Lithium and T cell colonies

In humans, therapeutic doses of lithium causes granulocytosis and lymphopenia. In vitro increased numbers of colony forming units (CFU-GM) are observed. The effect of lithium on lymphocyte colonies is unknown. We grew T cell colonies from normal individuals and patients who were on lithium only and found that T cell colony numbers were decreased in patients who were taking lithium. Recent evidence suggests that there is a PRECURSOR common to the granulocytic and lymphocytic cell lines. Since lithium causes increased granulocytic colonies and seems to decrease lymphocyte colonies we propose that lithium may have an effect on the precursor cell resulting in preferentially shifting maturation from the lymphocytic to the granulocytic series.