title: Enhanced lymphoid cell recovery after bone marrow transplantation: correlation with the presence of costimulatory antibodies in serum.
abstract: We describe a patient with T cell deficiency who underwent bone marrow transplantation (BMT) from an HLA-identical brother. The patient's white blood cell count recovered with exceptional rapidity post-BMT: after 7 to 9 days it rose sharply to 98x10(9) cells/L, 76% of which were mononuclear leukocytes. It then decreased, and a second peak was observed 250 days post-BMT. Lymphocytes from both peaks displayed a phenotype of mature T cells together with characteristics of a constitutively activated state; that is, they 1) exhibited high levels of tyrosine-phosphorylated T cell receptor (TCR) zeta chain, 2) spontaneously secreted IL-2, 3) expressed activation specific cell surface markers, and 4) were unresponsive to in vitro stimuli. The increased cell counts in both peaks correlated with the presence of anti-lymphocytic antibodies in the patient's serum, which reacted with peripheral blood lymphocytes (PBLs) both from the donor and from unrelated individuals. These antibodies were present before BMT and reappeared post-BMT. Variable number tandem repeats analysis revealed that the patient's PBLs were chimeras for up to 2 years post-BMT. This finding could explain the newly synthesized post-BMT anti-lymphocytic antibodies and the appearance of the second WBC peak during that period. The patient's anti-lymphocytic antibodies displayed costimulatory activity, enhancing the in vitro proliferation of normal T cells suboptimally activated via the TCR. The unique characteristics of these antibodies could explain the enhanced T cell recovery observed post-BMT as well as the constitutive activation state of these cells. Furthermore, such antibodies may eventually facilitate development of a therapeutic method for inducing enhanced post-BMT recovery.
authors.affiliation: Tissue Typing Unit, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Bishara
authors.forename: M
authors.initials: M
authors.lastname: Aker
authors.forename: A
authors.initials: A
authors.lastname: Amar
authors.forename: C
authors.initials: C
authors.lastname: Brautbar
authors.forename: M
authors.initials: M
authors.lastname: Schlesinger
authors.forename: R
authors.initials: R
authors.lastname: Rabinowitz
authors.forename: S
authors.initials: S
authors.lastname: Slavin
authors.forename: M
authors.initials: M
authors.lastname: Baniyash
mesh_terms: D000293:Adolescent; D000906:Antibodies / Q000097:blood; D001782:Blood Donors; D016026:Bone Marrow Transplantation / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies