ABSTRACT
HLA antigens were used as markers to establish the presence of chimerism (i.e. simultaneous presence of two lymphocyte populations from recipient as well as donor) in a patient with chronic granulomatous disease treated with one haplotype matched stem cell transplant. Neutrophil engraftment occurred on Day 6 post peripheral blood stem cell transplant (PBSCT). Platelet counts were maintained above 20x10[9]/L. Six months after the allogenic PBSCT, lymphocyte population was chimeric and cells of both donor (father) and host HLA type were present. The patient revealed a shift in his HLA antigen profile and there was evidence of donor cell engraftment. The HLA phenotype A26,CwXX,B8,DRB1*03//A32,Cw4,B35,DRB1*16// represented his true phenotype whereas A11,Cw7,B62,DRB1*14 represented donor (father) origin.. HLA system as a genetic marker is a useful additional approach to determine engraftment following an allogenic haplo-identical stem cell transplantation.