A peripheral blood leukocyte count that is consistently below 4.0×109/L is considered below normal and is referred to as leukopenia. Leukopenia can be classified as mild ≥1.0×109/L, moderate (0.5-1.0)×109/L and severe <0.5×109/L. Therefore, leukopenia of 2.7×109/L is considered mild. Patients with mild decreases may not have specific clinical symptoms, or may only have mild discomfort such as low fever and malaise. Moderately and severely reduced patients are prone to infections and non-specific symptoms such as fatigue, weakness, dizziness, and loss of appetite, etc. The common sites of infection are the respiratory, gastrointestinal and genitourinary tracts. For leukopenia, mild decreases generally do not require special precautions. Those with moderate deficiency have an increased rate of infection and should pay attention to prevention, maintain hygiene and remove chronic foci of infection. Those with severe deficiency are highly susceptible to serious infections and should be treated with aseptic isolation measures and symptomatic treatment with additional antibacterial drugs and immunomodulatory drugs according to the corresponding source of infection, as well as with leukocyte-producing drugs to increase the number of leukocytes in the body and reduce the development of complications. Therefore, leukocytes 2.7×109/L are mildly reduced and neutrophils ≥1.0×109/L do not require special protection, but the number of leukocytes should be monitored regularly, and if they are consistently lower than normal, timely consultation should be made to improve systematic and formal examination and laboratory tests for accurate treatment after clear diagnosis.