A high level may mean igd multiple myeloma, which is much less common than iga or igg multiple myeloma. The measurement is useful for diagnosis of igg subclass deficiency, to aid the diagnosis of specific antibody deficiency, as a supporting test for. They are each named with an ig prefix that stands for immunoglobulin and differ in their biological properties, functional locations, and ability to deal with different antigens, as depicted below. Inmunoglobulina a subclases 1 y 2 laclicsa laboratorios. The clinical utility of measuring igg subclass immunoglobulins. Monoclonal gammopathies of all types may lead to a spike in the gamma globulin zone seen on serum protein electrophoresis. Five classes of immunoglobulins igg, iga, igm, igd, and ige have been distinguished on the basis of noncrossreacting antigenic determinants in regions of. Patient information sheet igg subclass deficiencies. Enhanced igg4 production by follicular helper 2 t cells.
Previous studies have shown that its sensitivity is about 70% and its specificity exceeds 90% at a cutoff of 140. There are four igg subclasses igg1, 2, 3, and 4 in humans, named in order of their abundance in serum igg1 being the most abundant. In placental mammals, there are five antibody isotypes known as iga, igd, ige, igg and igm. Patient information sheet igg subclass deficiencies igg subclass deficiencies summary immunoglobulin g igg is the main type of immunoglobulin also called antibody in the blood, which helps the body to fight bacterial infections and prevent viral infections. Immunoglobulin g antibody responses to bacterial capsular polysaccharide antigens can be almost completely restricted to igg2 9, 11, and igg2 deficiency may result in the virtual absence of igg anticarbohydrate antibodies, although these responses can also be compensated for by enhanced levels of other igg subclasses, in particularly by elevated igg1 and igg3 levels. The major serological finding is an elevation of the serum igg 4 concentration. Enhanced igg4 production by follicular helper 2 t cells and the involvement of follicular helper 1 t cells in the pathogenesis of igg4related disease. Subclasses igg1, igg2, igg3, and igg4 are differentiated on the basis of the size of the hinge region, position of interchain disulfide bonds, and molecular weight.
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