Questions in Hodgkin Disease

QUESTIONS IN HODGKIN DISEASE

1.WHY A BIMODAL INCIDENCE BY AGE ?
2.WHY HX OF MONONUCLEOSIS INCREASES 3X THE RISK OF HODGKIN DISEASE ?
3.THE INFECTIOUS PROCESS MUST LEAVE A DEFICIENCY FOR HODGKIN LYMPHOMA TO DEVELOP (HIV, EBV,  BONE MARROW TRANSPLANT) ?CD8, HLA DR (ACQUIRED IMMUNITY) ?
4.DOES EXTRANODAL INFILTRATION MEAN T-CELL INVOLVEMENT OR JUST FAILURE OF A BLOOD VESSEL ?
(to be continued)