The Use of Plasmapheresis in Patients with Bronchiectasis with Pseudomonas aeruginosa Infection and Inhibitory Antibodies

Chronic Pseudomonas aeruginosa lung infections commonly occur in patients suffering from bronchiectasis, leading to increased morbidity and mortality (1-4). Severe bronchiectasis often affects patients beyond the age where lung transplantation is indicated resulting in a high mortality rate (5). Recently, we identified that ~20% of patients with bronchiectasis and chronic P. aeruginosa infection had excess IgG2 specific to the bacterial O-antigen (6). In contrast to the serum bactericidal effect normally associated with antibody, this IgG2 inhibited immune killing of the infecting strain (6). Crucially, patients with inhibitory antibody had worse lung disease (6). We hypothesised that removal of inhibitory antibody might restore host immune killing and improve patient health. Plasmapheresis is typically used to treat conditions where injurious auto-antibodies arise (7, 8). Here we used plasmapheresis to remove inhibitory IgG2 from the serum of two critically ill patients with chronic P. aeruginosa infections (6)