INTRODUCTION
Neurological complications from hematopoietic cell transplantation (HCT) often occur from the conditioning regimen (immediate or delayed), from the interval of pancytopenia (infection, bleeding), and from prophylactic drugs for graft versus host disease (GVHD) (particularly calcineurin inhibitors). Less common and more controversial are neurological problems related to chronic graft versus host disease (cGVHD) itself, the topic of this chapter.
With cGVHD defined narrowly as a systemic syndrome mediated by donor T cells, then only polymyositis would qualify as a bone fide neurological manifestation of cGVHD. However, a broader and probably more appropriate perspective would include neurological immune-mediated manifestations that occur in the context of characteristic manifestations of systemic cGVHD or at least in the appropriate time frame of cGVHD. With this broader perspective, myasthenia gravis, possibly immune-mediated polyneuropathies, and a variety of central nervous system (CNS) problems could be considered as instances of “neurological cGVHD.”
The obvious difficulty in this interpretation is that cGVHD occurs relatively late in the transplant course (after 3 months) and still later in the course of the hematological malignancy. With multiple intervening therapies and metabolic and infectious complications along the way, it may be problematic to attribute a particular neurological problem directly to cGVHD.
This chapter reviews peripheral nervous system (PNS) manifestations of cGVHD, describes some interesting CNS cases, and proposes criteria that may be appropriate in accepting particular cases as CNS cGVHD. Table 23.1 lists the various entities discussed with estimates of frequency and range of time post-HCT when they most commonly occur.