However, this is partially explained by the fact that the indication itself, that is, complete DiGeorge syndrome, increases the risk of autoimmune disease. Thymoma-associated multiorgan autoimmunity (TAMA)
A GvHD-like disease called thymoma-associated multiorgan autoimmunity (TAMA) can occur in patients with thymoma. In these patients rather than a donor being a source of pathogenic T cells, the patients own malignant thymus produces self-directed T cells. This is because the malignant thymus is incapable of appropriately educating developing thymocytes to eliminate self-reactive T cells. The result is a disease virtually indistinguishable from GvHD. Mechanism
The pathophysiology of GvHD includes three phases:
The afferent phase: activation of APC (antigen presenting cells)
The efferent phase: activation, proliferation, differentiation and migration of effector cells
The effector phase: target tissue destructionActivation of APC occurs in the first stage of GvHD. Prior to haematopoietic stem cell transplantation, radiation or chemotherapy results in damage and activation of host tissues, especially intestinal mucosa. This allows the microbial products to enter and stimulate pro-inflammatory cytokines such as IL-1 and TNF-α. These proinflammatory cytokines increase the expression of MHC and adhesion molecules on APCs, thereby increasing the ability of APC to present antigen. The second phase is characterized by the activation of effector cells. Activation of donor T-cells further enhances the expression of MHC and adhesion molecules, chemokines and the expansion of CD8 + and CD4 + T-cells and guest B-cells. In the final phase, these effector cells migrate to target organs and mediate tissue damage, resulting in multiorgan failure.
HIV elimination
Graft-versus-host disease has been implicated in eliminating several cases of HIV, including The Berlin Patient and 6 others in Spain. See also
Graft-versus-tumor effect
Immunosuppression
Transplant rejection

References
Further reading
Ferrara JLM, Deeg HJ, Burakoff SJ. Graft-Vs.-Host Disease: Immunology, Pathophysiology, and Treatment. Marcel Dekker, 1990 ISBN 0-8247-9728-0
Polsdorfer, JR Gale Encyclopedia of Medicine: Graft-vs.-host disease


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