MSFinals-2062

MSFinals-2062

This is the full blood count result of a 72-year-old male who presents with fatigue following his retirement 6 months ago:

Hb 130 g/L (120-160)
RBC 4.5 ×1012/L –
Haematocrit 0.39 (0.36-0.46)
MCV 86.5 fL (80-100)
MCH 28.1 pg (27-32)
Platelets 180 ×109/L (150-400)
WBC 6.5 ×109/L (4-11)
Neutrophils 3.8 ×109/L (2-7)
Lymphocytes 1.9 ×109/L (1-4)
Monocytes 0.5 ×109/L (0.2-1)
Eosinophils 0.2 ×109/L (0-0.5)
Basophils 0.1 ×109/L (0-0.1)

He is brought into the clinic by his wife who is concerned that her husband is constantly tired, has lost interest in his hobbies and has trouble sleeping.

Examination is pretty much normal except that he appears fatigued. There are no abnormalities on chest, abdominal or respiratory examination. Neurological examination is normal.

What is the most likely cause of this blood picture?