Severe combined immunodeficiencies are a group of rare genetic disorders characterized by a profound impairment in both cellular and humoral immune functions. This disorder is rapidly fatal without bone marrow transplantation. Unfortunately, most children lack a histocompatible donor. The development of T cell depletion allows for haploidentical transplantation with reduced risk of GVHD. In the present article, we discuss the case of a child diagnosed with X-linked severe combined immunodeficiency for whom haploidentical peripheral blood stem cell transplantation was performed by selecting CD34-positive cells followed by depletion of T cells. Both selection and purging were performed using immunoselection by the biotin-avidin system (CEPRATE System). The CD34-enriched T cell-depleted product contained 5.05 x 10(6)/kg CD34+ cells with only 0.01 [corrected] x 10(6)/kg CD3+ cells, achieving a T cell depletion of 4.2 log.