Neutrophils are responsible for the reappearance of chemiluminescence after allogeneic bone marrow transplantation. 
The nature of the cells generating the early chemiluminescence (CL) response after allogeneic bone marrow transplantation (BMT) was studied in six patients; five transplanted for acute leukaemia and one for multiple myeloma.  Peripheral blood was fractionated into 14 fractions with Percoll narrow range density gradient centrifugation on days +14, +17, +20, and +27 after BMT.  The leucocytes were recovered in fractions 7-14 which were analysed for cell morphology and CL response.  On days +14 to +20 after BMT the CL response was detected in the fractions containing morphologically mature neutrophils.  In one of these fractions the CL response per phagocyte was significantly higher than in the neighbouring fractions although morphologically the cells were similar.  The results suggest that the cells responsible for the early CL after BMT are neutrophils and possibly an active subpopulation of neutrophils produced by the marrow graft.