Lymphocytes recognize pathogens (infections and abnormal cells) and destroy them. There are 2 major subtypes of lymphocytes: B lymphocytes and T lymphocytes, also referred to as B cells and T cells.

B lymphocytes produce antibodies (proteins that circulate through the blood and lymph and attach to infectious organisms and abnormal cells). The combination attachment cell or antibody microbial organism essentially alerts other cells of the immune system recognize and destroy these intruders, also known as pathogens.

T cells, when activated, can kill pathogens directly. T cells also play a part in the mechanisms of immune system control, to prevent the system from inappropriate overactivity or underactivity.

After fighting off an invader, some of the B and T lymphocytes “remember” the invader and are prepared to fight it off if it returns.

Cancer occurs when normal cells undergo a transformation whereby they grow and multiply uncontrollably. Lymphoma is a malignant transformation of either lymphocytes B or T cells or their subtypes.