sentences:  The disease is believed to be induced by a combination of Epstein Barr virus infection and immunosuppression through immunosuppressive drugs (with case reports of methotrexate and azathioprine), infections such as HIV or chronic viral hepatitis or endogenous T cell defects.The onset of the disease results in proliferation of EBV-infected malignant B-cells and a cytotoxic T-cell response which in turn leads to organ infiltration and dysfunction of the affected organs.The disease typically always relapse after successful treatment due to inability of the immune system and current viral drugs to eliminate an EBV-infection.