White blood cell 2.76×10^9/L may be caused by non-disease reasons such as x-ray, or it may be caused by infectious diseases, hematologic diseases, and so on. 1. Non-disease factors: X-rays, radionuclide irradiation, and the use of certain anticancer drugs can lead to a lower white blood cell count. 2. Disease factors: white blood cell 2.76×10^9/L suggests that infectious diseases such as typhoid fever, paratyphoid fever, malaria, etc. may be present. Aplastic anemia, acute granulocyte deficiency and other hematologic disorders can also lead to low white blood cell counts. Autoimmune diseases such as systemic lupus erythematosus and dermatomyositis can also present with a decreased white blood cell count. There may be other reasons for a decreased white blood cell count, so it is recommended to go to the hospital in time to find out the cause and get timely treatment under the guidance of the doctor.