The main causes of high immunoglobulin A include disease factors and non-disease factors. Disease factors include hematologic diseases, kidney disease, liver disease, autoimmune disease, etc. Non-disease factors are seen in high immunoglobulin A alone. 1. hematologic diseases: multiple myeloma (MM) is an abnormal proliferation of monoclonal plasma cells in the bone marrow, which produces monoclonal immunoglobulin, resulting in elevated immunoglobulin A. Immunoglobulin A multiple myeloma is more common in clinic. 2. Liver disease and immune disease: serum immunoglobulin, as one of the antibody analogs in human body, can lead to immunoglobulin A elevation under pathological factors, and the common diseases are acute and chronic hepatitis, systemic lupus erythematosus, rheumatoid arthritis. 3. Renal disease: Immunoglobulin A-based immunoglobulin deposition in the glomerular plasma membrane area may lead to immunoglobulin A elevation, which is clinically seen in immunoglobulin A nephropathy. 4. Non-disease factors: clinically, it can also be seen that there are no non-disease factors for immunoglobulin A increase. It is recommended that if you have any symptoms, please consult a doctor in time to avoid delaying your condition.