Increased number of peripheral blood CD34+ cells in lithium-treated patients.

Eight adult patients with bipolar disorder were prospectively examined to find whether lithium carbonate increased their peripheral blood CD34+ haemopoietic stem cells. Following lithium therapy for 3-4 weeks their neutrophil counts increased by a mean of 88% (from 4625 +/- 1350 x 10(9)/l, mean +/- SD pretreatment, to a peak of 8300 +/- 3910 x 10(9)/l). Concommitantly, there was a significant increment in their CD34+ cells (from 0.11 +/- 0.01% to a peak of 0.18 +/- 0.08%). There was a significant correlation between the rise in neutrophil count and that of the CD34+ cells (r = 0.795, P = 0.019). Lithium therapy may be used to mobilize peripheral blood CD34+ cells for marrow transplantation.