Yvette Bonny

Demonstration of an osteoblast defect in two cases of human malignant osteopetrosis. Correction of the phenotype after bone marrow transplant.

Osteopetrosis is an inherited disorder characterized by bone sclerosis due to reduced bone resorption. Here we report that human osteopetrotic osteoblast-like (Ob) cells express a defective phenotype in primary cultures in vitro, and that bone marrow transplant (BMT) corrects osteoblast function. DNA analysis at polymorphic short-tandem repeat loci from donor, recipient, and primary Ob-like cells pre-BMT and 2 yr post-BMT revealed that Ob were still of recipient origin post-BMT. Osteopetrotic Ob-like cells obtained pre-BMT showed normal and abnormal 1,25(OH)2D3-induced alkaline phosphatase (ALPase) and osteocalcin production, respectively, and failed to produce macrophage colony-stimulating factor (M-CSF) in response to IL-1a and TNF-alpha. These parameters were all normalized in primary Ob-like cells prepared 2 yr post-BMT. X-linked clonality analysis at the human androgen receptor (HUMARA) locus revealed that osteoblasts showed a polyclonal and an oligoclonal derivation pre- and post-BMT respectively, indicating that a limited number of progenitor reconstituted this population. Because osteoblasts were still of recipient origin post-BMT, this suggests that functional osteoclasts, due to the replacement of hematopoeitic cells, provided a local microenvironment in vivo triggering the differentiation and/or recruitment of a limited number of functional osteoblasts.

Persistence of host Langerhans cells following allogeneic bone marrow transplantation: possible relationship with acute graft-versus-host disease

Langerhans cells (LC) are bone marrow‐derived dendritic antigen‐presenting cells found in the epidermis. In an effort to determine the origin (host versus donor) of LC at different intervals following bone marrow transplantation, we performed skin biopsies in 16 recipients of sex‐mismatched marrow. LC were identified using monoclonal antibody OKT6 in an indirect immunoperoxidase assay and their donor or host origin determined according to the presence or absence of Y body. The presence of Y‐positive (donor) LC could be demonstrated in all (6/6) skin biopsies of female recipients of male marrow tested between days 39 and 730 post‐transplant. Persistence of host LC in male recipients of female marrow was documented in all (6/6) recipients studied on day 39 and in two out of seven patients tested on day 120 post‐transplant. From day 365 onward, no residual host LC could be detected, suggesting that by this time all epidermal LC are donor‐derived. Our study demonstrates that host LC usually persist for 39 and up to 120 d following bone marrow transplantation. The relevance of this observation to the possible role of LC and other host dendritic antigen‐presenting cells in the graft‐versus‐host reaction is discussed.

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.

Lymphoid interstitial pneumonia after allogeneic bone marrow transplantation. A possible manifestation of chronic graft‐versus‐host disease

Interstitial pneumonia (IP) is a frequent and serious complication of bone marrow transplantation with a median time of onset about 2 months posttransplant. Most cases result either from toxicity of radiation and chemotherapy or from infection with pathogens such as cytomegalovirus. Described are two patients with chronic graft‐versus‐host disease (GVHD) who presented with late‐onset IP 242 and 632 days posttransplant. Histologic examination of lung biopsy specimens disclosed a lymphoid interstitial pneumonia (LIP) in both cases. The major lymphocyte subset found in bronchoalveolar lavages and lung tissue was OKT8(+) and showed a positive dot staining for acid phosphatase. Contrary to peripheral blood mononuclear cells, most OKT8(+) lymphocytes in the lungs were OKT3(‐). Since acute GVHD lesions are mediated mainly by cytotoxic T‐lymphocytes, our data suggest that LIP in marrow‐grafted patients may be a manifestation of chronic GVHD. It should be distinguished from the more common types of IP encountered following bone marrow transplantation.

Bone marrow transplantation for myelodysplastic syndromes

Summary. Eight patients with myelodysplastic syndromes (MDS) were treated with bone marrow transplantation (BMT). Median age was 34.5 years and ranged between 3 and 45. FAB diagnosis was refractory anaemia (RA) in three, RA with excess of blasts (RAEB) in four and RAEB in transformation (RAEB‐t) in one case. Four patients were prepared with cyclophosphamide and total body irradiation whilst the other four received busulphan and cyclophosphamide. Engraftment was documented in seven of eight patients. Two patients died from complications related to the procedure. One had early veno‐occlusive disease of the liver whilst the other died 46 months after BMT from pulmonary fibrosis. One patient died from recurrent disease 11 months after BMT. Five patients are alive and in complete remission 9–35 months post‐transplantation. Four of these patients have a Karnofsky score ≤ 90%. These results suggest that BMT can induce prolonged disease‐free survival in patients under 50 years of age. If a compatible donor is available, marrow transplantation should be seriously considered in the treatment of MDS.

Chronic B-cell lymphocytosis

Persistent elevation of lymphocyte counts is usually associated with a malignant monoclonal lymphoproliferative disease. Over the last 8 years, amongst patients investigated in our center for undetermined persistent lymphocytosis, a diagnosis of malignant lymphoproliferation was excluded in 6 cases as studies of surface membrane immunoglobulin light chains showed that they presented a polyclonal expansion of their B‐lymphocyte pool. All patients were young‐to‐middle aged women presenting peculiar immunohematologic findings characterized by 1) persistent (2–7 yr) elevation of lymphocyte counts (4–14 × 109/l), 2) presence of characteristic binucleated B cells on peripheral blood smears, 3) a normal bone marrow histology, 4) a polyclonal increase of serum IgM with low‐to‐normal IgG and IgA levels. Histologic examination of the spleen in 2 patients and lymph nodes in 1 showed a benign follicular lymphoid hyperplasia. The evolution was benign in every case. We suggest that chronic polyclonal B‐cell lymphocytosis is a distinct clinicopathologic entity that should not be confused with malignant lymphoproliferative disorders.

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.

Serum immunoglobulin levels following allogeneic bone marrow transplantation

SummaryIn order to study the posttransplant evolution of serum immunoglobulin levels, we measured serum IgG, IgA and IgM levels in 50 recipients of allogeneic bone marrow before transplantation and at different intervals thereafter (days 39, 120, 365 and 730). IgG and IgM levels were depressed for 1 year and IgA levels for 2 years posttransplant. Immunoglobulin deficiency was more severe and prolonged in patients with graft versus-host-disease. Hypogammaglobulinemia may contribute to the frequent infections observed in these patients, especially those with chronic graft-versus-host disease.

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

Summary 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 × 4 d) and cyclophosphamide (50 mg/kg/d × 4 d) (BuCy4) were given in 29 patients and 11 received busulfan (4 mg/kg/d × 4 d), etoposide (60 mg/kg) and cyclophosphamide (60 mg/kg/d × 2 d) (BuCy + VP‐16). Median age was 22 years (range 1–50); 11 patients were children ≤ 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 he 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).

Chronic Myeloid Leukemia with an Unusual Simple Variant Translocation: t(22;22)(q13;q11)

A second example of chronic myeloid leukemia (CML) with the unusual simple variant t(22;22) is reported. In this case, break points are readily identified at bands q13 and q11. The nature of simple variant translocations in CML is discussed in the light of recent knowledge acquired from in situ hybridization of c-Ableson proto-oncogen DNA probes to metaphase spreads of CML patients.