The effect of haematopoietic stem cell transplant on papules with 'pebbly' appearance in Hunter's syndrome.

Abstract

Hunter's syndrome is associated with several cutaneous findings. For instance, papules with 'pebbly' appearance are a specific marker for the disease. However, it remains uncertain whether they disappear after haematopoietic stem cell transplant (HSCT). To investigate the papules with 'pebbly' appearance before and after HSCT in infants with Hunter's syndrome, and to clarify the effect of HSCT on papules. We observed five Japanese boys with Hunter's syndrome who had received HSCT at 4-11 years of age. The post-HSCT physical examinations revealed that papules disappeared completely within 35 days after the transplant with progressive reduction of cutaneous tightness in all the patients. Histochemical findings showed that papules contained a large amount of hyaluronic acid in the extracellular materials of the dermis and sulphated acid mucopolysaccharides in dermal fibroblasts before HSCT. These results suggest that papules with a 'pebbly' appearance fade away through the digestion of a large amount of hyaluronic acid in cutaneous tissues by normal tissue histiocytes or enzymes of donor origin at an early stage after HSCT.