CDR 1-3 peptide-reactive T-cells (ELISPOT) secreting IL-2 (A) and IL-4 (B). PBMC of patient no. 4 were stimulated in vitro with autologous (▨) or allogeneic (□) peptides 15-20 aa long corresponding to the CDR1, 2, and 3 regions of the heavy chain and by F(ab′)₂ fragments of the autologous monoclonal IgG (▨). The autologous Id-induced response was also assayed in presence of mouse MoAbs against human MHC class II (▧) or MHC class I () (1 μg/mL) molecules. Standard error of means are shown on top of each column.