Parameters influencing membrane CD14 expression and soluble CD14 levels in sepsis

Introduction: Membrane (mCD14) and soluble (sCD14) CD14 are pattern recognition receptors for bacterial cell wall fragments. They play an important role in the generation of the innate immune response against bacterial pathogens. Differentia expression of these receptors may be relevant for the clinical course of patients with sepsis. Patients and Methods: 32 patients with an early onset of sepsis (duration of symptoms < 24h) were examined repeatedly by flow cytometry for expression of mCD14, and by ELISA for levels of sCD14, leukocyte elastase and C-reactive Protein (CRP). Results: At study entry, mCD14 expression was reduced in all patients with sepsis, but returned to normal levels during the course of the disease in survivors only. mCD14 was found to be inversely correlated with severity of disease, leukocyte elastase, and C-reactive protein. Among patients with severe disease and Apache II scores greater than or equal to 20, sCD14 levels at study entry were significantly higher in those who survived by day 28, as compared to non-survivors (p = 0.02). Conclusion: The data presented are compatible with a recently published hypothesis derived from in vitro experiments suggesting that leukocyte elastase may be responsible for cleavage of mCD14 from the monocyte surface. The data also suggest that higher sCD14 levels may be beneficial in sepsis. Persistently reduced mCD14 expression seems to be a marker for severity of disease in patients with sepsis.