SLPI: An Immunomodulator That Correlates with Linfoproliferative Ability in Lung Cancer Patients,

J.A. MAZZEI, M.D., D. GUERRIERI, M.D., R.M. REITERI, M.D., N. TATEOSIAN, M.D., A. BARRO, M.D., N. AMIANO, M.D., H. ESTEVA, M.D., H.E. CHULUYAN

Toronto, Canadá

Congreso; American Thoracic Society Toronto 2008 International Conference; 2008

American Thoracic Association

SLPI is an anti-inflammatory protein of 11,7 kDa. It is produced by lung epithelial cells and it is present in exhaled breath condensate (EBC) and serum of patients with lung pathology. The aim of the present study was to evaluate a putative correlation between SLPI levels and the proliferative ability of lymphocytes in response to IL-2. SLPI serum levels and the lymphoproliferative ability were examined in patients with COPD (n = 15), lung cancer (n = 15) and smokers (n = 10). We observed that serum SLPI levels of lung cancer patients were higher than COPD or smokers (CA: 3,45 1,23 g/ml; COPD 2,14 0,45 g/ml; smokers 2,6 0,7 g/ml; p<0.05). On the contrary, SLPI levels in EBC were the same regardless the patients analyzed. The proliferative ability of lymphocytes derived from lung cancer was lower than in smokers (CA: 1,02 0,99; smokers 2,76 0,81; p<0.05), but not with COPD. Finally, we found a negative correlation between serum SLPI levels and lymphoproliferative ability (r= - 0,7706; p= 0,0049) in cancer patients. In order to corroborate that SLPI can decrease the proliferative ability of lymphocyte, PBMC from healthy donors was isolated, stimulated with IL-2 and treated with SLPI for 5 days. The results showed that SLPI decreased the lymphocyte proliferation induced by IL-2 in a dose-dependent manner (control: 47 5 %, p < 0.001, n = 12). Overall, this study suggests that SLPI is an immunomodulator, which could participate in tumor-immune escape mechanisms. Furthermore, serum SLPI and lymphocyte proliferation could be used as a marker to follow up lung cancer patients.