Erratum in Bang et al. Unique processing pathways within recipient antigen-presenting cells determine IgG immunity against donor platelet MCH antigens. Blood. 2000;95:1735-1742.

In the article by Bang et al entitled “Unique processing pathways within recipient antigen-presenting cells determine IgG immunity against donor platelet MCH antigens,” which appeared in the March 1, 2000, issue of Blood (95:1735-1742), the references for the second paragraph should read as follows: Two recipient T-cell recognition mechanisms have been shown to initiate alloimmunity. The direct pathway occurs when recipient T-helper cells directly interact with MHC class II molecules on donor APC, whereas the indirect pathway is analogous to the normal immune response.^15–18Indirect recognition occurs when allogeneic non-APC are administered to a recipient and involves the processing and presentation of allelic donor antigens (eg, MHC class I molecules) by recipient APC to recipient T-helper cells. The indirect pathway of allorecognition has been implicated in rejection responses in various transplantation models of cardiac,¹⁷ kidney,¹⁸ and skin¹⁹²⁰ grafts. Within the context of indirect allorecognition, interactions between donor antigen and self-APC are critical to T-cell activation and subsequent antibody formation.²¹²² In 1995, 2 laboratories using different animal models (murine versus rat) of platelet immunity suggested that allogeneic platelets stimulated IgG antidonor immunity via indirect recognition.²³²⁴ We subsequently demonstrated that the indirect alloimmunity against platelets was dependent on the activation of inducible nitric oxide synthase (iNOS) within recipient macrophages.²⁵