Kosmaczewska A, Ciszak L, Stosio M, et al. - In this study, the levels of circulating CD4+CD28^null cells and CD8+CD28^null suppressor T cells were analyzed. The CD4+CD28^null were compared with CD4+CD28+ T-cell functional properties, involving the expression of interferon gamma (IFN-γ) and Ki67 among systemic lupus erythematosus (SLE) patients (n = 20) and healthy controls (n = 20). This study's findings noted increased CD4+CD28^null and unchanged levels of suppressor CD8+CD28^null T cells. No difference was found between patients and controls in IFN-γ and Ki67-expressing CD4+, CD4+CD28+, and CD4+CD28^null T cells, except for higher IFN-γ levels in CD4+CD28+ T cells in SLE. Outcomes suggested that SLE with a moderately active clinical course is defined by peripheral blood expansion of CD4+CD28^null T cells and a normal abundance of suppressor CD8+CD28 ^null T cells. Despite the lack of CD28, the findings reveal that these pathogenic CD4+ T cells, maintain the ability to create pro-inflammatory IFN-γ positively associated with disease activity as well as relatively high proliferative capacity may imply their potentially predictive role in SLE flares.