Altered Ca(2+)-homeostasis in single T-lymphocytes of depressed patients

After stimulation of T-lymphocytes from healthy volunteers with the mitogen phytohemagglutinin (PHA) 40% of the cells exhibit an oscillatory increase in intracellular calcium concentration ([Ca2+]i). During depression the number of cells responding to PHA is reduced to 20%. These cells show a marked decrease in [Ca2+]i-reaction to stimulation and flattened oscillations. This reduction of mitogen-induced Ca2+ signals in T-cells of depressed patients appears to be a reliable state marker in depressive illness and is reversed upon successful treatment with interpersonal psychotherapy (IPT).