PMID- 1967216 OWN - NLM STAT- MEDLINE DCOM- 19900209 LR - 20210216 IS - 0006-4971 (Print) IS - 0006-4971 (Linking) VI - 75 IP - 1 DP - 1990 Jan 1 TI - Natural history of mixed chimerism after bone marrow transplantation with CD6-depleted allogeneic marrow: a stable equilibrium. PG - 296-304 AB - Mixed hematopoietic chimerism (MC) is a common finding after allogeneic bone marrow transplantation (BMT), but the natural history of this phenomenon remains unclear. To understand the evolution and the implications of this finding, we performed a prospective analysis of the development of mixed chimerism in 43 patients with hematologic malignancies who received bone marrow (BM) from human leukocyte antigen (HLA)-identical sibling donors. T-cell depletion in vitro with anti-T12 (CD6) monoclonal antibody and rabbit complement was used as the only method of graft-versus-host disease (GVHD) prophylaxis. Overall, MC was identified in peripheral blood (PB) and BM in 22 of 43 (51%) patients evaluated. MC was found by restriction fragment length polymorphism (RFLP) analysis in 21 of 40 (53%) patients, by cytogenetic analysis in 6 of 29 (21%) patients, and by red blood cell phenotyping in 4 of 9 (44%) patients. RFLP studies were performed at 0.5, 1, 3, 6, 9, and 12 months post-BMT and then every 6 months, and showed a high probability of developing MC in the first 6 months after BMT followed by stabilization after 12 months. Cytogenetic analysis was less sensitive in detecting MC. Once MC was detected after BMT, the percentage of recipient cells increased very slowly over more than 3 years of follow-up, and no patient reverted to complete donor hematopoiesis (CDH). Thus, recipient and donor cells remained in a relative state of equilibrium for prolonged periods that seemed to favor recipient cells over donor cells. Patient's disease, remission status, or intensity of the transplant preparative regimen did not influence the subsequent development of mixed chimerism. Early immunologic reconstitution was the only factor that correlated with the subsequent chimeric status of the patients. The percentage and absolute number of T3 (CD3) and T4 (CD4) positive cells at day 14 after BMT were significantly higher in the patients who maintained CDH but NK cell reconstitution was similar in both groups, suggesting that early reconstitution with T cells may play a role in preventing recovery of recipient cells after BMT. GVHD was also associated with maintenance of CDH, but the probability of relapse, survival, and disease-free survival was identical in patients with MC and CDH. FAU - Roy, D C AU - Roy DC AD - Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115. FAU - Tantravahi, R AU - Tantravahi R FAU - Murray, C AU - Murray C FAU - Dear, K AU - Dear K FAU - Gorgone, B AU - Gorgone B FAU - Anderson, K C AU - Anderson KC FAU - Freedman, A S AU - Freedman AS FAU - Nadler, L M AU - Nadler LM FAU - Ritz, J AU - Ritz J LA - eng GR - N01-A1-62531/PHS HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - United States TA - Blood JT - Blood JID - 7603509 RN - 0 (Antigens, CD) RN - 0 (Antigens, Differentiation, T-Lymphocyte) RN - 0 (CD6 antigen) SB - IM MH - Antigens, CD/*analysis MH - Antigens, Differentiation, T-Lymphocyte/*analysis MH - Blood Grouping and Crossmatching MH - Bone Marrow Transplantation/immunology/*pathology MH - Cell Separation MH - Chimera MH - Cytogenetics MH - Hematopoiesis MH - Humans MH - Polymorphism, Restriction Fragment Length MH - Prognosis MH - Prospective Studies MH - Survival Analysis MH - Time Factors EDAT- 1990/01/01 00:00 MHDA- 1990/01/01 00:01 CRDT- 1990/01/01 00:00 PHST- 1990/01/01 00:00 [pubmed] PHST- 1990/01/01 00:01 [medline] PHST- 1990/01/01 00:00 [entrez] AID - S0006-4971(20)85852-2 [pii] PST - ppublish SO - Blood. 1990 Jan 1;75(1):296-304.