Eosinophils in health and diseases

Eosinophils are multifunctional cells whose activities are associated with a single gene and have a diverse role in inflammation as well as in immunity (both innate and adaptive). Our understanding of this multifunctional leukocyte over the past two decades has enhanced from a definitely damaging cell to a cell actively participating in many physiological and pathological processes. Eosinophils are different from other granulocytes by their dense population of cytoplasmic crystalloid granules also known as secretory granules. These secretory granules contain full-bodied stores of various preformed cationic proteins. Numerous functions of eosinophils have been identified over the years, and there capabilities to synthesize, accumulate, and express a varied range of cytokines. The machineries leading to selective formation of preformed cytokines are especially beneficial targets when treatment is concerned. The present review discusses the recent and upcoming notion about the complexities in the structure of human eosinophils and also discusses its role in health and diseases, especially in precancer and cancer. Furthermore, an update on our knowledge of various stains and markers has been discussed in this review.