Correlation between serum lactate dehydrogenase and stem cell mobilization

After observing a correlation between elevated serum lactate dehydrogenase (LDH) levels and good stem cell collections, retrospective data from 540 donors undergoing 650 stem cell apheresis procedures (87% autologous, 13% allogeneic) were studied to determine the correlation between preapheresis LDH levels and the absolute peripheral blood CD34+ cell count (PBCD34). PBCD34 (1-1611/μ median 40) correlated modestly with leukocytes (0.5-118.2 × 10⁹/l; median 30.2) (r = 0.16; P = 0.00005) and poorly with platelets (16-660 × 10⁹/l; median 131) (r = 0.02; P = 0.69). The correlation between LDH (64-1664 IU/l; median 310) and PBCD34 was very strong (r = 0.54; P = 10^-48). In multivariate regression analysis, serum LDH was the only factor correlating significantly with PBCD34. The correlation between serum LDH and PBCD34 was strong on the first day of collection (n = 517; r = 0.53; P < 10^-37), weakened on the second day (n = 74; r = 0.37; P = 0.0009) and disappeared beyond day 2 (n = 59; r = 0.09; P < 0.49). PBCD34 was significantly higher (median 53 versus median 11; P < 0.00001) when LDH was elevated (n = 511) compared to when LDH was normal (n = 139). The relationship between serum LDH and PBCD34 was strong for autologous (r = 0.54) as well as for allogeneic (r = 0.41) collections. Our data suggest that it is reasonable to assume good stem cell mobilization and start apheresis if the LDH is elevated.