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Abstract: FR-PO1075

Rituximab Associated Hypogammaglobulinaemia in Autoimmune Disease: Long Term Outcomes

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Tieu, Joanna, University of Cambridge, University of Adelaide, Cambridge, United Kingdom
  • Smith, Rona M., Cambridge University Hospitals, UK, Cambridge, United Kingdom
  • Gopaluni, Seerapani, University of Cambridge, Cambridge, United Kingdom
  • Jayne, David R.W., University of Cambridge, Cambridge, United Kingdom
Background

Despite a low incidence of hypogammaglobulinemia (HG) in clinical trials using rituximab (RTX), HG occurs in follow-up of patients with autoimmune disease.
Immunoglobulin replacement therapy (IRT) has been used to reduce infection rates but there is a paucity of data on its efficacy and impact on longer-term outcomes.
We examined the characteristics of patients with RTX associated HG in autoimmune disease, and their long-term outcomes with and without IRT.

Methods

Patients attending a Vasculitis and Lupus clinic, who received RTX for autoimmune disease between 2004 and 2012, with an immunoglobulin G (IgG) <7 g/L on at least 2 occasions were included in this retrospective case note review. Patients were categorized into nadir IgG subgroups of <3 g/L, 3 to <5 g/L and 5 to <7 g/L. Categorical variables are summarised as proportions, and continuous variables as mean ± standard deviation or median [interquartile range (IQR)]. Differences between nadir IgG subgroups were assessed by Chi squared tests and trends across subgroups confirmed by Somer’s D tests. Continuous variables were compared using analysis of variance (ANOVA), Kruskall-Wallis and Wilcoxon sign ranked tests as appropriate. Analyses were performed in SPSS.

Results

Of 142 patients, 101 (71.1%) had ANCA associated vasculitis, 18 (12.7%) systemic lupus erythematosus and 23 (16.2%) other diagnoses. Most received RTX for relapsing (69.3%) or refractory (25.0%) disease. Mean follow-up was 97.2 months.
Progressive HG was observed. Median time to IgG <5 g/L was 22.5 months [IQR 3.0 to 61.5] and to IgG <3 g/L was 24.5 months [IQR 4.0 to 80.75].
Mycophenolate use prior to RTX (p=0.05) and prednisolone use following RTX (p=0.04) were associated with a lower nadir of IgG.
IRT was commenced in 29 patients, the majority (65.5%) with IgG <3 g/L. It was well tolerated, with 2 discontinuing due to adverse effects. IRT was withdrawn without excess recurrent infections in 5 patients.
IRT was associated with a reduction in annual infection rates (p<0.001). Severe infections (requiring intravenous antibiotics or hospital admission) were uncommon, with no change with the use of IRT.

Conclusion

RTX associated HG is progressively identified with longer term follow-up. Although annual infection rates were low, in patients with recurrent infection, IRT was associated with a reduction in infection burden.