Biomedical subjects

R Szydlo

Publications and source records attributed to R Szydlo.

24 records · Page 2Linked to original sources

PubMed1997

Results of allogeneic bone marrow transplants for leukemia using donors other than HLA-identical siblings.

PURPOSE: To compare outcomes of bone marrow transplants for leukemia from HLA-identical siblings, haploidentical HLA-mismatched relatives, and HLA-matched and mismatched unrelated donors. PATIENTS: A total of 2,055 recipients of allogeneic bone marrow transplants for chronic myelogenous leukemia (CML), acute myelogenous leukemia (AML), and acute lymphoblastic leukemia (ALL) were entered onto the study. Transplants were performed between 1985 and 1991 and reported to the International Bone Marrow Transplant Registry (IBMTR). Donors were HLA-identical siblings (n = 1,224); haploidentical relatives mismatched for one (n = 238) or two (n = 102) HLA-A, -B, or -DR antigens; or unrelated persons who were HLA-matched (n = 383) or mismatched for one HLA-A, -B, or -DR antigen (n = 108). HLA typing was performed using serologic techniques. RESULTS: Transplant-related mortality was significantly higher after alternative donor transplants than after HLA-identical sibling transplants. Among patients with early leukemia (CML in chronic phase or acute leukemia in first remission), 3-year transplant-related mortality (+/-SE) was 21% +/- 2% after HLA-identical sibling transplants and greater than 50% after all types of alternative donor transplants studied. Among patients with early leukemia, relative risks of treatment failure (inverse of leukemia-free survival), using HLA-identical sibling transplants as the reference group, were 2.43 (P < .0001) with 1-HLA-antigen-mismatched related donors, 3.79 (P < .0001) with 2-HLA-antigen-mismatched related donors, 2.11 (P < .0001) with HLA-matched unrelated donors, and 3.33 (P < .0001) with 1-HLA-antigen-mismatched unrelated donors. For patients with more advanced leukemia, differences in treatment failure were less striking: 1-HLA-antigen-mismatched relatives, 1.22 (P = not significant [NS]); 2-HLA-antigen-mismatched relatives, 1.81 (P < .0001); HLA-matched unrelated donors, 1.39 (P = .002); and 1-HLA-antigen-mismatched unrelated donors, 1.63 (P = .002). CONCLUSION: Although transplants from alternative donors are effective in some patients with leukemia, treatment failure is higher than after HLA-identical sibling transplants. Outcome depends on leukemia state, donor-recipient relationship, and degree of HLA matching. In early leukemia, alternative donor transplants have a more than twofold increased risk of treatment failure compared with HLA-identical sibling transplants. This difference is less in advanced leukemia.

Age Factors↗

PubMed1996

Cytomegalovirus antibody avidity in allogeneic bone marrow recipients: evidence for primary or secondary humoral responses depending on donor immune status.

The reconstitution of the human cytomegalovirus (CMV) antibody response in CMV seropositive bone marrow transplant patients was investigated by comparing 11 patients whose donors were CMV seropositive with 8 whose donors were CMV seronegative. Evidence for primary or secondary responses to CMV was sought by determining IgG antibody avidity using an avidity index method, and antibody titre over a period of up to 3 years after transplant. For the patients whose donors were CMV seropositive, the results showed the characteristics of a secondary response, i.e., rising antibody titres of high avidity immediately after transplant. In contrast, the patients with CMV seronegative donors showed evidence of a primary antibody response usually occurring at about 250 days after transplant, i.e., rising antibody levels initially of low avidity maturing to high avidity over the following 100 to 200 days. It is concluded that a secondary response and hence transfer of humoral immunity had occurred in those patients whose donor was CMV seropositive, whereas a delayed primary response occurred in those patients whose donor was CMV seronegative.

Antibodies, Viral↗

PubMed1993

Choice of pretransplant treatment and timing of transplants for chronic myelogenous leukemia in chronic phase.

We analyzed the outcome of 450 HLA-identical sibling bone marrow transplants for chronic myelogenous leukemia (CML) in chronic phase performed between 1985 and 1990 and reported to the International Bone Marrow Transplant Registry (IBMTR). All patients received either hydroxyurea (n = 292) or busulfan (n = 158) to treat their CML before transplant. The median interval between diagnosis and transplant was 10 months (range, 1 to 191). Patients treated with hydroxyurea had a higher probability (95% confidence interval) of leukemia-free survival (LFS) at 3 years than those treated with busulfan (61% [51% to 70%] v 45% [36% to 55%], P < .0003). Probability of LFS was also higher in patients transplanted within 1 year of diagnosis (61% [53 to 68%] v 47% [38% to 57%], P < .001). After adjustment for patient and transplant covariables in a multivariate analysis, prior chemotherapy and duration of disease pretransplant were independently associated with LFS. These data support the use of hydroxyurea rather than busulfan and transplant within 1 year of diagnosis for patients with CML and an HLA-identical sibling.

Actuarial Analysis↗

PubMed1993

Phenotypic characterization of normal and CML CD34-positive cells: only the most primitive CML progenitors include Ph-neg cells.

We studied the sequence of acquisition of CD33, CD38 and HLA-DR antigens on CD34+ cells from marrow and blood of Ph-chromosome positive CML patients and normal marrow. We examined the Ph status of the various CML cell populations. The mean proportions of normal and CML CD34+ cells expressing CD33 and CD38 were not significantly different. However, a significantly greater proportion of CML CD34+ cells expressed HLA-DR antigens compared with normal CD34+ cells and the level of HLA-DR expression per CML cell was abnormally high. When the sequence of acquisition of these antigens on normal and CML CD34+ cells was evaluated using 3-colour fluorescence analysis, the results suggested that HLA-DR was expressed earlier than CD38 or CD33 and these findings were confirmed by following the acquisition of CD38 and CD34+/DR+/CD38-subpopulation during liquid culture. We performed cytogenetic studies on CD34+ subpopulations in 6 cases. In 4 cases there were some Ph-negative metaphases detectable in the CD34+/DR-subpopulation (range 12.5 to 60%). In the CD34+/DR+ fractions, however, all 6 patients had only Ph-positive metaphases and only 1/5 patients had detectable Ph-negative metaphases in the CD34+/CD38-subpopulation. We conclude that expression of HLA-DR antigens may precede the expression of CD38 on CD34+ cells during normal stem cell differentiation. In CML DR may be expressed aberrantly and Ph-negative cells are found predominantly in the DR negative subpopulation.

ADP-ribosyl Cyclase↗

PubMed1992

HLA-identical sibling donor bone marrow transplantation for chronic myeloid leukaemia in first chronic phase: influence of GVHD prophylaxis on outcome.

We have analysed the results of treating 140 consecutive patients with chronic myeloid leukaemia (CML) in chronic phase by bone marrow transplantation (BMT) using marrow from HLA-identical siblings performed between February 1981 and July 1991. Three different regimens were used sequentially to prevent graft-versus-host disease (GVHD): cyclosporin A (CsA) alone (n = 39), T-cell depletion of donor marrow (n = 51) and CsA with methotrexate (MTX) (n = 50). Eighty-four patients (61%) survive at a median of 49 months from BMT (range 3-120). The actuarial overall and leukaemia-free survivals at 5 years were 52% and 41% respectively. The actuarial probabilities of leukaemia-free survival and haematological relapse at 2 years for the CsA only group were 65% and 4%, for the T-cell depletion group 40% and 41% and for the CsA/MTX group 68% and 6% respectively. For the T-cell depletion group the probability of leukaemia-free survival was significantly lower (P less than 0.001) and the probability of relapse significantly higher (P less than 0.001) than for other methods of GVHD prophylaxis; differences between the other two groups were not significant. Previous reports that T-cell depletion with Campath-1M results in a high rate of relapse are confirmed. Patients in the CsA/MTX group have been monitored with cytogenetic and polymerase chain reaction studies for residual BCR/ABL transcripts. We conclude that the combination of CsA/MTX is currently the best available approach to prevention of GVHD after BMT for CML and in our hands it is not associated with a major risk of relapse.

Adolescent↗

PubMed1992

Unrelated donor marrow transplants for severe acquired aplastic anemia.

This report is divided into two parts. The first part is a retrospective analysis of 40 unrelated transplants [UD-BMT] for severe acquired aplastic anemia [SAA], performed at five transplant centers between 1981 and 1990. The second is an interim analysis of 15 UD-BMT for SAA compared with a matched cohort of 16 sibling transplants [ID-BMT] carried out since February 1989 using prospectively collected data provided by the IMUST Study Group. In the retrospective study the actuarial survival was 28% [+/- 15] with a median follow-up of 1485 [266-3890] days post BMT. Univariate analysis showed a considerable survival advantage for patients younger than 15 years at BMT [p = 0.03]. More recently patients entered in the IMUST Study showed an actuarial survival of 50% [+/- 27] for UD-BMT compared with 58% [+/- 31] for ID-BMT recipients. These data suggest that UD-BMT is a realistic option for paediatric patients with SAA. Although numbers are very small there is some indication from IMUST Study data that better patient selection and intensive BMT protocols may also improve the results of UD-BMT in young adult patients with SAA.

Adolescent↗