Cell-mediated cytotoxicity against platelets in patients with chronic immune thrombocytopenic purpura (ITP).

CD14⁻CD19⁻ blood mononuclear cells (75 ± 4% CD3⁺ and 14 ± 3% NK cells) were incubated with ¹¹¹In-labeled platelets at an effector/target ratio of 0.625:1 in the presence of anti-CD3 antibody (to stimulate cytolytic effector T cells) for 4 hours followed by centrifugation. Platelet lysis was determined as follows: (observed lysis-spontaneous lysis)/(maximal lysis-spontaneous lysis). The dashed line is the mean ± 2 s.d. recorded for controls. Data points represent mean ± s.d. of five measurements for each individual, using different CD3 antibody concentrations (15.6 ng/mL to 4 μg/mL). Patients with active ITP had significantly increased platelet lysis compared with patients in remission and control patients.

Reprinted with permission from Olsson et al. Nature Medicine. 2003;9:1123–1124.