title: Circumscribed intestinal protein loss with deficiency in CD4+ lymphocytes after the Fontan procedure.
abstract: Protein-losing enteropathy is an important complication after right heart bypass operations (Fontan procedure). Laboratory examinations usually reveal hypoalbuminaemia, hypoproteinaemia, elevated alpha(1)-antitrypsin clearance, and lymphocytopenia. A case of protein-losing enteropathy after Fontan procedure is reported with a circumscribed protein loss in the region of the terminal ileum despite good haemodynamics. The patient developed only mild hypoalbuminaemia and no diarrhoea but severe cellular and humoral immune abnormalities, namely a markedly decreased proportion of CD4+ lymphocytes but normal proportion of CD8+ lymphocytes (CD4+ 14%, CD8+ 23%) and decreased serum levels of immunoglobulin G. Intestinal biopsies revealed normal mucosa. This report is unique as it is the first to describe a ratio of CD4+ to CD8+ lymphocytes <1 due to an almost selective loss of CD4+ lymphocytes and a circumscribed intestinal protein loss in a patient who developed protein-losing enteropathy after Fontan operation.
  
  
  CONCLUSIONS
  There is a severe decrease of CD4+ lymphocytes of unknown origin in a patient with circumscribed intestinal protein loss after Fontan operation. Passive leakage of lymph fluid due to abnormal systemic venous pressure is not a sufficient explanation of the almost selective loss of CD4+ lymphocytes. Primary or secondary activation of the immune system may influence structural integrity and permeability of the intestinal wall and may play a triggering role in protein-losing enteropathy after the Fontan procedure.
authors.affiliation: Department of Nuclear Medicine, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Koch
authors.forename: M
authors.initials: M
authors.lastname: Hofbeck
authors.forename: H
authors.initials: H
authors.lastname: Feistel
authors.forename: G
authors.initials: G
authors.lastname: Buheitel
authors.forename: H
authors.initials: H
authors.lastname: Singer
mesh_terms: D018791:CD4 Lymphocyte Count; D016516:CD4-CD8 Ratio; D002648:Child; D005260:Female; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000150:complications / Q000601:surgery*; D006343:Heart Septal Defects / Q000601:surgery; D006801:Humans; D011183:Postoperative Complications / Q000209:etiology* / Q000276:immunology; D011504:Protein-Losing Enteropathies / Q000209:etiology* / Q000276:immunology; D011666:Pulmonary Valve Stenosis / Q000601:surgery; D018785:Tricuspid Atresia / Q000601:surgery