Active systemic lupus erythematosus is associated with decreased blood conventional dendritic cells.

OBJECTIVE: The aim of the study is to determine the frequency and functionality of blood conventional dendritic cells (cDCs) in relation to disease activity in systemic lupus erythematosus. METHODS: Blood cDCs were enumerated for 34 SLE patients, defined as "active" (SLEDAI ≥ 4) or "inactive" (SLEDAI < 4), 26 RA subjects and 8 healthy subjects by FACS. cDC activation was measured by IL-12p40/70 staining following resiquimod stimulation. RESULTS: The frequency of blood cDCs was significantly lower in active compared to inactive patients, however, with comparable cDC functionality. CONCLUSION: cDC frequency in active SLE is decreased with no perturbation in cDC function, possibly due to enhanced turnover and/or tissue-specific migration.