A 21-year-old female presents with irregular fever for half a month, accompanied by fatigue and weight loss. Physical examination reveals multiple pea-to-bean-sized, hard, non-tender lymph nodes in bilateral cervical, supraclavicular, and axillary regions. Liver is palpable 1 cm below the costal margin, and spleen is palpable 3 cm below the costal margin, both of medium consistency and non-tender. Laboratory tests: hemoglobin (Hb) 80 g/L, white blood cell count (WBC) 4.2×10<sup>9</sup>/L, platelet count (PLT) 70×10<sup>9</sup>/L, reticulocytes 0.11 (11%), Coombs test (+). During lymph node biopsy, Reed-Sternberg cells are found. These cells may be seen in all of the following conditions EXCEPT: