Fig. 1

Poststimulated membrane CD154 was overexpressed in SLE patients and associated with SLE disease severity. Level of CD154 expression on purified CD4⁺ T cells examined by flow cytometry after 6 hours of 1 μg/ml ionomycin activation in relation to the healthy controls (n = 8) or lupus patients (n = 20), low or high SLE disease activity, presence or absence of nephritis, or an elevated ESR. Definition of high disease activity was SLEDAI score > 9. Definition of nephritis was the presence of proteinuria (daily urine protein > 0.5 g/day) closest to the time of analysis. MFI mean fluorescence intensity, SLEDAI SLE Disease Activity Index, ESR erythrocyte sedimentation rate, NS not significant, SLE systemic lupus erythematosus