Hi, Is your grandmother suffering from any clotting disorder? I have to know her complete blood count . anyway why was she given blood transfusion? has she received any component or platelet or packed cell? anyway at this age in immunocompromised state it is common to catch respiratory tract infection. lymphoma can be of many types, most of them are treatable but you should take care not to expose her to overcrowded places. At this stage any sort of infection may be life threatening. keep in touch with your oncologist.