RT Journal Article SR Electronic T1 Iatrogenic antibody deficiency from B-cell targeted therapies in autoimmune rheumatic diseases JF Lupus Science & Medicine JO Lupus Sci Med Lupus Sci Med FD Lupus Foundation of America SP e000337 DO 10.1136/lupus-2019-000337 VO 6 IS 1 A1 Sonali Wijetilleka A1 David Jayne A1 Chetan Mukhtyar A1 Mohammed Yousuf Karim YR 2019 UL http://lupus.bmj.com/content/6/1/e000337.abstract AB B-cell targeted therapies (BCTT) are now widely used in autoimmune rheumatic diseases, including SLE, antineutrophil cytoplasmic antibody-associated vasculitis and rheumatoid arthritis. Early studies suggested that rituximab did not influence serum immunoglobulins. However, subsequently, with increased patient numbers, longer follow-up duration and many patients having received multiple BCTT courses, multiple subsequent studies have identified hypogammaglobulinaemia as a potential side effect. Patients developing hypogammaglobulinaemia appear to fit into two principal categories: the majority who develop transient, often mild reduction in immunoglobulins without increased infection and a much smaller but clinically significant group with a more sustained antibody deficiency, who display increased risk of infection. Monitoring immunoglobulin levels represents an opportunity for the early detection of hypogammaglobulinaemia, and the prevention of avoidable morbidity. In the two major studies, approximately 4%–5% of BCTT-treated patients required immunoglobulin replacement due to recurrent infections in the context of hypogammaglobulinaemia. Despite this, monitoring of immunoglobulins is suboptimal, and there remains a lack of awareness of hypogammaglobulinaemia as an important side effect.