Genetic control of B-lymphocyte numbers in man

The pathogenesis of Graves' disease

The abnormally increased thyroid activity that is characteristic of Graves' disease is caused by immunoglobulins which specifically interact with the thyroid cell and stimulate it. Increases and decreases in thyroid activity in Graves' disease can be clearly related to rise and fall of these immunoglobulin-mediated activities. The level of immunoglobulin stimulatory activity can be used for prediction of the likelihood of neonatal Graves' disease and of recurrence of disease after cessation of treatment with antithyroid drugs. Investigation of patients with Graves' disease and their families has led to identification of particular human leukocyte antigens and genetically linked markers on immunoglobulins which both appear to incur increased susceptibility to certain autoimmune diseases. Differences in immune function, when compared with control populations, have been found in patients with these genetically linked markers. Protection against autoimmune disease is maintained by purposeful inhibition of any self-directed activity within each function of the immune system and by the controlling interaction of other immune functions. No single deficiency of immune function can be selected as giving the major risk of autoimmune disease, but rather a sum of relative defects resulting in an increased risk. In some patients with Graves' disease the self-protection mechanisms regain sufficient control of the immune functions to reduce the activity of the autoimmune disease, and the patient may achieve clinical remission. Often, however, there is evidence that abnormal immune activity directed against thyroid tissue has persisted with liability to recurrence of the Graves' disease.

Association between HLA-A1,B8 in children with extrinsic asthma and IgA deficiency

The tissue types, immunoglobulin levels, and the presence of circulating autoantibodies were investigated in 57 children. Fifteen of these children suffered from bronchial asthma and, in addition, had no or very little IgA in their serum and saliva (Group 1 patients). Another fifteen children with asthma but normal immunoglobulin levels in serum and saliva (Group 2 patients), seven patients with selective IgA deficiency but without allergic diseases (Group 3 patients), and twenty healthy children served as controls. Sixty per cent of the Group 1 patients had the phenotype HLA-A1,B8, whereas this tissue type was found only in 27, 14 and 15 per cent, respectively, of the Group 2 and Group 3 patients and the healthy children. Furthermore, high IgM- and IgE levels were observed in most Group 1 patients, and in five of these patients (33 per cent) autoantibodies were present in the serum. In addition, eczema and glomerulonephritis occurred rather frequently in this group of patients. Conversely, normal immunoglobulin levels and absence of circulating autoantibodies were found in the remaining three groups of children. The results emphasize the heterogeneity of the IgA deficiency syndrome, and the question is raised as to whether the tissue type HLA-A1,B8 observed in most Group 1 patients reflects the abnormal immune reactivity of these patients.