title: Low pre-treatment B-cell counts are not a risk factor of infection in patients treated with rituximab for autoimmune diseases: An observational study.
abstract: OBJECTIVE
  Rituximab (RTX) is increasingly used in patients with refractory rheumatoid arthritis (RA) and other severe autoimmune diseases (AID). In practice, many clinicians are reluctant to prescribe RTX in patients with low B-cell counts because of the presumed risk of infection. The aim of this study was therefore to investigate whether B-cell counts before treatment or retreatment with RTX predict the occurrence of infections.
  
  
  METHODS
  Observational, single-centre study of 161 patients treated with RTX for RA and other AID at a tertiary hospital. CD19+ B-cell counts were assessed by flow cytometry and multivariate statistical analysis adjusted for various potential predictors was performed.
  
  
  RESULTS
  The rate of severe infection was 5.9/100 patient-years in RA patients and 24.9 in non-RA AID (P<0.001). Low B-cell counts at the time of RTX infusion were not associated with subsequent severe (HR=0.55, P=0.60) or overall infection (HR=0.85, P=0.58). Significant pre-treatment predictors of severe infection were a diagnosis other than RA (HR=4.68, P<0.001), immunoglobulin (Ig) G levels <7g/L (HR=2.36, P=0.01), age (HR=1.03, P=0.01), and diabetes (HR=3.61, P=0.01).
  
  
  CONCLUSIONS
  Low B-cell counts before RTX infusion did not predict subsequent infections in this population treated with RTX for RA and other AID, therefore not supporting the practice of pre-treatment assessment of B-cells. Nevertheless, a higher risk of severe infection was confirmed for low pre-treatment IgG levels, older age, diabetes, and AID other than RA.
authors.affiliation: Division of Rheumatology, University Hospital and Medical Faculty of Geneva, 26, avenue Beau-Séjour, 1206 Geneva, Switzerland. Electronic address: Ilias.Lazarou@hcuge.ch.
authors.forename: Ilias
authors.initials: I
authors.lastname: Lazarou
authors.affiliation: Division of Rheumatology, University Hospital and Medical Faculty of Geneva, 26, avenue Beau-Séjour, 1206 Geneva, Switzerland.
authors.forename: Axel
authors.initials: A
authors.lastname: Finckh
authors.affiliation: Division of Immunology and Allergology, University Hospital and Medical Faculty of Geneva, 1206 Geneva, Switzerland.
authors.forename: Lara
authors.initials: L
authors.lastname: Fischer
authors.affiliation: Division of Immunology and Allergology, University Hospital and Medical Faculty of Geneva, 1206 Geneva, Switzerland.
authors.forename: Camillo
authors.initials: C
authors.lastname: Ribi
authors.affiliation: Division of Rheumatology, University Hospital and Medical Faculty of Geneva, 26, avenue Beau-Séjour, 1206 Geneva, Switzerland.
authors.forename: Danielle
authors.initials: D
authors.lastname: Gascon
authors.affiliation: Division of Immunology and Allergology, University Hospital and Medical Faculty of Geneva, 1206 Geneva, Switzerland.
authors.forename: Jörg D
authors.initials: JD
authors.lastname: Seebach
authors.affiliation: Division of Rheumatology, University Hospital and Medical Faculty of Geneva, 26, avenue Beau-Séjour, 1206 Geneva, Switzerland.
authors.forename: Pierre-André
authors.initials: PA
authors.lastname: Guerne
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000188:drug therapy* / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000009:adverse effects / Q000276:immunology / Q000627:therapeutic use*; D007239:Infections / Q000139:chemically induced / Q000209:etiology* / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D000069283:Rituximab / Q000009:adverse effects / Q000276:immunology / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D007155:Immunologic Factors; D000069283:Rituximab
keywords: Autoimmune disease; B-cells; Infection; Rheumatoid arthritis; Rituximab