Redefining 'self': the role of microflora (commensals) mismatch in the development of GvHD after allogeneic stem cell transplantation and some possible remedies.
The discovery of human leukocyte antigen (HLA) molecules and their role in allorecognition has facilitated the initiation of allogeneic stem cell transplantation in human beings. HLA mismatch to a large extent explains the phenomenon of graft rejection and graft versus host disease (GvHD). Incidence of GvHD even in syngeneic transplants suggests a role for extra genetic factors in the causation of GvHD. We hereby propose a hypothesis that the definition of 'self' (in the immunological sense) should be broadened to include both genetically determined molecules (e.g. HLA) and the microbial flora that colonize an individual. This hypothesis explains several observations about GvHD which can not fully be accounted for by the HLA mismatch theory and gives some clues towards circumventing GvHD.
Singh
H P
HP
Department of Medical Oncology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
Gupta
S
S
Raju
G M
GM
Kochupillai
V
V
D000367:Age Factors; D006086:Graft vs Host Disease / Q000276:immunology / Q000382:microbiology*; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D014184:Transplantation, Homologous