Figure 3.

The effect of killer B cells on autologous CD4⁺ T cell apoptosis in healthy controls and hepatitis C virus (HCV) patients. (a) Representative fluorescence activated cell sorter (FACS) results of CD4⁺ T cells apoptosis: I. Spontaneous apoptosis II. Apoptosis induced by CD19⁺CD5^low B cells. III. Apoptosis induced by CD19⁺CD5^hiFas‐ligand (FasL)^hi B cells. (b) Summary of 17 experiments, results of healthy controls [analysis of variance (anova) significance = 0·0019]: the spontaneous apoptosis of CD4⁺ T cells was 14·53 ± 8·36% mean ± standard deviation (s.d.), median = 12·2%. When CD4⁺ T cells were co‐cultured with CD19⁺CD5^low the rate of apoptosis increased to 19·24 ± 9·13% mean ± s.d., median = 18·2%, P = 0·38. However, when CD4⁺ T cells were co‐cultured with CD19⁺ CD5^hiFasL^hi, the rate of apoptosis rose to 25·92 ± 8·65% mean ± s.d., median = 24.1%, P = 0·0013. (c) Summary of 17 experiments results of HCV patients (anova significance  <   0·0001): the spontaneous apoptosis of CD4⁺ T cells was 16·9 ± 9·1% mean ± s.d., median = 16·1. When CD4⁺ T cells were co‐cultured with CD19⁺CD5^low the rate of apoptosis increased to 24·66 ± 9·44% mean ± s.d., median = 19·9, P = 0·28. However, when CD4⁺ T cells were co‐cultured with CD19⁺CD5^hiFasL^hi, the rate of apoptosis rose to 39·17 ± 7·18% mean ± s.d., median = 39·6, P  <   0·0001.