Circumscribed intestinal protein loss with deficiency in CD4+lymphocytes after the Fontan procedure

Protein-losing enteropathy is an important complication after right heart b ypass operations (Fontan procedure). Laboratory examinations usually reveal hypoalbuminaemia, hypoproteinaemia, elevated al-antitrypsin clearance, and lymphocytopenia. A case of protein-losing enteropathy after Fontan procedu re is reported with a circumscribed protein loss in the region of the termi nal ileum despite good haemodynamics. The patient developed only mild hypoa lbuminaemia and no diarrhoea but severe cellular and humoral immune abnorma lities, namely a markedly decreased proportion of CD4+ lymphocytes but norm al proportion of CD8+ lymphocytes (CD4+ 14%, CD8+ 23%) and decreased serum levels of immunoglobulin G. Intestinal biopsies revealed normal mucosa. Thi s report is unique as it is the first to describe a ratio of CD4+ to CD8+ l ymphocytes <1 due to an almost selective loss of CD4+ lymphocytes and a cir cumscribed intestinal protein loss in a patient who developed protein-losin g enteropathy after Fontan operation. Conclusion There is a severe decrease of CD4+ lymphocytes of unknown origin in a patient with circumscribed intestinal protein loss after Fontan opera tion. Passive leakage of lymph fluid due to abnormal systemic venous pressu re is not a sufficient explanation of the almost selective loss of CD4+ lym phocytes. Primary or secondary activation of the immune system may influenc e structural integrity and permeability of the intestinal wall and may play a triggering role in protein-losing enteropathy after the Fontan procedure .