Towards personalized and rational use of immunoglobulins amid expanding indications and shortages.

The development of intravenous IgG (IVIG) formulations in the 1970s enabled expanded use for treating primary antibody deficiency syndromes and autoimmune conditions. Recent advancements include the use of IVIG in secondary immune deficiencies related to hematologic malignancies and stem cell transplantation, along with the newly emerging prophylactic applications following chimeric antigen receptor T-cell (CAR-T) therapies. Novel therapeutic areas such as bispecific antibodies (BsAbs) for lymphoma and myeloma have increased the use of IgG, given the associated risks of infections. Today, the concept of a rational personalized clinical use of IgG in the context of evolving clinical indications in high-income countries (HIC) is emerging, as unmet challenges in line with managing shortages due to increasing demands globally. The current work aims to review and link the indications for IgG to their characteristics and formulations, their dose, route and frequency of administrations and duration of therapy to meet the needs of individual patients. It will also explore the means to rationalize and monitor IgG use in HIC in the time of shortage, while explaining pragmatic strategies to improve supply and use in low- and middle-income countries (LMIC).