title: Diagnostic Utility of Complement Immunohistochemical Studies in Post-Stem Cell Transplant Intestinal Thrombotic Microangiopathy: Case Report.
abstract: Thrombotic complications are a significant source of morbidity and mortality following hematopoietic stem cell transplants. Among them, transplant-associated thrombotic microangiopathy (TA-TMA) is a well-recognized syndrome that can affect various organ systems. Its etiology is related to endothelial injury accompanied by complement activation. As many of the signs and symptoms of the disease are also encountered in other complications following hematopoietic stem cell transplant, it can often be difficult to establish the diagnosis based on clinical data alone. Histopathologic examination of various tissues may be performed in difficult cases. However, the microscopic features of TA-TMA also overlap with those seen in other posttransplant complications, suggesting a need for additional tests to help in diagnosis. Here we describe a patient who presented with hemolytic anemia, thrombocytopenia, renal and neurological impairment, who also developed significant bloody diarrhea. Flexible sigmoidoscopy with biopsies was performed to determine the exact etiology of his gastrointestinal bleed. A diagnosis of intestinal TA-TMA was established with the use of immunohistochemical stains for complement components C5b-9 and C4d. This is the first report that highlights the utility of complement staining on histologic sections from digestive samples to render a definitive diagnosis of intestinal TA-TMA.
authors.affiliation: *Department of Pediatrics †Department of Pediatrics, Division of Hematology, Oncology and Stem Cell Transplant ‡Department of Pathology and Laboratory Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.
authors.forename: Jenna E
authors.initials: JE
authors.lastname: Rossoff
authors.forename: Jennifer
authors.initials: J
authors.lastname: Schneiderman
authors.forename: Sonali
authors.initials: S
authors.lastname: Chaudhury
authors.forename: Nicoleta C
authors.initials: NC
authors.lastname: Arva
mesh_terms: D002648:Child; D015935:Complement C4b / Q000032:analysis; D050776:Complement C5b / Q000032:analysis; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D007150:Immunohistochemistry; D007410:Intestinal Diseases / Q000175:diagnosis*; D008297:Male; D010446:Peptide Fragments / Q000032:analysis; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D057049:Thrombotic Microangiopathies / Q000175:diagnosis* / Q000473:pathology
chemical_list: D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d; D050776:Complement C5b