Brief Answer: Vitamin B complex and antioxidant supplements Detailed Answer: Hello, Welcome to health care magic I reviewed your symptoms of recurrent cold with fever, sore throat... The causes for recurrent colds are either because of persisting allergies or because of constant exposure to a source of infection as in chronic sinusitis. You need to get evaluation to rule out these two conditions. The normal white blood cell count ranges in the range of 5000- 11,000 cells/cubic mm. The causes for white blood cell count are Viral infections Diseases of bone marrow drugs like chemotherapeutic drugs Viral infections may be the probable cause in your case as white blood cell count increased spontaneously over a period of 10 days. Coming to your question of suggestions to improve immunity, Consuming nutritious diet with proteins Vitamin supplements containing vitamin B complex group and folic acid Antioxidants Along with this I can give you few healthy living tips Avoiding stress Having adequate sleep Regular exercises Consumption of diet rich in fruits and vegetables Avoiding smoking and alcohol (if not please ignore) Hope I have answered your query. Thank you

---