Modulation of T-cell regenerative pathways by IL-7.

Following T-cell depletion, regeneration of the peripheral T-cell pool can occur through multiple mechanisms. Thymic differentiation is the predominant pathway through which new T cells are generated if thymic capacity is sufficient. However, with diminished thymic function related to therapy-related toxicity, disease, or age related declines, the peripheral expansion of remaining mature T cells can substantially regenerate the T-cell pool. Extrathymic differentiation from bone marrow progenitors is a relatively minor pathway through which new T cells develop. IL-7 can profoundly increase thymic differentiation, peripheral expansion and, potentially, extrathymic differentiation pathways to T-cell regeneration.