The most common causes of elevated white blood cells, neutrophils, and lymphocytes are infections, leukemia, and malignancies can also lead to elevated neutrophils and lymphocytes. Leukocyte is actually an umbrella term that encompasses five types of cells, neutrophils, eosinophils, basophils, monocytes, and macrophages. The function of neutrophils is to phagocytose foreign substances and act as the body’s first line of defense against the outside world. The most common causes of high neutrophils are infections of various origins, which can also lead to increased neutrophils after strenuous exercise. Lymphocytes are an important group of cells involved in the body’s immune response. Increased lymphocytes can be seen in various viral infections, as well as during recovery from infectious diseases, such as tuberculosis, and after bone marrow transplants. In conclusion, if you find that your neutrophils and lymphocytes are elevated, it is recommended that you consult a medical professional, who will determine the cause and treatment based on clinical manifestations or further examination.