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S R McCann

Publications and source records attributed to S R McCann.

At least 19 recordsLinked to original sources
PubMed1995

Studies on hemopoietic chimerism following allogeneic bone marrow transplantation in the molecular biology era.

Donor hematopoiesis or donor chimerism in the host following allogeneic bone marrow transplantation (BMT) has appeared crucial to the engraftment process. However, as molecular techniques exploiting neutral variation in human genetic material have been used in the study of chimerism, the detection of residual host cells or mixed hemopoietic chimerism has indicated that donor chimerism is not obligatory following BMT. This review focuses on the detection and significance of mixed chimerism (MC) in patients transplanted for both malignant and non-malignant hemopoietic disease and attempts to tease out the contribution of MC to engraftment, leukemia relapse, graft rejection and long-term disease-free survival.

Anemia, Aplastic↗
PubMed1995

Methylprednisolone in advanced chronic lymphocytic leukaemia: rationale for, and effectiveness of treatment suggested by DiSC assay.

The effect of methylprednisolone on fresh cells from patients with chronic lymphocytic leukaemia (CLL) has been studied using the differential staining cytotoxicity (DiSC) assay resulting in LC90s of < or = 0.2 to 2,000 micrograms/ml. Cells from previously treated patients were, on average, significantly more sensitive to methylprednisolone than those from untreated patients (mean LC90 = 5.7 micrograms/ml, n = 61 vs 31.0 micrograms/ml, n = 17, respectively; p < 0.05). Twelve patients with advanced disease were given high-dose methylprednisolone (1 g/m2/day i.v. x 5 days). In 7 cases, > or = 3 courses were given; 3 patients did not respond (2 achieved palliation) and 4 (57%) achieved a good partial response. These latter 4 patients were all clinically resistant to chlorambucil and anthracyclines and 2 were resistant to fludarabine. In 5 cases, 1 or 2 courses were given but no patients responded. The 8 nonresponders survived a median of 3.5 months whilst the responders have survived a median of 28.5+ months (3 of 4 still alive). This work suggests a rationale for why CLL patients resistant to standard chemotherapy may benefit from high-dose methylprednisolone therapy. Due to cost and toxicity associated with therapy, the decision to treat would be best made on the basis of a DiSC assay result. This pilot study requires confirmation with a well-designed controlled clinical trial.

Adult↗
PubMed1995

Bone marrow transplantation for Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a rare disorder usually diagnosed in the first year of life. Although most cases respond to corticosteroids, > 20% are, or become, steroid-resistant. We report 10 children with DBA who received a bone marrow transplant from an HLA-identical sibling (n = 8), maternal (n = 1) or unrelated (n = 1) donor and reported to the International Bone Marrow Transplant Registry. Among eight recipients of HLA-identical sibling transplants, six are alive 5-87 months after transplant with no evidence of DBA and with Karnofsky performance scores of 90-100%. The two recipients of non-HLA-identical sibling transplants died < 2 weeks after transplant. The actuarial 2-year probability of survival for the eight sibling transplants was 72 (37-92)% (95% confidence interval).

Adolescent↗
PubMed1994

Haemopoietic growth factors in aplastic anaemia: a cautionary note. European Bone Marrow Transplant Working Party for Severe Aplastic Anaemia.

We are concerned about the inappropriate use of haemopoietic growth factors in patients with severe aplastic anaemia (SAA). The treatment of choice for this disorder is bone-marrow transplantation from an HLA-identical sibling donor if the patient is younger than 45 years, but it must be done soon after onset before the patient becomes sensitised by multiple red-cell and platelet transfusions. Other patients should receive immunosuppressive therapy with antithymocyte globulin alone or with cyclosporin or oxymetholone. Haemopoietic growth factors may have a role in stimulation of granulopoiesis after immunosuppressive therapy, but there is no evidence that they can correct the underlying stem-cell defect in SAA, and therefore no justification for their use alone in newly diagnosed SAA. Such treatment is harmful because it delays bone-marrow transplantation, or immunosuppressive therapy in older patients and those without suitable donors, thus reducing the chances of a successful outcome.

Age Factors↗
PubMed1994

Localized, late-onset, high-grade lymphoma following bone marrow transplantation: response to combination chemotherapy.

Non-Hodgkin's lymphoma is the commonest secondary cancer following bone marrow transplantation (BMT). We report the case of a 42-year-old man who developed a laryngeal high-grade B-cell lymphoma 5 years following a matched T depleted BMT for CML. Polymerase chain reaction (PCR) analysis using the microsatellite marker Cyp 19 demonstrated the donor origin of involved tissue. Epstein-Barr virus (EBV) genomic sequences were identified by PCR. Although EBV related B-cell lymphoproliferative disorders (BLPD) post BMT are difficult to treat, there was a complete remission in this patient following three courses of chemotherapy (CHOP) administered with G-CSF. This case of late-onset BLPD appears clinically distinct from the well-defined, aggressive, early post-transplant BLPD.

Adult↗
PubMed1994

Infection of donor lymphocytes with human T lymphotrophic virus type 1 (HTLV-I) following allogeneic bone marrow transplantation for HTLV-I positive adult T-cell leukaemia.

Human T lymphotrophic virus type 1 (HTLV-I) associated leukaemia has a poor prognosis even with chemotherapy. We describe a patient with adult T-cell leukaemia treated with allogeneic bone marrow transplantation from an HTLV-I negative identical sibling donor. During follow-up after bone marrow transplantation, HTLV-I could be repeatedly isolated inspite of anti-viral prophylaxis. The patient died of an acute encephalitis and HTLV-I could be detected in autopsy material from the brain. By a PCR-based technique using short tandem repeats (STRs) it was shown that the patient's haemopoiesis was of donor origin. This shows the infection of donor cells in vivo by an aetiological agent which has been implicated in the leukaemogenic process for adult T-cell leukaemia.

Bone Marrow↗
PubMed1994

Successful bone marrow transplant for Fanconi anaemia in transformation.

We present a patient who was diagnosed as suffering from Fanconi anaemia at the age of 36 years. At the time of diagnosis his bone marrow showed features of pre-leukaemic transformation. He received an allogeneic bone marrow transplant (BMT) from his HLA-identical sibling. The post-transplant course was unremarkable with evidence of trilineage engraftment at day +32 and no acute or chronic GVHD. He is well with sustained engraftment and no haematological evidence of Fanconi anaemia 18 months post-transplant.

Adult↗
PubMed1992

Probability of finding a compatible sibling donor for bone marrow transplantation in Ireland.

This study was undertaken to ascertain the frequency of compatible sibling donors for individuals requiring bone marrow transplantation (BMT) in Ireland. During the study period 1984-89, a total of 392 patients were HLA typed. Of these, 218 (55.6%) had a compatible sibling donor. Among the latter there were 4 degrees of compatibility: 168 (42.9%) were HLA-A,B,DR identical MLC unreactive: three (0.8%) were HLA-A,B,DR identical MLC reactive: 12 (3.0%) were HLA-A,B,DR identical (no MLC performed) and 35 (8.9%) were HLA-A, B identical (no DR or MLC performed). The leukaemias and aplastic anaemia comprised 82.9% of all requests. The majority of patients with acute myeloid leukaemia (64.4%), acute lymphoblastic leukaemia (51.2%), chronic myeloid leukaemia (73.9%) and aplastic anaemia (77.3%) had a potential sibling donor. Subsequently 144 of these patients had an allogeneic BMT, 79.9% of which were for patients with leukaemia (acute and chronic). This study found that there was a higher probability of finding a donor within the family than reported in most series. A clear relationship was demonstrated between family size and the likelihood of obtaining a HLA-identical sibling donor.

Bone Marrow Transplantation↗
PubMed1991

Evaluation of mixed chimerism by in vitro amplification of dinucleotide repeat sequences using the polymerase chain reaction.

The influence of mixed hematopoietic chimerism (MC) after allogeneic bone marrow transplantation remains unknown. Increasingly sensitive detection methods have shown that MC occurs frequently. We report a highly sensitive novel method to assess MC based on the polymerase chain reaction (PCR). Simple dinucleotide repeat sequences called microsatellites have been found to vary in their repeat number between individuals. We use this variation to type donor-recipient pairs following allogeneic BMT. A panel of seven microsatellites was used to distinguish between donor and recipient cells of 32 transplants. Informative microsatellites were subsequently used to assess MC after BMT in this group of patients. Seventeen of the 32 transplants involved a donor of opposite sex; hence, cytogenetics and Y chromosome-specific PCR were also used as an index of chimerism in these patients. MC was detected in bone marrow aspirates and peripheral blood in 18 of 32 patients (56%) by PCR. In several cases, only stored slide material was available for analysis but PCR of microsatellites or Y chromosomal material could be used successfully to assess the origin of cells in this archival material. Cytogenetic analysis was possible in 17 patients and MC was detected in three patients. Twelve patients received T-cell-depleted marrow and showed a high incidence of MC as revealed by PCR (greater than 80%). Twenty patients received unmanipulated marrow, and while the incidence of MC was lower (44%), this was a high percentage when compared with other studies. Once MC was detected, the percentages of recipient cells tended to increase. However, in patients exhibiting MC who subsequently relapsed, this increase was relatively sudden. The overall level of recipient cells in the group of MC patients who subsequently relapsed was higher than in those who exhibited stable MC. Thus, while the occurrence of MC was not indicative of a poor prognosis per se, sudden increases in the proportions of recipient cells may be a prelude to graft rejection or relapse.

Anemia, Aplastic↗
PubMed1991

Mixed chimaerism.

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Anemia, Aplastic↗
PubMed1991

Stromal colonies can be grown from the non-adherent cells in human long-term bone marrow cultures.

The absence of a pluripotent stem cell assay for human cells means that we must rely on assays of committed progenitors as a means for examining the ability of long-term bone marrow culture (LTBMC) to support haemopoiesis. The CFU-GM assay has been employed by many authors to demonstrate that the proliferative capacity and differentiation potential has been retained in LTBMC. In this study the non-adherent cells from human LTBMC were set up using a liquid culture technique for the clonal proliferation of stromal colonies (CFU-F). Weekly plating of the non-adherent cells produced CFU-F for up to 7 wk. Morphological, cytochemical and antigenic characterisation of these colonies revealed that they were identical to those grown from bone marrow de novo. LTBMC can now be used to identify the interactions between the haemopoietic inductive microenvironment and stromal progenitors and allow us to investigate the precise role of cell-cell interactions or cytokine influences on the proliferative capacity of stromal cell progenitors.

Adolescent↗
PubMed1991

Inhibitory effect of cyclosporin A on erythroid and stromal colonies.

Cyclosporin A is used to prevent graft-versus-host disease (GvHD) following bone marrow transplantation (BMT) and it has been implicated in reducing the time to engraftment for leukaemia and aplastic anaemia patients. To evaluate the effect of cyclosporin A on engraftment, the proliferative capacity of bone marrow progenitors (CFU-E, CFU-F and CFU-C) was assessed both in vitro and following treatment with cyclosporin A over a 9-week period using an animal model. Cyclosporin had a differential effect on the haemopoietic progenitors, with the myeloid series unaffected at therapeutic concentrations. Both erythroid and stromal progenitors were significantly inhibited at similar concentrations. The mechanism by which cyclosporin A enhances engraftment remains unclear; however, it is not mediated by enhancing any of the haemopoietic progenitors.

Administration, Oral↗
PubMed1991

Persistent polyclonal B lymphocytosis with Epstein-Barr virus antibodies and subsequent malignant pulmonary blastoma.

Persistent polyclonal B lymphocytosis (PPBL), a rare benign lymphoproliferative disorder, occurred in a 25 year old woman. The lymphocytes showed the phenotype cIgM+, FMC7+, CD19+, CD20+, which was similar to that seen in Waldenstrom's macroglobinaemia, but the proliferation was repeatedly shown to be polyclonal both immunologically and by immunoglobulin gene rearrangement studies. Eleven years after presentation the patient developed a malignant pulmonary blastoma, a rare pulmonary tumour of combined epithelial and mesenchymal origin. The failure to develop a lymphoid malignancy over 11 years together with immunological and genetic evidence of polyclonality confirms that PPBL is a benign lymphoproliferative disorder. The subsequent occurrence of a nonhaemopoietic malignancy suggests that benign lymphoid proliferations, like their malignant counterparts, may predispose to the development of neoplasia. A role for Epstein-Barr virus in the pathogenesis of one or both of these rare conditions is suggested by the finding of raised Epstein-Barr viral capsid antigen titres.

Adult↗