Acute rejection has occurred in 79% of patients undergoing intestine-only transplants. Once again the liver, and perhaps other organs, may have a protective effect since the acute rejection rates for liver/intestine and multivisceral transplants have been 71% and 56% respectively. Similarly, chronic rejection, which has been demonstrated in 13% of intestine-only transplants, has been uncommon in liver/ intestine (3%) and multivisceral transplants (0%). Despite the fact that most centers avoid transplanting intestinal grafts from cytomegalovirus (CMV) positive donors, CMV infections occurred in 24% of intestine-only grafts, 18% of liver/ intestine grafts, and 40% of multivisceral grafts.

Post-transplant lymphoproliferative disorders (PTLDs) have been seen in 8.3% of intestine-only, 13.3% of liver/intestine, and 15.8% of multivisceral grafts.10 PTLDs often manifest as fever and lymphadenopathy or lymphoproliferation in either donor or recipient tissue. Lymphoma can also manifest with gastrointestinal symptoms including nausea, vomiting, diarrhea, bowel obstruction, GI bleeding, or perforation.

The incidence of PTLD in intestinal transplant recipients is higher than in other organ transplant recipients. The occurrence of PTLD clearly correlates with the intensity of immunosuppression. Significant increases in the incidence of PTLD are noted in-patients who receive OKT3 or ATGAM, especially if their total antibody course exceeds 21 days. While PTLD tends to first manifest between 2 weeks and 6 months after a transplant, it can appear at any time.

The diagnosis of PTLD usually requires a biopsy. Often this is most easily obtained from an enlarged superficial lymph node or from clinically or radiologi-cally involved tissue. If the suspected organ is the intestine graft itself, it can sometimes be difficult to differentiate PTLD from rejection, or CMV infection. When this is the case it is often useful to obtain further studies including EBER staining of suspicious tissue. It is often also useful to evaluate the serum for a typical monoclonal or polyclonal immunoglobulin bands which can sometimes be present. Gene studies are often helpful to identify abnormal karyotypes which can aid in diagnosis and prognosis (C-myc, N-ras, p 53) is polyclonal or monoclonal. It should also be determined whether the abnormal lymphocytes sites are primarily B cells or T cells. T cell lymphomas are less common than B cell lymphomas in post-transplant PTLDs.

If the diagnosis of PTLD is made, immunosuppression should be reduced to approximately half of what it had been. In approximately one third of cases, this will result in a remission of the PTLD. Anti B-cell mAB (Rituximab) therapy is initiated. If after 2 weeks there is no evidence of improvements, all immunosup-pression should be discontinued and serious consideration should be given to additional therapeutic measures including chemotherapy and/or adoptive immunotherapy. If necessary, an intestine-only graft can also be removed.

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