T-CELL ACTIVITY AND CYTOKINE PRODUCTION IN X-LINKED AGAMMAGLOBULINEMIA - IMPLICATIONS FOR VACCINATION STRATEGIES

In the 5 X-linked agammaglobulinelnia (XLA) patients studied we show t hat memory T cells are present and that T lymphocytes proliferate norm ally to mitogens, monoclonal antibodies and, in particular, to recall antigens demonstrating normal in vivo T cell priming despite the absen ce of B cells. Furthermore, in vitro T cell activation in response to both T cell receptor-independent and T-cell receptor-dependent signals leads to a pattern of cytokine production characteristic of primed T cells and necessary for normal T cell function. These data are in good agreement with results obtained in gene-targeted mice and further sup port the concept that the absence of B cells does not impair induction of in vivo T cell memory and effector function which is generally con sidered to be of great importance in conferring protection against vir al infections. Thus, while there is no risk of inducing infections in XLA patients by administering vaccines containing killed viruses or re combinant viral proteins, stimulation of T cell immunity by such vacci nes may be of potential benefit particularly in the defense against in fections with viruses such as the hepatitis B virus to which hypogamma globulinemic patients are particularly exposed.