The normal value of white blood cells in the human body is 4 to 10×10^9/L. White blood cells mainly consist of neutrophils and lymphocytes, along with some other types of eosinophilic and basophilic granulocytes. If the total white blood cell count decreases, generally falling below 4 to 10×10^9/L, it is referred to as leukopenia. Among these, neutrophils are the most related to the body's immune response. If neutrophils decrease to less than 1.5×10^9/L, it is defined as neutropenia, which is very serious. If neutropenia occurs, the resistance to infections is greatly lowered, making the body highly susceptible to various infections. Active treatment to increase white blood cells is necessary; otherwise, any infection may lead to severe conditions like septicemia and septic shock, which can even be life-threatening.