The phenotype of SLE associated with complete deficiency of complement isotype C4A

Authors present a multiparameter pathological study in a case of rapid biclonal primary plasma cell leukemia. The immunohistochemical data revealed aberrant phenotypes (monocyte, epithelial and T-cell) probably in connection with microenvironmental influences. Biclonality can be attributed to class switching during malignant transformation. Static image cytometry showed aneuploidy. The blasts of this process are active immunoregulatory cells.