[1] Newcastle Upon Tyne Hosp Trust, Dept Paediat Immunol, Florence, Italy
[2] Newcastle Univ, Inst Cellular Med, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[3] Paediatr Bone Marrow Transplant Unit, Florence, Italy
[4] Newcastle Upon Tyne Hosp Trust, Immunol Lab, Newcastle Upon Tyne, Tyne & Wear, England
[5] Newcastle Upon Tyne Hosp Trust, Dept Paediat Gastroenterol, Newcastle Upon Tyne, Tyne & Wear, England
[6] Newcastle Upon Tyne Hosp Trust, Dept Cellular Pathol, Newcastle Upon Tyne, Tyne & Wear, England