Intravascular survival of red cells coated with a mutated human anti-D antibody engineered to lack destructive activity.

摘要: Alloimmune feto-maternal destruction of blood cells is thought to be mediated by binding alloantibodies Fc receptors on effector cells. Blocking the antigen using inert antibodies might prolong cell survival. We have performed a “proof principle” study in volunteers measure intravascular survival autologous red coated with human recombinant IgG antibody containing novel constant region, G1Δnab, devoid vitro cytotoxic activity. RhD-positive (RBCs), labeled chromium-51 or technetium-99m, were separately equal levels wild-type IgG1 G1Δnab anti-D (Fog-1). After re-injection, there was complete, irreversible clearance IgG1-coated RBCs 200 minutes, concomitant appearance radiolabel plasma. Gamma camera imaging revealed accumulation spleen and, at higher coating levels, liver. In contrast, G1Δnab-coated slower, incomplete, and transient, whole counts falling 7% 38% injected dose about minutes before increasing 12% 67% thereafter. There no plasma hepatic accumulation. These findings suggest that not hemolysed but temporarily sequestered our approach merits investigation larger studies.