Lymphatic pump treatment augments lymphatic flux of lymphocytes in rats.

BACKGROUND Lymphatic pump techniques (LPT) are used by osteopathic practitioners for the treatment of edema and infection; however, the mechanisms by which LPT enhances the lymphatic and immune systems are poorly understood. METHODS AND RESULTS To measure the effect of LPT on the rat, the cisterna chyli (CC) of 10 rats were cannulated and lymph was collected during 4 min of 1) pre-LPT baseline, 2) 4 min LPT, and 3) 10 min post-LPT recovery. LPT increased significantly (p < 0.05) lymph flow from a baseline of 24 ± 5 μl/min to 89 ± 30 μl/min. The baseline CC lymphocyte flux was 0.65 ± 0.21 × 10⁶ lymphocytes/min, and LPT increased CC lymphocyte flux to 6.10 ± 0.99 × 10⁶ lymphocytes/min (p < 0.01). LPT had no preferential effect on any lymphocyte population, since total lymphocytes, CD4+ T cells, CD8+ T cells, and B cell numbers were similarly increased. To determine if LPT mobilized gut-associated lymphocytes into the CC lymph, gut-associated lymphocytes in the CC lymph were identified by staining CC lymphocytes for the gut homing receptor integrin α4β7. LPT significantly increased (p < 0.01) the flux of α4β7 positive CC lymphocytes from a baseline of 0.70 ± 0.03 × 10⁵ lymphocytes/min to 6.50 ± 0.10 × 10⁵ lymphocytes/min during LPT. Finally, lymphocyte flux during recovery was similar to baseline, indicating the effects of LPT are transient. CONCLUSIONS Collectively, these results suggest that LPT may enhance immune surveillance by increasing the numbers of lymphocytes released in to lymphatic circulation, especially from the gut associated lymphoid tissue. The rat provides a useful model to further investigate the effect of LPT on the lymphatic and immune systems.