B cells refer to B lymphocytes, B lymphocyte count normal reference 20%-40%. B lymphocytes can differentiate into plasma cells under antigenic stimulation, and plasma cells can synthesize and secrete antibodies, which are important cellular components of the body’s immune response function. Mature B lymphocytes are usually found in the superficial lymph nodes, the red and white medulla of the spleen, and the lymph nodes of the white medulla. If the B-lymphocytes are only slightly elevated and there are no clinical symptoms, no treatment is needed and regular checkups are recommended. If there is a significant increase in B-lymphocytes, it may be related to pathogenic infections, such as viral infections. It can also be seen in hematologic diseases, such as lymphoblastic leukemia, lymphoma and other diseases. In addition, low B lymphocytes may be associated with the presence of radiation damage, immunodeficiency, etc., such as rheumatologic disorders, e.g., desiccation syndrome. When abnormal B lymphocyte count occurs, it is recommended to consult a doctor for further examination as prescribed by the doctor, to clarify the cause with the help of the doctor, and to carry out targeted treatment or therapy.