title: Lymphopenia and treatment-related infectious complications in ANCA-associated vasculitis.
abstract: OBJECTIVE
  ANCA-associated vasculitis (AAV) is treated with potent immunosuppressive regimens. This study sought to determine risk factors associated with infections during first-intention therapy.
  
  
  METHODS
  This retrospective study involved two separate cohorts of consecutive cases of AAV seen from 2004 to 2011 at two university hospitals. The following were assessed: vasculitis severity; therapy; and periods with no, moderate (lymphocyte count, 0.3-1.0× 10(9)/L), or severe (lymphocyte count ≤ 0.3×10(9)/L) lymphopenia and neutropenia (neutrophil count ≤ 1.5×10(9)/L).
  
  
  RESULTS
  One hundred patients had a mean age of 57±15 years and a Birmingham vasculitis activity score of 7.7±3.6. Therapy consisted of pulse methylprednisolone (59%), cyclophosphamide (85%), methotrexate (6%), and plasmapheresis (25%) in addition to oral corticosteroids. During follow-up, 53% of patients experienced infection and 28% were hospitalized for infection (severe infection). Only 18% experienced neutropenia, but 72% and 36% presented moderate and severe lymphopenia for a total duration of <0.1%, 73%, and 8% of the treatment follow-up, respectively. Lower initial estimated GFR, longer duration of corticosteroid use, and presence of lymphopenia were risk factors of infections. The rate was 2.23 events/person-year in the presence of severe lymphopenia compared with 0.41 and 0.19 during periods with moderate or no lymphopenia (P<0.001). Similarly, the rate of severe infections was 1.00 event/person-year with severe lymphopenia and 0.08 and 0.10 with moderate and no lymphopenia (P<0.001). This association remained independent of other risk factors.
  
  
  CONCLUSIONS
  Lymphopenia is frequent during the treatment of AAV, and its severity is associated with the risk of infectious complications.
authors.affiliation: Nephrology, Hôpital du Sacré-Coeur de Montréal, Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Rémi
authors.initials: R
authors.lastname: Goupil
authors.forename: Soumeya
authors.initials: S
authors.lastname: Brachemi
authors.forename: Annie-Claire
authors.initials: AC
authors.lastname: Nadeau-Fredette
authors.forename: Clément
authors.initials: C
authors.lastname: Déziel
authors.forename: Yves
authors.initials: Y
authors.lastname: Troyanov
authors.forename: Valery
authors.initials: V
authors.lastname: Lavergne
authors.forename: Stéphan
authors.initials: S
authors.lastname: Troyanov
mesh_terms: D000328:Adult; D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology / Q000401:mortality; D016009:Chi-Square Distribution; D003141:Communicable Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000276:immunology / Q000401:mortality; D003520:Cyclophosphamide / Q000009:adverse effects; D005260:Female; D006785:Hospitals, University; D006801:Humans; D016867:Immunocompromised Host; D007166:Immunosuppressive Agents / Q000009:adverse effects*; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000139:chemically induced* / Q000175:diagnosis / Q000276:immunology / Q000401:mortality; D008297:Male; D008727:Methotrexate / Q000009:adverse effects; D008775:Methylprednisolone / Q000009:adverse effects; D008875:Middle Aged; D015999:Multivariate Analysis; D009503:Neutropenia / Q000139:chemically induced / Q000276:immunology; D010956:Plasmapheresis; D011792:Quebec; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D007166:Immunosuppressive Agents; D003520:Cyclophosphamide; D008775:Methylprednisolone; D008727:Methotrexate