Immunoglobulin is a highly diverse autologous molecule able to influence immunity in different physiological and diseased situations. Its effect may be visible both in terms of development and function of B and T lymphocytes. Polyclonal immunoglobulin may be used as therapy in many diseases in different circumstances such as primary and secondary hypogammaglobulinemia, recurrent infections, polyneuropathies, cancer, after allogeneic transplantation in the presence of infections and/or GVHD. However, recent studies have broadened the possible uses of polyclonal immunoglobulin showing that it can stimulate certain sub-populations of T cells with effects on T cell proliferation, survival and function in situations of lymphopenia. These results present a novel and considerable impact of intravenous immunoglobulin (IVIg) treatment in situations of severe lymphopenia, a situation that can occur in cancer patients after chemo and radiotherapy treatments. In this review paper the established and experimental role of polyclonal immunoglobulin will be presented and discussed as well as the manufacturing processes involved in their production.

The results presented here demonstrate that polyclonal immunoglobulin indirectly improves the function of the reconstituted B cells and their IgG production by means of Fc-mediated effects on bystander cells. These results further stimulate the discussion about the advantages of IVIg therapy during immune reconstitution after human ASCT.