Reduced-intensity conditioning hematopoietic SCT for pediatric patients with LAD-1: clinical efficacy and importance of chimerism.

Pediatric patients with leukocyte adhesion deficiency type-I (LAD-I) experience severe and recurrent life-threatening bacterial infections with failure of pus formation and delayed wound healing. LAD-I is a rare inherited disease caused by mutation in the leukocyte CD18 integrin expression, resulting in defective adherence and migration of leukocytes, in particular neutrophilic granulocytes through the intravascular space. Hematopoietic SCT is the only curative treatment option available to patients with LAD-I. Since 2007, in a prospective trial, reduced-intensity conditioning regimen have been developed for 10 consecutive patients with LAD-I who were referred to our center. Based upon available data, it is the first time that such a number of patients affected by LAD-I have been treated with this regimen. This study attempts to show that reduced-intensity regimen leads to a favorable result in LAD-I patients even in those who have experienced comorbid complications. Following transplantation, some patients develop mixed chimerism, however, in our study mixed chimerism was not followed by transplant rejection.