Human neutrophils release IL6R upon induction of apoptosis. Peripheral blood neutrophils from 3 different donors were adjusted to 10⁶ cells/mL and were UV treated (200 000 μJ/cm²) or left untreated for 6 hours. The metalloprotease inhibitors TAPI (10 μM), GI254023X (3 μM), or GW280264X (3 μM) were added 30 minutes prior to UV stimulation. (A) Immunoprecipitated sIL6R was analyzed by Western blot as before. (B) Band intensities were quantified using ImageJ software (National Institutes of Health, Bethesda, MD), and relative values represent the mean (± SD; *P ≤ .05) from the 3 independent donor experiments shown in panel A.