Detection of MHC class II expression on human basophils is dependent on antibody specificity but independent of atopic disposition.

A debate has recently arisen as to whether murine basophils can function as antigen presenting cells in allergic inflammation. However, mouse and human basophils differ considerably, and the expression of MHC class II on human basophils has been investigated as a proxy for their capability of antigen presentation but conflicting results have emerged. In this technical note, we show that an antibody specific for all three MHC class II subtypes (HLA-DR, -DP, and -DQ), leads to a significantly higher amount of MHC class II+ basophils compared to antibodies specific for HLA-DR only. A significant difference was also observed between the HLA-DR specific antibodies, indicating that the choice of antibody is crucial. Furthermore, critical compensation was essential to avoid false HLA-DR+ basophils. Finally, we found that detection of MHC class II on human basophils was independent of atopic disposition.