[[IgM]] antibodies are capable of fixing complement on the surface of red blood cells leading to the assembly of a membrane attack complex. This complex causes the direct lysis of erythrocytes and '''intravascular haemolysis'''. Since IgM antibodies have a high avidity, they are also able to co-ordinate the formation of large numbers of red blood cells into aggregates, a phenomenon known as '''auto-agglutination'''. | [[IgM]] antibodies are capable of fixing complement on the surface of red blood cells leading to the assembly of a membrane attack complex. This complex causes the direct lysis of erythrocytes and '''intravascular haemolysis'''. Since IgM antibodies have a high avidity, they are also able to co-ordinate the formation of large numbers of red blood cells into aggregates, a phenomenon known as '''auto-agglutination'''. |