Acute psychological stress increases peripheral blood CD3⁺CD56⁺ natural killer T cells in healthy men: possible implications for the development and treatment of allergic and autoimmune disorders

Figures & data

Table 1. Influence of psychological stress on cardiovascular parameters in healthy male volunteers (N = 31).

	Pre		Stress			Post
	Mean	SEM	Mean	SEM	p Value	Mean	SEM	p Value
HR (beats/min)	69.2	1.5	76.0	2.3	***	68.9	1.7
BP systolic (mmHg)	146.3	3.9	176.9	4.2	***	155.7	4.0	***
BP diastolic (mmHg)	91.9	3.1	107.2	3.0	***	96.0	3.2	***

HR = heart rate; BP = blood pressure.

Asterisks indicate significant (***p < 0.001) differences compared to baseline values as determined by Wilcoxon’s rank sum test.

Figure 1. Acute psychological stress influences T cells expressing Th1 or Th2 phenotypes. The stress-induced redistribution of CRTH2⁺ and CD226⁺ T cell subsets was analyzed in healthy male subjects (N = 31) after resting phase 1 (pre), immediately after completion of the stress test (stress), and following the final resting phase (post) using four-color flow cytometry. Analysis was performed using a combination of a morphological lymphocyte gate and gates for CD4⁺ T cells (CD3⁺CD4⁺) and CD8⁺ T cells (CD3⁺CD8⁺), respectively. Asterisks indicate significant (**p < 0.01, ***p < 0.001) differences compared to baseline values as determined by Wilcoxon’s rank sum test (A). Dot plots representative for CCR7 versus CD226 staining of CD4⁺ and CD8⁺ T cells are shown for one test subject (B).

Figure 2. Acute psychological stress causes a short-lasting increase in circulating γδ T cells. Percentages of circulating T cells expressing the γδ T cell receptor (TCR) were determined in healthy male subjects (N = 31) after resting phase 1 (pre), immediately after completion of the stress test (stress), and following the final resting phase (post) using four-color flow cytometry. Analysis was performed using a combination of a morphological lymphocyte gate and gates for CD4⁺ T cells (CD3⁺CD4⁺) and CD8⁺ T cells (CD3⁺CD8⁺). Percentages of CD4 and CD8 double-negative T cells expressing the γδ TCR were then measured using an appropriate isotype control. Asterisks indicate significant (**p < 0.01) differences compared to baseline values as determined by Wilcoxon’s rank sum test.

Figure 3. Peripheral numbers of conventional CD56⁺ NKT cells, but not invariant chain NKT (iNKT) cells, increase after acute psychological stress. Percentages of circulating NK cells, CD56⁺ NKT cells (A) and iNKT cells (B) were determined in healthy male subjects (N = 31) after resting phase 1 (pre), immediately after completion of the stress test (stress) and following the final resting phase (post) using four-color flow cytometry. Analysis was performed using a combination of a morphological lymphocyte gate and gates for NK cells (CD3⁻CD56⁺), conventional NKT cells (CD3⁺CD8⁺CD56⁺ or CD3⁺CD4⁺CD56⁺) and iNKT (CD3⁺6B11⁺ or CD3+CD1d-tetramer⁺). Percentages of the respective lymphocyte subsets were measured using appropriate isotype controls. Asterisks indicate significant (*p < 0.05, ***p < 0.001) differences compared to baseline values as determined by Wilcoxon’s rank sum test.