Cord blood mononuclear cells are comprised of a heterogenous population of hematopoietic and mesenchymal stem cells, endothelial progenitor cells, and immature immunological cells [1, 2]. The conventional medical use of cord blood is limited to hematopoietic reconstitution , with clinical trials ongoing in type I diabetes , and cerebral palsy . Preclinical studies have demonstrated efficacy of cord blood in diverse conditions ranging from heat stroke [6, 7], to amyotrophic lateral sclerosis , to post infarct regeneration , to liver failure .
In hematopoietic stem cell transplants ablation of recipient marrow is required to eradicate the endogenous stem cell compartment, and HLA matching with post transplant immune suppression is used to prevent GVHD . For non-hematopoietic applications such as cardiovascular or neurological indications, the therapeutic activities of the cord blood are believed to be mediated in many cases by growth factor secretion [11, 12], therefore permanent graft survival is not essential. In these situations the use of non-matched, allogeneic cells may be acceptable. The major barrier to this approach is the theoretical fear of inducing GVHD.
From practical experience there is some evidence that in immune competent recipients, non-matched allogeneic cord blood cells do not elicit GVHD. Specifically: a) Recipients of cord blood in the transfusion scenario, in some cases up to 37 units, have not reported GVHD; b) T cells comprise the GVHD-causing component of cord blood. Administration of allogeneic lymphocytes for prevention of recurrent spontaneous abortion has not led to GVHD, despite higher T cell doses than found in cord blood transplants; and c) Despite presence of fetal T cells in mothers, GVHD associated with pregnancy has not been reported .
Under the practice of medicine, several treatment facilities have been using cord blood stem cells without matching or immune suppression [14–17]. Despite identification of a "clinical signal", studies have been extremely limited in patient numbers. In the current report we analyzed safety parameters of 114 patients treated with non-matched, allogeneic cord blood mononuclear cells. Treatments included intravenous and intrathecal administration. No immunological reactions, GVHD, or serious adverse effects were observed. Hematological, biochemical, and immunological parameters remained within normal range.