A 45-year-old woman presented to the immunology clinic with complaints of lifelong fatigue and frequent, prolonged infections often requiring antibiotics for resolution.History Ten years earlier, during a workup for an ovarian cyst, the patient had an incidental finding of scattered lymphadenopathy throughout the abdomen and pelvis on CT scan. This prompted an excisional left inguinal lymph node biopsy, which, like the ovarian cyst, was benign. She was referred to hematology/oncology and allergy/immunology for further evaluation. During these consultations, diagnostic evaluations were negative for myeloproliferative disease, hepatitis A and B, HIV, Epstein-Barr virus (EBV), and autoimmune conditions. The only abnormal finding was a low quantitative serum immunoglobulin G (IgG). No cause for lymphadenopathy or low IgG was determined.Eight years later, the patient presented to the ED with profuse vaginal bleeding and petechiae diagnosed as an acute episode of immune thrombocytopenia (ITP). ITP often is triggered by a viral infection that sets off an autoimmune