Titrating graft-versus-host disease: is it worth a try?

Endpoints for clinical trials testing treatment of acute graft-versus-host disease: a joint statement

Currently, no agents are approved by the United States Food and Drug Administration (FDA) for either prevention or treatment of acute graft-versus-host disease (aGVHD). Formal precedents establishing a comparative basis for assessing the efficacy and safety of new investigational agents are still lacking. As a step toward addressing this problem, a panel of experts met on 2 occasions to reach consensus on recommendations for terminology describing a clinically meaningful primary endpoint in studies assessing treatment for aGVHD. The panel recommended terminology for "very good partial response" (VGPR) that includes both diagnostic and functional criteria. The central hypothesis leading to this proposal is that the potential harm of giving more treatment than needed to produce or maintain complete response exceeds the harm of slight undertreatment that may be associated with less than complete response. VGPR clearly cannot be used as the sole outcome measure in GVHD treatment trials, and must be considered in the context of survival and safety. The proposed use of VGPR as the primary endpoint in GVHD treatment trials will remain provisional until its use has been validated through experience.

Oral graft-versus-host disease

Hematopoietic cell transplantation is used to treat malignancies, hematologic and immune deficiency states, marrow failure syndromes, and autoimmune diseases. Graft-versus-host disease (GVHD) is a clinical syndrome seen following allogeneic transplantation where donorderived immunocompetent T cells and inflammatory responses attack host tissues. GVHD can cause significant morbidity and even result in mortality. The oral cavity is a frequently involved site with clinical changes resembling autoimmune collagen vascular diseases. Recognition, diagnosis, and monitoring of oral GVHD can help with diagnosis and grading of GVHD and judging responses to therapy. Topical and local management of symptomatic oral GVHD can reduce oral symptoms that can interfere with oral function and quality of life, and can reduce the need for more intensive immunosuppressive systemic therapies.

Radiation protocols determine acute graft-versus-host disease incidence after allogeneic bone marrow transplantation in murine models

PURPOSE

Effects of radiation sources used for total body irradiation (TBI) on Graft-versus-Host Disease (GvHD) induction were examined.

MATERIALS AND METHODS

In a T cell receptor (TCR) transgenic mouse model, single fraction TBI was performed with different radiation devices ((60)Cobalt; (137)Cesium; 6 MV linear accelerator), dose rates (0.85; 1.5; 2.9; 5 Gy/min) and total doses before allogeneic bone marrow transplantation (BMT). Recipients were observed for 120 days. Different tissues were examined histologically.

RESULTS

Acute GvHD was induced by a dose rate of 0.85 Gy/min ((60)Cobalt) and a total dose of 9 Gy and injection of 5 x 10(5) lymph node cells plus 5 x 10(6) bone marrow cells. Similar results were obtained using 6 MV linear accelerator- (linac-) photons with a dose rate of 1.5 Gy/min and 0.85 Gy/min, a total dose of 9.5 Gy and injection of same cell numbers. TBI with (137)Cesium (dose rate: 2.5 Gy/min) did not lead reproducibly to lethal acute GvHD.

CONCLUSIONS

Experimental TBI in murine models may induce different immunological responses, depending on total energy, total single dose and dose rate. GvHD might also be induced by TBI with low dose rates.