title: Association of Crohn's disease, thiopurines, and primary epstein-barr virus infection with hemophagocytic lymphohistiocytosis.
abstract: OBJECTIVE
  To assess the incidence of hemophagocytic lymphohistiocytosis (HLH) in a well-defined population of children with inflammatory bowel disease (IBD) and evaluate the common clinical and laboratory characteristics of individuals with IBD who developed HLH.
  
  
  METHODS
  We conducted a retrospective study of all children who developed HLH over an 8-year period. The incidence of HLH in patients with IBD was calculated using US census data and a statewide project examining the epidemiology of pediatric IBD.
  
  
  RESULTS
  Among children in Wisconsin, 20 cases of HLH occurred during the study period; 5 cases occurred in children with IBD. Common characteristics include: Crohn's disease (CD), thiopurine administration, fever lasting more than 5 days, lymphadenopathy, splenomegaly, anemia, lymphopenia, and elevated serum triglycerides and ferritin. Of the patients, 4 had primary Epstein-Barr virus infections. The incidence of HLH among all children in Wisconsin was 1.5 per 100 000 per year. The risk was more than 100-fold greater for children with CD (P < .00001).
  
  
  CONCLUSIONS
  Pediatric patients with CD are at increased risk for developing HLH; primary Epstein-Barr virus infection and thiopurine administration may be risk factors.
authors: Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology, and Nutrition, The Medical College of Wisconsin, The Children's Hospital of Wisconsin, Milwaukee, WI, USA.
authors: Vincent F
authors: VF
authors: Biank
authors: Mehul K
authors: MK
authors: Sheth
authors: Julie
authors: J
authors: Talano
authors: David
authors: D
authors: Margolis
authors: Pippa
authors: P
authors: Simpson
authors: Subra
authors: S
authors: Kugathasan
authors: Michael
authors: M
authors: Stephens
mesh_terms: D000293:Adolescent; D000740:Anemia / Q000150:complications; D001379:Azathioprine / Q000627:therapeutic use; D003424:Crohn Disease / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D020031:Epstein-Barr Virus Infections / Q000150:complications*; D005293:Ferritins / Q000097:blood; D005334:Fever / Q000150:complications; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D015994:Incidence; D008206:Lymphatic Diseases / Q000150:complications; D051359:Lymphohistiocytosis, Hemophagocytic / Q000150:complications*; D008231:Lymphopenia / Q000150:complications; D015122:Mercaptopurine / Q000627:therapeutic use; D012189:Retrospective Studies; D013163:Splenomegaly / Q000150:complications; D014280:Triglycerides / Q000097:blood; D014922:Wisconsin / Q000453:epidemiology
chemical_list: D007166:Immunosuppressive Agents; D014280:Triglycerides; D005293:Ferritins; D015122:Mercaptopurine; D001379:Azathioprine