Different subclasses and isotypes of antibodies against phosphorylcholine in haemodialysis patients: association with mortality

Abstract

Background The risk of premature death is high among patients on haemodialysis (HD‐patients). We previously determined that IgM antibodies against phosphorylcholine (anti‐PC) are negatively associated with increased risk of cardiovascular disease (CVD), atherosclerosis, some autoimmune diseases and with mortality among HD‐patients in this cohort. We here study also other subclasses and isotypes of anti‐PC in HD‐patients, in relation to mortality, inflammation and gender. Methods The study group is a cohort of 209 prevalent HD patients (median age 66 (interquartile range (IQR): 51–74]) years, vintage time 29 (IQR 15–58; 56% men) months) with a mean follow‐up period of 41 (IQR 20–60 months). Fifty‐six % were men. We also divided patients into inflamed (CRP>5.6 mg/ml and non‐inflamed. Antibody levels were determined by in‐house ELISA. Results IgG1 anti‐PC below median was significantly associated with increased all‐cause mortality (after adjustment for confounders: p=0.02) while IgG, IgA and IgG2 anti‐PC were not associated with this outcome. Among non‐inflamed patients, IgM and IgG1 anti‐PC were significantly associated with mortality (p=0.047 and 0.02). IgG1 anti‐PC was significantly associated with mortality among men (p=0.03) and trendwise among women (p=0.26). Conclusion IgM (as previously reported) and IgG1 anti‐PC are negatively associated with survival among HD‐patients and non‐inflamed HD‐patients, but among inflamed patients there were no associations. IgG, IgA or IgG2 anti‐PC were not associated with survival in these groups and subgroups. Further studies are needed to determine if raising anti‐PC levels, especially IgM and IgG1 anti‐PC, through immunization, is beneficial.