Autoantibodies to the basal cells of squamous epithelium react with thymic epithelial cells

Hypothesis: Could Hepatitis B vaccine act as an immune adjuvant in glioblastoma? Clues to conduct further epidemiological analyses

A failure of neurodevelopmental differentiation at the level of oligodendroglial-astrocytic biprogenitors (O2A) is shown to be involved in the pathogenesis of both multiple sclerosis (MS) and glioblastoma multiforme (GBM). In this review article, we suggest that certain antigens of Hepatitis B Virus (HBV) and HBV-Vaccine (HBV-V) could act as immune stimulants in GBM treatment based on several lines of evidence. HBV-Vs may cause rare but prominent neuroimmune side effects including demyelination and multiple sclerosis, which may be associated with HBV-proteins creating antigenic mimicry of oligodendroglial progenitors. The combined prevalance of HBV and Hepatitis C Virus-carrier state is less in patients with brain tumors compared to healthy subjects. Furthermore, within the population of patients with brain tumors, the prevalence is even about two times lesser in GBM in comparison to those with a diagnosis of meningioma. Although indirectly, this epidemiological data may indicate that the immune response triggered against hepadnavirus antigens would eliminate aberrantly differentiating O2A progenitor cells giving rise to GBMs. Moreover, Hepatitis B surface antigen-antibody variable domain is among the top 100 differentially expressed transcripts in fresh frozen and formalin-fixed paraffin-embeded specimens obtained from pediatric GBM tissues in comparison to the control brain tissues. However, the provided evidence is still premature and we think that HBV-V warrants investigation first by epidemiological studies and then by animal experiments to determine whether it reduces the risk of GBM and whether it could slow GBM growth via immune stimulation.

Autoantibodies in hepatitis delta

Hepatitis delta virus infection is associated with a wide range of different autoantibodies. The humoral immune response in chronic hepatitis D is directed against the cytoskeleton, the nucleus, the nuclear lamina and the endoplasmic reticulum. Smooth muscle antibodies (SMA), basal cell layer antibodies (BCLA), stellate epithelial cell antibodies (SECA), thymic reticular cell antibodies (TRA), perithymocytic cell antibodies (PTA), and anti-calmodulin antibodies are reactive with constituents of the cytoskeleton. Antinuclear antibodies (ANA) and anti-lamin C antibodies recognize antigens of the nucleus and the nuclear lamina, respectively. Autoantibodies directed against antigens of the endodoplasmic reticulum (LKM) are also common in chronic hepatitis D. Recently, the major molecular target of LKM-3 autoantibodies was described as an epitope on UDP-glucuronosyltransferases of family 1. In view of the important role of UGTs in drug metabolism, LKM-3 autoantibodies represent a new model to study virus induced autoimmunity in man. Future studies should focus on the role of the host immune response and the clinical relevance of these autoantibodies in chronic hepatitis D.

Serum antibodies to thymus epithelial cells in non-A, non-B and cryptogenic chronic liver disease

Antibodies against thymus epithelial cells (anti-TEC) and the basal cell layer (BCLA) of squamous epithelia have been described in association with HDV-related chronic liver disease (CLD). Data are lacking on their presence during nAnB virus infection. Sera from 51 patients with nAnB post-transfusion hepatitis, including acute and chronic cases diagnosed during a prospective study on candidates for cardiac surgery, and 167 with various forms of CLD were tested for the presence of anti-TEC and BCLA using indirect immunofluorescence on human thymus and rat forestomach sections. Both antibodies mainly occurred in nAnB, HDV and cryptogenic CLD (anti-TEC: 51%, 47% and 42%; BCLA: 29%, 38% and 31%, respectively). The prevalence of anti-TEC in nAnB CLD turned out to be higher than that recorded in alcoholic, HBV-related, autoimmune, liver and kidney microsomal antibody positive CLD and primary biliary cirrhosis (p ranging from less than 0.03 to less than 0.0004). Two monoclonal antibodies (Mabs) to cytokeratins gave a pattern superimposable on that of spontaneous anti-TEC (both Mabs) and BCLA (only one). Antibodies against epithelial constituents, presumably targeting cytokeratin-associated antigens, occur not only in HDV CLD, as previously reported, but also in nAnB CLD, where they might represent a diagnostic aid, due to the unavailability of reliable serological markers of nAnB infection. The close similarity of anti-TEC and BCLA status between nAnB and cryptogenic CLD suggests a nAnB etiology of at least a proportion of chronic liver patients at present scored as cryptogenic.

Thymic medullary cells expressing B lymphocyte antigens

A small subpopulation of human thymic medullary cells was found to express B cell-restricted and -associated antigens in various combinations. The cells were detected in fetal, juvenile, and adult thymi using indirect immunoenzymatic methods and monoclonal antibodies (MoAbs). Morphologically, they could be subdivided into small, round lymphoid cells, accounting for less than 1% of medullary lymphoid cells, and into a larger variant, even more infrequent in number and asteroid in shape because of short cytoplasmic processes. Immunophenotype (CD19+, CD20+, CD22+, CD37+, IgM+, IgD+) and morphology of the first cell type led to the conclusion that the lymphoid cells were B lymphocytes. The second, asteroid cell type constantly expressed CD20 and inconstantly expressed IgM, CD19, CD22, and CD37; they were often found to form rosettes with non-B lymphocytes. It can be concluded that a small number of B cells and asteroid cells of still uncertain origin, but expressing B cell-restricted antigens, are constitutive elements of the fetal and adult thymic medulla. It can be hypothesized that the asteroid cell might represent a novel type of thymic accessory cell and that the rosetting of non-B lymphocytes around this asteroid cell might simulate or in fact be the earliest B cell interaction of maturing T cells.

Intra- and extrathymic B cells in physiologic and pathologic conditions. Immunohistochemical study on normal thymus and lymphofollicular hyperplasia of the thymus

Normal thymuses and thymuses with lymphofollicular hyperplasia have been examined immunohistologically using immunoenzymatic single and double labelling methods and a panel of monoclonal antibodies against B lymphocyte differentiation antigens (CD19-, CD20-, CD21-, CD22-, CD23- and CD37ag) and human immunoglobulins (IgM, IgD) for the presence and localisation of B lymphocytes and cells expressing B cell differentiation antigens. The numerous hyperplastic lymph follicles which occur in the pathological condition of lymphofollicular hyperplasia of the thymus were found to originate in the extrathymic compartment of the interlobular septal space. This area was found to be blown up by the growing lymph follicles with exactly the same cellular composition as their counterparts in the peripheral lymphatic tissue. Some of the B lymphocytes expressing the immunophenotype of follicular mantle zone lymphocytes which were detected in the thymic medulla probably infiltrated through discontinuities of the border between the perivascular space and the thymic medulla. Apart from this primarily extrathymic B cell compartment, B lymphocytes and cells expressing B cell antigens were found within the thymus medulla of normal control thymuses of different ages from fetal to adult life. These cells were detected as a small subpopulation in normal fetal, juvenile and adult thymuses. Morphologically they could be subdivided into small, round lymphoid cells accounting for less than 1% of medullary lymphoid cells, and into a larger variant, asteroidally shaped because of short cytoplasmic processes. These asteroid cells were even more infrequent than the lymphoid variant. Immunophenotype (CD19ag+, CD20ag+, CD22ag+, CD37ag+, IgM+, IgD+) and morphology of the first cell type led to the conclusion that the lymphoid cells were in fact B lymphocytes. They were scattered throughout the medulla of fetal and juvenile and adult thymuses alike. The second, the asteroid cell type, constantly expressed CD20ag and inconstantly IgM, CD22ag and CD37ag; furthermore, CD23ag was detected in a subset of the asteroid cells either restricted to the perinuclear zone or expressed in the entire cytoplasma and on the plasma membrane. The asteroid cells were located in the corticomedullary region of the fetal thymuses but were randomly distributed with a tendency to Hassall's corpuscles in juvenile and adult thymuses. They often formed rosettes with non-B lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoimmunity in chronic liver disease caused by hepatitis delta virus

Recent evidence shows that chronic liver disease induced by hepatitis delta virus is closely associated with production of autoantibodies. To verify this sera from patients with hepatitis delta virus and from those with hepatitis B virus mediated chronic liver disease were tested for a panel of autoantibodies. Although the traditional non-organ specific autoantibodies were similarly distributed in the two groups, a considerably higher prevalence of IgG basal cell layer antibodies, IgM anti-intermediate filaments, and IgG antimicrotubule antibodies was found. Although these phenomena might be secondary to hepatitis delta virus infection, they might be the serological markers of underlying immune events.