Comparison of neutrophil CD64 and monocytic HLA-DR with existing biomarkers for the diagnosis and prognosis of sepsis

Introduction
We measured the expression of serum procalcitonin (PCT), quantitative C-reactive protein (QCRP), neutrophil CD64 (nCD64) and monocytic HLA-DR (mHLA-DR) sequentially in patients admitted to the intensive care unit (ICU) and correlated the expression of these biomarkers to predict development of sepsis and its outcome.

Material and methods
Consenting adult patients of more than 18 years of age, who developed sepsis during an observation period of 20 days with a sequential organ failure assessment score (SOFA) score ≥ 2 or those who already had sepsis at admission to the ICU were included. SOFA score, serum PCT, QCRP, nCD64 and mHLA-DR assays were recorded on the first and third day of admission to the ICU. A total of 27 sepsis cases and 24 controls (all admitted to the ICU) were included in the study.

Results
SOFA score, serum PCT, QCRP, nCD64 were significantly higher and mHLA-DR was significantly lower in cases compared to controls, both on day 1 and day 3. There was no significant difference in any of the parameters between day 1 and day 3. PCT and nCD64, both with sensitivity of 77.8% and specificity of 70.8% (95% CI, 0.73–0.95), had the best predictive value for diagnosing sepsis. Lower mHLA-DR (< 5000/cell) was associated with higher mortality among cases.

Conclusions
Serum PCT and nCD64 are the best biomarkers with similar sensitivity and specificity in detecting sepsis. mHLA-DR could have a role in prognosis as lower levels were associated with higher mortality.