Karyotype differentiation between two stickleback species (Gasterosteidae).

The stickleback family (Gasterosteidae) of fish is less than 40 million years old, yet stickleback species have diverged in both diploid chromosome number (2n) and morphology. We used comparative fluorescence in situ hybridization (FISH) on 2 stickleback species, Gasterosteus aculeatus (2n = 42) and Apeltes quadracus (2n = 46), to ascertain the types of chromosome rearrangements that differentiate these species. The A. quadracus karyotype contains more acrocentric and telocentric chromosomes than the G. aculeatus karyotype. By using bacterial artificial chromosome probes from G. aculeatus in our FISH screen, we found that 6 pericentric inversions and 2 chromosome fusions/fissions are responsible for the greater number of acrocentric and telocentric chromosomes in A. quadracus. While most populations of G. aculeatus have an XX/XY sex chromosome system, A. quadracus has a ZZ/ZW sex chromosome system, as previously reported. However, we discovered that a population of A. quadracus from Connecticut lacks heteromorphic sex chromosomes, providing evidence for unexpected sex chromosome diversity in this species.

Wilms' tumor gene 1 (WT1) expression in childhood acute lymphoblastic leukemia: a wide range of WT1 expression levels, its impact on prognosis and minimal residual disease monitoring.

Wilms' tumor gene 1 (WT1) is overexpressed in the majority (70-90%) of acute leukemias and has been identified as an independent adverse prognostic factor, a convenient minimal residual disease (MRD) marker and potential therapeutic target in acute leukemia. We examined WT1 expression patterns in childhood acute lymphoblastic leukemia (ALL), where its clinical implication remains unclear. Using a real-time quantitative PCR designed according to Europe Against Cancer Program recommendations, we evaluated WT1 expression in 125 consecutively enrolled patients with childhood ALL (106 BCP-ALL, 19 T-ALL) and compared it with physiologic WT1 expression in normal and regenerating bone marrow (BM). In childhood B-cell precursor (BCP)-ALL, we detected a wide range of WT1 levels (5 logs) with a median WT1 expression close to that of normal BM. WT1 expression in childhood T-ALL was significantly higher than in BCP-ALL (P<0.001). Patients with MLL-AF4 translocation showed high WT1 overexpression (P<0.01) compared to patients with other or no chromosomal aberrations. Older children (> or =10 years) expressed higher WT1 levels than children under 10 years of age (P<0.001), while there was no difference in WT1 expression in patients with peripheral blood leukocyte count (WBC) > or =50 x 10(9)/l and lower. Analysis of relapsed cases (14/125) indicated that an abnormal increase or decrease in WT1 expression was associated with a significantly increased risk of relapse (P=0.0006), and this prognostic impact of WT1 was independent of other main risk factors (P=0.0012). In summary, our study suggests that WT1 expression in childhood ALL is very variable and much lower than in AML or adult ALL. WT1, thus, will not be a useful marker for MRD detection in childhood ALL, however, it does represent a potential independent risk factor in childhood ALL. Interestingly, a proportion of childhood ALL patients express WT1 at levels below the normal physiological BM WT1 expression, and this reduced WT1 expression appears to be associated with a higher risk of relapse.

Donor chimaerism is a strong indicator of disease free survival following bone marrow transplantation for chronic myeloid leukaemia.

Although Chronic Myeloid Leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT), leukaemia relapse remains a significant clinical problem. Molecular monitoring of the post transplant marrow can be useful in predicting relapse particularly in CML patients where the Philadelphia chromosome or its molecular counterpart, the BCR-ABL fusion messenger RNA can be used as a leukaemia specific marker of minimal residual disease (MRD). We have investigated chimaerism (using polymerase chain reaction of short tandem repeat sequences (STR-PCR)) and MRD status (using reverse transcriptase PCR of the BCR-ABL fusion mRNA) in a serial fashion in 18 patients who were in clinical and haematological remission post allogeneic BMT for chronic phase CML. Eleven patients exhibited complete donor chimaerism with no evidence of minimal residual disease. Five patients had transient or low level stable MC. Late MC and MRD was observed in two patients who relapsed > 6 years after T cell depleted BMT for CML. Thus STR-PCR is an appropriate screening test in the post transplant setting for CML patients, but those patients exhibiting mixed haemopoietic chimaerism should also be monitored using a leukaemia specific sensitive molecular assay.

Autologous stem cell transplantation in myeloma: the St James's Hospital experience, 1997-2003.

BACKGROUND: High-dose treatment with autologous stem cell transplantation (ASCT) has become the standard of care for patients with myeloma below the age of 65 years. AIMS: We report an audit of 60 patients (median age: 52.5 years) who underwent ASCT in the National Bone Marrow Transplant centre in St James's Hospital in Dublin between 1997 and 2003 inclusive. METHODS: Clinical and laboratory data were retrieved from patient medical records and hospital information management systems. RESULTS: Thirty-six patients had IgG, 11 IgA, 1 IgD, 9 light chain and 3 non-secretory MM. Fifty-seven (95%) patients received anthracycline-corticosteroid combination chemotherapy prior to autografting. There was no transplant-related mortality (TRM). Complete (CR) and Partial Responses (PR) were seen in 16 (29.6%) and 29 (53.7%) of those evaluable (n = 54 (90%)). The actuarial Progression-Free (PFS) and Overall Survival (OS) rates at five years are 13% and 55% respectively. CONCLUSION: Centre outcome is comparable to published international series and supports the use of ASCT in the treatment of this malignancy.

IgM pyroglobulinemia with erythrocytosis presenting as hyperviscosity syndrome. II. Biochemical properties and mechanisms of pyrogel formation.

An immunoglobulin M with kappa light chains (IgMK) pyroglobulin from a patient with hyperviscosity syndrome, erythrocytosis and coagulation defects has been studied for its immunochemical properties. At physiologic temperatures the purified macropyroglobulin showed a striking tendency to aggregate in the pentamer as well as in the monomer form. This property was also observed in its H chains. Aggregate formation of the pentamers may have contributed to the blood viscosity and coagulation defects. Formation of pyrogel at 56degreesC was observed with pentamers as well as monomers, but not with separated H or L chains. Amino acid analysis showed quantitative abnormalities of aspartic acid, glycine, cystine and leucine within the H chains. Solubility of the pyrogel in sodium dodecyl sulfate, the pyroglobulin's tendency to aggregate and the cystine deficit of H chains implicate conformational changes leading to hydrophobic bonding at 56degreesC in the formation of pyrogel.

IgM pyroglobulinemia with erythrocytosis presenting as hyperviscosity syndrome. I. Clinical features and viscometric studies.

The hyperviscosity syndrome is described in a patient with erythrocytosis and an immunoglobulin M with kappa light chain (IgMK) macroglobulinemia. Viscometric studies were carried out on whole blood and demonstrated the contribution of both the increased hematocrit value and the macroglobulinemia to the whole blood viscosity. Clinical improvement followed phlebotomy and was accompanied by a decrease in whole blood viscosity. Continued treatment with chlorambucil has been associated with a long symptom-free period. The macroglobulin was characterized as a monoclonal IgMK pyroglobulin which retained its thermoprecipitability was reduced to 7S monomers. The presence of IgMK aggregates in the serum may have contributed to the increase in blood viscosity.

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.

Myeloid antigen expression on common acute lymphatic leukaemia blasts after culture.

Blast cells from seven out of ten patients with common acute lymphoblastic leukaemia (cALL) developed the myeloid antigen MY7 (CD13) after culture, and one of these coexpressed the myeloid antigen MY9 (CD33). CD13 expression appeared to be independent of maturation since it could be induced more readily in cultures which did not contain the differentiation promoter 12-O-tetradecanoyl-phorbol 13 acetate (TPA). CD13 expression in culture was not seen on one null ALL, or 6 B-CLL investigated or on normal tonsillar B cells or PBMC under similar conditions. CD13 expression on cALL blasts probably represents evidence of abnormal gene expression in the leukaemic cells. However the absence of CD13 expression on the earlier B null ALL or the later B-CLL suggests we cannot exclude the possibility that CD13 expression is a feature of normal precursor B cells.

Mixed chimaerism; detection and significance following BMT.

Residual recipient haematopoietic cells may coexist with donor haemopoietic tissue following BMT. This is known as mixed chimaerism. The incidence of mixed chimaerism varies with the sensitivity of the detection system used; DNA based methodologies are the most sensitive. The influence of mixed chimaerism on leukaemia relapse and graft rejection is unclear. The lineages in which mixed chimaerism occurs may affect outcome.

A rapid dot-blot assay to assess chimerism following sex-mismatched bone marrow transplantation.

Mixed chimerism may occur more frequently than previously thought following allogeneic bone marrow transplantation and may have implications in terms of relapse, graft-versus-host disease and immune reconstitution. DNA analysis using single or multilocus polymorphic probes cannot reliably discriminate between donor and recipient cells below a level of 10%. We used probe pHY2.1, a cloned segment of tandemly repeated DNA (2000 copies) on the long arm of chromosome Y. A dot blot procedure allowed us to immobilize DNA directly from 50 microliter of peripheral blood or bone marrow. Cross-reactivity was eliminated by hybridization at conditions of extreme stringency (65 degrees C, 50% formamide). Mixing experiments detected male DNA at a level of 0.1% after 10 h exposure. Five patients were studied serially post-bone marrow transplantation. One patient showed mixed chimerism for 12 months, one had complete autologous recovery and the remaining three showed complete engraftment. All results were verified by standard karyotyping on bone marrow cells. This technique is a simple, rapid and sensitive assay for chimerism following sex mismatched bone marrow transplantation.

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.

Leukaemic transformation of donor cells in a patient receiving a second allogeneic bone marrow transplant for severe aplastic anaemia.

Allogeneic blood or bone marrow transplantation is a successful treatment for leukaemia and severe aplastic anaemia (SAA). Graft rejection following transplantation for leukaemia is a rare event but leukaemic relapse may occur at varying rates, depending upon the stage of leukaemia at which the transplant was undertaken and the type of leukaemia. Relapse is generally assumed to occur in residual host cells, which are refractory to, or escape from the myeloablative conditioning therapy. Rare cases have been described, however, in which the leukaemia recurs in cells of donor origin. Lack of a successful outcome of blood or bone marrow transplantation for severe aplastic anaemia (SAA), however, is due to late graft rejection or graft-versus-host disease. Leukaemia in cells of donor origin has rarely been reported in patients following allogeneic bone marrow transplantation for SAA. This report describes leukaemic transformation in donor cells following a second allogeneic BMT for severe aplastic anaemia. PCR of short tandem repeats in bone marrow aspirates and in colonies derived from BFUE and CFU-GM indicated the donor origin of leukaemia. Donor leukaemia is a rare event following transplantation for severe aplastic anaemia but may represent the persistence or perturbation of a stromal defect in these patients inducing leukaemic change in donor haemopoietic stem cells.

Retinal microvascular changes following bone marrow transplantation: the role of cyclosporine.

Three patients complained of deteriorating vision 16, 20 and 29 weeks following bone marrow transplantation (BMT) while receiving cyclosporine (CsA). Opthalmic examination revealed a marked microvascular retinopathy with multiple cotton-wool spots, macular stars and retinal oedema. These appearances could not be accounted for by the mild to moderate hypertension in two cases, the third patient being normotensive. Two of the patients had received total body irradiation (TBI) and cyclophosphamide (CY) as conditioning therapy for BMT as well as previous cranial irradiation for acute lymphoblastic leukaemia; one case with chronic myeloid leukaemia was conditioned with busulphan and CY. Withdrawal of CsA in two patients and reduction of dose in the third led to complete resolution of retinopathy and restoration of visual function. Previous reports have documented ischaemic fundus lesion in BMT recipients treated with CsA and TBI. Our findings suggest that CsA in association with busulphan can produce a similar retinopathy.

Persistent donor chimaerism is consistent with disease-free survival following BMT for chronic myeloid leukaemia.

Chronic myeloid leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT) leading to long-term disease-free survival. Leukemia relapse, however, remains a significant clinical problem. Relapse following BMT presumably results from the expansion of small numbers of recipient leukaemic cells which have survived the conditioning therapy. In order to define patients who are at a high risk of leukaemia relapse, a variety of techniques have been employed to detect persistence of host haemopoiesis (mixed chimaerism, MC) or residual leukaemia (minimal residual disease, MRD). However, the precise relationship between the detection of MC and MRD post-BMT is unknown. We have investigated chimaerism and MRD status in 22 patients who were in clinical and haematological remission post-allogeneic BMT for chronic phase CML. Chimaerism was assessed using short tandem repeat PCR (STR-PCR) while BCR-ABL mRNA detection using reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect the presence of MRD. Seventeen patients received unmanipulated marrow (non-TCD) while in five patients a T cell-depleted transplant (TCD) was performed as additional GVHD prophylaxis. Chimaerism was evaluated in 18 patients (14 non-TCD, four TCD). Mixed chimaerism was an uncommon finding in recipients of unmanipulated BMT (21%) when compared to TCD BMT (100%). No evidence of MRD, as identified using the BCR-ABL mRNA RT-PCR assay, was detected in those patients who were donor chimaeras. Early and transient MC and MRD was detected in four patients (two non-TCD, two TCD) who have subsequently converted to a donor profile. One patient has stable low-level MC but remains MRD negative 4 years post-BMT. Late MC and MRD was observed in two patients who relapsed >6 years after TCD BMT for CML. We conclude that mixed chimaerism is a rare event in recipients of unmanipulated BMT and that donor chimaerism as detected by STR-PCR assay is consistent with disease-free survival and identifies patients with a low risk of leukaemic relapse post-BMT for CML.

Early detection of leukaemic relapse after bone marrow transplantation using the polymerase chain reaction.

We report a case of acute lymphoblastic leukaemia relapsing after allogeneic bone marrow transplantation in which the polymerase chain reaction (PCR) was used to assess chimeric status. This technique demonstrated the progressive reappearance of host cells prior to clinical relapse. The relapse was of host cell origin as shown by the presence of female (recipient) metaphases containing an abnormal chromosomal marker (iso 9q) which had also been present at initial diagnosis. The emergence of host cells in this case, detected only by PCR techniques but not by cytogenetic methods, appeared to herald overt relapse. PCR analysis provides a sensitive tool for detecting a progressive rise in host cell numbers which may predict clinical relapse.

Nebulized amphotericin B as prophylaxis against invasive aspergillosis in granulocytopenic patients.

The efficacy of inhaled amphotericin B in prevention of invasive aspergillosis in patients with granulocytopenia (granulocytes less than 0.5 X 10(9)/l for greater than 10 days) was investigated over a 12-month period. Amphotericin B prophylaxis was administered twice daily for the period of granulocytopenia to 34 patients who were at risk during 144 episodes of granulocytopenia. The cohort at risk was compared with historical controls. In the 2 years prior to institution of prophylaxis, 14 patients (11.4% of those at risk) developed invasive aspergillosis. All cases occurred whilst the patients were nursed on the open wards. Aspergillosis did not develop in 25 granulocytopenic patients nursed in single rooms with HEPA filtration. Since institution of prophylaxis, there have been no cases of invasive aspergillosis. These data suggest that nebulized amphotericin B may be useful in preventing invasive pulmonary aspergillosis in granulocytopenic patients, especially those nursed on the open wards, and warrants further investigation.

Monitoring of lineage-specific chimaerism allows early prediction of response following donor lymphocyte infusions for relapsed chronic myeloid leukaemia.

Donor lymphocyte infusions (DLI) have been shown to enhance the graft-versus-leukaemia (GVL) effect and induce haematological and molecular remission in patients with relapsed CML following allogeneic bone marrow transplantation (BMT). The potent donor cell-mediated cytolysis following DLI may lead to a short period of aplasia before the re-establishment of donor haematopoiesis. The absence of detectable donor cells in patients prior to DLI infusion may result in permanent aplasia in certain patients. We report on four patients who relapsed 1, 3, 6.5 and 7 years post-BMT for chronic phase CML and were treated with DLI from their original BMT donor. Polymorphic short tandem repeats (STRs) were used to assess haematological chimaerism both prior to and following DLI. At the time of relapse, STR-PCR indicated the presence of donor cells in all four patients, at levels ranging from 1-40%. A clinical and molecular response was seen in 4/4 patients following a short period of cytopenia and all patients remain in clinical remission with a follow-up of 2 months-3 years post-DLI. STR-PCR indicated that a response was occurring during the period of pancytopenia when metaphase analysis was unsuccessful. Lineage-specific analysis of the cellular response to DLI was monitored using STR-PCR of peripheral blood (PB) and bone marrow (BM) lymphocyte-enriched fractions and CD2-positive and -negative T cell fractions. In one patient BM and PB CD34-positive and -negative fractions were also assessed. A change in the ratio of donor:recipient cells in the PB lymphocyte fraction was the earliest molecular indication of an anti-leukaemic response. Subsequent conversion to donor chimaerism occurred in the other lineages and the granulocyte fraction was the last lineage to convert. In conclusion, lineage-specific STR-PCR permits detailed monitoring of subtle changes in donor/recipient cell dynamics in specific lineages following DLI during the crucial pancytopenic phase and may be a useful predictor of haematological response to DLI therapy.

Psychosocial adaptation of patients and families following bone marrow transplantation: a prospective, longitudinal study.

Using a prospective, repeated measures design, this study investigated the psychosocial functioning of patients and a close relative pre- and post-allogeneic and autologous bone marrow transplantation (BMT). All patients (n = 28) undergoing BMT in a 1 year period, and their relatives, were interviewed 1 week pre-transplant and at 3, 6 and 12 months post-BMT, using quantitative and qualitative measures. Pre-transplant data revealed a high level of anxiety (61% with moderate to severe anxiety), and a low level of depression (14% with moderate to severe depression). Twelve patients died in the study period. For the surviving patients there was a statistically significant improvement in physical, psychological and social functioning. Most relatives (88%) reported considerable psychological distress pre-transplant and at 3 months post-transplant, but this was largely resolved by 12 months post-transplant. Significant correlations between the relative's distress and patient's physical and psychological wellbeing were observed at 3 months post-transplant, but not at the other assessment points. The findings from this study will help in counselling patients and their relatives as to what to expect in the year following BMT.

An outbreak of multiply resistant Serratia marcescens: the importance of persistent carriage.

An outbreak of multi-resistant Serratia marcescens involving 24 patients occurred in a bone marrow transplant and oncology unit, from September 1998 to June 1999, of whom 14 developed serious infection. This is the first such outbreak described in a BMT unit. All isolates demonstrated the same antimicrobial susceptibility pattern and were the same unusual serotype O21:K14. The antimicrobial susceptibility profile showed reduced susceptibility to ciprofloxacin, gentamicin and piperacillin-tazobactam. As the latter two antimicrobials are part of our empiric therapy for febrile neutropenia, they were substituted with meropenem and amikacin during the outbreak. Investigation revealed breaches in infection control practices. Subsequently, the outbreak was contained following implementation of strict infection control measures. A prominent feature of the outbreak was prolonged carriage in some patients. These patients may have acted as reservoirs for cross-infection. This report also indicates that patients who become colonised with Serratia marcescens may subsequently develop invasive infection during neutropenic periods.

Cutaneous mucormycosis due to Absidia corymbifera occurring after bone marrow transplantation.

Mucormycosis is an uncommon severe life-threatening fungal infection in the immunocompromised host caused by fungi belonging to the order Mucorales, most commonly Rhizopus arrhizus (R. oryzae). We report a patient who developed a severe right atrial catheter exit site infection with Absidia corymbifera. The catheter was removed and necrotic tissue debrided. With liposomal amphotericin B and G-CSF, the infection subsided. He remains well 8 months later.