case_images: PMC11419984_01
case_images: Patient treatment and outcome from admission until hospital discharge and follow-up.
case_images: fimmu-15-1460317-g001.jpg
case_images: PMC11419984_01_fimmu-15-1460317-g001.jpg
case_images: f1
case_images: Due to persistent thrombocytopenia, on 2 November, he received a 5-day course of intravenous immunoglobulins (2 g/kg total dose), with no clinical or biochemical improvement ( Figure 1 ).
case_images: Ex vivo C5b-9 deposition on cultured human microvascular endothelial cell (HMEC-1) line induced by serum of the patient collected before (PRE-infusion) and 10 days after (POST-infusion) eculizumab treatment. (A, B) HMEC-1 resting (A) or activated with ADP (B) were incubated for 2 h with serum (diluted 1:2 with test medium, Hank's Balanced Salt Solution (HBSS) with 0.5% Bovine Serum Albumin (BSA)) from the patient or with a control serum pool. At the end of incubation, cells were washed, fixed, and stained with rabbit antihuman complement C5b-9 complex antibody followed by Fluorescein Isothiocyanate (FITC)-conjugated secondary antibody. Fluorescence microscopy was used to view the fluorescent staining on the endothelial cell surface, and the HMEC-1 area covered by C5b-9 staining was calculated by automatic edge detection (Image J software) in 15 high-power fields. For each sample, the highest and lowest values were discarded, and the mean of the other 13 fields was calculated. Values were expressed as the percentage of C5b-9 deposits induced by a pool of sera from 10 healthy controls run in parallel (reference, 100%). Dashed lines indicate the upper and lower limits of the normal range. Data are reported +- SE. *
  p < 0.0001 versus control serum pool;  p < 0.0001 versus patient PRE-infusion. Statistical analysis: ANOVA.
case_images: fimmu-15-1460317-g002.jpg
case_images: PMC11419984_01_fimmu-15-1460317-g002.jpg
case_images: f2
case_images: Marked C5b-9 formation was found on the microvascular endothelial cells (208% on resting and 263% on activated endothelial cells, normal values < 150%) ( Figure 2 ), which completely normalized after exposure to eculizumab in vitro (13).