Early Immune Reactions Following Reduced-Intensity Cord Blood Transplantation.

Background: We have demonstrated the feasibility of reduced-intensity cord blood transplantation (RI-CBT) in adult patients(

Methods: We retrospectively investigated clinical features of immune reactions in 57 adult RI-CBT recipients. The preparative regimen comprised fludarabine, melphalan (n=51) or busulfan (n=6), and 4 Gy TBI. GVHD prophylaxis was cyclosporin. When patients with no evidence of infection or adverse effects of medication exhibited features such as fever >38°C, skin eruption, diarrhea, jaundice, or body weight gain >10% of baselines, these findings were defined as immune reactions. Reactions were classified into the following subtypes: those which developed 6 or more days before engraftment were defined as preengraftment immune reactions (PIR), those within 5 days of engraftment were defined as engraftment syndrome (ES), and the others were defined as postengraftment syndrome, which generally corresponded to acute GVHD.

Results: Forty five patients achieved engraftment, on a median day of day 19. Twelve patients who developed documented infection were excluded from the analysis of PIR, 42 of the remaining 45 patients developed PIR on a median of day 9 (range, 5–13), including 6 patients who had never engrafted. Body weight gain, high-grade fevers, and elevated CRP levels were more frequent in PIR than in ES and GVHD. Jaundice was infrequent in PIR (Table). ES developed in 41 of the evaluable 44 patients. Five patients with ES developed central nervous system complication. Twenty-nine of the evaluable 44 patients developed acute GVHD: grade I (n=1), II (n=7), III (n=15), and IV (n=6). Cumulative incidences of relapse and non-relapse mortality (NRM) at day 180 were 15% and 62%, respectively. Relapse-related mortalities were 11% and 0% in patients with and without PIR, respectively (p=0.17). NRM were 77% and 52%, in patients with and without PIR, respectively (p=0.07). Since development of ES was associated with PIR, they could not be separated from each other in evaluation of their effect on relapse and NRM. Development of GVHD was not a significant prognostic factor for relapse or NRM, when PIR was treated as a time-dependent covariate.

Discussion: Three immune reactions occur after RI-CBT. PIR is a novel finding in RI-CBT. It develops even in patients who have never engrafted. When compared to ES and GVHD, the higher levels of CRP and fever in PIR suggest that the inflammation in PIR is intense. Further studies are required to clarify its pathogenesis and prognostic values in RI-CBT.

Clinical characteristics of immune responses following reduced-intensity cord-blood transplantation