Rita Mirakian

Organ-specific autoimmunity: a 1986 overview.

The normally functioning immune system is subject to intricate networks of regulatory mechanisms: it is therefore not surprising to find that autoimmune diseases present a complex pathogenic picture in which the relative contributions of various factors probably determine the precise nature and course of disease. This is particularly evident in the effector mechanisms of organ-specific autoimmunity which are described in this chapter. These ultimately give rise to the disease symptoms, and can be directly cytotoxic, or may either stimulate or block functional activity or growth of the target cells. Their various contributions to human diseases are becoming more firmly established, as in Type I diabetes, or are only now being described, as in the case of EC-Ab in protracted diarrhea of infancy and as evidenced by the growing lists of receptor-stimulating or -blocking antibodies. The nature and precise location of relevant autoantigens is also coming under closer scrutiny. The answers to the question of why these diseases arise in the first place remain more elusive. However, it is again likely that a variety of factors can contribute. The attractive possibility of a role for idiotypic interactions is gaining ground, particularly within the context of antibodies to hormones and their receptors. Another potential mechanism which we believe may be of central importance, particularly in the development of organ-specific destructive autoimmunity, and which we have discussed here in detail, is the aberrant expression of HLA Class II molecules by target cells. Whether this is actually an initiating factor is presently not known, but its potential for promoting pathogenesis both early and late in the process is clear. Furthermore, the complex nature of the regulation of epithelial Class II expression may help to explain the heterogeneity of features and course of disease in different patients with the same underlying pathology. All these advances in our basic understanding of the disease processes should ultimately lead to more effective and specific means of therapeutic intervention.

Differential expression and regulation of major histocompatibility complex (MHC) products in neural and glial cells of the human fetal brain

Abstract The cells of the central nervous system (CNS) have the peculiarity of physiologically expressing very low levels of HLA molecules. In multiple sclerosis (MS), however, as in endocrine autoimmune diseases, there is a marked increase of HLA expression in the tissue (i.e. the plaques) and this is attributable not only to infiltrating cells but also to the astrocytes. To gain an insight into the regulation of HLA in the different cell types in the CNS and to compare it to that observed in the endocrine organs, we have studied the effect of the lympho/monokines interferon (IFN)-α and -γ, tumour necrosis factor (TNF)-α, and interleukin (IL)-2 and other agents on this aspect of the biology of human fetal brain cells in culture. A two-colour immunofluorescence technique which combines antibodies to diverse CNS cell markers and monoclonal antibodies (MoAbs) to the non-polymorphic region of HLA molecules was used throughout this study. In control cultures, only astrocytes expressed MHC class I, but after incubation with either IFN-γ or TNF-α oligodendrocytes acquired class I expression. Surprisingly, astrocytes became spontaneously class II positive in culture and this was greatly enhanced by IFN-γ. Other agents such as IL-2, epidermal growth factor, phorbolmyristate acetate and lectins had no effect. The expression of HLA molecules in the cells of the CNS both in basal conditions and in response to lymphokines is therefore selective and highly heterogenous, thus reflecting their intrinsic biological diversity. These findings may help to explain the features of the immunopathology of MS and also of latent viral infections of neural cells.

The Immunological Features of Peyronie's Disease

PURPOSE We investigated the immunological features and possible autoimmune basis of Peyronies disease. MATERIALS AND METHODS The sera of 100 patients with Peyronies disease were tested for circulating autoantibodies, including anti-penis antibodies, by indirect immunofluorescence. Antibody deposition and the immunological activity in Peyronies plaque tissue from patients with early and long-standing disease were also assessed. RESULTS Circulating anti-penis antibodies were not found in any patient although antinuclear antibodies were present in 24%. Patients with early Peyronies disease had IgM antibody deposition, marked T lymphocytic and macrocytic infiltration in the sub-tunical space, increased expression of adhesion molecules by endothelial cells and an increased human lymphocyte antigen class 2 expression by the cellular infiltrate, indicating cellular immune activation. CONCLUSIONS These results show that some of the features of autoimmunity, in particular the cell mediated response, are present in Peyronies disease.

Transfection with SV40 gene of human pancreatic endocrine cells

At present, only islet cell lines of animal origin have been successfully generated (e.g. RIN, HIT). A fully differentiated human beta cell line would be advantageous for diabetes research. We now report the generation of a human endocrine pancreatic cell line obtained by transfection using a plasmid containing the early region of SV40 viral DNA. Viral integration and transcription was assessed by Southern and Northern blotting. This cell line has been growing continuously for more than 2 years and maintains several of the characteristics of the parental cells from which they were generated. The presence of Neuron Specific Enolase, Protein Gene Product 9.5, cytokeratin, microvilli, cytoplasmic electrodense granules and the secretion of insulin, glucagon and somatostatin supports the neuroendocrine origin of this cell line. However, hormone production progressively decreased and finally stopped at passage 8. Flow cytometric analysis showed that HLA expression in this cell line is readily induced by IFN-gamma and modulated by TNF-alpha. The establishment of this human endocrine cell line indicates the feasibility of immortalizing human islets by transfection with viral oncogenes. To obtain a fully differentiated cell line it may be necessary to use other DNA constructs which immortalize the cells without fully transforming their phenotype.