Expansion and de novo generation of potentially therapeutic regulatory T cells in patients with autoimmune hepatitis

✍ Scribed by Maria Serena Longhi; Francesca Meda; Pengyun Wang; Marianne Samyn; Giorgina Mieli-Vergani; Diego Vergani; Yun Ma

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 590 KB
• Volume: 47
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.22071

✦ Synopsis

CD4؉CD25؉ regulatory T cells (T-regs

) are central to the maintenance of immune tolerance and represent an immune intervention candidate in autoimmune hepatitis (AIH), a condition characterized by impaired T-reg number and function. We investigated whether T-regs can be expanded from the existing CD4؉CD25؉ T cell pool and generated de novo from CD4؉CD25؊ T cells in AIH patients and healthy controls. Purified CD4؉CD25؉ and CD4؉CD25؊ T cells from 24 patients with type 1 AIH and 22 healthy controls were cultured for up to 5 weeks with anti-CD3/anti-CD28 T cell expander and high-dose interleukin-2 (IL-2). Cell phenotypes, suppressor ability, forkhead winged/helix transcription factor box P3 (FOXP3) gene, and protein expression were assessed weekly by cytofluorimetry, proliferation assay, real-time polymerase chain reaction (PCR), and immunoblot. During culture, the number of CD4؉CD25؉ T cells derived from the existing T-reg pool (expanded T-regs) and generated de novo from CD4؉CD25؊ T cells (newly generated T-regs) increased constantly up to week 4 in both healthy controls and, to a lesser extent, in AIH patients. Expanded T-regs retained conventional T-reg phenotype and, compared with baseline, demonstrated more vigorous suppressive function and increased FOXP3 gene and protein expression. Newly generated T-regs not only acquired T-reg phenotype but underwent greater growth and were more resistant to apoptosis than expanded T-regs. Their suppressive function augmented throughout culture, reaching a peak at week 4, preceded by a peak FOXP3 gene and protein expression at week 2. Suppressor function and FOXP3 expression of both expanded and newly generated T-regs were higher in normal controls than in AIH patients. Conclusion: Functionally enhanced T-regs can be expanded and generated de novo in patients with AIH. This finding may assist in reconstituting impaired immune regulation and restoring peripheral tolerance through T-reg infusion in this condition.