Evaluation of neutrophil CD 64 and CD 11b expression as early predictors of sepsis severity and outcome

ABSTRACT

CD64, the high affinity Fcy receptor 1, and CDllb, an alpha-subunit of the beta[2] integrin adhesion molecule, are specific neutrophil-surface antigens activated in response to systemic inflammation, therefore, they could potentially be used as early predictors of sepsis and the associated mortality in patients with systemic inflammatory response syndrome [SIRS]. Sixty-one SIRS patients with clinically suspected infection were enrolled and subjected to sepsis work-up, within the first 24 hours of sepsis onset, including complete blood count, blood culture, serum C-reactive protein [CRP] in addition to flow cytometric analysis of CD64 and GD11b. Patients were classified prospectively on the basis of clinical observation and blood culture results into two groups SIRS with sepsis group [n=36] and SIRS without sepsis group [n=25] served as patient control. According to outcome, patients with sepsis were classified after a follow-up period up to 28 days after inclusion into two groups survivors [n=29] and non-survivors [n=7]. A highly significant increase of neutrophil CD64 and CD11b expression was detected in the sepsis group as compared to the non-infected group. CD64 and CDllb expression had the best diagnostic performance for prediction of early-onset sepsis. Expression of CD64 at a cut-off value of 49% had 88.9% sensitivity, 92% specificity and 90.2% efficacy, while CD1 Ib expression at a cut-off value of 71% had 86.1% sensitivity, 84% specificity and 85.2% efficacy. Combined use of both markers yielded 91.7% sensitivity, 96% specificity and 93.4% efficacy. Sepsis survivors showed significantly lower expression of CD64 and CDllb as compared to non-survivors. An optimal cut-off value of 70% expression for CD64 predicted mortality with 100% sensitivity, 96.6% specificity and 97.2% efficacy. Meanwhile, a cut-off value of 86% for CDllb predicted mortality with 85.7% sensitivity, 93.1% specificity and 91.7% efficacy. Assessment of neutrophil CD64 and CDllb expression is superior to standard laboratory tests for early detection of sepsis, within the first 24 hours of sepsis onset, before the evolution of clinical signs which would facilitate therapeutic decisions. Prediction of outcome is an additional advantage borne by these two biomarkers