Characteristic T cell dysfunction in patients with chronic active Epstein-Barr virus infection (chronic infectious mononucleosis).

We evaluated immune functions in 16 patients with chronic active Epstein-Barr virus (EBV) infection (chronic infectious mononucleosis). Chronic infectious mononucleosis is an illness characterized primarily by chronic and occasionally disabling fatigue and other constitutional complaints, only sometimes beginning with an episode of acute infectious mononucleosis, and associated with an abnormal pattern of serum antibodies to EBV. In these patients, the frequency of circulating EBV-infected B cells that manifested spontaneous outgrowth in vitro was comparable to that found in EBV-seropositive normals, and the levels of EBV-specific suppressor activity were also normal. Upon stimulation with polyclonal activators, unseparated cells from these patients produced a relatively normal number of immunoglobulin-secreting cells. However, when purified T cells from these patients were mixed with normal mononuclear cells in co-culture, immunoglobulin production was strikingly suppressed. The degree of this T cell suppression correlated directly with the abnormally elevated titer of antibody to the early antigens of EBV. Interestingly, during normal convalescence from acute EBV-induced infectious mononucleosis a period is also seen during which T cells suppress the response of allogeneic but not autologous cells. Thus, from an immunologic viewpoint, patients with chronic active EBV infection appear "frozen" in a state typically found only briefly during the convalescence from acute EBV infection.