A 32-year-old welder complains of weakness and fever. His illness started as tonsillitis a month before. On exam, BT of 38,9°C, RR of 24/min, HR of 100/min, BP of 100/70 mm Hg, hemorrhages on the legs, enlargement of the lymph nodes. CBC shows Hb of 70 g/l, RBC of 2,2 × 1012/l, WBC of 3,0 × 109/l with 32% of blasts, 1% of eosinophils, 3% of bands, 36% of segments, 20% of lymphocytes, and 8% of monocytes, ESR of 47 mm/h. What is the cause of anemia?