Lymphoproliferative DisordersEpstein-Barr Virus InfectionsHerpesvirus 4, HumanOrgan TransplantationAutoimmune Lymphoproliferative SyndromeLymphomaTransplantationLymphoma, B-CellB-LymphocytesLeukemia, Hairy CellHerpesviridae InfectionsLymphomatoid GranulomatosisGiant Lymph Node HyperplasiaLeukemia, Lymphocytic, Chronic, B-CellLymphoma, T-CellImmunosuppressive AgentsImmunophenotypingT-LymphocytesAntibodies, Monoclonal, Murine-DerivedLymphocytosisKidney TransplantationLymphomatoid PapulosisImmunosuppressionInfectious MononucleosisAntigens, CD30Leukemia, ProlymphocyticLeukemia, Large Granular LymphocyticTumor Virus InfectionsPostoperative ComplicationsLymphoma, Non-HodgkinHodgkin DiseaseLeukemia, LymphoidLymphatic DiseasesImmunocompromised HostPseudolymphomaFatal OutcomeEpstein-Barr Virus Nuclear AntigensWaldenstrom MacroglobulinemiaLymphocytesLymphoma, T-Cell, CutaneousAutoimmune DiseasesSplenomegalyAntibodies, MonoclonalLymph NodesBurkitt LymphomaLeukemia, B-CellGammaherpesvirinaeAntigens, CDLymphocyte ActivationFlow CytometryLiver TransplantationTransplantation, HomologousDNA, ViralAllograftsCladribineCryoglobulinemiaImmunologic Deficiency SyndromesTransplantsLeukemia, T-CellLung TransplantationParaproteinemiasPolymerase Chain ReactionAntigens, CD20Viral Matrix Proteins