Graft-versus-host disease after multiorgan transplantation

Area of Science:

• Transplantation immunology
• Graft-versus-host disease research
• Surgical research

Background:

• Graft-versus-host disease (GVHD) is a significant complication following allogeneic transplantation.
• The role of specific organ grafts in modulating GVHD severity remains incompletely understood.
• Multiorgan transplantation (MOTx) presents a complex scenario for immune responses.

Purpose of the Study:

• To investigate the induction and lethality of GVHD following multiorgan transplantation (MOTx) in a rat model.
• To determine the influence of small bowel (SB) inclusion in MOTx on GVHD development and outcome.
• To establish a correlation between the quantity of transplanted lymphoid tissue and GVHD severity.

Main Methods:

• Development of a rat model for multiorgan transplantation (liver, pancreas, duodenum, and variable SB segments).
• Utilized a semiallogeneic combination (Lewis to LBNF1) to ensure unidirectional GVHD.
• Varied the extent of SB inclusion in the en bloc grafts to assess impact on GVHD incidence and mortality.

Main Results:

• En bloc MOTx with liver, pancreas, duodenum, and entire jejunum resulted in lethal GVHD in 100% of recipients (mean time to death: 16.5 days).
• Reducing SB graft to one-half jejunum still led to 100% lethal GVHD (mean time to death: 18 days).
• MOTx without SB (liver, pancreas, duodenum only) reduced lethal GVHD to 50%, with survivors exhibiting milder GVHD.

Conclusions:

• Multiorgan transplantation (MOTx) reliably induces GVHD in this rat model.
• The incidence and lethality of GVHD are significantly influenced by the inclusion and extent of small bowel (SB) transplantation.
• Transplanted lymphoid tissue quantity, particularly from the SB, is a critical determinant of GVHD severity and outcome in MOTx.