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 10⁹/l, mean ± SD pretreatment, to a peak of 8300 ± 3910 x 10⁹/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.