The novel applications of the quantitative analysis of neutrophil cell surface FcγRI (CD64) to the diagnosis of infectious and inflammatory diseases

Purpose of review Several studies show that the number of Fc gamma RI (CD64) on the surface of neutrophils increases in infections. However, in spite of increased research interest in recent years, there is no clear general view on the usability of neutrophil FcgRI in clinical infection diagnostics. This review tries to bring the clarity to this matter. Recent findings It is shown here that although the high number of FcgRI on neutrophils is a sensitive marker of bacterial infection, it is highly expressed also in DNA virus infections. As a consequence, neutrophil FcgRI cannot be used in distinguishing between bacterial and viral infections. It is also clear that FcgRI on neutrophils cannot be used in distinguishing between Gram-positive and Gram-negative bacterial infections or between microbiologically confirmed and clinically diagnosed bacterial infections. In addition, neutrophil FcgRI cannot be used to reliably detect RNA virus infections, inflammatory diseases, or cancer. Summary The best clinical benefit from the quantitative analysis of FcgRI on neutrophils will be obtained when it is used simultaneously with a reliable bacterial infection marker. DNA virus score point is an efficient novel method in differentiating between DNA and RNA virus infections.