title: Lymphopenia as risk factor for development of severe infections in patients with systemic lupus erythematosus: a case-control study.
abstract: OBJECTIVE
  Hematological abnormalities, particularly lymphopenia, are common in patients with systemic lupus erythematosus (SLE), whether the disease is active or not. The aim of this study is to assess whether lymphopenia (blood counts ≤1000 K/µl) is a risk factor for severe infections in patients with SLE.
  
  
  METHODS
  A retrospective case-control study was performed. We reviewed the clinical records of 167 SLE patients throughout a 5-year period. SLE patients with severe infections were compared with those without infection and the presence of lymphopenia was obtained from the blood count previous to the infection date. Also, other clinical and laboratory features as well as immunosuppressive therapy and SLE disease activity index (SLEDAI) were recorded.
  
  
  RESULTS
  Univariate analysis shows multiple risk factors for severe infections in SLE, such as lymphopenia, high SLEDAI index, prednisone (PDN) and mycophenolate mofetil treatment and low levels of C3 and C4. Moreover, hydroxychloroquine treatment conferred protection. However, after multivariate analysis, only lymphopenia [odds ratio (OR) 5.2, 95% confidence interval (CI) 2.39-11.3], PDN treatment (OR 4.8, 95% CI 2.1-11.9) and low levels of C3 (OR 2.97, 95% CI 1.1-7.9) remained as independent risk factors.
  
  
  CONCLUSIONS
  Our data suggest that lymphopenia, PDN treatment and low levels of C3 are independent risk factors for the development of severe infections in SLE patients, including diverse microorganisms, not only opportunistic infections.
authors: Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
authors: J
authors: J
authors: Merayo-Chalico
authors: D
authors: D
authors: Gómez-Martín
authors: A
authors: A
authors: Piñeirúa-Menéndez
authors: K
authors: K
authors: Santana-De Anda
authors: J
authors: J
authors: Alcocer-Varela
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000188:drug therapy / Q000276:immunology; D008231:Lymphopenia / Q000150:complications* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections / Q000150:complications* / Q000276:immunology; D012307:Risk Factors; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; D003176:Complement C3; D003181:Complement C4; D007166:Immunosuppressive Agents