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C Helg

Publications and source records attributed to C Helg.

At least 55 records · Page 3Linked to original sources
PubMed1993

High-resolution histocompatibility testing of a group of sixteen B44-positive, ABDR serologically matched unrelated donor-recipient pairs. Analysis of serologically undisclosed incompatibilities by cellular techniques, isoelectrofocusing, and HLA oligotyping.

We have characterized HLA incompatibilities in a group of 16 B44-positive patients who were serologically ABDR matched with their 23 (unrelated) potential bone marrow donors. After analysis with a combination of cellular techniques, IEF for HLA-A/B and oligotyping for class II and HLA-B44, 44% of the patients revealed one or more HLA incompatibility with at least one of their potential donors. CTL activity was detected in 12 of the 22 combinations tested. CTL incompatibility occurred more frequently in DR subtype-mismatched combinations, but CTL reactivity was always directed against class I. To characterize these incompatibilities between matched unrelated individuals, we analyzed the specificity of T-cell clones from seven primary CTL cultures. In three combinations, CTL reactivity was directed against a subtype of B44. In two combinations, the CTL reactivity was directed against a non-B44 class I subtype. In two of seven combinations, the CTLs recognized an antigen that, though unconditionally associated with B4403, was expressed by 60% of the B4403+ cells only. Because all 12 of these B4403+ targets recognized could be typed for one HLA-C allele only (Cwl-Cw8), we believe that this alloreactivity might be directed against a serologically undefined Cw antigen.

Base Sequence↗
PubMed1993

The frequency of pretransplant donor cytotoxic T cell precursors with anti-host specificity predicts survival of patients transplanted with bone marrow from donors other than HLA-identical siblings.

Transplantation with bone marrow from other than genotypically HLA-identical donors is associated with an increased incidence and severity of graft-versus-host disease (GvHD). The precise influence of HLA incompatibilities is not easy to analyze as even perfectly matched, HLA-identical unrelated donors might still express HLA differences that remain undetected by conventional typing. To measure T cell activity against serologically detectable and nondetectable HLA antigens, we analyzed the frequencies of CTL precursors (CTLp) between 11 unrelated HLA-matched and five related haploidentical donor/recipient pairs in graft-versus-host direction. Our results show that whenever HLA class I disparities could be identified by serology, high precursor frequencies (1/28,000-1/94,000) were measured. In contrast, in donor/recipient pairs that differed for class II only, no precursors were detected. CTLp were elevated in two out of eight fully matched donor/recipient combinations. These combinations displayed activities as high (1/21,000; 1/52,000) as the combinations that were serologically HLA class I disparate. The incompatibilities detected by the cellular assay were highly significant for the clinical results after transplantation. High CTLp frequencies before transplantation correlated with unfavorable clinical results independent of the incidence of detected HLA differences. Five out of the six patients with high (> 1/100,000) CTLp frequencies died within 120 days after transplantation. GvHD IV was the cause of death for all (3/5) patients who had received an unmanipulated bone marrow. In the group with intermediate or undetectable CTLp frequencies, eight out of 10 patients are alive, seven (CTLp frequency undetectable) without GvHD more severe than grade II, while one patient (CTLp frequency = 1/180,000) suffered from GvHD grade III. One patient rejected the graft and was rescued by an autologous BMT.

Adolescent↗
PubMed1993

Conditioning the leukemic patient before allogeneic BMT: value of intensifying immunosuppression in the context of different levels of T lymphocyte depletion of the graft.

We have studied the value of additional immune suppression in BMT conditioning regimens in 45 patients with leukemia and 4 with myelodysplastic syndrome allografted between 1984 and 1991. A dose of 6 Gy total lymphoid irradiation (TLI) was delivered to 12 of 24 and 15 of 25 patients conditioned with 10 Gy and 12 Gy total body irradiation (TBI), respectively. Thirteen patients also received methylprednisolone (MP) before BMT to enhance immunosuppression. Differences in immunosuppression between the TBI with or without TLI or MP regimens and the influence of different levels of graft T cell depletion were measured in terms of transplant rejection, and complete versus mixed chimerism. The treatment-related complications were evaluated in terms of GVHD and incidence of pneumonitis. The overall transplant rejection rate was 6% (3 of 49). Complete chimerism was not significantly modified by increasing the TBI dose or by additional TLI (p > 0.10) but was more often seen in patients receiving MP given as pre-transplant immunosuppressor booster (p = 0.01). The incidence of GVHD was only influenced by the level of T cell depletion (p = 0.003). All 49 patients received a TBI lung dose in the range 9.5-10 Gy. A crude pneumonitis range of 19% (9 of 47 evaluable patients) was found. Neither the addition of TLI, MP nor the T cell depletion influenced the lung toxicity rate (p > 0.10) but pneumonitis was more frequent in patients with GVHD (p = 0.005).

Adolescent↗
PubMed1993

Adoptive immunotherapy for recurrent CML after BMT.

Three patients with CML who relapsed after transplantation with T-depleted BM from their HLA-identical siblings were treated with transfusions of donor peripheral blood mononuclear cells, in combination with (short) IFN alpha 2 therapy. CML was successfully controlled as shown by the complete disappearance of Philadelphia-positive metaphases within 90 days of treatment. This treatment appears to be very effective as neither bcr-abl transcripts nor markers specific for hematological cells of recipient origin could be detected by very sensitive PCR techniques. Two patients treated in chronic phase are without evidence of disease 300 and 360 days after treatment. The third patient, treated in accelerated phase, died with BM aplasia, 39 days following PBMC infusions. Failure to detect residual donor-derived granulocytes, as was the case in this patient prior to initiating adoptive immunotherapy, may indicate loss of donor-derived BM activity. This may help predict and possibly prevent the occurrence of life-threatening aplasia after successful clearance of malignant hematopoiesis.

Acute Disease↗
PubMed1993

Characterization of pretransplant CTL activity in "perfectly matched" unrelated bone marrow donor/recipient combinations.

To characterize the pre-transplant cytotoxic T cell precursor (CTLp) activity of unrelated bone marrow donors towards their HLA-ABDR compatible recipients, we have established T cell clones from the primary (positive) CTLp cultures. Two "perfectly matched" oligo-typed DR/DQ identical combinations and two A/B identical, DR subtype incompatible combinations have been studied in detail. Analysis of the clones shows that in the first two combinations the alloreactivity was directed towards a subtype of A2 (A205) and a subtype of Bw60 respectively. In the other two cases, where class II incompatibilities were present, we have not yet defined the exact specificity. However, because the majority of recipient specific clones were of the CD8 phenotype, it is very likely that also in these two cases differences in class I are being recognized.

Bone Marrow Transplantation↗
PubMed1992

[Swiss Register for unrelated bone marrow donors: preliminary results].

Bone marrow transplantation from the unrelated volunteer donor is today a realistic possibility for patients lacking an HLA-identical family donor. In 1988, the Swiss Unrelated Bone Marrow Donor Registry was founded to coordinate such bone marrow transplants and create the Swiss volunteer donor registry. Thus for a search has been initiated for 71 patients and 16 transplants have been performed. Donor and recipient were HLA-A-, -B- identical by serology and HLA-Dr-identical by DNA-oligotyping. 10 of the 16 patients are alive without signs of basic disease 2 weeks to 2 years and 4 months after the transplant. These results illustrate that unrelated donor transplantation, using careful selection criteria, is a realistic new therapeutic modality.

Adolescent↗
PubMed1992

Evolution of mixed chimerism after allogeneic bone marrow transplantation as determined on granulocytes and mononuclear cells by the polymerase chain reaction.

To evaluate the clinical relevance of mixed chimerism (MC) after allogeneic bone marrow transplantation (BMT), we developed a method based on amplification of DNA minisatellites by the polymerase chain reaction (PCR). This sensitive method by which MC lower than 1% can be detected is applicable to any patient-donor pair. Furthermore, because the analysis requires only small amounts of DNA, it allowed us to analyze samples early after BMT and during graft rejection. Results were obtained within 48 hours after blood sampling. Determination of MC in granulocytes (GR) and in mononuclear cells (Mnc) was performed in 20 patients treated for various hematologic malignancies. In patients who received untreated BM, recipient cells disappeared rapidly after BMT. In patients transplanted with T-cell-depleted BM, MC occurred in 15 of 16 cases. The percentage of host Mnc was always significantly higher than the percentage of host GR. The evolution of MC in patients who received T-cell-depleted marrow showed distinct patterns depending on whether patients remained in continuous complete remission, relapsed, or rejected their grafts. During complete remission, a relatively stable and significant number of host cells could be detected during the first 2 years after transplantation. Thereafter, their number decreased, but even after 4 years, low numbers of host cells could persist. When the patients relapsed, an increase in host Mnc was monitored without significant changes in the number of donor Mnc. In contrast, after the relapse, donor GR were no longer detected. Two cases of graft rejection were studied. Directly after the onset of the rejection, donor GR and Mnc disappeared rapidly. During that period, no significant changes in the number of host Mnc were detected.

Adult↗
PubMed1992

Clonal imbalances of serum immunoglobulins after allogeneic bone marrow transplantation: an analysis by high-resolution two-dimensional gel electrophoresis.

The clonality pattern of immunoglobulins (Igs) produced after allogeneic bone marrow transplantation (BMT) was studied by high-resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) of serum samples and purified Igs. With this technique, the light (L) chain of a monoclonal Ig usually appears as a single spot. Thus, the degree of clonal diversity of the functional B cells can be appreciated by the electrophoretic pattern of the serum L chains. Furthermore, 2D-PAGE allows a semi-quantitative determination of prominent Ig clones according to the size of L chain spots. We found that serum electrophoretograms of 8/19 patients after BMT (5-9 months) revealed L chain patterns which were similar to those of normal polyclonal Igs, that is, less than five distinguishable small spots among a cloud-like indiscrete L chain spots region ('polyclonal' pattern). A spectrum of clonal abnormalities was observed on the electrophoretograms of 11/19 patients: in five patients, multiple small L chain spots (corresponding to Ig concentrations between 0.2 and 2 g/l) were detected ('oligoclonal' pattern), whereas in six others, 'typical' monoclonal Igs (Ig concentrations > 2 g/l) were observed with (3/19 patients) or without (3/19 patients) multiple small clonal components. Sequential analysis of serum obtained from patients at different times after BMT revealed that imbalanced clonal reconstitution was transient and evolved towards apparently normal polyclonal Ig production. Our observations show that the development of clonal 'gammopathies' after BMT is a frequent, but not obligatory phenomenon. It may reflect a transient restriction of the B cell repertoire either through a limited outgrowth of precursor cells or through selective antigenic pressures.

Antibody Diversity↗
PubMed1992

Bullous pemphigoid associated with acute graft-versus-host disease after allogeneic bone marrow transplantation.

A 47-year-old patient was treated with allogeneic bone marrow transplantation (BMT) for chronic myelogenous leukaemia in blast crisis. Three months after the procedure he developed bullous pemphigoid (BP) and symptoms suggestive of BP oesophageal involvement, associated with skin and liver acute graft-versus-host disease. The occurrence of BP is exceptional after BMT.

Acute Disease↗
PubMed1991

Disseminated toxoplasmosis in a severely immunodeficient patient: demonstration of cysts in bone marrow smears.

A 30-year-old woman was treated with unrelated HLA-compatible bone marrow transplantation for acute myeloid leukemia. Examination of her bone marrow smears because of fever and pancytopenia revealed the presence of Toxoplasma cysts. Although Toxoplasma cysts are rarely found in the bone marrow, bone marrow examination in the immunocompromised patient offers rapid diagnosis of systemic toxoplasmosis.

Adult↗
PubMed1990

[Acute myeloid leukemia with poor prognosis: treatment with oral 4-demethoxydaunorubicin (idarubicin) and low-dose cytarabine via subcutaneous route].

26 patients with poor risk acute myelogenous leukemia (elderly, in relapse or resistant) were treated with a combination of oral idarubicin (30 mg/m2/d for 3 days) and low dose subcutaneous cytarabine (10 mg/m2 twice a day for 10 days). Of 26 patients, 14 achieved complete remission, 2 partial remission, and 5 died in aplasia (3 without evidence of response, 2 inevaluable); 5 further patients were non-responders. All responses but two occurred among patients treated for AML at presentation or in relapse. Side effects consisted mainly of severe hematologic and moderate gastrointestinal toxicities. The main interest of this regimen is adaptability to outpatient conditions and rapid cytoreduction in patients with hyperleukocytic presentation.

Administration, Oral↗
PubMed1988

[Super intensive treatment followed by bone marrow autograft in cases of hematologic neoplasms and solid tumors].

Thirty-one patients underwent autologous bone marrow transplantation (ABMT) after intensive radio and/or chemotherapy. On 18 occasions, bone marrows were treated in vitro with either Asta-Z 7557, Asta-Z 7654 or the rat monoclonal antibody Campath-1M and complement. Sixteen patients were transplanted for acute leukemia: 6 patients were in first complete remission (CR), 5 in CR greater than 1 and 5 in relapse. Twelve out of fourteen evaluable patients have relapsed. Two patients transplanted in CR 2 and CR 1 remain in CR after 9.5 and 12 months respectively. Nine patients were transplanted for aggressive lymphoma: four patients were in CR 1, 2 in CR greater than 1, 1 in first relapse and 2 refractory to best available second line chemotherapy. All 3 achieved CR after ABMT. Nine patients are evaluable: 4 relapsed and 5 remain in CR at 5, 6.5, 21, 25 and 39 months, this last patient transplanted in a refractory state, the others in CR 1. Four patients were transplanted for refractory Hodgkin's disease: 3 patients are evaluable. One patient achieved complete remission which lasted 9 months. Two patients were transplanted for relapsed solid tumors and achieved a partial response. In conclusion, the response rate is encouraging for patients transplanted during active and sometimes refractory phases of the diseases (8/13 evaluable patients achieved CR). However, for the whole group of patients, including those transplanted for acute leukemia in CR 1, the relapse rate was high. Durable remissions were achieved for patients with aggressive lymphoma who were transplanted early in the disease.

Acute Disease↗
PubMed1986

[Transplantation of allogeneic bone marrow treated in vitro with Campath-1 monoclonal antibody].

Out of 14 bone marrow transplants, 12 patients received transplantations with allogeneic bone marrow after in vitro T-cell depletion with monoclonal Campath 1. The patients also received short term cyclosporin. This small series is in agreement with the results of larger series using T-depleted marrow as far as the prevention of graft versus host disease is concerned, and with respect to mixed chimerism, slow take, late rejection and, possibly, increased risk of recurrence.

Aged↗
PubMed1985

[Transplantation of allogeneic bone marrow treated in vitro with Campath-1 monoclonal antibody].

5 patients underwent bone marrow transplantation for severe aplastic anemia (2) and acute leukemia (ALL) in first remission (3). Graft versus host disease prophylaxis was performed by depleting T lymphocytes in the donor bone marrow with the rat monoclonal Campath-1 and autologous complement. In addition, patients received cyclosporin A. Engraftment occurred normally in all 5 patients but 1 patient (SAA) had a late graft failure. Two patients suffered mild degrees of GvHD. All patients are currently in complete remission, one having undergone a second transplantation.

Adult↗