Lymphocyte subset numbers depend on the bacterial origin of sepsis

Objective To determine the quantitative variances in peripheral blood lymphocyte subsets during sepsis, and their clinical significance. Methods Peripheral blood lymphocyte subsets were enumerated in 32 non-surgical septic patients during the first 14 days of hospitalization; results from septic patients were compared with those from 34 healthy controls. Influences of the severity and the bacterial etiology of sepsis on changes in lymphocyte subsets were also assessed. Results Significant decreases (P < 0.05) from normal values of CD4(+), CD8(+) and total T-lymphocytes were observed in septic patients, but the decline persisted only for CD4(+) T-lymphocytes and natural killer (NK) cells for 3 and 7 days, respectively. In addition, the numbers of CD3(+) DR+ lymphocytes were significantly elevated on day 14. There were no correlations between these alterations and the severity of sepsis. Gram-positive sepsis (n = 10), which was mainly due to Streptococcus pneumoniae and Staphylococcus aureus, caused prolonged decreases in CD4(+), CD8(+) and total T-lymphocytes, and a reduction in NK cells, that lasted for greater than or equal to14 days. Conversely, patients with sepsis due to Gram-negative pathogens (Neisseria meningitidis, n = 8; enterobacteria, n = 2) achieved full recovery of the subsets within 3 days. Moreover, the patients with Gram-negative sepsis demonstrated a significant increase in B-lymphocytes, and a rise in the numbers of CD3(+)/DR+ and CD4(+) T-lymphocytes, which were more rapid than in patients with Gram-positive sepsis. Conclusion Our results indicate that Gram-positive sepsis causes stronger suppression of peripheral blood lymphocyte subsets in comparison to sepsis due to Gram-negative pathogens.