Antibody titres to a rough-mutant strain of Escherichia coli in patients undergoing allogeneic bone-marrow transplantation. Evidence of a protective effect against graft-versus-host disease.

Much clinical and experimental evidence suggests that infection and graft-versus-host disease (GvHD) are commonly associated as complications of bone-marrow transplantation (BMT). A likely basis for this association is the gram-negative faecal flora,the origin of many septicaemias and a source of bacterial endotoxin, which has potent immunostimulatory effects. A rough-mutant strain, Escherichia coli J5, has only core determinants in its endotoxin,and antibodies to E coli J5 protect animals and human beings from the consequences of septic shock. Naturally occurring antibodies to E coli J5 ("anti-endotoxin") were assayed in serum from patients undergoing BMT, healthy controls, and patients with obstructive jaundice. BMT recipients had significantly lower titres than the other two groups. Furthermore, the titre of IgM class anti-J5 antibody was significantly associated with protection from GvHD.