Nobuhiro Ikuno

The peculiar autoimmunity of primary biliary cirrhosis.

Summary: Autoantibodies to mitochondria (AMA, anti‐M2) are a serologic hallmark of primary biliary cirrhosis (PBC). These react with three structurally and functionally related multienzymic complexes, the 2‐oxoacid dehydrogenase complexes, but chiefly with the E2 subunit of pyruvate dehydrogenase complex (PDC‐E2). Their very close (95%) and specific association with PBC underpins the autoimmune concept of pathogenesis of that disease, notwithstanding several non‐congruent features. Detailed studies, including structural analysis of epitopes, do not disclose how these autoantibodies originate. Their ubiquity in PBC has overshadowed the existence of a second set of relatively PBC‐specific autoantibodies to nuclear antigens for which reactants have been cloned and characterized. These include centromeric proteins; proteins of the nuclear pore complex; nuclear dot proteins, which include Sp‐100 and the promyelocytic leukemia antigen; and a recently identified autoantigen, SOX13. Certain of these reactants are DNA‐binding proteins with transcriptional regulatory activity. Thus serum from individuals with the same clinical syndrome can have autoimmune reactivity to disparate mitochondrial and nuclear constituents in different cellular compartments. Antibody probing of phage displayed random peptide libraries, together with epitope scanning using overlapping sequential octameric peptides from the PDC‐E2 sequence, showed that the discontinuous motifs MH, FV(E) and SYP contributed to a predicted conformational antibody epitope in the inner lipoyl domain of PDC‐E2.

Antimitochondrial autoantibodies in saliva and sera from patients with primary biliary cirrhosis

Background and Aims: Primary biliary cirrhosis (PBC) is a cholestatic autoimmune liver disease characterized by antimitochondrial autoantibodies (AMA) in serum, for which the reactants are E2 subunits of the three 2‐oxoacid dehydrogenase (2‐OAD) enzymes, particularly pyruvate dehydrogenase complex (PDC‐E2). Some 70% of patients with PBC have a coexisting autoimmune disease including Sjögrens syndrome. We aimed to ascertain the frequency and isotype of AMA in saliva in PBC.

Adenosquamous carcinoma of the pancreas

A 58-year-old Japanese man was admitted complaining of abdominal pain. An abdominal computed tomography examination demonstrated a tumor in the head of the pancreas and multiple calcifications. A laparotomy was performed and the tumor was removed by Whipples operation. Histologically, the neoplasm that invaded the duodenal wall and the papilla of Vater was composed of nests of malignant squamous cells with intercellular bridges and showed the formation of keratinized pearls with a small area of concurrently neoplastic glandular and squamous elements. On the basis of these features, the diagnosis of adenosquamous carcinoma of the pancreas was made. The patient died 18 months after the operation. The neoplastic behavior of this rare primary pancreatic carcinoma is similar to that of duct cell carcinoma as well as pure squamous cell carcinoma of the pancreas. As the pancreas can be the target of metastases of squamous carcinomas from other organs it is wise to be aware of this rare entity.

Frequency of IgG, IgM, and IgA class autoantibodies against 2-oxo-acid dehydrogenase complex in 102 Japanese patients with primary biliary cirrhosis

Abstract We investigated the proportion of serum samples containing IgG, IgM, and IgA class autoantibodies against 2-oxo-acid dehydrogenase complex (2-OADC) tested by sensitive immunoblotting with enhanced chemiluminescence in 102 Japanese patients with primary biliary cirrhosis (PBC). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in our assay condition were 99, 86, 89, 99 and 93%, respectively. Among these patients, 13 were seronegative for antimitochondrial antibodies (AMA) by indirect immunofluorescence (AMA-negative group). Of the 102 serum samples, 98 (96%), 85 (83%), and 72 (71%) contained IgG, IgM, or IgA class antibodies against at least one of the 2-OADC enzymes, respectively. All of the 13 AMA-negative sera contained IgG, IgM, or IgA class antibodies against at least one of the 2-OADC enzymes. In contrast, only one serum sample positive for AMA by immunofluorescence at a titer of 1:20 did not contain any IgG, IgM, or IgA class antibodies. Although the proportion of samples containing IgG class autoantibodies against E2 subunit of branched chain oxo-acid dehydrogenase complex (BCOADC-E2) (77%) was similar to that against E2 subunit of pyruvate dehydrogenase complex (PDC-E2) (74%), IgM and IgA class antibodies against BCOADC-E2 were not frequently detected compared with those against PDC-E2. Overall, our results indicated that IgG class antibodies against PDC-E2 and BCOADC-E2 showed the most dominant reactivities both in AMA-positive and -negative groups of PBC.

Autoimmune reactivity of sera to hepatocyte plasma membrane in type 1 autoimmune hepatitis.

Abstract: Type 1 autoimmune hepatitis (AIH-1) is an organ-specific autoimmune liver disease for which no tissue-specific autoantigen has yet been identified. We examined the reactivity by sensitive immunoblotting with enhanced chemiluminescence (IB-ECL) of 43 sera from patients with AIH-1 and 182 sera from patients with other diseases on hepatocyte plasma membrane derived from rat or human liver (RHPM, HHPM) and separated by aqueous two-phase partition. The sera studied were from patients with AIH-1, primary biliary cirrhosis, chronic viral hepatitis, and systemic lupus erythematosus (SLE); and from normal subjects. Specificity of reactivity by IB-ECL was sought: (i) by testing sera on human or rat liver membrane; (ii) by testing sera on liver or kidney membrane; (iii) by serial titration of reactive sera; and (iv) by testing reactive sera from AIH-1 before and after successful treatment with prednisolone. The results were that in AIH-1 there were multiple reactive components which were not species-specific, since they were detected with both RHPM and HHPM, but were mostly tissue-specific for liver. There was no significant correlation between antinuclear antibodies (ANA) titer and the frequencies of sera reactivities against RHPM. Most of these reactive components were demonstrable at a lesser frequency in other liver diseases and in SLE. There was a striking decrease in reactivity by IB-ECL of AIH-1 sera with liver membrane after clinical remission, further suggesting that differences between AIH-1 and other inflammatory liver diseases and SLE are predominantly quantitative rather than qualitative. However, our study did point to candidate liver membrane antigens with molecular sizes of 136, 116, 81, and 49 kDa, additional to components previously described by others. The molecular identification of these prominent reactants with AIH-1 sera could prove informative for ascertaining pathogenesis.

RET-ONCOGENE EXPRESSION CORRELATES WITH NEURONAL DIFFERENTIATION OF NEUROBLASTIC TUMORS

An antibody to the ret proto-oncogene product (RET) was raised and applied to formalin-fixed, paraffin-embedded neuroblastic tumors (NBTs) to investigate its usefulness in diagnosis and evaluation of cell differentiation. In normal neural crest-derived tissues, most ganglion cells were moderately stained while large ganglion cells were weakly stained. In NBTs, the intensity of the staining in moderately differentiated neuroblasts and small ganglion cells was more prominent than in undifferentiated neuroblasts, while the cytoplasm of large ganglionic cells was weakly stained as in normal ganglion cells. The RET immunoreactivity was compared with that of nine neural and neuroendocrine markers. The results revealed a parallelism with the protein gene product 9.5 (PGP9.5), neuron specific enolase (NSE) and NF-150 kD (NF = M). These findings indicated that the RET immunoreactivity was correlated with ganglionic differentiation and maturation. Thus, RET was considered to be a new marker that would be implemented in diagnosis and estimation of neuronal differentiation of NBTs.

Interferon Alfa-2a Treatment for Chronic Hepatitis C without Cirrhosis and Its Effects on the Incidence of Hepatocellular Carcinoma

The aim of interferon treatment for chronic hepatitis C is eradication of the hepatitis C virus during the early stages of the disease to prevent progression to liver cirrhosis or hepatocellular carcinoma. However, the effects of interferon on preventing the development of hepatocellular carcinoma for chronic hepatitis C without cirrhosis remain obscure. We wished to study these effects. In this retrospective study, we followed up 66 patients with chronic hepatitis C who were treated with interferon alfa-2a (total dose 324 to 792 MIU) for an average period of 3 years after treatment. Of these 66 patients, 3 patients developed hepatocellular carcinoma during the follow-up period (range, 0.3 to 2.8 years; yearly incidence 1.5%). All 3 patients were among 27 patients who did not respond to interferon treatment. Of these 3 patients, 1 patient developed liver cirrhosis after interferon treatment, and the histologic staging of the remaining 2 patients before interferon treatment was F3, according to the new Inuyama classification. None of the 18 patients who were complete responders to interferon treatment or the 21 patients with incomplete responses developed hepatocellular carcinoma. Our results suggest that patients with chronic hepatitis C who have no response to interferon treatment and histologically advanced disease should be closely followed up after interferon treatment, although the mechanism of malignant transformation to hepatocellular carcinoma in patients with chronic hepatitis C virus infection is still obscure.

Malignant lymphoma of the stomach after chemotherapy for hepatocellular carcinoma

A rare case of malignant lymphoma of the stomach after treatment for hepatocellular carcinoma (HCC) is reported. A 72-year old man presented with a large mass on the right hypochondrium, which was diagnosed as HCC associated with chronic hepatitis C with cirrhosis. The inoperable tumor was treated conservatively with cisplatin, etoposide, carboplatin, and Lipiodol infused into the hepatic artery, together with transcatheter arterial embolization. The patient presented 38 months later with features suggestive of gastric ulceration. Endoscopy and histological examination of biopsy material confirmed the presence of malignant lymphoma of the stomach. He ultimately died as a result of hepatic failure. The clinical presentation suggests that gastric lymphoma was possibly related to the lymphotropic effect of hepatitis C virus (HCV) and exacerbated by intraarterial injection of the cytotoxic drugs.

Laparoscopic and Histopathologic Features of the Liver in Severe Chronic Active Epstein‐Barr Virus Infection Syndrome: A Case Report

Abstract: A 40‐year‐old man was admitted to our hospital with persistent fever, generalized lymphadenopathy and hepatosplenoamegaly. Immunological examination demonstrated high titers of several anti‐Epstein‐Barr virus (EBV) antibodies, including anti‐viral capsid antigens 1gG‐antibody 1: 20, 480, anti‐early antigens‐DR IgG‐antibody 1: 5, 120, and reduced activity of EBV‐specific cytotoxic T lymphocytes. Laparoscopic features resembled those of chronic active viral hepatitis, including an uneven surface appearance and diffuse hepatic enlargement. Histopathological examination of a liver biopsy specimen showed inflammatory cell infiltration along sinusoidal surfaces (single file appearance) and enlarged portal areas with intralobular punched‐out necrosis. The diagnosis was confirmed by detecting the EB viral genome in serum. Despite treatments with natural alpha‐interferon, adenosine arabinocide and recombinant human interleukin‐2, the patient died of progressive hepatic failure.