Thoracic Duct Lymph Reduces the Production of TNF-alpha IFN-gamma by Pulmonary Leukocytes in vitro

Purpose: Streptococcus pneumoniae, a cause of community acquired pneumonia, accounts for nearly one million hospitalizations in the U.S., annually. The lymphatic pump technique (LPT) is a manipulative medicine technique used by osteopathic physicians to mobilize lymph and treat pneumonia. Our objective was to identify the biological effect of thoracic duct lymph (TDL) mobilized with LPT on the immune response against S. pneumoniae. We hypothesized that lymph mobilized during LPT would suppress the in vitro activity of lung leukocytes in mice infected with S. pneumoniae. Methods: TDL was collected from dogs during 4min of baseline, 4min of LPT, and 10min post-LPT. Mice were intranasally infected with 5x10^5 CFU of S. pneumoniae. Lung leukocytes were isolated from healthy and infected mice (24hr post-infection.) Leukocytes were cultured with media plus 5% saline, 5% baseline TDL, 5% LPT TDL, or 5% post-LPT TDL, and co-cultured with/without LPS. The TNFa and TNFg were measured in supernatants after 24hrs. Results: When cultured with LPS, the addition of baseline LPT, LPT, or post-LPT lymph decreased TNFa and TNFg production by leukocytes from healthy mice. Leukocytes from infected mice did not produce cytokines even when stimulated with LPS, suggesting expended biological activity in vivo. There were no differences in TNFa and TNFg production by leukocytes cultured with baseline LPT, LPT, or post-LPT lymph. Conclusion: TDL reduced inflammatory cytokine production by lung leukocytes. Mobilization of lymph during LPT may release protective factors that limit inflammation and protect the lungs from pulmonary disease.