Identification of additional stem cell-transplanted patients with high titers of antibodies specific for ILT5 variants 1 and 2. (A) Control cells (Bw) and cells expressing ILT5 variant 1 (Bw-ILT5v1) or 2 (Bw-ILT5v2) and control cells (Bw) were probed with sera reacting with ILT5 variant 1 (G486/2, G260/3, and G419/3) or ILT5 variant 2 (G21/1). (B) Serial dilutions of indicated ILT5 variant 1-reactive sera were probed with control Bw cells (open histograms) or Bw cells expressing ILT5 variant 1 (gray histograms).