IgG2 class red cell antibodies and autoimmune haemolysis

Haematologia
R J SokolD J Booker

Abstract

To examine the role of IgG2 red cell autoantibodies in autoimmune haemolysis. Study of immunohaematology case records. Six patients had only IgG2 autoantibodies detected by direct antiglobulin testing and in red cell eluates; two individuals, whose red cells were also coated with complement, suffered from autoimmune haemolytic anaemia. IgG2 antibodies are found alone in <1% of patients with warm autoantibodies and even more rarely cause red cell destruction. Several factors are important for inducing haemolysis. They include allele differences in the FCRIIA genes encoding for the FcyRII receptors--an allele with high affinity for IgG2 is needed for haemolysis. Topography of red cell antigens may also be significant; IgG2 is a relatively inflexible molecule and access of effector cell Fc receptors to the recognition sites on the IgG2 might be impossible unless the antigens are on, or proud to, the red cell surface. On rare occasions, IgG2 activates complement (as in our patients with active haemolysis); the synergistic effect between red cell bound immunoglobulins and C3 in causing haemolysis is well recognised.

Related Concepts

Related Feeds

Antibody Specificity

Antibodies produced by B cells are highly specific for antigen as a result of random gene recombination and somatic hypermutation and affinity maturation. As the main effector of the humoral immune system, antibodies can neutralize foreign cells. Find the latest research on antibody specificity here.

Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient number of oxygen-carrying red blood cells in the circulation. Discover the latest research on AIHA here.

Autoimmune Diseases

Autoimmune diseases occur as a result of an attack by the immune system on the body’s own tissues resulting in damage and dysfunction. There are different types of autoimmune diseases, in which there is a complex and unknown interaction between genetics and the environment. Discover the latest research on autoimmune diseases here.

Related Papers

Proceedings of the European Dialysis and Transplant Association
A Blumberg, H R Marti
Scandinavian Journal of Haematology
C Dudok de Wit, C van Gastel
The Journal of the Association of Physicians of India
K C Das, K S Chugh
© 2021 Meta ULC. All rights reserved