The pattern of serotonin transporter (SERT) clustering in the plasma membrane of peripheral lymphocytes can differentiate between two categories of depressed patients who show different outcomes to antidepressant treatment as determined by a reduction in HAMD score.
More recently, a study investigated whether SERT clustering in lymphocytes could distinguish antidepressant responders on the basis of their reduction in anhedonia as measured by the Self-Rated Anhedonia Scale (SAAS). Blood samples were collected from 38 untreated depressed individuals at enrollment and after 8 weeks of pharmacological treatment. Quantitative immunocytochemistry was used to measure SERT clusters in blood lymphocytes.
The size distribution of SERT clusters in the plasma membrane of lymphocytes identified two subpopulations of depressed patients, D-I and D-II. Before treatment, D-I and D-II patients had similar anhedonia scores. After 9 weeks of antidepressant treatment, however, D-II patients showed a good response in anhedonia symptoms, whereas D-I patients showed no improvement.
Thus, SERT clustering in peripheral lymphocytes can be used to identify patients who are likely to respond to antidepressant treatment as determined by anhedonia scores.