Loss of tolerance associated with disappearance of B cells in a patient sequentially transplanted with paternal and maternal bone marrow for the treatment of severe combined immunodeficiency disease.
Academic Article
Overview
abstract
We have studied the tolerance of engrafted T cells from a severe combined immunodeficiency disease patient sequentially transplanted with T-cell-depleted bone marrow from both HLA haploidentical parents. The T cells from this patient were shown by HLA typing and cytogenetic analysis to be of material origin (donor of the second graft) while HLA typing of peripheral E--populations and of an Epstein-Barr virus-transformed B-cell line established 2 1/2 years after transplantation revealed the presence of host, maternal, and paternal (donor of the first graft) HLA antigens. When tested at 30 and 60 months after the last transplant, engrafted T cells from this patient had only weak mixed lymphocyte culture reactivity to paternal cells which could be inhibited by monoclonal antibodies to HLA-DQ and DR but not by anti-DP. T cells obtained 60 months after transplant were stimulated with paternal cells in both bulk and limiting dilution cultures and failed to generate typical allocytotoxic cells to paternal T- or B-cell targets. Mixed lymphocyte cultures performed at 71 months revealed an increased proliferative response by patient cells to paternal antigens; however, the engrafted T cells remained tolerant to maternal and host antigens. Limiting dilution analysis performed at this time revealed the presence of cytolytic cells directed to paternal antigens. There were no detectable B cells (only identified source of paternal antigen) as measured by immunofluorescent analysis of peripheral blood, nor any evidence of B-cell function as assessed by in vitro assays (proliferation to staphylococcus aureus Cowen strain A and mitogen-stimulated immunoglobulin production) or in vivo production of serum immunoglobulin at 60 and 71 months. The appearance of alloreactivity associated with the loss of B cells in this patient further supports the conclusion that the maintenance of tolerance to major histocompatibility complex disparate cells requires the continued in vivo presence of cells bearing the tolerizing antigens.
