FL and IL-15 plasma levels and NK-cell reconstitution after SCT. (A) Correlation between FL levels on day 7 and numbers of circulating NK cells on day 14 in individual patients. (B) Levels of IL-15 in PB of patients on days 7, 14, and 30 days after SCT, as determined by ELISA. The mean value (bars) and SEM is indicated. (C) Correlation between IL-15 levels on day 7 and numbers of circulating NK cells on day 14 in individual patients. Solid line shows the correlation.