Lymphopenia at presentation is associated with increased risk of infections in patients with systemic lupus erythematosus

Background: Patients with systemic lupus erythematosus (SLE) frequently suffer from infections, but the predisposing risk factors, as well as the exact frequency and nature of such infections, are not fully understood. Aim: To describe the frequency, types and risk factors for infections in a group of Chinese patients in the early stage of SLE in Hong Kong. Design: Retrospective record study. Methods: We reviewed the case records of 91 Chinese SLE patients, presenting <12 months after SLE diagnosis. Details of major infections (requiring intravenous antimicrobial therapy, or any confirmed mycobacterial infection) and minor infections were reviewed. Clinical and laboratory features, the systemic lupus erythematosus disease activity index (SLEDAI) at presentation and drug treatment were recorded and analysed. Results: There were 48 major infections and 62minor infections during 260 patient-years of follow-up. A lymphocyte count ≤1.0 × 10⁹/l at presentation was independently associated with an increased risk for major infection: hazard ratio 4.7 (95%CI 1.6-13.7), p=0.005. SLEDAI, use of corticosteroids and immunosuppressive therapy were all not associated with increased risk of infection. Discussion: Lymphopenia was an important risk factor for major infections in this group of Chinese patients in the early stages of SLE. SLE patients with lymphopenia at presentation should be closely monitored for the development of infective complications.