Purpose of review: Several studies show that the number of FcgammaRI (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 FcgammaRI 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 FcgammaRI on neutrophils is a sensitive marker of bacterial infection, it is highly expressed also in DNA virus infections. As a consequence, neutrophil FcgammaRI cannot be used in distinguishing between bacterial and viral infections. It is also clear that FcgammaRI 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 FcgammaRI cannot be used to reliably detect RNA virus infections, inflammatory diseases, or cancer.
Summary: The best clinical benefit from the quantitative analysis of FcgammaRI 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.