Primate Monocytes - CD14, CD16 - Ziegler-Heitbrock

Reconstitution and functional analyses of neutrophils and distinct subsets of monocytes after allogeneic stem cell transplantation

Abstract

PURPOSE: The aim of the study was to investigate the recovery of the innate immune system within the first 100 days after allogeneic peripheral blood stem cell transplantation (PBSCT) and to elucidate a potential correlation with such important events as severe infectious complications or graft-versus-host disease (GvHD). METHODS: In 30 consecutive patients who underwent allogeneic PBSCT, absolute numbers of neutrophils and monocytes were determined and different functional analyses performed at different time points (day +30, +60 and +90, respectively). The capacity to phagocyte Escherichia coli (E. coli) as well as the induction of oxidative burst after incubation with different stimuli (Phorbol-12-myristate-13-acetate; PMA, the chemotactic peptide N-formyl-Met-Leu-Phe; f-MLP or opsonized E. coli) were analysed after engraftment. RESULTS: There was a rapid reconstitution concerning the capability of both neutrophils and monocytes to phagocyte E. coli without a significant increase between day +30 and +90. In contrast, a twofold increase of monocyte oxidative burst after incubation with PMA at day +90 was observed (P = 0.017). Furthermore, the ability of neutrophils to induce oxidative burst after ingestion with E. coli was impaired on day +30 with a significant functional reconstitution on day +60 (P = 0.01). The oxidative burst activity following incubation with f-MLP did not show significant changes after stem cell engraftment. Analysis of numeric reconstitution of CD14+CD16+ monocytes demonstrated a potential correlation with a decreased incidence of chronic GvHD. CONCLUSION: The functional recovery of neutrophils and monocytes in the early period after allogeneic PBSCT differs not only concerning phagocytosis and oxidative burst but also with respect to the stimulus and the cell population that was analysed for oxidative burst activity. The subset of CD16+CD14+ monocytes might be a predictor for a reduced risk of chronic GvHD