Autoimmune gastritis and parietal cell reactivity in two children with abnormal intestinal permeability.

Autoimmune gastritis is characterised by lymphocytic infiltration of the gastric submucosa, with loss of parietal and chief cells and achlorhydria. Often, gastritis is expressed clinically as cobalamin deficiency with megaloblastic anaemia, which is generally described as a disease of the elderly. Here, we report on two prepubertal children who developed autoimmune gastritis. One child developed autoimmune gastritis as part of a polyglandular autoimmune disease from a family with polyglandular autoimmune disease type II (PGA type II) and the other as part of a classic "thyro-gastric cluster," which may have been triggered by emotional trauma. Both children presented with normal small bowel biopsies, with abnormal gut permeability, which subsequently resolved. These patients are among the youngest reported to date. The immune systems targetted the gastric parietal cell autoantigens (ATP4A and ATP4B) in both children, similar to the elderly. The study of children with autoimmune gastritis and their families may provide additional insights into the disease's pathogenesis and may also lead to the identification of inheritable factors influencing susceptibility. This report underlines the necessity to screen paediatric patients with organ-specific autoimmune diseases for co-existent conditions. Children with polyglandular autoimmune disease are at particularly high risk.

Murine experimental autoimmune gastritis models refractive to development of intrinsic factor autoantibodies, cobalamin deficiency and pernicious anemia.

Researchers have developed murine lymphopenic, non-lymphopenic, transgenic, spontaneous and infectious agent based models to induce an experimental autoimmune gastritis (EAG) for the study of human organ-specific autoimmune disease. These models result in a chronic inflammatory mononuclear cell infiltrate in the gastric mucosa, destruction of parietal and zymogenic cells with autoantibodies reactive to the gastric parietal cells and the gastric H+/K+ ATPase (ATP4), arguably hallmarks of a human autoimmune gastritis (AIG). In the case of AIG, it is well documented that, in addition to parietal cell antibodies being detected in up to 90% of patients, up to 70% have intrinsic factor antibodies with the later antibodies considered highly specific to patients with pernicious anemia. This is the first report specifically investigating the occurrence of intrinsic factor antibodies, cobalamin deficiency and pernicious anemia in EAG models. We conclude, in contrast to AIG, that, in the three EAG models examined, intrinsic factor is not selected as a critical autoantigen.

MCA1 detection of histone H3 serine 10 phosphorylation, a novel biomarker for determination of mitotic indices.

Previously we identified circulating autoantibodies in high titre in the serum of a patient with biopsy-proven discoid lupus erythematosus reactive to serine/threonine phosphoepitopes of the novel mitotic chromosomal autoantigen we named MCA1. MCA1-reactive antibodies have subsequently been demonstrated to bind to the modified histone H3 (H3K9me3S10ph). In this study we utilised Epstein Barr virus (EBV) infection of peripheral blood mononuclear cells collected from this patient to immortalise B-lymphocytes producing MCA1-reactive antibodies. We found MCA1-reactive antibody production by the EBV-immortalised B-lymphocytes unstable in culture. We discuss the possibilities of producing MCA-1-reactive reagents through protein engineering methods (variable or complementarity-determining region grafting) and to modulate antibody affinity through library technologies (such as phage, yeast or ribosome display). Clinical studies have shown that carcinogenesis is most often linked to the development of proliferative abnormalities and proliferative activity has prognostic significance in a variety of human tumours. Here we demonstrate the potential utility of antibodies reactive to H3K9me3S10ph (MCA1), which is only detected on mitotic chromatin, as a marker for cell proliferation in FACS analysis, tissue section staining and in determination of mitotic indices.

Autoantibodies in neuropsychiatric lupus.

The American College of Rheumatology presented a consensus document in 1999 proposing the classification of 19 different syndromes defined by neurological and psychiatric manifestations of systemic lupus erythematosus (SLE). The detection of autoantibodies in patient's serum or cerebrospinal fluid has not been used as diagnostic markers for the proposed neuropsychiatric lupus classifications as their disease associations remain highly contentious. Autoantibodies detected in the serum and/or cerebrospinal fluid, that have been reported to segregate with patients presenting with neuropsychiatric lupus include: (1) anti-neuronal antibodies, (2) brain-lymphocyte cross-reactive antibodies, (3) anti-ribosomal P antibodies, (4) anti-phospholipid antibodies and (5) anti-ganglioside antibodies. Tests for anti-neuronal, anti-brain-lymphocyte cross-reactive and anti-ganglioside antibodies remain highly specialized whereas tests for ribosomal P antibodies and for antiphospholipid antibodies are currently routinely available in most diagnostic laboratories. Anti-ribosomal antibodies segregate with SLE. Antiphospholipid P antibodies are markers for the antiphospholipid syndrome. This syndrome may be associated with another disease, commonly SLE. In this setting, neuropsychiatric manifestations in SLE may arise as a consequence of thrombotic episodes involving the cerebral vasculature. There is a pressing need for antibodies to ribosomal P and to phospholipids to be standardized for routine diagnostic application. We conclude that the search for specific antibody marker(s) that can be applied for the routine laboratory diagnosis for neuropsychiatric lupus remains elusive.

Early endosomes, late endosomes, and lysosomes display distinct partitioning strategies of inheritance with similarities to Golgi-derived membranes.

The pattern of inheritance of compartments of the endocytic pathway has been rarely reported, and the precise mechanism(s) are yet to be elucidated. We used antibodies reactive to early endosomes (anti-EEA1), late endosomes (anti-LBPA and anti-LAMP-1), lysosomes (anti-LAMP-1) and trans-Golgi network (TGN) (anti-GOLGA4) to examine the inheritance of these compartments in fixed human HEp-2 cells. Prior to entering M phase, these compartments display a perinuclear bias in their cytoplasmic distribution with areas of local accumulation juxtaposed to the centrosome. The location of these compartments during mitosis was examined relative to each other, the chromosomes, centrosomes and the microtubule network. During M phase early endosomes and TGN-derived compartments share overlapping subcellular distributions. A portion of these compartments display discernible clustering around the separated and migrating centrosomes in prophase. At metaphase these compartments co-localise with the mitotic spindle, are absent at the metaphase plate and do not overlay the astral microtubules. At anaphase these compartments are concentrated between shortening kinetochore microtubules and centrosomes. In addition, they appear distributed over the elongating polar microtubules in the body of the cell. From telophase and into cytokinesis these compartments concentrate around the minus ends of the constricted remnants of polar spindle microtubules and re-establish a prominent presence juxtaposed to the centrosome. In contrast, there is little evidence of movement of late endosomes and lysosomes with migrating centrosomes in prophase, and these compartments are excluded from the mitotic spindle at metaphase. However, by the end of telophase, the subcellular distribution of a portion of late endosomes and lysosomes share overlapping distributions with that of early endosomes. We conclude a portion of endosomal compartments and Golgi-derived membranes undergo ordered partitioning based on the centrosome and mitotic spindle.

Animal models of human disease: experimental autoimmune gastritis--a model for autoimmune gastritis and pernicious anemia.

Human autoimmune gastritis is an organ-specific autoimmune disease of the stomach. It is characterized by the development of disease-specific autoantibodies and a pathology that specifically targets specialized cells within the gastric environment. The autoantigens associated with this disease have been defined as the gastric H+/K+ ATPase and intrinsic factor. The development of experimental disease models has been pivotal in our contemporary understanding of autoimmunity. Here we review mouse models of autoimmune gastritis and their relevance to human autoimmune gastritis associated with pernicious anemia. We appraise some historical as well as recent studies of experimental autoimmune gastritis (EAG), highlighting key findings that have formed the basis of our current understanding of the etiology and mechanism(s) associated with autoimmune gastritis. A precise understanding of the pathogenesis of autoimmune gastritis will permit the design of innovative and rational therapeutic strategies to prevent, arrest, ameliorate or reverse the disease.