High immunoglobulin G may be caused by systemic lupus erythematosus, dry syndrome, rheumatoid arthritis and so on. 1. Systemic lupus erythematosus: this disease is mainly related to genetic, endocrine, infection, ultraviolet rays, drugs and immune abnormality, etc. Patients will have mild arthritis, rash, cryptogenic nephritis and thrombocytopenic purpura, and patients can have high immunoglobulin G. 2. Dry syndrome: If patients are affected by genetic, infectious, environmental and other factors, it will lead to high immunoglobulin G. It is mainly related to immune dysfunction caused by the disease, and the patients mainly manifest dry mouth, dry eyes, dry tongue, dry skin, dry cough, diarrhea and other symptoms. 3. Rheumatoid arthritis: patients with high immunoglobulin G may be caused by rheumatoid arthritis, which may be caused by a variety of factors such as genetics, infection, environment, etc., often accompanied by morning stiffness, fatigue, weight loss and other symptoms. High immunoglobulin G, it is recommended to go to the rheumatology and immunology department of the regular hospital in a timely manner, to clarify the cause of the disease, and follow the doctor’s instructions to standardize the diagnosis and treatment.