CD4 and systemic lupus erythematosus: Consistent with the results from healthy donors, blockade of ICAM-1 in CD4+ T-B cell coculture from moderate/severe SLE patients also led to the increase in IgG production (Figure 7F, right) whereas no difference existed in those from mild SLE patients with lower expression of ICAM-1 on CD4+ T cells (Figure 7F, left).