#2963 Light chain deposition in the kidney is more frequent in patients with proliferative lupus nephritis

Abstract

Abstract Background and Aims Light chain deposition in the kidney is an important histologic feature having a significant role in the pathogenesis of glomerular and autoimmune diseases, including lupus nephritis (LN). However, there is no study examining differences in light chain deposition profile between proliferative and non-proliferative LN. Method We have conducted a retrospective cohort study to evaluate the characteristics and prognostic significance of light chain deposition profile in the kidney of subjects with proliferative and non-proliferative LN. We have collected data on demographics, clinical and laboratory parameters and histopathology (light, immunofluorescent and electron microscopy). Lambda domination (LD) was defined as lambda intensity—kappa intensity ≥ +1. SLE was diagnosed using the American College of Rheumatology criteria and renal outcomes per KDIGO guidelines. Proliferative LN was defined as those containing classes III and IV, while all other classes comprised non-proliferative LN. Results A total of 56 patients with biopsy-proven LN were followed up for at least one year after kidney biopsy (79% women, mean age at biopsy 38 ± 13 years). A total of 71% of patients had proliferative LN. Mean number of glomeruli per biopsy sample was 26 ± 12. Mean immunofluorescent intensity was 1.6 ± 1.0 for lambda and 1.8 ± 1.0 for kappa light chain. A total of 42 (75%) patients had light chain deposition in the glomerulus with 4 (7%) having restricted lambda chain deposition and none had restricted kappa chain deposition. Patients with proliferative LN had more frequent light chain deposition in glomeruli than those with non-proliferative lupus (88% vs. 57%, p = 0.049) , with no difference in LD (24% vs. 14%, p = 0.71). There was no difference between frequency of restricted lambda chain deposition between proliferative and non-proliferative LN (5% vs. 17%, p = 0.60). A total of 12 (21%) patients had LD in the glomerulus. When examining renal outcomes at one year post-biopsy, 55% of patients achieved complete response (CR), 30% achieved partial response (PR) and 15% had no response. There were no differences in achievement of remission (CR or PR) between patients with proliferative and non-proliferative LN (87% vs. 90%, p = 0.93). We also found no difference in frequency of light chain deposition and achievement of remission in proliferative or non-proliferative LN (both p>0.05). Conclusion Light chain deposition is prevalent in LN and is more frequent in patients with proliferative LN. Further studies examining their pathophysiologic properties and potential prognostic value are much warranted.