Figure 1
Inhibition of complement deposition and destruction of RBC by C1-inhibitor in AIHA. (A) C1-INH was administered at a dose of 6000 U before transfusion of 3 RBC concentrates. After transfusion, another 4000 U of C1-INH was administered, followed by 2 doses of 2000 U and 1000 U every 12 hours (as indicated by arrows). The inset at the top represents the DAT for complement C3d during and after treatment with C1-INH. The DAT for C3d is indicated as very strong (3+), strong (2+), moderate (1+), weak (0.5+), or negative (0). V/R indicates vincristine/rituximab; ##, methylprednisolone; and gray shaded areas, transfusion of 3 RBC concentrates. (B) Hemolysis of bromelain-treated human O-typed erythrocytes (2% hematocrit, 90 minutes of incubation at 37°C) after incubation with either patient serum (n = 5) or healthy control serum (n = 4) in the presence of 25% normal human AB serum. Percentage of lysis was compared with a 100% lysis control that was determined by incubating the erythrocytes in distilled water. Incubation with only AB serum served as a negative control. Results are shown as means and SEM (error bars). (C) Hemolysis of bromelain-treated human O-typed erythrocytes (2% hematocrit) after incubation with patient serum was inhibited by C1-INH (20 U/mL) and mAb anti-C5 (100 μg/mL). Representative graph of one patient serum sample is shown. (D) Twenty U/mL of C1-INH significantly (P < .05) inhibited the hemolysis induced by 16% patient serum. Means and SEM (error bars) of 5 selected patients are shown. (E) Representative graph of C3 deposition on human erythrocytes after incubation with either patient serum or healthy control serum in the presence of 25% normal human AB serum. Data are expressed as means and SEM (error bars) of triplicate measurements. MFI indicates mean fluorescence intensity. (F) C1-inhibitor dose dependently inhibited C3 deposition after incubation of human O-typed erythrocytes (1% hematocrit) with 0.1% patient serum (serum 1). Data are expressed as means and SEM (error bars) of triplicate measurements. (G) Twenty U/mL of C1-INH inhibited C3 deposition induced by 0.1% patient serum. Incubation in the presence of 20mM EDTA served as a control. Results are depicted as a percentage of control, which was not inhibited and was set to 100%. Means and SEM (error bars) of 5 selected patients are shown.

Inhibition of complement deposition and destruction of RBC by C1-inhibitor in AIHA. (A) C1-INH was administered at a dose of 6000 U before transfusion of 3 RBC concentrates. After transfusion, another 4000 U of C1-INH was administered, followed by 2 doses of 2000 U and 1000 U every 12 hours (as indicated by arrows). The inset at the top represents the DAT for complement C3d during and after treatment with C1-INH. The DAT for C3d is indicated as very strong (3+), strong (2+), moderate (1+), weak (0.5+), or negative (0). V/R indicates vincristine/rituximab; ##, methylprednisolone; and gray shaded areas, transfusion of 3 RBC concentrates. (B) Hemolysis of bromelain-treated human O-typed erythrocytes (2% hematocrit, 90 minutes of incubation at 37°C) after incubation with either patient serum (n = 5) or healthy control serum (n = 4) in the presence of 25% normal human AB serum. Percentage of lysis was compared with a 100% lysis control that was determined by incubating the erythrocytes in distilled water. Incubation with only AB serum served as a negative control. Results are shown as means and SEM (error bars). (C) Hemolysis of bromelain-treated human O-typed erythrocytes (2% hematocrit) after incubation with patient serum was inhibited by C1-INH (20 U/mL) and mAb anti-C5 (100 μg/mL). Representative graph of one patient serum sample is shown. (D) Twenty U/mL of C1-INH significantly (P < .05) inhibited the hemolysis induced by 16% patient serum. Means and SEM (error bars) of 5 selected patients are shown. (E) Representative graph of C3 deposition on human erythrocytes after incubation with either patient serum or healthy control serum in the presence of 25% normal human AB serum. Data are expressed as means and SEM (error bars) of triplicate measurements. MFI indicates mean fluorescence intensity. (F) C1-inhibitor dose dependently inhibited C3 deposition after incubation of human O-typed erythrocytes (1% hematocrit) with 0.1% patient serum (serum 1). Data are expressed as means and SEM (error bars) of triplicate measurements. (G) Twenty U/mL of C1-INH inhibited C3 deposition induced by 0.1% patient serum. Incubation in the presence of 20mM EDTA served as a control. Results are depicted as a percentage of control, which was not inhibited and was set to 100%. Means and SEM (error bars) of 5 selected patients are shown.

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