An OKT4 super(+) T-cell population in Sezary syndrome: Attempts to elucidate its lack of proliferative capacity and its suppressive effect

The authors have previously reported a case of Sezary syndrome (sS), in which an OKT4 super(+) T-cell population exhibited a defective response to non-specific mitogens, and an ability to suppress lectin-induced T-cell proliferation and pokeweed mitogen (PWM)-induced B-cell differentiation of normal donor peripheral blood mononuclear cells (PBMC). The authors report now that resting Sezary cells (SC) were essentially negative negative for activation antigens (Ag) detected by monoclonal antibodies (MoAb) B1.49.9, anti-Tac, OKT9, OKT10, and OKIa1. The data suggest that the target of suppressor activity is probably an important obligatory intracellular event controlling DNA replication, which is common to both IL-2-dependent and IL-2-independent T-cell activation processes. Human T-cell leukaemia/lymphoma virus I (HTLV-I) related p.19 and p.24 Ag were absent on fresh and 30-day cultured SC, suggesting the absence of HTLV-I infection, although not ruling out a proviral integration in the SC DNA.