Introduction: A child, 6 years following isolated small bowel transplant (SBTx) for intestinal failure secondary to gastroschisis with impaired venous access, developed faltering growth associated with increased stool output. The gastrointestinal biopsies (GI) showed severe eosinophilia throughout the GI tract, affecting native as well as graft bowel. It is unclear whether mucosal eosinophilia is causative of gastrointestinal symptoms, a novel pattern of rejection, a feature of infection, or inconsequential.

Aim: Review the histology of patients who are greater than 5 years post SBTx to identify mucosal eosinophilia and correlate this with patient clinical course.

Population: 32 patients (18 boys) underwent annual GI biopsies. Indications for SBTx were short gut =20; motility disorder 10; microvillus inclusion disease =2. Ten had isolated bowel or modified multivisceral, whilst 22 had liver containing grafts.

Results: In total 327 biopsy reports were analysed ranging from 5 to 17 years following transplant. 153 /327 (47%) reported to have normal amounts of mucosal eosinophils; 121/327 (37%) moderate; 53/327 (16%) severe eosinophilia.

12 patients had no increase in eosinophils at any time; 10 had a moderate increase; 10 had a severe increase, of which 7 had severe eosinophilia confined to the oesophagus only which was diagnostic of eosinophilic oesophagitis (EO). Of the 3 with severe eosinophilia in other areas of the GI tract, 2 were at the time of late onset severe acute rejection and the other is the index case as described above.

As a proxy for graft function, 4/12 (33%) required enteral supplements in those with normal mucosal eosinophils; 60% with moderate; 60% with severe, of which 3 require PN.

Discussion: Eosinophils are increased in over 50% of biopsies. EO was an isolated finding in 22% of patients indicating a need for long term upper GI endoscopic surveillance. In those confined to EO, there is little impact on graft function. A moderate increase in eosinopils is associated with increased need for enteral supplementation. Eosinophilia is an important finding in late onset acute rejection.

Conclusion: Increased mucosal eosinophils may be associated with reduced graft function and the inflammatory reaction of late onset acute cellular rejection. Whether this is causative or secondary is unclear.

Longitudinal studies from the time of SBTx will ascertain whether early eosinophilic infiltrates have a bearing on subsequent transplant pathology.