20 Engraftment of donor cells and donor-derived effective hematopoiesis has been documented by cytogenetic analysis in sex-mismatched donors 21 or by the use of genetically determined isoenzyme patterns. Successful engraftment after conventional myeloablative conditioning is indicated by recovery of peripheral blood counts, which is accompanied by normal bone marrow morphology. 17, 18 A recent study comparing myeloablative and nonmyeloablative SCT in patients more than 50 years of age 19 found that the overall outcome of the NMSCT approach was at least as good as that of the myeloablative approach. 4–13 Nonmyeloablative allogeneic stem cell transplantation (NMSCT) is also the preferred method for treating relatively indolent diseases in which the risks associated with a conventional myeloablative transplant would be considered unacceptable 14–16 as well as in some cases of failed autografts. The realization that the curative potential of any stem cell transplantation was largely the result of a graft-versus-tumor effect 1–3 has led to wider use of reduced intensity or nonmyeloablative conditioning in preparation for allogeneic SCT during the past few years. It provides an alternative to the conventional, myeloablative conditioning regimen with high-dose chemotherapy and total-body radiation, which is poorly tolerated by older patients, those receiving second transplants, and those with comorbid conditions. Similarly, early recurrence of disease was detected first by morphologic examination in 4 of 13 cases before a decline in donor engraftment occurred.Ĭonclusion.-Morphologic examination of bone marrow provides additional information that is complementary to donor engraftment analysis for optimal management after NMSCT.Īllogeneic stem cell transplantation (SCT) or bone marrow transplantation is a potentially curative procedure for patients with malignant and nonmalignant hematologic conditions, and appears to have at least a palliative role in controlling nonhematologic malignancies as well. Marrow failure without recurrent disease at 3 to 6 months after transplant was detected by engraftment study in only approximately 15% of cases. Marrow cellularity for the first 2 months after NMSCT was significantly lower in those patients receiving stem cells mismatched at 1 to 3 loci as compared with those who received fully matched grafts (mean cellularity, 38.1% vs 54.1% at day 14). Early posttransplant marrow in nearly one half of the patients showed myeloid hyperplasia and atypical localization of immature myeloid precursors. Morphologically detectable disease was still present in day 14 posttransplant marrow specimens in more than one half of these patients, but there was no difference in engraftment in those with or without marrow disease. Results.-Pretransplant bone marrow specimens from 43% of the patients were involved by disease, and these marrow specimens were significantly more cellular than those that were free of disease. Pretransplant and sequential posttransplant bone marrow specimens were evaluated and the findings were correlated with corresponding engraftment data. Objective.-To determine the role of morphologic examination of bone marrow after NMSCT.ĭesign.-Seventy-three patients undergoing NMSCT under the Campath 1H (humanized anti-CD52 antibody) protocol were studied. Patients are monitored principally by molecular analysis of donor engraftment. Context.-Nonmyeloablative stem cell transplantation (NMSCT) is a mode of immunotherapy increasingly employed in treating hematologic, lymphoid, and solid tumors.
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