Antigen Society #12 Report (Bw54, Bw55, Bw56 and Bw42)

The antigen Bw54 was officially designated as a split of Bw22 at the Seventh International Histocompatibility Workshop. This antigen was primarily defined in the Japanese population by several laboratories independently, and designated as J-1 by Juji et al. (l), as SAP-1 by Nakayama et al. (2) and as SN-1 by Saito et al. (3). Splits of Bw22 in Caucasians were recognized mainly by the association with either Cw1 or Cw3. The antigens Bw55 and Bw56, splits of Bw22 in Caucasians that were primarily called BT22 (4) and Te22 (5), Da30 (6) and AA-AJ (7), were confirmed at the Eighth International Workshop in 1980. The antigen Bw55 is associated with Cw3 in Caucasians and with Cw1 in Japanese. The antigen Bw56 is associated with Cw1 in Caucasians and with Cw4 in Japanese. A new Bw22 antigen as a split of Bw56 was primarily described by Tokunaga in 1983 at the Eighth Japanese Histocompatibility Workshop, but was not clearly defined. The antigen Bw42, previously called MWA (8), was defined at the Fifth International Workshop in 1972. This antigen was primarily found in Negroid populations.