Severe graft-versus-host disease after allogeneic hematopoietic stem cell transplantation with residual mogamulizumab concentration

Excerpt

We read with great interest the two articles by Tsubokura et al. and Ishitsuka et al. on allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult T-cell leukemia/lymphoma (ATLL) [1, 2]. Regimens containing mogamulizumab (Mog), an anti-CC chemokine receptor 4 (CCR4) monoclonal antibody, are expected to achieve good disease control before allo-HSCT and may result in low relapse rate after allo-HSCT. However, there is a concern that the use of Mog before allo-HSCT may cause severe acute graft-versus-host disease (aGVHD), as Mog eradicates normal CCR4-positive cells, including regulatory T cells (Tregs). Fuji et al. reported that Mog administration is associated with significantly increased risk of severe aGVHD due to such reduction in Tregs [3]. At present, there is no consensus on how to use Mog before allo-HSCT in Japan. Recently, Tsubokura et al. reported that monitoring of Tregs was useful for avoiding severe aGVHD [1]. Ishitsuka et al. demonstrated that the interval between the last administration of Mog and transplantation affected aGVHD [2]. In addition to monitoring of Tregs and the interval of administration, Fuji et al. proposed that monitoring of serum Mog level in peripheral blood is warranted [3]. However, little is known about the association between serum Mog level, Tregs, and aGVHD at the moment, and the threshold of serum Mog concentration at allo-HSCT has not been established. Here, we report the clinical course of an ATLL patient in whom Tregs and serum Mog concentration were measured after allo-HSCT (Fig. 1).

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