Clonal Evolution of B Cells in High-risk CLL After Idelalisib-rituximab

The purpose of the study is to assess the evolution of B cells at a genetic and surface-marker level in high-risk CLL after idelalisib-rituximab treatment. The targeted population includes 20 subjects ages 18 or older diagnosed with high-risk CLL. This will include patients with relapsed or refractory disease who require therapy with idelalisib and rituximab as per FDA label. This is an observational study for peripheral blood samples of these patients collected at pre-determined time points.