IgG heavy chain allotype (Gm), a genetic marker for human chromosome 14q32, and haematopoietic malignancies.

IgG heavy chain constant region allotypes, Gm, the genetic marker of human chromosome 14q32, are markers for susceptibility to certain diseases. We tested Gm allotypes in 365 patients with various types of haematological malignancies, 528 healthy controls and 35 healthy HTLV carriers. The frequency of specific Gm phenotypes was significantly increased in patients with adult onset null-ALL, AML, AMoL and CML in blastic crisis. Among these diseases, the frequency of Gm1,2,21 haplotype was significantly increased with adult onset null-ALL, AML and AMoL.