DESIGN - Open-label, single-arm, Phase I/IIa interventional clinical trial. Participants will be evaluated at baseline (prior to study treatment) and according to the protocol follow-up schedule, receiving a total of 2 cycles of rhIL-7 (CYT107) during the induction phase and up to 8 cycles during the maintenance phase. Safety assessments of rhIL-7 will be the primary focus at each study visit, with secondary analyses of immune parameters, including changes from baseline in T cell number and function at Weeks 24 and 48.