Adjusted neutropenia is associated with early serious infection in systemic lupus erythematosus

Objectives: The susceptibility to infection increases in systemic lupus erythematosus (SLE) patients with neutropenia, but the link between infection risk and the cutoff neutrophil count still remains controversial. In this study, we investigated a valuable parameter associated with early serious infection in SLE patients during the first follow-up year. Methods: We reviewed the medical records of 160 patients with SLE. The initial levels were defined as the mean of the results of the first two consecutive tests. The adjusted levels were defined as the results of the accumulated area under the curve divided by interval follow-up days. Patients were divided into two groups according to early serious infection and initial and adjusted neutropenia and were then compared. Results: Immunosuppressive-naïve SLE patients with early serious infection more frequently had initial, latest, and adjusted leukopenia and neutropenia (<2,500/mm³) and hypocomplementemia than those without. Adjusted neutropenia was the only independent predictive value for early serious infection [odds ratio (OR 11.366)]. Initial neutropenia was the independent predictive value for adjusted neutropenia (OR 6.504). Conclusions: We suggest that adjusted neutropenia is useful for predicting early serious infection in SLE patients during the first follow-up year.