Development of a C1q-ABO-ELISA to measure C1q binding by human anti-A alloantibodies
Related Experiment Videos
E von Allmen1, R Rieben, U E Nydegger
1Regional Red Cross Blood Transfusion Center, University of Berne, Switzerland.
Little is known about the correlation between the amount of anti-A antibodies and the respective complement activating capacity. We have therefore developed a new ELISA procedure for the study of complement activation by anti-A antibodies bound to immobilized blood group substance A through the classical pathway. C1q binding capacity of anti-A was then compared to both anti-A immunoglobulin (Ig) isotype serum concentrations and to the hemolysing capacity of O type sera. We have demonstrated that sera with low anti-A IgG and IgM levels produced low C1q binding activity and no hemolysis of human A1 red blood cells (RBC), whereas higher anti-A Ig levels resulted in either weak or strong C1q binding capacity as well as weak or strong RBC hemolysis. A correlation of rs = 0.755 was observed between C1q-ABO-ELISA and hemolysin assay results, although only 58% of the O type sera containing C1q binding anti-A lysed A1 type RBC under the used conditions. The C1q-ABO-ELISA is therefore a more sensitive assay for detecting 'dangerous' O type donors for blood transfusion to A type recipients than screening tests for hemolytic anti-A or determination of anti-A Ig levels alone.
Little is known about the correlation between the amount of anti-A antibodies and the respective complement activating capacity. We have therefore developed a new ELISA procedure for the study of complement activation by anti-A antibodies bound to immobilized blood group substance A through the classical pathway. C1q binding capacity of anti-A was then compared to both anti-A immunoglobulin (Ig) isotype serum concentrations and to the hemolysing capacity of O type sera. We have demonstrated that sera with low anti-A IgG and IgM levels produced low C1q binding activity and no hemolysis of human A1 red blood cells (RBC), whereas higher anti-A Ig levels resulted in either weak or strong C1q binding capacity as well as weak or strong RBC hemolysis. A correlation of rs = 0.755 was observed between C1q-ABO-ELISA and hemolysin assay results, although only 58% of the O type sera containing C1q binding anti-A lysed A1 type RBC under the used conditions. The C1q-ABO-ELISA is therefore a more sensitive assay for detecting 'dangerous' O type donors for blood transfusion to A type recipients than screening tests for hemolytic anti-A or determination of anti-A Ig levels alone.