Determinants of Infant and Child Mortality in Bangladesh: Time Trends and Comparisons across South Asia

In spite of various effective intervention programs, the under-5 child mortality rate (U5MR) is still high in Bangladesh. The present paper focused on the levels, trends and determinants of U5MR in Bangladesh utilizing data from Bangladesh Demographic and Health Survey (BDHS), 2007. Differential pattern in U5MR in Bangladesh was examined using life table technique as a bi-variate analysis and Cox proportional hazard model was used to analyze the determinants of U5MR mortality. Data from BDHS (2007) showed that U5MR during the five years preceding the survey was 65 per 1,000 live births, i.e. one in fifteen children born in Bangladesh died before reaching the fifth birthday. The risk of dying in the first month of life (37 per 1,000) was nearly two and a half times greater than in the subsequent 11 months (15 per 1,000). Deaths in the neonatal period accounted for 57 percent of all under-five deaths. In the Cox proportional hazard model analysis, factors such as the place of residence, parent’s education, father’s working status, sources of drinking water, type of toilet facility, wealth status, watching of television, mother’s age, months of breastfeeding, birth interval had significant influence on infant and child mortality. The most significant predictors of neonatal, post-neonatal, infant and child mortality were residence, parent’s education, type of toilet facility, wealth status, watching TV, months of breastfeeding, and birth interval. Despite the improvement of medical technology, child mortality remained alarmingly high, indicating that demographic, socioeconomic, household and environmental conditions must be improved to substantially reduce child mortality in this population. DOI: http://dx.doi.org/10.3329/bjms.v13i4.20590 Bangladesh Journal of Medical Science Vol.13(4) 2014 p.431-437

Bcl-xL anti-apoptotic network is dispensable for development and maintenance of CML but is required for disease progression where it represents a new therapeutic target

The dismal outcome of blast crisis chronic myelogenous leukemia (CML-BC) patients underscores the need for a better understanding of the mechanisms responsible for the development of drug resistance. Altered expression of the anti-apoptoticBcl-xL has been correlated with BCR-ABL leukemogenesis; however, its involvement in the pathogenesis and evolution of CML has not been formally demonstrated yet. Thus, we generated an inducible mouse model in which simultaneous expression of p210-BCR-ABL1 and deletion of bcl-x occurs within hematopoietic stem and progenitor cells. Absence of Bcl-xL did not affect development of the chronic phase-like myeloproliferative disease, but none of the deficient mice progressed to an advanced phenotype, suggesting the importance of Bcl-xL in survival of progressing early progenitor cells. Indeed, pharmacological antagonism of Bcl-xL, with ABT-263, combined with PP242-induced activation of BAD markedly augmented apoptosis of CML-BC cell lines and primary CD34(+) progenitors but not those from healthy donors, regardless of drug resistance induced by bone marrow stromal cell-generated signals. Moreover, studies in which BAD or Bcl-xL expression was molecularly altered strongly support their involvement in ABT-263/PP242-induced apoptosis of CML-BC progenitors. Thus, suppression of the antiapoptotic potential of Bcl-xL together with BAD activation represents an effective pharmacological approach for patients undergoing blastic transformation.

Stem cell therapy for the broken heart: mini-organ transplantation

BACKGROUND

Myocardial infarction (MI) is characterized by irreversible loss of cardiomyocytes, resulting in impaired ventricular function. Stem cell therapy using autologous progenitor cells has emerged as a promising approach. Experimental studies have demonstrated that highly selected hematopoeitic stem cells, which are characterized by the presence of the surface markers CD34 and CD133, may contribute to repair of the acutely infarcted myocardium by inducing neovascularization, inhibiting apoptosis, and promoting cardiomyogenesis. We sought, to evaluate the intracoronary injection of CD133+ stem cells for cardiac repair in patients with dysfunctional myocardium after an acute MI.

PATIENTS AND METHODS

In this Canadian randomized, double-blind, placebo-controlled, Phase I-II study ("COMPARE-AMI"), we are evaluating the feasibility, safety, and efficacy of intracoronary injection of selected CD133+ stem cells for cardiac repair in patients with impaired cardiac function after successfully stented acute MI. Since November 2007, we have enrolled 14 patients in the study. Their mean age was 50.5 +/- 9.1 years, including 93% men. The culprit lesion was always on the left anterior descending artery (LAD). Their maximum troponin and CKMB levels were 8.4 +/- 6.1 microg/L and 322 +/- 225 U/L, respectively.

RESULTS

Compared with the baseline, we observed a significant 8.7% improvement in left ventricular ejection fraction at 4 months follow-up, namely, from 41.3 +/- 5.5% to 50.0 +/- 8.2% (n = 7; P = .008). There were no protocol-related complications. Our trial is designed to recruit 40 patients who are randomized 1:1 to receive CD133+ cells or placebo.

PERSPECTIVE

There is a need to seek out new therapeutics for the treatment of ischemic heart disease addressing the early loss of viable myocytes. Stem cell transplantation has shown early promise; this appraisal needs well-designed, controlled studies.

Telomere length is severely and similarly reduced in JAK2V617F-positive and -negative myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized by chronic proliferation of hematopoietic progenitors. We studied the telomere length (TL) of 335 MPN patients and 93 gender- and age-matched controls using a quantitative PCR method (relative TL calculated as the ratio of the amount of telomere DNA vs single-copy DNA: T/S ratio). TL was markedly reduced in MPN patients compared with controls (T/S 0.561 vs 0.990, P<0.001). In JAK2V617F MPN patients, TL correlated inversely with allelic burden (P<0.001). Patients homozygous for the mutation (allelic burden 90-100%) had the shortest TL, even when compared with patients with lower allele burdens consistent with a dominant heterozygous population (allelic burden 55-65%) (T/S 0.367 vs 0.497, P=0.037). This suggests that the high degree of proliferation of the MPN clone reduces TL and suggests the possibility that TL shortening may be indicative of progressive genomic instability during MPN progression. The TL of JAK2V617F-negative MPN patients was similar to JAK2V617F-positive counterparts (T/S 0.527 vs 0.507, P=0.603), suggesting that the yet-to-be-discovered causative mutation(s) impact the mutated stem cell similarly to JAK2V617F, and that TL measurement may prove useful in the diagnostic workup of JAK2V617F-negative MPN.

What is the clinical significance of infusing hematopoietic cell grafts contaminated with bacteria?

Although hematopoietic stem cell (HSC) products are routinely cultured for sterility, bacterial contamination of these products is rarely observed and little is known about the clinical consequences of infusing contaminated grafts. We retrieved the sterility cultures of bone marrow and peripheral HSC grafts from 938 patients transplanted at our center from January 1990 to July 2005. Fever, septicemia and other adverse events were assessed for up to 14 days following infusion of the graft. Out of the 1502 grafts collected during this 15-year period, 15 (1.0%) had a positive sterility culture (11 Gram-positive cocci, 2 Gram-positive bacilli and 2 Gram-negative bacilli). No correlation was observed between the graft contamination rate and the extent of graft manipulation or the patient's underlying condition. Thirteen recipients were transplanted with contaminated grafts. Five patients were treated with specific pre-emptive antibiotics. Only one episode of Staphylococcus epidermidis bacteremia possibly related to a contaminated graft was observed on day +5. As the infusion of contaminated grafts with Gram-positive skin contaminants rarely results in unfavorable clinical outcomes, close patient monitoring without the use of specific pre-emptive antibiotics could be appropriate and could avoid antibiotic-associated adverse events.

Elimination of alloreactive T cells using photodynamic therapy

GvHD, the most important cause of morbidity and mortality after allogeneic stem cell transplantation, depends primarily on the ability of a donor T-cell subset to react to immunogenic host Ag. Recently developed culture conditions and treatment strategies may bring us closer to the selective elimination of such alloreactive T cells, often considered the holy grail of transplantation. Among the various therapeutic modalities, photodynamic therapy (PDT) offers a biological and global approach to the eradication of unwanted allo-activated T cells by combining mitochondrial targeting, P-glycoprotein inhibition and reactive oxygen species production. Indeed, the high potency of PDT against malignant cells has been harnessed to exert selective and extensive elimination of alloreactive T-cell subsets mediating GvHD, while preserving resting T cells with the ability to reconstitute the immune system for GvL activity and prevent or suppress viruses and fungi. The present paper reviews the basis of the PDT strategy, and the methodology employed. In vitro and in vivo studies that formed the proof of principle as a basis for human studies to investigate the clinical potential of PDT in the context of GvHD will be presented together with insights into future clinical applications of this versatile treatment platform.

Maintaining high autopsy rates in a Canadian blood and marrow transplant program: preserving a diagnostic and research tool

Autopsy series have revealed patterns of injury in graft-versus-host disease and provided insight into infectious and toxic complications following hematopoietic stem cell transplantation (HSCT). Overall autopsy rates have declined significantly in recent decades including specialized services such as neonatal medicine and cardiac care. However, rates of post-mortem exams at HSCT centers have not been specifically documented. We reviewed hospital records between 1992 and 2002 to determine overall autopsy rates at our hospital and within the HSCT program. Although the overall autopsy rate declined steadily from 24% in 1992 to 9% in 2002, rates of post-mortem exams in the HSCT program remained relatively stable at 32% (24-46%). Autopsy rates were not significantly different for recipients of allogeneic vs autologous transplants and no clear difference was observed for the proportion of autopsies requested on weekdays compared with weekends. Autopsies confirmed major clinical diagnoses and/or suspected causes of death in 45 of 61 autopsies (74%) and yielded major or minor disagreements in clinical diagnosis in 10 cases (16%) and seven cases (11%), respectively. The preservation of high rates of autopsy within our HSCT program demonstrates that specialized programs are able to maintain elevated rates of post-mortem examinations despite overall declining rates.

Allogeneic transplantation for multiple myeloma: further evidence for a GVHD-associated graft-versus-myeloma effect

We report a series of 37 consecutive patients with multiple myeloma (MM) who received an allograft between 1990 and 2000 at our institution. Median age was 47 years, and nearly 70% of patients were Durie-Salmon stage III. A median of five cycles of chemotherapy were given before transplant, with a median interval between diagnosis and transplant of 9.3 months. We report a nonrelapse mortality rate of 22% with a median follow-up period of 40 months, whereas complete remission (CR) rate at 12 months is estimated at 57%. Treatment failure rate and overall survival at 40 months are estimated at 52% and 32%, respectively. The number of chemotherapy cycles prior to allotransplantation achieved borderline statistical significance as a poor prognosis factor for overall survival (P = 0.05), while the presence of chronic graft-versus-host disease (cGVHD) was significantly correlated with CR achievement (P = 0.036). Our study confirms that early allografting in MM can yield toxicity rates significantly lower than those associated with historical cohorts, and supports the hypothesis that cumulative chemotoxicity has a negative influence on mortality and survival rates. More importantly, our study clearly demonstrates an association between cGVHD and CR and brings further evidence in favor of a graft-versus-myeloma effect.

Adoptive transfer of minor histocompatibility antigen-specific T lymphocytes eradicates leukemia cells without causing graft-versus-host disease

Adoptive transfer of T cells reactive to minor histocompatibility antigens has the unmatched ability to eradicate malignant hematopoietic cells. Unfortunately, its use is hampered by the associated graft-versus-host disease. The critical issue of a possible dissociation of the antileukemic effect and graft-versus-host disease by targeting specific minor histocompatibility antigens remains unresolved because of the unknown nature and number of minor histocompatibility antigens necessary or sufficient to elicit anti-leukemic activity and graft-versus-host disease. We found that injection of T lymphocytes primed against a single major histocompatibility complex class I-restricted immunodominant minor histocompatibility antigen (B6dom1) caused no graft-versus-host disease but produced a curative anti-leukemic response. Avoidance of graft-versus-host disease required that no other host-reactive T cells be co-injected with T cells primed with B6dom1. Here we show that effective and non-toxic immunotherapy of hematologic malignancies can be achieved by targeting a single immunodominant minor histocompatibility antigen.

Relapse after bone marrow transplantation: evidence for distinct immunological mechanisms between adult and paediatric populations

Donor lymphocyte infusions are particularly effective for remission induction in malignant cells in patients who relapse after allogeneic progenitor cell transplantation (PCT) and who remain sensitive to the administration of unprimed donor T and/or natural killer (NK) cells present in donor lymphocyte infusions. To determine whether relapse after unmanipulated PCT could be ascribed to donor T and/or NK cell loss or tolerization, we evaluated the chimeric status of 81 patients with haematological malignancies who were receiving allogeneic unmanipulated PCT. The incidence of mixed chimaerism (MC) in unfractionated mononuclear leucocyte samples decreased rapidly after transplant, and was not detectable 4 months after PCT, even in patients who subsequently relapsed. The chimeric status of immune effector cell subsets was then evaluated in 15 patients at the time of relapse. All adults demonstrated complete donor haematopoiesis (CDH) for all cell lineages, whereas T- and NK-cell MC was only found in patients younger than age 13 years (P = 0.004). MC was not found in T nor NK cells of a control group consisting of age-matched paediatric patients in remission after allogeneic PCT. Thus, in adults, T and NK cell MC disappears early after unmanipulated allogeneic PCT and is absent at the time of relapse. However, the identification of donor T and NK cell loss in the paediatric relapsed but not remission patients suggests a distinct mechanism of relapse.

The in vivo fate of APCs displaying minor H antigen and/or MHC differences is regulated by CTLs specific for immunodominant class I-associated epitopes

The goal of this work was to evaluate the fate of APCs following interactions with T cells in unprimed mice with a normal T cell repertoire. We elaborated a model in which male adherent peritoneal mononuclear cells were injected into the foreleg footpads of naive female recipients mismatched for either minor or major histocompatibility Ags. At various times after injection, APC numbers in the draining (axillary and brachial) lymph nodes were assessed using a Ube1y gene-specific PCR assay. Our experimental model was designed so that the number of APCs expressing the priming epitope was similar to what is observed under real life conditions. Thus, early after injection, the frequency of afferent lymph-derived APCs expressing the priming epitope was in the range of 101-102/106 lymph node cells. We found that APCs presenting some, but not all, nonself epitopes were killed rapidly after entrance into the lymph nodes. Rapid elimination of APCs occurred following interactions with MHC class I-restricted, but not class II-restricted, T cells and was observed when APCs presented an immunodominant (B6dom1/H7a), but not a nondominant (HY), epitope. Killing of APCs was mediated partly, but not exclusively, by perforin-dependent process. We propose that killing of APCs by CTLs specific for immunodominant MHC class I-restricted epitopes may be instrumental in regulating the intensity, duration, and diversity of T cell responses.

Haploinsufficiency of CBFA2 causes familial thrombocytopenia with propensity to develop acute myelogenous leukaemia

Familial platelet disorder with predisposition to acute myelogenous leukaemia (FPD/AML, MIM 601399) is an autosomal dominant disorder characterized by qualitative and quantitative platelet defects, and propensity to develop acute myelogenous leukaemia (AML). Informative recombination events in 6 FPD/AML pedigrees with evidence of linkage to markers on chromosome 21q identified an 880-kb interval containing the disease gene. Mutational analysis of regional candidate genes showed nonsense mutations or intragenic deletion of one allele of the haematopoietic transcription factor CBFA2 (formerly AML1) that co-segregated with the disease in four FPD/AML pedigrees. We identified heterozygous CBFA2 missense mutations that co-segregated with the disease in the remaining two FPD/AML pedigrees at phylogenetically conserved amino acids R166 and R201, respectively. Analysis of bone marrow or peripheral blood cells from affected FPD/AML individuals showed a decrement in megakaryocyte colony formation, demonstrating that CBFA2 dosage affects megakaryopoiesis. Our findings support a model for FPD/AML in which haploinsufficiency of CBFA2 causes an autosomal dominant congenital platelet defect and predisposes to the acquisition of additional mutations that cause leukaemia.

Massive activation-induced cell death of alloreactive T cells with apoptosis of bystander postthymic T cells prevents immune reconstitution in mice with graft-versus-host disease

After hematopoietic stem cell transplantation, the persistence and expansion of grafted mature postthymic T cells allow both transfer of donor immunologic memory and generation of a diverse T repertoire. This thymic-independent process, which is particularly important in humans, because most transplant recipients present severe thymus atrophy, is impaired by graft-versus-host disease (GVHD). The goal of this study was to decipher how GVHD influences the fate of grafted postthymic T cells. Two major findings emerged. First, we found that, after a brisk proliferation phase, alloreactive antihost T cells underwent a massive activation-induced cell death (AICD). For both CD4(+) and CD8(+) T cells, the Fas pathway was found to play a major role in this AICD: alloreactive T cells upregulated Fas and FasL, and AICD of antihost T cells was much decreased in the case of lpr (Fas-deficient) donors. Second, whereas non-host-reactive donor T cells neither upregulated Fas nor suffered apoptosis when transplanted alone, they showed increased membrane Fas expression and apoptosis when coinjected with host-reactive T cells. We conclude that GVHD-associated AICD of antihost T cells coupled with bystander lysis of grafted non-host-reactive T cells abrogate immune reconstitution by donor-derived postthymic T lymphocytes. Furthermore, we speculate that massive lymphoid apoptosis observed in the acute phase of GVHD might be responsible for the occurrence of autoimmunity in the chronic phase of GVHD.

The effect of graft-versus-host disease on T cell production and homeostasis

The aim of this work was to decipher how graft-versus-host disease (GVHD) affects T cell production and homeostasis. In GVHD+ mice, thymic output was decreased fourfold relative to normal mice, but was sufficient to maintain a T cell repertoire with normal diversity in terms of Vbeta usage. Lymphoid hypoplasia in GVHD+ mice was caused mainly by a lessened expansion of the peripheral postthymic T cell compartment. In 5-bromo-2'-deoxyuridine pulse-chase experiments, resident T cells in the spleen of GVHD+ mice showed a normal turnover rate (proliferation and half-life). When transferred into thymectomized GVHD- secondary hosts, T cells from GVHD+ mice expanded normally. In contrast, normal T cells failed to expand when injected into GVHD+ mice. Thus, the reduced size of the postthymic compartment in GVHD+ mice was not due to an intrinsic lymphocyte defect, but to an extrinsic microenvironment abnormality. We suggest that this extrinsic anomaly is consistent with a reduced number of functional peripheral T cell niches. Therefore, our results show that GVHD-associated T cell hypoplasia is largely caused by a perturbed homeostasis of the peripheral compartment. Furthermore, they suggest that damage to the microenvironment of secondary lymphoid organs may represent an heretofore unrecognized cause of acquired T cell hypoplasia.

Quantitative assessment of hematopoietic chimerism after allogeneic bone marrow transplantation has predictive value for the occurrence of irreversible graft failure and graft-vs.-host disease

Primary graft failure, secondary to either host-vs.-graft reaction or delayed engraftment, and graft-vs.-host disease (GVHD) are among the most difficult clinical problems to manage in the field of allogeneic bone marrow transplantation (BMT). Early diagnosis of both conditions would greatly improve their outcome. Using fluorescence in situ hybridization (FISH) with an X- and Y-probe mixture, we sequentially monitored chimerism of neutrophils and lymphoid cells from day 1 to 100 in 28 consecutive recipients of sex-mismatched unmanipulated bone marrow grafts. The objective was to quantitatively assess the evolution of chimerism during this crucial time interval and to determine whether chimerism patterns would be predictive of engraftment and GVHD. In recipients with primary graft failure (n=7), the presence of donor-type neutrophils and NK cells as well as the predominance of donor-type T cells distinguished patients who responded to G-CSF (n=5) from nonresponders (n=2). Furthermore, the clearance of host CD3+CD56- cells during days 5-10 posttransplantation was significantly hastened in patients who subsequently developed acute (delta=80%) or chronic (delta=81%) GVHD compared with patients without GVHD (delta=17%). Thus, our data suggest that molecular monitoring of the fate of host/donor hematopoietic cells in the early posttransplantation period could be useful in differentiating patients with delayed engraftment from those with irreversible rejection and in predicting the occurrence of GVHD as soon as day 10. This investigational approach may provide an appropriate basis on which to select adequate treatment for primary graft failure and high-risk candidates that could benefit from novel preemptive therapies for GVHD.

Lymphoma cell burden in progenitor cell grafts measured by competitive polymerase chain reaction: less than one log difference between bone marrow and peripheral blood sources

A controversy persists in autologous transplantation as to which source of progenitor cells, bone marrow (BM) or peripheral blood (PB), contains the lowest number of contaminating lymphoma cells, and how mobilization procedures affect these numbers. To accurately measure the number of non-Hodgkin's lymphoma (NHL) cells harboring the bcl-2/immunoglobulin H (IgH) rearrangement in progenitor cell grafts, we developed a nested quantitative competitive polymerase chain reaction assay (QC-PCR). DNA from lymph nodes of four patients with NHL were cloned into the pSK(+) vectors to generate four internal controls (ICs) (two with major breakpoint region [MBR] and two with minor cluster region [mcr] rearrangements). The kinetics of amplification of ICs paralleled those of bcl-2/IgH rearranged genomic DNA. When used in a QC-PCR assay, these ICs were accurate at a 0.2-log level and provided reproducible results, as shown by low intrarun and interrun variability. An excellent correlation between predicted and observed lymphoma cell content (r = .99) was observed over a range of at least 5 logs of rearranged cells. This approach was used to measure involvement by NHL cells at the time of progenitor cell harvest in 37 autologous transplant patients. The number of bcl-2/IgH rearranged cells in BM, PB, and mobilized PB (mPB) was found to vary from 1 to 1.1 x 10(5) per million cells. The number of lymphoma cells present in BM was significantly higher than in PB (P = .0001), with a median difference in lymphoma cell content between BM and PB of 0.48 log of cells (range, -0.7 to 5 logs). In contrast, we found no difference in the concentration of bcl-2/IgH rearranged cells present in BM versus PB progenitor cells mobilized with cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) (mPB) (P = .57). In conclusion, the QC-PCR assay described in this study could measure accurately and reproducibly the number of bcl-2/IgH rearranged cells among normal cells. Differences in levels of contamination by lymphoma cells between BM and PB were of less than one log (10-fold), and no differences in lymphoma cell concentrations were observed between BM and mobilized PB. As more cells are usually infused with mPB than with BM grafts, mPB progenitor cell grafts may actually be associated with higher levels of contamination by lymphoma cells. Furthermore, this QC-PCR assay should provide an important tool to assess the prognostic impact of lymphoma cell burden both in progenitor cell grafts and in vivo.

Conjugation of blocked ricin to an anti-CD19 monoclonal antibody increases antibody-induced cell calcium mobilization and CD19 internalization

CD19 (B4) is a signal transduction molecule restricted to the B-cell lineage and the target of the immunotoxin anti-B4-blocked ricin (anti-B4-bR), which is composed of the monoclonal antibody (MoAb) anti-B4 and the modified plant toxin blocked ricin. To explore the influence of conjugation of blocked ricin to anti-B4 on functional activation of CD19, we investigated the effects of anti-B4-bR, and that of unconjugated anti-B4, on intracellular calcium mobilization and ligand/receptor internalization. The data showed that anti-B4-bR was more potent than anti-B4 in triggering cell calcium mobilization. Two other immunotoxins that bind to the B-cell surface, anti-CD20-bR and anti-CD38-bR, were devoid of the calcium increasing effect of anti-B4-bR. Furthermore, anti-B4 conjugated to ricin A-chain was also without effect in Namalwa cells, indicating that the ricin B-chain component was required for anti-B4-bR effect. Anti-B4-bR-induced calcium mobilization was inhibited in the presence of lactose, yet the calcium response induced by cross-linking anti-B4-bR with a second step antibody was not affected. The extent of CD19 modulation induced by anti-B4-bR was higher than that induced by anti-B4, and lactose dampened the effect of the immunotoxin down to that of the MoAb. Moreover, the number of internalized immunotoxin molecules was higher than that of unconjugated MoAb. Although a mechanism involving dimerization of the immunotoxin cannot be excluded, our findings suggest that the residual binding activity of the blocked ricin B-chain to cell surface molecules plays an important role in the greater calcium fluxes and greater internalization rate of anti-B4-bR, and is of functional significance in the mechanism of intoxication of cells by the immunotoxin.

Thymic and extrathymic differentiation and expansion of T lymphocytes following bone marrow transplantation in irradiated recipients

Thymic function is severely impaired in most marrow transplant recipients. To evaluate the impact of thymic hypoplasia on T cell reconstitution following marrow transplantation, we compared the phenotype and function of T lymphocytes in thymectomized recipients with those of euthymic hosts. Irradiated C57BL/6 mice (Thy1.2+, Ly5.1+) received 10(7) T cell-depleted B6.Ly5.2 bone marrow cells (Thy1.2+, Ly5.2+), with or without 3 x 10(5) B6.PL lymph node cells (Thy1.1+, Ly5.1+) as a source of T lymphocytes. Multiparameter flow cytometry analysis showed that in euthymic mice (group 1), T cell reconstitution was carried out by donor hematopoietic stem cells that differentiated in the host's thymus, whereas the production of chimeric T cells in athymic recipients depended on the presence or absence of T cells in the graft. When T lymphocytes were present in the graft (group 2), their progeny constituted the vast majority of splenic T cells on day 100 posttransplant. When the graft did not contain T lymphocytes (group 3), T cell reconstitution resulted from extrathymic maturation of donor hematopoietic progenitors; T cells differentiating along this pathway expressed lower levels of T cell receptor and a large proportion of the CD8+ subset expressed CD8alpha alpha homodimers. The T cell receptor Vbeta profile of all chimeras was similar to that of normal C57BL/6 mice. Compared with T cells found in euthymic recipients, those in mice from groups 2 and 3 were less abundant (particularly with respect to the CD4+ subset), displayed the CD44/CD45 phenotype of activated memory cells, and expressed high levels of IL-2 receptor beta chain. These results show that both the presence or absence of the thymus and the composition of the grafted inoculum determine the source and extent of posttransplant T cell reconstitution. Because they determine the nature of the differentiation pathway taken during T cell development in the host, these two factors can exert a critical influence on the appearance of graft vs. host disease and the level of host immunocompetence.

Elimination of neuroblastoma and small-cell lung cancer cells with an anti-neural cell adhesion molecule immunotoxin

BACKGROUND

The development of immunotoxins has been hampered by difficulties, particularly in solid tumors, of finding appropriate target antigens and of linking sufficiently potent toxins.

PURPOSE

We evaluated the tissue specificity of an immunotoxin, N901-blocked ricin (N901-bR), and assessed its potential for eliminating neural cell adhesion molecule (NCAM)-positive tumor cells in conditions appropriate for in vitro purging, prior to autologous stem cell transplantation, and its potential for myelosuppression. N901-bR consists of a monoclonal antibody (MAb), N901, directed against CD56, an antigen of the family of NCAMs, covalently linked to blocked ricin as the cytotoxic effector moiety.

METHODS

The tissue specificity of the N901 MAb and the N901-bR immunotoxin was tested against a wide array of human tumor tissues and normal human tissues by immunohistochemical staining. The cytotoxic activity of N901-bR was tested against both small-cell lung cancer (SCLC) cells and neuroblastoma cells, either alone or among normal bone marrow mononuclear cells, and the efficacy of this treatment to specifically eliminate these cells was evaluated in a limiting dilution assay. In addition, normal bone marrow mononuclear cells were incubated with N901-bR, and the toxic effects of the immunotoxin on normal hematopoietic progenitors was evaluated.

RESULTS

N901 and N901-bR exhibited specificity for several neoplasms of neuroectodermal origin, including SCLC and neuroblastoma. Staining of normal tissues was essentially limited to various neuroendocrine cells, cardiac muscle cells, and cells in peripheral nerve tissue. We observed a time- and dose-dependent elimination of tumor cells in vitro, with three logs (i.e., > 99.9%) of malignant cells being killed following only 5 hours of exposure to 10 nM N901-bR. Unconjugated N901 MAb specifically blocked the elimination of NCAM-positive cells by N901-bR, whereas neither an isotype-matched control MAb nor galactose (the ligand of native ricin) had any effect on the activity of the immunotoxin, confirming the specificity of its cytotoxic activity. Importantly, N901-bR used under optimal conditions for in vitro tumor cell depletion was not toxic to hematopoietic precursors.

CONCLUSIONS

N901-bR has the properties required to target CD56, an antigen present not only on cells from a large number of cancers of neuroendocrine origin, but also on some important normal tissues. In addition, treatment with this immunotoxin results in the highly effective and specific elimination of neuroblastoma and SCLC cells and does not affect normal hematopoietic progenitors.

IMPLICATIONS

N901-bR may have clinical utility for purging of neuroblastoma cells and SCLC cells before autologous stem cell transplantation. Further toxicology studies are warranted to assess the potential of N901-bR for in vivo administration.

Identification of an immunodominant mouse minor histocompatibility antigen (MiHA). T cell response to a single dominant MiHA causes graft-versus-host disease

T cell responses to non-MHC antigens are targeted to a restricted number of immunodominant minor histocompatibility antigens whose identity remains elusive. Here we report isolation and sequencing of a novel immunodominant minor histocompatibility antigen presented by H-2Db on the surface of C57BL/6 mouse cells. This nonapeptide (AAPDNRETF) shows strong biologic activity in cytotoxic T lymphocyte sensitization assays at concentrations as low as 10 pM. C3H.SW mice primed with AAPDNRETF in incomplete Freund's adjuvant generated a potent anti-C57BL/6 T cell-mediated cytotoxic activity, and T lymphocytes from AAPDNRETF-primed mice caused graft-versus-host disease when transplanted in irradiated C57BL/6 recipients. These results (a) provide molecular characterization of a mouse dominant minor histocompatibility antigen, (b) identify this peptide as a potential target of graft-versus-host disease and, (c) more importantly, demonstrate that a single dominant minor antigen can cause graft-versus-host disease. These findings open new avenues for the prevention of graft-versus-host disease and should further our understanding of the mechanisms of immunodominance in T cell responses to minor histocompatibility antigens.

Sequential analysis of early hematopoietic reconstitution following allogeneic bone marrow transplantation with fluorescence in situ hybridization (FISH)

Using in situ hybridization with an X and Y chromosome probe mixture, we have sequentially studied peripheral blood samples from 10 patients (four males/six females) in an HLA-matched allogeneic setting in order to monitor the kinetics of early hematopoietic reconstitution. Interphase cells from smears consisting of purified granulocytic and lymphocytic populations respectively were studied in three patients at 24, 48, 72 and 96 h post-transplant. This period was arbitrarily defined as the immediate post-transplant period. These three patients plus seven others were studied sequentially at days 5, 10, 15, 20, 25 and 50 post-transplant, defined as the intermediate post-transplant period. The X and Y probes were indirectly labelled with rhodamine and fluoresceine isothiocyanate, respectively. Donor neutrophils were detected as early as 24 h post marrow infusion followed by a significant expansion at 48 h. At 96 h post-transplant, the median percentage of donor neutrophils was > 90%. In the immediate post-transplant period, most of the lymphocytes were of recipient origin. However, we have documented a significant expansion in donor lymphocytes, starting at day 5 post-transplant in most patients. Almost complete chimerism for the myeloid and lymphoid lineages was established at days 10 and 25 post-transplant, respectively. All patients engrafted normally according to standard clinical criteria. Follow-up data for those surviving > or = 100 days (eight patients), showed persistence of this pattern of hematopoietic reconstitution in all but one patient. Molecular monitoring of early engraftment has enabled us to unravel a distinct biphasic pattern of myeloid and lymphoid engraftment.

Flow cytometric evaluation of leukocyte subpopulations in the follicular fluids of infertile patients

OBJECTIVES

To evaluate the leukocyte subpopulations present in follicular fluid (FF) of infertile patients undergoing IVF-ET for tubal factor, idiopathic infertility, and endometriosis.

PATIENTS

Sixty patients undergoing IVF-ET with a tubal factor diagnosis (n = 35), idiopathic infertility (n = 13), and endometriosis (n = 12) had their subpopulations of FF leukocytes analyzed by flow cytometry.

MAIN OUTCOME MEASURE

Nonblood-contaminated samples of FF were collected under sterile conditions and centrifuged. Cells were labeled with a panel of monoclonal antibodies: anti-CD3, -CD4, -CD8, -CD14, -CD20, -CD45, and -CD56, and analyzed by cytofluorometry.

RESULTS

Follicular fluid leukocytes from patients with idiopathic infertility had a significantly higher proportion of T lymphocytes than tubal factor and endometriosis patients. Endometriosis patients had significantly higher proportions of natural killer (NK) cells, B lymphocytes, and monocytes compared with groups of idiopathic infertility and tubal factor.

CONCLUSIONS

The differences observed in the leukocyte subpopulations from FF of patients with idiopathic infertility and endometriosis may affect folliculogenesis and oocyte maturation. Moreover, these modifications could be one of the factors altering their fertility.

Endometrial T, B, and NK cells in patients with recurrent spontaneous abortion. Altered profile and pregnancy outcome

Several lines of evidence indicate that immunologic effectors, particularly suppressor T cells and NK cells, may play a role in the pathogenesis of idiopathic repetitive abortions. To investigate the involvement of these immune cell populations, we determined the immunophenotypic characteristics of endometrial leukocytes from nonpregnant recurrent aborters. Habitual aborters with a negative investigation underwent an endometrial biopsy during their secretory phase and were followed prospectively to assess clinical outcome. Endometrial leukocytes were evaluated by two-color flow cytometric analysis. The percentage of endometrial CD8+ T lymphocytes was significantly decreased in recurrent aborters, and their CD4:CD8 ratio was increased. In contrast, the proportion of B lymphocytes (CD20+) was strikingly increased in these patients' endometria. The proportion of NK cells was identical in recurrent aborters and normal controls, but the CD16-CD56 bright NK cell subset, which is predominant in normal decidua and endometrium, was significantly decreased in favor of an important contingent of CD16+CD56 dim NK cells in all habitual aborters. Repetitive aborters who had normal CD8+ and CD20+ cell numbers and a normal CD4:CD8 ratio subsequently underwent successful pregnancies, while patients with continuing abortions presented lymphoid populations observed in the habitual aborters group. In conclusion, endometrial lymphocytes of recurrent spontaneous aborters harbor a distinct immunophenotypic profile that antedates implantation and suggests that endometrial immunologic conditions are intrinsically altered in recurrent aborters. Also, the prognostic impact of CD8 and CD20 expression supports their predominant role in the development of fetal tolerance. Finally, a role for NK cells in the abortion process is suggested by their altered subsets in all repetitive aborters.

Endometrial T, B, and NK cells in patients with recurrent spontaneous abortion. Altered profile and pregnancy outcome

Several lines of evidence indicate that immunologic effectors, particularly suppressor T cells and NK cells, may play a role in the pathogenesis of idiopathic repetitive abortions. To investigate the involvement of these immune cell populations, we determined the immunophenotypic characteristics of endometrial leukocytes from nonpregnant recurrent aborters. Habitual aborters with a negative investigation underwent an endometrial biopsy during their secretory phase and were followed prospectively to assess clinical outcome. Endometrial leukocytes were evaluated by two-color flow cytometric analysis. The percentage of endometrial CD8+ T lymphocytes was significantly decreased in recurrent aborters, and their CD4:CD8 ratio was increased. In contrast, the proportion of B lymphocytes (CD20+) was strikingly increased in these patients' endometria. The proportion of NK cells was identical in recurrent aborters and normal controls, but the CD16-CD56 bright NK cell subset, which is predominant in normal decidua and endometrium, was significantly decreased in favor of an important contingent of CD16+CD56 dim NK cells in all habitual aborters. Repetitive aborters who had normal CD8+ and CD20+ cell numbers and a normal CD4:CD8 ratio subsequently underwent successful pregnancies, while patients with continuing abortions presented lymphoid populations observed in the habitual aborters group. In conclusion, endometrial lymphocytes of recurrent spontaneous aborters harbor a distinct immunophenotypic profile that antedates implantation and suggests that endometrial immunologic conditions are intrinsically altered in recurrent aborters. Also, the prognostic impact of CD8 and CD20 expression supports their predominant role in the development of fetal tolerance. Finally, a role for NK cells in the abortion process is suggested by their altered subsets in all repetitive aborters.

Phenotypic and functional characterization of peripheral blood and bone marrow natural killer cells prior to autologous transplantation

NK cells can exert potent anti-leukemia activity after either autologous or allogeneic BMT. However, in autologous blood or marrow transplant patients, NK cell number and/or function could be reduced, and also may vary according to the sampling site. In order to evaluate the hypothesis that blood or marrow grafts from autologous transplant patients exhibit impaired NK cell activity that could contribute to disease recurrence, we evaluated the immunologic characteristics of NK cells in the bone marrow (BM) and peripheral blood (PB) from 27 patients undergoing autologous BMT, and also from 20 normal donors. We measured baseline and interleukin-2 (IL-2)-activated NK cell cytotoxicity, as well as expression of IL-2 receptors (IL-2R) (alpha-chain (p55) and beta-chain (p75)), and adhesion molecules. The cytotoxic activity of PB NK cells was significantly lower in autologous transplant patients than in normal donors (P < 0.0005) and this difference was not mitigated following IL-2 activation. In contrast, BM from autologous patients showed normal NK cell cytotoxicity, but contained higher numbers of NK cells (P < 0.025), with more intense CD56 expression (P < 0.05). Expression of p75 was lower on BM than on PB NK cells in both patients and normal donors. In addition, induction of p55 by IL-2 was abrogated in autologous PB NK cells. Therefore, depending on the site of harvest and the nature of donor cells (pre-BMT vs normal), our results show significant differences in NK cell number, function, and IL-2 receptor expression. This may affect relapse rates following autologous transplants performed with either PB or BM grafts.

Flow-cytometric characterization of hematopoietic cells in non-pregnant human endometrium

PROBLEM

Immunologic evaluation and quantitation of hematopoietic cells in human endometrium has been difficult to perform, particularly in nonpregnant subjects. In this study, we describe a method for the flow-cytometric characterization of hematopoietic cells present in the endometrium of non-pregnant women.

METHOD

Endometrial biopsy samples from normal donors were first mechanically disrupted and filtered to generate a single-cell suspension of leukocyte-enriched endometrial cells. Cells were labeled with a panel of monoclonal antibodies, stained with propidium iodide (PI), and one- or two-color flow-cytometric analysis performed on cells excluding PI.

RESULTS

The methodology described in this study was highly reproducible in experiments evaluating the interrun and intrarun variability. We then determined the immunophenotypic profile of endometrial leukocytes from 12 normal females. The majority of leukocytes were T cells (CD3: 47%; CD4: 24%; CD8: 28%) with an important contingent of NK cells (CD56: 32%), the majority of which harbored the unusual CD16-CD56 bright phenotype, and a minority of B cells (CD20: 6%) and monocytes (CD14: 7%).

CONCLUSIONS

Flow cytometry can be used to assess antigen expression on the surface of endometrial leukocytes from nonpregnant women. In future studies, it will be possible to use this approach to investigate the role of immune cell populations in the endometrium of patients experiencing reproductive failure.

Oligoclonal expansion of CTLs directed against a restricted number of dominant minor histocompatibility antigens in hemopoietic chimeras

To understand how T cells respond to allogeneic minor histocompatibility Ags (MiHAs), we studied the fate of Thy-1.1+ lymphocytes, as well as their TCR usage and functional activity, in irradiated LP (Thy-1.2+) recipients transplanted with a mixture of C57BL/6 (Thy-1.2+) hemopoietic progenitors supplemented with either low or high numbers of B6.PL lymphocytes (Thy-1.1+). Mice transplanted with low numbers of T cells experienced a dramatic expansion (&gt; or = 10(5)-fold) of donor Thy-1.1+/CD8+ cells during the first 15 days post-transplant. Flow-cytometric analysis and sequencing of junctional nucleotide sequences showed that the nature of this expansion was oligoclonal and involved primarily one or a few clones using V beta 5.1 or V beta 8.1 TCR elements. Expanded T lymphocyte populations displayed MHC-restricted cytotoxicity for a restricted number of MiHAs, that were found in only two peaks following fractionation of LP MiHAs by reverse-phase HPLC. Expansion of donor T cells was limited to the spleen, and short-lived in these recipients that became healthy long-term chimeras without any signs of graft-vs-host disease (GVHD). In contrast, mice transplanted with high numbers of T cells (GVHD+) showed proliferation of Thy-1.1+ donor cells not only in the spleen, but also in the thymus, and recipients died rapidly of GVHD. These results show that: 1) in the MiHA-incompatible transplantation setting, lack of GVHD cannot be explained simply by the absence of antihost T cell responses, 2) GVHD+ recipients present a massive thymic infiltration by donor mature T lymphocytes, and 3) antihost T cell responses are oligoclonal in nature and targeted to only a few MiHAs. These findings shed new light on the pathogenetic mechanisms involved in GVHD and on the selection of the T cell repertoire involved in response to immunodominant MiHAs.

Oligoclonal expansion of CTLs directed against a restricted number of dominant minor histocompatibility antigens in hemopoietic chimeras

To understand how T cells respond to allogeneic minor histocompatibility Ags (MiHAs), we studied the fate of Thy-1.1+ lymphocytes, as well as their TCR usage and functional activity, in irradiated LP (Thy-1.2+) recipients transplanted with a mixture of C57BL/6 (Thy-1.2+) hemopoietic progenitors supplemented with either low or high numbers of B6.PL lymphocytes (Thy-1.1+). Mice transplanted with low numbers of T cells experienced a dramatic expansion (> or = 10(5)-fold) of donor Thy-1.1+/CD8+ cells during the first 15 days post-transplant. Flow-cytometric analysis and sequencing of junctional nucleotide sequences showed that the nature of this expansion was oligoclonal and involved primarily one or a few clones using V beta 5.1 or V beta 8.1 TCR elements. Expanded T lymphocyte populations displayed MHC-restricted cytotoxicity for a restricted number of MiHAs, that were found in only two peaks following fractionation of LP MiHAs by reverse-phase HPLC. Expansion of donor T cells was limited to the spleen, and short-lived in these recipients that became healthy long-term chimeras without any signs of graft-vs-host disease (GVHD). In contrast, mice transplanted with high numbers of T cells (GVHD+) showed proliferation of Thy-1.1+ donor cells not only in the spleen, but also in the thymus, and recipients died rapidly of GVHD. These results show that: 1) in the MiHA-incompatible transplantation setting, lack of GVHD cannot be explained simply by the absence of antihost T cell responses, 2) GVHD+ recipients present a massive thymic infiltration by donor mature T lymphocytes, and 3) antihost T cell responses are oligoclonal in nature and targeted to only a few MiHAs. These findings shed new light on the pathogenetic mechanisms involved in GVHD and on the selection of the T cell repertoire involved in response to immunodominant MiHAs.

Distinct patterns of minimal residual disease associated with graft-versus-host disease after allogeneic bone marrow transplantation for chronic myelogenous leukemia

PURPOSE

Allogeneic bone marrow transplantation (BMT) has been shown to provide effective therapy for chronic myelogenous leukemia (CML), but previous reports have also demonstrated the persistence of bcr-abl-positive cells for months to years after BMT in the majority of patients. To evaluate the biologic significance of persistent bcr-abl-positive cells, we examined the relationship between clinical parameters known to affect the risk of relapse and the ability to detect bcr-abl-positive cells post-BMT.

PATIENTS AND METHODS

We analyzed 480 samples from 92 patients at two transplant centers for the presence of bcr-abl-positive cells by polymerase chain reaction (PCR). Two different BMT preparative regimens and protocols for prevention of graft-versus-host disease (GVHD) were used. One center used cyclophosphamide plus total-body irradiation (CY/TBI) and T-cell-depleted marrow; the second center used busulfan plus cyclophosphamide (Bu/CY) and untreated marrow with cyclosporine and methotrexate (Csp/MTX) as GVHD prophylaxis.

RESULTS

We first determined the percent of patients at each center with > or = one PCR-positive (PCR+) result at defined intervals post-BMT. Between 0 and 6 months post-BMT, the majority of patients (80% to 83%) in both populations had PCR-detectable bcr-abl-positive cells. Between 6 and 24 months post-BMT, 80% to 88% of patients who received T-cell-depleted marrow remained PCR+, as compared with 26% to 30% of patients who received unmodified marrow. After 24 months post-BMT, the percentage of PCR+ patients was not significantly different in the two populations. This pattern of detection of bcr-abl-positive cells post-BMT followed the development of chronic GVHD in patients who received unmodified marrow. All patients were also divided into three groups based on post-BMT PCR results as follows: (1) persistent PCR+ (n = 29), (2) intermittent PCR-negative ([PCR-] n = 40), and (3) persistent PCR- (n = 23). These three groups were found to have a low, intermediate, and high probability of maintaining remission and disease-free survival, respectively (P = .0001). Intermittent or persistent PCR- results, which reflect levels of minimal residual disease < or = the limit of detection by PCR, were clearly associated with both acute (P = .004) and chronic (P = .000005) GVHD. Nevertheless, 44% of patients without GVHD also had intermittent or persistent PCR- assays.

CONCLUSION

The persistence of PCR-detectable bcr-abl-positive cells early post-BMT in more than 80% of patients suggests that neither BMT preparative regimen effectively eradicates CML cells in most patients. Subsequently, acute and/or chronic GVHD are associated with a decreased ability to detect residual bcr-abl-positive cells, which suggests that immunologic mechanisms mediated by donor cells are important for inducing long-term remissions after BMT. The demonstration that 44% of patients without GVHD had either low or undetectable levels of residual leukemia suggests the presence of mechanisms capable of suppression or eradication of CML independent of GVHD.

Elimination of B-lineage leukemia and lymphoma cells from bone marrow grafts using anti-B4-blocked-ricin immunotoxin

Bone marrow is the primary site of disease in patients with acute lymphoblastic leukemia (ALL) and is frequently involved in patients with non-Hodgkin's lymphoma (NHL). At the time of autologous bone marrow transplantation, marrow grafts from patients with leukemia and lymphoma are often still contaminated by malignant cells, even when such patients achieve complete clinical remission. In this study, we evaluated the potential of anti-B4-blocked-ricin (anti-B4-bR) immunotoxin to eliminate residual ALL and NHL cells from bone marrow. Anti-B4-bR binds to the CD19 antigen, which is B-lineage specific, and, at concentrations of 5 x 10(-9) M or greater, could eliminate more than 3 logs of CD19+ Nalm-6 or Namalwa cells in a 20-fold excess of normal irradiated bone marrow after only 5 hr of incubation. This activity was abrogated by the addition of anti-B4 but not by the presence of galactose, which is the natural ligand for native ricin. Also, when used at these high concentrations, anti-B4-bR showed little nonspecific toxicity against normal hematopoietic progenitors. In conclusion, a single short exposure to anti-B4-bR is capable of inducing high levels of depletion of CD19+ leukemia and lymphoma cells without significant nonspecific toxicity against normal marrow progenitors. Therefore, anti-B4-bR offers an interesting approach to the elimination of B-lineage malignant cells prior to autologous bone marrow transplantation.

A non-isotopic nested polymerase chain reaction method to quantitate minimal residual disease in patients with non-Hodgkin's lymphoma

The polymerase chain reaction (PCR) is a highly sensitive technique for the detection of lymphoma cells presenting specific rearrangements or translocations, like the t(14;18). However, few methods are available for the quantitative evaluation of clinical samples, especially using nested PCR. In this study, we describe a method for the semiquantitative estimation of low numbers of lymphoma cells using the nested PCR methodology. Samples evaluated consisted of RL cells, a non-Hodgkin's lymphoma cell line harbouring a bcl-2 translocation, mixed with normal mononuclear cells (MC) obtained from bone marrow or peripheral blood. DNA was extracted from samples with RL:MC ratios ranging from 5 x 10(-2) to 5 x 10(-7), and amplified for detection of this translocation. The product of this first amplification reaction was serially diluted 10-fold from 10(0) to 10(-7). Then each fraction was PCR-amplified with nested oligonucleotide primers. Aliquots of the second amplification were electrophoresed on a 2% agarose gel and stained with ethidium bromide. Within the range tested, there was a log-linear relationship between the number of PCR positive bands and the number of translocated cells in each sample. This procedure was highly reproducible in experiments evaluating the interrun and intrarun variability. In addition, there was no interaction with normal cells obtained from peripheral blood or bone marrow, or from different individuals. Furthermore, results were identical with two different cell lines and consistent with patient lymphoma cells obtained from a lymph node biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistence of myeloid progenitor cells expressing BCR-ABL mRNA after allogeneic bone marrow transplantation for chronic myelogenous leukemia

Previous studies have shown that tumor-specific bcr-abl mRNA can often be detected by polymerase chain reaction. (PCR) for months to years after allogeneic bone marrow transplantation (BMT) for chronic myelocytic leukemia (CML). Nevertheless, the presence of bcr-abl mRNA by itself does not invariably predict for clinical relapse post-BMT. This has led to the hypothesis that bcr-abl mRNA might be expressed in cells that have lost either proliferative or myeloid differentiation potential. To directly characterize the cells detected by PCR in patients with CML after allogeneic BMT, we first identified five individuals in whom PCR-positive cells could be detected at multiple times post-BMT. Bone marrow samples from these individuals were cultured in vitro and single erythroid, granulocytic, and macrophage colonies, each containing 50 to 100 cells, were examined for the presence of bcr-abl mRNA by PCR. PCR-positive myeloid colonies could be detected in four of five individuals in marrow samples obtained 5 to 56 months post-BMT. Overall, 7 of 135 progenitor cell colonies (5.2%) were found to be PCR-positive. The expression of bcr-abl mRNA appeared to be equally distributed among committed erythroid, macrophage, and granulocyte progenitors. These patients have now been followed-up for an additional 20 to 33 months from the time of progenitor cell PCR analysis but only one of these individuals has been found to have cytogenetic evidence of recurrent Ph+ cells. These results show that long-term persistence of PCR-detectable bcr-abl mRNA after allogeneic BMT can be caused by the persistence of CML-derived clonogenic myeloid precursors that have survived the BMT preparative regimen. These cells continue to have both proliferative and myeloid differentiation capacity in vitro. Nevertheless, these PCR-positive cells do not appear to either expand or differentiate in vivo for prolonged periods, suggesting the presence of mechanisms for suppression of residual clonogenic leukemia cells in vivo.

Allogeneic bone marrow transplantation following busulfan-cyclophosphamide with or without etoposide conditioning regimen for patients with acute lymphoblastic leukaemia

We have investigated the feasibility and efficacy of administering a radiation-free preparative regimen in the setting of allogeneic bone marrow transplantation (BMT) in 40 consecutive patients with acute lymphoblastic leukaemia (ALL). Busulfan (4 mg/kg/d x 4 d) and cyclophosphamide (50 mg/kg/d x 4 d) (BuCy4) were given in 29 patients and 11 received busulfan (4 mg/kg/d x 4 d), etoposide (60 mg/kg) and cyclophosphamide (60 mg/kg/d x 2 d) (BuCy+VP - 16). Median age was 22 years (range 1-50); 11 patients were children < or = 15 years of age. All children and 20 adults were at high risk of relapse pretransplant. Nine adults and one child died from transplant-related toxicity. 11 patients relapsed at a median of 11 months post-transplant (range 2-27). The 3-year Kaplan-Meier estimated probability of relapse was 42.1% and found to be significantly lower in patients with chronic GVHD (P = 0.03). 19 patients are leukaemia-free survivors with a median follow-up of 33 months (range 7-59). The Kaplan-Meier actuarial probability of disease-free survival at 3 years was 43% for all patients. 63.6% for children versus 30.2% for adults (P = 0.24) and 51.6% for patients transplanted in first remission versus 30.2% for those transplanted in subsequent remissions (P = 0.20).

Monoclonal antibody-purged autologous bone marrow transplantation in adults with acute lymphoblastic leukemia at high risk of relapse

The prognosis for adults with B lineage ALL who have relapsed after an initial remission is poor. High-dose chemoradiotherapy followed by autologous BMT can induce prolonged clinical remissions in some children with recurrent ALL. In this study, we evaluated the efficacy of autologous BMT in adults. Autologous marrow was treated in vitro with J5 and J2 monoclonal antibodies (CD10/CD9) plus rabbit complement to purge residual ALL cells. Twenty-two adults with B lineage ALL were treated with high-dose chemoradiotherapy followed by infusion of J2/J5 purged autologous BM. The median age was 28 years (range 18-54 years). Twenty-one of 22 patients had experienced at least one relapse prior to BMT. All patients achieved complete hematologic engraftment. Disease-free survival (DFS) in this cohort of patients was 20%, with all survivors alive and free of disease between 2.5 and 7.5 years post-BMT. Age at the time of BMT was an important prognostic factor, with patients < 28 years old faring much better than older individuals (DFS, 45% vs 0%, p = 0.01). Our experience suggests that high-dose chemoradiotherapy followed by infusion of J2/J5 purged autologous marrow is as efficacious in young adults as it is in children and is a reasonable alternative for patients who lack HLA-matched donors. Results in older adults are poor, however, and demonstrate the need for more effective transplant strategies in these individuals.

Acute graft-versus-host disease prophylaxis with methotrexate and cyclosporine after busulfan and cyclophosphamide in patients with hematologic malignancies

The combination of two powerful immunosuppressive agents, methotrexate (MTX) and cyclosporine (CSP), has resulted in a significant decrease in the morbidity and mortality after allogeneic bone marrow transplantation (BMT). However, the additive toxicities from ablative preparative regimens may lead to suboptimal use of this combined immunoprophylaxis. We evaluated the efficacy and feasibility of administering MTX/CSP with busulfan (4 mg/kg/d for 4 days) and cyclophosphamide (50 mg/kg/d for 4 days) (BuCy4) in 101 consecutive patients with hematologic malignancies categorized into high- and low-risk groups receiving HLA-matched marrow grafts. Postgrafting immunosuppression consisted of MTX short course (15 mg/m2 on day 1 and 10 mg/m2 on days 3, 6, and 11) and intravenous CSP (1.5 mg/kg every 12 hours). Eighty-three patients (82.1%) received 100% of MTX calculated dose and 87 (86.1%) achieved a CSP therapeutic level (250 to 600 ng/mL) within a median of 16 days. Seventy-three patients (72.2%) received optimal immunosuppressive therapy comprising a full MTX course and achieving CSP therapeutic concentrations. The Kaplan-Meier estimated incidence of grade II to IV acute graft-versus-host disease (GVHD) was 9.2% for all patients and 5.5% in patients receiving optimal GVHD prophylaxis. Eighty-nine patients (88.2%) survived > or = 100 days posttransplant and 43 (48.3%) developed chronic GVHD, the majority of which were de novo (31 of 43). The estimated incidence of relapse was 28.9% for all patients and 14.8% in the low-risk group, with a median follow-up of 24.5 months. High-risk features and the absence of chronic GVHD were significantly associated with relapse (P = .002 and .036, respectively) in multivariate analyses. Projected disease-free survival at 2 years was 52.3% for all patients and 65.2% in low-risk patients. Disease-free survival was significantly improved in optimally treated patients (P = .03) due to a lower incidence of early deaths from acute GVHD and infectious episodes. In conclusion, optimal delivery of MTX/CSP in association with BuCy4 resulted in a near complete abrogation of acute GVHD in HLA-matched transplants and a significantly improved disease-free survival.

Tolerance to host minor histocompatibility antigens after allogenic bone marrow transplantation. Specific donor-host unresponsiveness is maintained by peripheral tolerizing cells

The development of graft-host tolerance after allogeneic bone marrow (BM) transplantation is more demanding than the acquisition of self-tolerance because both donor-derived mature T cells and immature thymocytes encounter host Ag. The mechanism involved in tolerization of mature T cells, contained in unmanipulated BM, remains undefined. In previous experiments, we showed in vivo unresponsiveness to host minor histocompatibility Ag (MiHA) in immunocompetent chimeras obtained after MiHA-incompatible BM transplantation. In this study, we wanted to determine: first, what was the specificity of this graft-host unresponsiveness, and second, whether peripheral cells were involved in tolerization? LP recipients were irradiated (9, 5 Gy), injected with 10(7) undepleted BM cells from B10 donors and studied 100 to 150 days later. (B10-->LP) chimeras were immunized in vivo and restimulated in vitro with cells displaying one or multiple incompatible MiHA. In bulk culture experiments, chimeras demonstrated specific CTL unresponsiveness to host MiHA but responded normally to third party MiHA. In limiting dilution analysis conditions, chimeras showed a profound deficit, but not a complete absence of anti-host CTL precursor. Studies with congenic stimulators/targets showed that graft-host tolerance was induced against both immunodominant (e.g., H-3.2) and nonimmunodominant (e.g., H-8.2) MiHA although at the CTL precursor level, it was more complete against the former. Furthermore, chimera spleen cells inhibited the generation of CTL activity against host- and donor-type MiHA but not against third party Ag. This specific suppressor activity was not T cell dependent, and was mediated by radiosensitive cells that are not found in freshly explanted organs from normal mice. Taken together, our results suggest that peripheral tolerization can be a remarkably efficient process to maintain tolerance to MiHA after BM transplantation. Thus, peripheral tolerizing mechanisms may contribute not only to the induction of tolerance to Mls superantigens or to the product of transgenes (if expressed at high levels) but also to a wide array of MiHA.

Tolerance to host minor histocompatibility antigens after allogenic bone marrow transplantation. Specific donor-host unresponsiveness is maintained by peripheral tolerizing cells

The development of graft-host tolerance after allogeneic bone marrow (BM) transplantation is more demanding than the acquisition of self-tolerance because both donor-derived mature T cells and immature thymocytes encounter host Ag. The mechanism involved in tolerization of mature T cells, contained in unmanipulated BM, remains undefined. In previous experiments, we showed in vivo unresponsiveness to host minor histocompatibility Ag (MiHA) in immunocompetent chimeras obtained after MiHA-incompatible BM transplantation. In this study, we wanted to determine: first, what was the specificity of this graft-host unresponsiveness, and second, whether peripheral cells were involved in tolerization? LP recipients were irradiated (9, 5 Gy), injected with 10(7) undepleted BM cells from B10 donors and studied 100 to 150 days later. (B10--&gt;LP) chimeras were immunized in vivo and restimulated in vitro with cells displaying one or multiple incompatible MiHA. In bulk culture experiments, chimeras demonstrated specific CTL unresponsiveness to host MiHA but responded normally to third party MiHA. In limiting dilution analysis conditions, chimeras showed a profound deficit, but not a complete absence of anti-host CTL precursor. Studies with congenic stimulators/targets showed that graft-host tolerance was induced against both immunodominant (e.g., H-3.2) and nonimmunodominant (e.g., H-8.2) MiHA although at the CTL precursor level, it was more complete against the former. Furthermore, chimera spleen cells inhibited the generation of CTL activity against host- and donor-type MiHA but not against third party Ag. This specific suppressor activity was not T cell dependent, and was mediated by radiosensitive cells that are not found in freshly explanted organs from normal mice. Taken together, our results suggest that peripheral tolerization can be a remarkably efficient process to maintain tolerance to MiHA after BM transplantation. Thus, peripheral tolerizing mechanisms may contribute not only to the induction of tolerance to Mls superantigens or to the product of transgenes (if expressed at high levels) but also to a wide array of MiHA.

Immunologic purging of marrow assessed by PCR before autologous bone marrow transplantation for B-cell lymphoma

BACKGROUND

The use of autologous bone marrow transplantation is increasing in the management of advanced cancers. Many investigators have attempted to "purge" autologous marrow of residual tumor cells because of concern that reinfused tumor cells might contribute to relapse. The efficacy of purging remains unproved.

METHODS

We performed clonogenic assays in a tumor cell line in culture to determine the efficiency of immunologic purging. Amplification by the polymerase chain reaction (PCR) was used to detect residual lymphoma cells before and after purging of bone marrow from 114 patients with B-cell non-Hodgkin's lymphoma in whom a translocation (t(14;18] that could be amplified by PCR was detected at the time of their initial evaluation.

RESULTS

Immunologic purging in vitro resulted in a 3-to-6-log destruction of cells in the tumor cell line. Residual lymphoma cells were detected by PCR in the bone marrow of all patients before purging. No lymphoma cells could be detected in the marrow of 57 patients after purging. Disease-free survival was increased in these 57 patients as compared with those whose marrow contained detectable residual lymphoma (P less than 0.00001). The ability to purge residual lymphoma cells was not associated with the degree of bone marrow involvement (P = 0.4494) or the previous response to therapy (P = 0.1298).

CONCLUSIONS

The inability to purge residual lymphoma cells was the most important prognostic indicator in predicting relapse. These results provide evidence of the clinical usefulness of ex vivo purging of autologous bone marrow in the treatment of patients with lymphoma and suggest that the reinfusion of malignant cells in autologous marrow contributes to relapse

Anti-MY9-blocked-ricin: an immunotoxin for selective targeting of acute myeloid leukemia cells

The use of immunotoxins (IT) to selectively destroy acute myeloid leukemia (AML) cells in vivo or in vitro is complicated by both the antigenic similarity of AML cells to normal progenitor cells and the difficulty of producing a sufficiently toxic conjugate. The monoclonal antibody (MoAb) anti-MY9 is potentially ideal for selective recognition of AML cells because it reacts with an antigen (CD33) found on clonogenic AML cells from greater than 80% of cases and does not react with normal pluripotent stem cells. In this study, we describe an immunotoxin that is selectively active against CD33+ AML cells: Anti-MY9-blocked-Ricin (Anti-MY9-bR), comprised of anti-MY9 conjugated to a modified whole ricin that has its nonspecific binding eliminated by chemical blockage of the galactose binding domains of the B-chain. A limiting dilution assay was used to measure elimination of HL-60 leukemic cells from a 20-fold excess of normal bone marrow cells. Depletion of CD33+ HL-60 cells was found to be dependent on the concentration of Anti-MY9-bR and on the duration of incubation with IT at 37 degrees C. More than 4 logs of these leukemic cells were specifically depleted following short exposure to high concentrations (10(-8) mol/L) of Anti-MY9-bR. Incubation with much lower concentrations of Anti-MY9-bR (10(-10) mol/L), as compatible with in vivo administration, resulted in 2 logs of depletion of HL-60 cells, but 48 to 72 hours of continuous exposure were required. Anti-MY9-bR was also shown to be toxic to primary AML cells, with depletion of greater than 2 logs of clonogenic cells following incubation with Anti-MY9-bR 10(-8) mol/L at 37 degrees C for 5 hours. Activity of Anti-MY9-bR could be blocked by unconjugated Anti-MY9 but not by galactose. As expected, Anti-MY9-bR was toxic to normal colony-forming unit granulocyte-monocyte (CFU-GM), which expresses CD33, in a concentration- and time-dependent manner, and also to burst-forming unit-erythroid and CFU-granulocyte, erythroid, monocyte, megakaryocyte, although to a lesser extent. When compared with anti-MY9 and complement (C'), Anti-MY9-bR could be used in conditions that provided more effective depletion of AML cells with substantially less depletion of normal CFU-GM. Therefore, Anti-MY9-bR may have clinical utility for in vitro purging of AML cells from autologous marrow when used at high IT concentrations for short incubation periods. Much lower concentrations of Anti-MY9-bR that can be maintained for longer periods may be useful for elimination of AML cells in vivo.

Natural history of mixed chimerism after bone marrow transplantation with CD6-depleted allogeneic marrow: a stable equilibrium

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.

Electrocardiographic abnormalities in tropical pulmonary eosinophilia

A 12 lead electrocardiogram in 70 patients with tropical pulmonary eosinophilia showed abnormalities 28.57%. ECG changes observed were right axis deviation (10%), 'P' pulmonale (10%), clockwise rotation (5.7%), right ventricular hypertrophy (1.4%), partial RBBB (2.8%), first degree A-V block (1.4%) and ST-T changes (1.4%). All ECG changes reverted back to normal after diethyl carbamzine therapy in the dose of 10 mg/kg body weight for a total duration of 14 days.

Comparative activities of rabbit complements of different ages using an in-vitro marrow purging model

In order to determine the best time to obtain complement for use in marrow purging in vitro, we have used 51Cr-release and limiting dilution assays (LDA) to evaluate the ability of serum from rabbits 20-30 (25d), 30-40 (35d) and 40-50 (45d) days old to lyse a series of neoplastic target cells in the presence of complement activating antibodies. Utilizing a limiting dilution assay (LDA) to measure log depletion of tumor cells in a 20-fold excess of normal bone marrow, treatment with monoclonal antibody and 25d complement depleted at least 4 logs of leukemia or lymphoma cells. 35d and 45d complements were approximately one log less effective. When normal bone marrow alone was treated with either J5 (CD10) antibody alone, each complement alone or a combination of J5 antibody with each complement, there was no significant depletion of hematopoietic progenitors in any subgroup. These results suggest that complement from 20-30 day old rabbits should be used for the purpose of ex-vivo purging due to its highly sensitive and specific activity.

Importance of smoking index for assessing lung damage by lung function tests

A total of 89 smokers of age varying between 15-52 years were assessed for lung function forced vital capacity (FVC), forced expiratory volume in one second (FEV1) ratio of FEV1 and FVC as FEV1% and peak expiratory flow rate (PEFR), before smoking (BS) and 30 min after smoking (AS). All the above lung function tests were reduced in smokers in comparison to those of age-matched non-smokers. Further, when observed test values of lung function were tabulated according to smoking index (SI), it was noted that reduction of lung function increased with SI.

Oesophago-pleuro-cutaneous fistula

We describe a case of oesophago-pleuro-cutaneous fistula occurring as a complication of tuberculous pyopneumothorax in a young adult.