CYBB and systemic lupus erythematosus: To investigate how NOX2 deficiency promotes autoimmunity in various cell subsets, we used in vivo chimeric and conditional KO approaches to delete Cybb, the gene encoding a critical subunit of the NOX2 complex, in specific cell subsets of MRL.Faslpr SLE-prone mice, a strain in which we previously demonstrated strong regulatory activity of NOX2 via global KO of Cybb (20).