Matrix illustrating the genetic composition of platelet autoantibodies.
The horizontal axis represents the unique γ heavy chains (H01 through H98) and the vertical axis represents the unique κ and λ light chains (L01 through L124) used by antibodies cloned and sequenced from the patients with ITP and the control patient. The letter at the intersection of a heavy-chain–light-chain pair indicates the composition of a platelet-reactive (red box) or platelet-unreactive (clear box) antibody isolated from ITP patient A or B or control patient C. For positive clones, H and L designations are indicated. The order of heavy chains (left to right) and light chains (top to bottom) was determined by multiple alignments based on amino acid similarity and then grouped by putative Ig variable-region germline gene and germline gene family. Note the marked predominant use of the VH3-30 germline gene to encode platelet-binding antibodies in both patient repertoires (red-framed area).
