Approximately forty-eight (48) participants will be randomized 1:1 to receive (a) Intramuscular (IM) administration of CYT107 at 3 g/kg followed, after 48hrs of observation, by 10 g/kg twice a week for 2 weeks or (b) Intramuscular (IM) placebo (normal saline) at the same frequency. An interim safety review will take place after the first 12 patients. If the CYT107 is well tolerated, the test dose (3 g/kg) will cease and that initial dose will become the same as the rest of the doses (10 g/kg). So, the remaining patients will be randomized to receive 5 administrations of (a) CYT107 at 10 g/kg every 3 to 4 days for 2 weeks or (b) Intramuscular (IM) placebo (normal saline) at the same frequency. The aim of the study is to test the ability of CYT107 to produce an immune reconstitution of these patients and observe possible association with a clinical improvement