Cell-surface expression of L-selectin (CD62L) by blood lymphocytes: correlates with affective parameters and severity of panic disorder.

The surface immune phenotype of peripheral blood lymphocytes (PBL) was examined in 30 patients meeting DSM-III-R criteria for panic disorder and in 10 normal controls by immunostaining and cytofluorimetry. Patients with panic disorder and controls showed comparable numbers of PBL and no differences in the percentages of blood T-cells, B-cells, or NK-cells. The PBL in panic disorder patients showed a trend toward enrichment for "naive" CD45RA+ T-lymphocytes (35.0 +/- 7.6 vs. 28.7 +/- 9.8, P = 0.09) and significant enrichment for cells expressing CD62L (L-selectin, 22.9 +/- 5.9 vs. 14.6 +/- 6.3, P = 0.002), a lymphocyte homing receptor that mediates binding to lymph node endothelium. Increased expression of CD62L correlated directly with the global severity of illness, Hamilton Anxiety (HAM-A) and Hamilton Depression (HAM-D) scores. Although in the normal range, plasma cortisol levels were significantly increased in patients with panic disorder (P = 0.003) with respect to controls and correlated with the expression of CD62L by PBL. We conclude that the peripheral blood in panic disorder shows phenotypic changes that may reflect diminished cell activation in vivo.