PERNICIOUS ANAEMIA, MYXOEDEMA, AND HYPOGAMMAGLOBULINAEMIA--A FAMILY STUDY

Immunological aspects of gastritis and pernicious anaemia

Pernicious anaemia (PA) and chronic atrophic gastritis (CAG) aggregate in families, occur more often in women, and are associated with various heritable traits such as fair skin and blue eyes. They are linked to certain HLA types. Linkages are relatively weak for A and B antigens, but somewhat stronger in the case of DR antigens. There are strong associations between PA and other organ-specific autoimmune diseases, particularly those affecting the thyroid. Discordance for PA in monozygotic twins has been reported, and it may well be that expression of the disease requires, in a genetically susceptible individual, initial injury to the gastric mucosa by some environmental agent such as a virus or some physical irritant, with perpetuation of injury then depending upon autoimmune mechanisms. Numbers of T cells are substantially increased in the gastric mucosa of patients with PA, but the ratio of T suppressor to T helper cells is normal. There is a relatively greater increase in numbers of cells not of T lineage, presumably B-cells. Gastric autoantibodies, both to different components of the parietal cell and to two sites on the IF molecule, are present in a majority of patients with PA. There is evidence that these autoantibodies, especially PCA, may be cytotoxic to parietal cells, and may also inhibit their maturation and proliferation. Antibodies to chief cells have not been described, and the parallel disappearance of these cells in atrophic gastritis is unexplained. The peripheral blood lymphocytes of some patients with autoimmune gastritis transform, or produce lymphokines, when exposed to gastric antigens, and patients with PA have been shown to have delayed type cutaneous hypersensitivity to gastric antigens. The relevance of these observations to the pathogenesis of their gastric mucosal lesion is unclear. There is a growing body of evidence to support the operation of humoral immune mechanisms in autoimmune gastritis, but this clearly does not preclude the coexistent involvement of cellular mechanisms. For example, impaired suppressor T cell function has been strongly implicated in certain other autoimmune disorders, but has received scant attention in PA. By generally accepted criteria, PA is an excellent example of an organ-specific autoimmune disease. As yet, there is no acceptable single unifying hypothesis which will account for all of the phenomena which have been described in the disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Gastric mucosal lymphocyte subpopulations in pernicious anemia and in normal stomach

Gastric mucosal lymphocyte subpopulations were determined by an indirect immunoperoxidase method applied to cryostat sections of gastric biopsies obtained from 12 patients with pernicious anemia (PA group) and from 12 patients whose stomachs were endoscopically and histologically normal (comparison group). T-Cell populations were identified by means of monoclonal antibodies directed against all T cells (UCHT1), T suppressor cells (anti-Leu-2a), and T helper cells (anti-Leu-3a). Non-T cell numbers were estimated indirectly. Concentrations of all T cells, T suppressor cells, T helper cells, and non-T cells were all significantly greater in the PA than in the comparison group. The most striking difference was in non-T cell numbers, which showed an approximately sixfold increase in the PA group. Mean T/non-T cell ratios in PA and comparison groups were significantly different (0.49 and 1.50, respectively). T suppressor/T helper cell ratios were similar in the two groups. There were highly significant positive correlations between numbers of non-T and T helper cells, and non-T and T suppressor cells in PA, but not in comparison groups. If, as seems likely, the majority of non-T cells in these gastritic stomachs were in fact cells of B lineage, these results would be consistent with the hypothesis that gastric mucosal damage in pernicious anemia is mediated primarily by a humoral mechanism, which may involve cytotoxic autoantibodies.

Idiopathic late-onset immunoglobulin deficiency. Clinical observations in 50 patients

Fifty patients with late-onset idiopathic immunoglobulin deficiency were studied and the frequency of various clinical associations and complications was observed. Men and women were equally affected, although the age at onset in men peaked in the third decade whereas it was more uniformly distributed in women. Sinobronchopulmonary infections were common and were caused by Haemophilus influenzae. Diplococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus: bronchiectasis occurred in 28 per cent. Thirty patients (60 per cent) had diarrhea, which was often associated with steatorrhea, giardiasis, achlorhydria, abnormal Schilling tests and morphologic abnormalities on small bowel biopsy specimens, including nodular lymphoid hyperplasia; three patients had pernicious anemia. In the 20 patients without diarrhea these abnormalities were not observed except for giardiasis in one patient and achlorhydria in two patients. Cholelithiasis occurred in both groups in about a third of the patients tested. A high degree of susceptibility to neoplasia was noted. Thyroid abnormalities, including primary hypothyroidism and Graves' disease, were observed in six patients. Additional occasional findings were vitiligo, keratoconjunctivitis sicca and arthritis. Splenomegaly occurred in 14 (28 per cent) patients. The percentage of B lymphocytes in the blood was determined in 10 patients; it was normal or slightly decreased in eight patients and low in two patients.

The role of vitamin B 12 and its transport globulins in the production of antibodies

Immunological functions were repeatedly tested in a patient with hereditary deficiency of transcobalamin II (TC II): he was unable to synthesize immunoglobulins and specific antibodies, but was able to do so normally after injection of high doses of vitamin B 12 (1000 mug per week). Lymphocytes (B and T) were present in normal numbers prior to therapy, thus indicating normal differentiation of stem cells. In contrast, clonal expansion, necessary for immunoglobulin production, was possible only after vitamin B 12 administration. These observations, as well as the well known disturbances in haemopoiesis, indicate that vitamin B 12 is indispensable to rapidly replicating tissues, and that a severe deficiency of this vitamin in the cells can result from the absence of TC II.

An analysis of gastric parietal cell antibodies and thyroid cell antibodies in patients with pernicious anaemia and thyroid disorders

An analysis of immunoglobulins responsible for gastric parietal cell antibodies and for antibodies to thyroid cell has been performed in twenty-four patients with pernicious anaemia and thirteen patients with thyroid disorders. Immunofluorescent technique with conjugated antisera specific to each of the three main immunoglobulins and to β_1c-globulin was used.

IgG-globulin was responsible for gastric parietal cell antibodies in all patients investigated; IgA was found in gastric parietal cell antibodies of four thyroid patients but in none of the pernicious anaemia patients; IgM antibodies were found in two pernicious anaemia patients and in six thyroid patients. With regard to thyroid cell antibodies, IgG and IgA were both found responsible for antibody activity in thirteen cases and IgM in ten cases. In six patients, antibodies to thyroid cell were not β_1c-fixing, whereas all sera with gastric parietal cell antibodies fixed β_1c-globulin.

An obvious relationship could not be found either between the titres of the different types of antibodies within the same category of antibody, or between the titres of gastric parietal cell antibodies and thyroid cell antibodies in the same individual. An occasional relationship was found between the titres of IgG-parietal cell or thyroid cell antibodies and the capacity to bind β_1c-globulin.

These results demonstrate that each of the three main immunoglobulins may contribute to gastric parietal cell antibodies and to antibodies to thyroid cell.

Incidence and pathogenesis of megaloblastic erythropoiesis in multiple myeloma

Intermediate megaloblastic changes occurred in six (19%) of 32 patients with multiple myeloma and trivial megaloblastic changes in a further ten (31%). Folate deficiency was the predominant cause of these changes and in at least two patients was sufficiently severe to contribute to anaemia. Folate deficiency appeared to be due to exćess folate utilization by the tumour and was related to the amount of paraprotein produced daily. Five of the 32 patients had subnormal serum B(12) levels. Reduction in the serum B(12) level was related to the reduction in the normal circulating immunoglobulins and occurred despite normal B(12) absorption. Possible explanations for this finding are discussed.