Application of lymphocyte immunophenotyping in selected diseases.

The results of lymphocyte immunophenotyping in a variety of autoimmune disorders confirm major T cell immunoregulatory defects. The defects associated with autoreactive T cells appear to exist at the level/interface of the CD4 inducer of suppression and the CD8 effector cell. Although activated CD4 cells are occasionally found, subpopulations of activated CD8 cells are seen more commonly. A similar observation has been made in a subpopulation of patients with common variable hypogammaglobulinemia. In conjunction with antigen-specific T cell clones, we anticipate that flow cytometry will continue to aid in the further dissection of these HLA-restricted, anti-idiotype-controlled and pharmacological-mediated reactions. The known immunological distinction between AML and ALL are such that blast immunophenotyping will confirm and complement the clinical and morphological diagnosis in the vast majority of patients. With regards to chronic lymphocytosis in general and CLL in particular, flow cytometry offers an unusual opportunity to characterize lineage, monoclonality, stage of differentiation, presence or absence of activation antigens, aneuploidy and oncogene expression. Flow cytometry will continue to contribute to our understanding of the etiology and pathogenesis of CLL.