Human DOCK2 mutations underlie an autosomal recessive pleiotropic immunodeficiency with early-onset invasive infections.

The overall emphasis of Dr. Buckley's research is in human T,B and NK cell development and in aberrations in their development and regulation. The work involves three particular areas of investigation: 1) the cellular and molecular bases of genetically-determined human immunodeficiency diseases, 2) the use of bone marrow stem cells to cure genetically-determined immunodeficiency diseases, and 3) the use of human SCID bone marrow stem cell chimeras to study human thymic education, T and B cell ontogeny, tolerance induction and MHC restriction mechanisms. Methodology includes monoclonal antibody (mAb) analyses of lymphocyte phenotypes, a variety of T cell and natural killer (NK) cell functional assays, studies of thymic output by T cell receptor recombination excision circle measurement, studies of T cell diversity by spectratyping, studies of T cell longevity by telomere analysis and assessment of B cell differentiation and function. A unique resource available for her studies is the largest population of patients with genetically-determined immunodeficiency diseases in the U.S., which includes the largest population in the world of longterm SCID chimeras treated at a single center, some of whom have been studied and followed for more than 37 years. The administration of rigorously T cell depleted haploidentical bone marrow stem cells to SCID recipients without pre-transplant conditioning or post-transplant use of immunosuppressive drugs to prevent GVHD provides an unmanipulated system for studying human thymic education, T and B cell ontogeny, MHC restriction mechanisms and tolerance induction. Studies to identify mutations in patients with primary immunodeficiency are continuing, particularly in those with SCID.