Analysis of T lymphocytes after bone marrow transplantation using monoclonal antibodies.

Using monoclonal antibodies to cell surface antigens and fluorescent cell sorter analysis, we studied peripheral blood lymphocyte subsets after bone marrow transplantation (BMT). In 13 patients studied 3 mo or more after BMT, the ratio of T-cell subsets defined by antibodies OKT4 and OKT8 was reversed (OKT4/OK%8 = 0.7 +/- 0.3) in comparison to normal volunteers or bone marrow donors (ratio OKT4/OKT8 = 1.7 +/- 0.4) (p less than 0.001). This reversed ratio persisted for up to 3 yr after BMT. In contrast to a previous report, presence of an abnormal ratio of T-cell subsets did not correlate with clinically significant graft-versus-host disease (GVHD). In agreement with a previous study, (26% +/- 8%; less than 4% in normals (p less than 0.001) and antibody OKT10 reactive cells (39% +/- 20% versus 10% +/- 4%) (p less than 0.01), suggesting in vivo activation. However, their PBL did not react with antibody B3/25 (antitransferrin receptor), a marker found on normal PBL after in vitro activation by mitogens (BMT patients less than 5%; normal PBL T cells plus PHA 45% +/- 11%). These results demonstrate that BMT patients have: (A) an abnormal ratio of T-cell subsets in the presence or absence of clinically significant GVDH disease so that these measurements were not useful in monitoring patients; (B) an increased number of T cells with cell surface phenotype (OKT8+, Ia+, OKT10+, B3/25-) that is distinct from normals but similar to patients with infectious mononucleosis or acquired hypogammaglobulinemia.