Lymphoid cells in infectious mononucleosis classified according to T and B cell markers.

It has been demonstrated that peripheral blood lymphocytes, particularly the "atypical" ones, are predominantly of the T type in infectious mononucleosis (IM). This is based on membrane marker studies (E rosettes, receptor for complement, receptor for Fc fragment of immunoglobulins (Ig), and membrane Ig) and by anti-T lymphocyte serum. On the other hand, lymphoblastoid cell lines derived from IM patients show the characteristics of B lymphocytes. This permits the suppostion that EBV infects B lymphocytes and stimulates them to proliferate. The cell proliferation is unlimited in vitro and is probably controlled in vivo by T cells. The reduction of cellular immunity in vivo, which contrasts with the high number of T cells in peripheral blood, could be explained by the fact that T cells are engaged in the regulation of B cell proliferation.