A method for diagnosing for the presence of systemic lupus erythematosus (SLE)in a patient is disclosed. In accordance with this method, megakaryocytes presentin bone marrow of a person suspected of having SLE are assayed for the presenceof internal bacterial structures that specifically stain with an intercalatingdye. The presence of those specifically stainable structures within the patientsmegakaryocytes indicates that the patient has SLE. Treatment of an SLE patientwith an antibiotic is contemplated. Treatment of a patient that has SLE comprisesadministering to that patient (i) an antibacterial amount of a rifamycin alongwith an antibacterial amount of a macrolide, (ii) an antibacterial amount ofa tetracycline, or (iii) an antibacterial amount of a quinolone, or a mixtureof two or more of (i) , (ii) and (iii). The treatment is continued until the patientsmegakaryocytes no longer contain specifically stainable structures, and untilno further evidence of infection is present.
