The immnuohistochemical determination of immunoglobulins IgA, IgG and IgM in axillary lymph nodes from 50 unselected breast ductal carcinomas disclosed that lymph nodes with IgG-positive lymphoid follicles and/or metastasized lymph nodes with IgM-positive lymphoid cells are statistically related to breast tumors with a high histologic grade and more than 3 lymph node metastases.