were observed in acute self-limited delta infection. IgM anti-delta was invariably found in hepatitis B surface antigen (HBsAg) carriers with active delta infection and liver disease, while it was absent in HBsAg-positive or negative individuals with anti-delta of IgG class but without liver damage or intrahepatic delta antigen. IgM anti-delta appears useful in defining the epidemiology of acute delta infection and in the serological diagnosis of active delta disease from nonpathogenic or past delta infection.

Enzyme-linked immunosorbent assay for detection of antibody to the hepatitis B surface antigen-associated delta antigen.

A blocking enzyme-linked immunosorbent assay (ELISA) was developed for specific detection of antibody to the hepatitis B surface antigen-associated delta antigen. The sensitivity of ELISA was intermediate between that of previously described immunofluorescence and radioimmunological assays for anti-delta. Performance of ELISA was simple and required only ordinary and inexpensive laboratory equipment.

Immunohistochemistry of brain 5-hydroxytryptamine.

An immunohistochemical assay for 5-hydroxytryptamine (5HT) has been developed, validated by parallel radioimmunoassay and a series of tests with monoamines or related molecules, and applied to the detection of 5HT in rat brain sections. The procedure seems to be more sensitive and specific than the classical Falck-Hillarp technique. Among amines and related compounds tested, only 5-methoxytryptamine has been found to cross-react. 5HT-immunoreactive neurons and/or fibres have been observed in the spinal cord, brain stem, hypothalamic nuclei, epiphysis and subcommissural organ, thalamus, striatum, corpus callosum, amygdala, hippocampus, olfactory tubercle, and cerebral cortex.

Complement-mediated binding of immunoglobulins to some endocrine cells of the pancreas and gut.

Unspecific binding of immunoglobulins to gastrin, somatostain and glucagon cells of the gastrointestinal mucosa or pancreas has been found to occur through a nonantigen-antibody mechanism mediated by the C14 fraction of complement. The phenomenon represents an important drawback in hormone immunohistochemistry, which can be overcome by using complement deprived, highly dilute anti-hormone sera.