Disclosed herein is an anti-migis-ααantibody specific for the migis-α of human mα chain that can bind to mIgA on B lymphocytes, cause the lysis of mIgA-expressing B lymphocytes, and decrease IgA production by IgA-secreting B lymphocytes. Disclosed further is a pharmaceutical composition comprising the anti-migis-α antibody and a pharmaceutically acceptable carrier. Disclosed further is a method for lysing mIgA-expressing B lymphocytes and reducing IgA production in a human subject in vivo by employing an antibody specific for the migis-α of human mα chain that can bind to mIgA on B lymphocytes, cause the lysis of mIgA-expressing B lymphocytes, and decrease IgA production by IgA-secreting B lymphocytes. Disclosed herein is also a method for treating a disease in a subject, comprising administering to the subject an antibody specific for the migis-α of human mα chain that can bind to mIgA on B lymphocytes, thereby lysing mIgA-expressing B lymphocytes and reducing IgA production in the immune system of the subject. In addition, Disclosed also is use of said anti-migis-α antibody or said fragment thereof for treating a disease in a subject that can benefit from the elimination of mIgA-expressing cells or the reduction of IgA antibodies in the immune system.
