ICOS and systemic lupus erythematosus: In female SLE patients in remission, the insufficient immunosuppression seems to be associated with excessive age-independent activation of the RTE Tresps, whereby their age-dependent differentiation via pathway 1 and pathway 2 or 3 may be suppressed, so that the percentage of ICOS+ Tresps does not increase within total CD4+ T cells in women (Fig. 1C).