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312 / Chapter 23 Stem cell transplantation

(a) (b) (c) (d)

Figure 23.13 Post - transplantation lymphoproliferative diseases: 17 - year - old male 5 months after renal transplan-

tation had small bowel perforation caused by diffuse large B - cell lymphoma. (a) Low - power view of lymphoid
mass invading small bowel. (b) High - power view of lymphoid mass. (c) Immunostaining for CD20. (d) EBV - ISH
( in situ hybridization) stain showing the tumour cells are positive for Epstein – Barr virus (EBV). (Courtesy of
Professor P. Amrolia and Dr N. Sebire.)

samples for evidence of recurrence of the BCR - Post - t ransplant l ymphoproliferative

ABL1 transcript before karyotypic or clinical d iseases
relapse occurs (Fig. 23.11 ). DLI can then be used Th ese are polyclonal or monoclonal lymphoid

in cases of molecular relapse. The response to DLI proliferations that occur in recipients of stem
may take several weeks but usually results in a cell or more frequently solid organ allografts, as

permanent cure. The mechanism is unclear but a a result of the intensive immunosupression.
T - cell - mediated alloreactive immune response is Th ey may be EBV driven and are usually of B - cell
likely to be a major component. Positron emission origin. Th ere is often involvement of bowel, lung
tomography (PET) scans are now being used to or bone marrow (Fig. 23.13 ). Treatment is by
detect the presence of residual disease and can be reduction of immunosupression (if feasible), anti -
used to guide both the requirement for DLI CD20 (rituximab) and, if appropriate, chemother-
and also determining the disease response (Fig. apy or cytotoxic T cells engineered to kill the
23.12 ). EBV + tumour cells.

SUMMARY ■ Stem cell transplantation (SCT) involves ■ Allogeneic SCT requires a tissue (HLA)

replacing the haemopoietic and immune
matching sibling or unrelated donor. The
systems by stem cells from either the same
human leukocyte antigens (HLA) are
coded for by genes on chromosome 6.
subject (autologous) or another individual
They are extremely polymorphic and are
(allogeneic). The donor stem cells can be
involved in presentation of antigens to T
harvested from bone marrow, peripheral

blood or umbilical cord.
lymphocytes.

■ Autologous SCT is most frequently

performed for lymphomas or ■ Allogeneic SCT is indicated in selected
cases of acute leukaemia, other malignant
myeloma. bone marrow diseases, and severe

■ For allogeneic SCT the recipient ’ s own acquired or genetic marrow diseases (e.g.
haemopoietic and immune systems are aplastic anaemia, thalassaemia major).
eliminated by chemotherapy, radiotherapy Reduced intensity conditioning SCT may
and monoclonal antibodies. be preferred in older subjects.