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Biomedical subjects

J A Hansen

Publications and source records attributed to J A Hansen.

At least 145 records · Page 8Linked to original sources
PubMed1993

Experiences of the first 493 unrelated marrow donors in the National Marrow Donor Program.

More than 410,000 people participated in the National Marrow Donor Program (NMDP) as of October 1, 1991, and more than 850 volunteers had donated marrow. While the incidence of serious morbidity as a result of bone marrow donation is rare, the incidence of lesser complications and the long-term consequences of marrow donation are not known. To determine the incidence of donor complications and measure the recovery time of volunteer, unrelated marrow donors, we analyzed the results of surveys of the first 493 persons who donated marrow through the NMDP. The marrows were collected at 42 centers. The median age of the donors was 37.9 years (range 19.1 to 55.6 years). The median volume of marrow collected was 1,050 mL (range 180 to 2,983 mL). Autologous red blood cells were transfused to 89.8% (439) of donors but only 0.6% (3) of donors received allogeneic blood. Acute complications related to the collection procedure occurred in 5.9% of donors; but a serious complication, apnea during anesthesia, occurred in only one donor. When donors were questioned approximately 2 days following discharge from their hospitalization, most donors described symptoms related to the collection; 74.8% experienced tiredness, 67.8% experienced pain at the marrow collection site, and 51.6% of the donors experienced low back pain. Donors were surveyed repeatedly until they felt that they had recovered completely. Mean recovery time was 15.8 days; however, 42 (10%) donors felt that it took them > or = 30 days to recover fully. The duration of the marrow collection procedure and duration of anesthesia both positively correlated with donor pain and/or fatigue following the collection; but the duration of the collection procedure had the highest correlation with post-collection pain and fatigue. The volume of marrow collected per unit of donor weight was more weakly correlated with donor pain and/or fatigue than the anesthesia and collection times. When multivariate analysis was used to analyze the correlation between donor recovery time and these variables, only the duration of the collection was found to correlate significantly with donor recovery time (P = .001). This analysis demonstrates that marrow donation is well tolerated with few complications. To decrease further the incidence of donor discomfort and recovery time following donation, the duration of the collection procedure, and probably the duration of anesthesia, and the volume of marrow collected, should be kept to a minimum.

Adult↗
PubMed1993

Analysis of 462 transplantations from unrelated donors facilitated by the National Marrow Donor Program.

BACKGROUND AND METHODS: Allogeneic bone marrow transplantation is curative in a substantial number of patients with hematologic cancers, marrow-failure disorders, immunodeficiency syndromes, and certain metabolic diseases. Unfortunately, only 25 to 30 percent of potential recipients have HLA-identical siblings who can act as donors. In 1986 the National Marrow Donor Program was created in the United States to facilitate the finding and procurement of suitable marrow from unrelated donors for patients lacking related donors. RESULTS: During the first four years of the program, 462 patients with acquired and congenital lymphohematopoietic disorders or metabolic diseases received marrow transplants from unrelated donors. The probability of engraftment by 100 days after transplantation was 94 percent, although 8 percent of patients later had secondary graft failure. The probability of grade II, III, or IV acute graft-versus-host disease was 64 percent, and the probability of chronic graft-versus-host disease at one year was 55 percent. The rate of disease-free survival at two years among patients with leukemia and good prognostic factors was 40 percent and among patients at higher risk, 19 percent. Twenty-nine percent of the patients with aplastic anemia were alive at two years, and the rate of two-year disease-free survival among patients with myelodysplasia was 18 percent. For patients with congenital immunologic or nonimmunologic disorders, the probability of survival was 52 percent. CONCLUSIONS: The National Marrow Donor Program has benefited a substantial number of patients in need of marrow transplants from closely HLA-matched unrelated donors and has facilitated the recruitment of unrelated donors into the donor pool and the access to suitable marrow.

Adolescent↗
PubMed1993

Induction of alloantigen-specific hyporesponsiveness in human T lymphocytes by blocking interaction of CD28 with its natural ligand B7/BB1.

The specificity of T lymphocyte activation is determined by engagement of the T cell receptor (TCR) by peptide/major histocompatibility complexes expressed on the antigen-presenting cell (APC). Lacking costimulation by accessory molecules on the APC, T cell proliferation does not occur and unresponsiveness to subsequent antigenic stimulus is induced. The B7/BB1 receptor on APCs binds CD28 and CTLA-4 on T cells, and provides a costimulus for T cell proliferation. Here, we show that prolonged, specific T cell hyporesponsiveness to antigenic restimulation is achieved by blocking the interaction between CD28 and B7/BB1 in human mixed leukocyte culture (MLC). Secondary T cell proliferative responses to specific alloantigen were inhibited by addition to the primary culture of monovalent Fab fragments of anti-CD28 monoclonal antibody (mAb) 9.3, which block interaction of CD28 with B7/BB1 without activating T cells. Hypo-responsiveness was also induced in MLC by CTLA4Ig, a chimeric immunoglobulin fusion protein incorporating the extracellular domain of CTLA-4 with high binding avidity for B7/BB1. Cells previously primed could also be made hyporesponsive, if exposed to alloantigen in the presence of CTLA4Ig. Maximal hyporesponsiveness was achieved in MLC after 2 d of incubation with CTLA4Ig, and was maintained for at least 27 d after removal of CTLA4Ig. Accumulation of interleukin 2 (IL-2) and interferon gamma but not IL-4 mRNA was blocked by CTLA4Ig in T cells stimulated by alloantigen. Antigen-specific responses could be restored by addition of exogenous IL-2 at the time of the secondary stimulation. Addition to primary cultures of the intact bivalent anti-CD28 mAb 9.3, or B7/BB1+ transfected CHO cells or exogenous IL-2, abrogated induction of hyporesponsiveness by CTLA4Ig. These data indicate that interaction of CD28 with B7/BB1 during TCR engagement with antigen is required to maintain T cell competence and that blocking such interaction can result in a state of T cell hyporesponsiveness.

Animals↗
PubMed1993

Marrow transplantation from unrelated donors for treatment of hematologic malignancies: effect of mismatching for one HLA locus.

One hundred twelve patients less than 36 years old received marrow grafts from unrelated donors as treatment for hematologic malignancy. Seventy donor/recipient pairs were phenotypically identical for HLA-A, -B, and -D, while 42 had a "minor" disparity at one HLA locus. There was an increase in the risk of acute graft-versus-host disease (GVHD) in patients receiving HLA-partially matched grafts compared with those receiving HLA-matched grafts (51% v 36% probability of grades III-IV acute GVHD). However, in this cohort of patients, there was no significant difference in survival (at 1.5 years, 46% v 51% for good-risk patients, 44% v 30% for poor-risk patients). This finding suggests that some degree of HLA disparity can be tolerated in young patients transplanted from unrelated donors for malignant disease, thus making transplantation an option available to larger numbers of patients.

Acute Disease↗
PubMed1993

Fecundity before disease onset in women with rheumatoid arthritis.

OBJECTIVE: To examine fecundity prior to disease onset in women with rheumatoid arthritis (RA). METHODS: Two hundred fifty-nine RA patients with an opportunity for pregnancy were compared with 1,258 control women as part of a prospective case-control study of recent-onset RA in women. RESULTS: A 12-month or longer interval to pregnancy was found in 42% of RA cases compared with 34% of controls (odds ratio = 1.44, 95% confidence interval 1.10, 1.91). This difference was not accounted for by an older age when attempting to become pregnant among the RA cases compared with the controls. The result was unrelated to rheumatoid factor or HLA-DR4 status. CONCLUSION: Women with RA were found to have decreased fecundity prior to disease onset, compared with control women.

Adolescent↗
PubMed1993

Allelic variations clustered in the antigen binding sites of HLA-Bw62 molecules.

HLA-Bw62 is a serologically defined class I antigen specificity, but we show that it represents a family of five distinct alleles in this study. Five variants of HLA-Bw62 antigens were identified by isoelectric focusing, and sequencing studies revealed that these are a family of closely related alleles differing from one another by one to six amino acid substitutions at eight positions: 63 in the alpha 1 domain and 94, 95, 97, 99, 113, 152, and 156 in the alpha 2 domain. These substitutions are located in the two alpha-helices and two adjacent beta-strands, and the side chains of most amino acids face into the antigen binding groove. Functional assays using an in vitro generated Epstein-Barr virus (EBV)-specific Bw62-restricted cytotoxic T lymphocyte clone indicated that the minimal structural variations located in the antigen binding sites of the HLA-Bw62 variant molecules could affect the presentation of the nominal EBV antigen. This study revealed that the HLA-Bw62 antigen family consists of at least five closely related alleles, and further demonstrated that these alleles with minimal structural variations might play distinct functional roles in regard to antigen presentation.

Alleles↗
PubMed1993

Selection of an unrelated donor for marrow transplantation facilitated by the molecular characterization of a novel HLA-A allele.

Precise HLA typing is crucial in the selection of marrow donors for the treatment of patients with hematologic malignancy. This study was undertaken to characterize an unusual variant of HLA-A30, designated HLA-A30JS, identified in a patient with leukemia who was a candidate for unrelated donor marrow transplantation. IEF and cDNA-sequencing analyses revealed that A30JS is a novel variant differing from the IEF-defined subtype A30.1 (encoded by the A*3002 allele) by a single amino acid substitution. An unrelated marrow donor was identified who was matched with the patient for HLA-A3, B7, B18, DR2, and DR3, but mismatched within the A30 antigen family for the two distinct alleles A*3002 versus A30JS. These two alleles encode a single amino acid substitution, Arg versus Gly, at position 56 in the alpha 1 domain. Position 56 is located outside the antigen-binding cleft of the class I molecule, suggesting that this substitution may not be functionally significant. Transplantation from this donor was performed and the patient is surviving free of leukemia for more than 700 days after transplant. The maximum acute GVHD observed was scored as grade II, but immunosuppressive therapy is still required for control of chronic GVHD. This study demonstrates how the molecular characterization of a novel HLA-A allele in a patient could facilitate the selection of an unrelated donor. Lacking this information, it would not have been possible to select a donor for this patient, and thus apparently successful marrow transplant could not have occurred.

Adult↗
PubMed1993

Inhibition of allostimulated HLA-DQ and DP-specific T cells by staphylococcal enterotoxin A.

Bacterial superantigens have two immunologically important features. They bind MHC class II molecules and stimulate T cells bearing certain V beta TCR phenotypes. Superantigens such as SEA, SEB, and TSST bind to each of the three HLA class II isotypes (DR, DQ, and DP). Allotypic variation seems to play an important role in superantigen binding to class II molecules, but the functional implications of these differences remain largely unknown. In the present investigation, we studied the effects of SEA, SEB, and TSST on allostimulation of HLA-DR-, DQ-, and DP-allospecific T-cell clones. To avoid direct stimulation of T-cell responses by the superantigens, SEA and/or SEB nonresponsive T-cell clones were selected. We show that SEA strongly inhibited DQ- and DP-specific T-cell responses. In contrast, SEB and TSST had only weak inhibitory effects. DR-specific T-cell responses were unaffected or only weakly inhibited by the superantigens tested. The inhibition appeared not to be due to induction of cytotoxicity or suppression of either T cells or EBV-LCLs by SEA. In conclusion, the bacterial superantigen SEA can block alloantigen-specific stimulation of T clones in vitro. These results suggest that SEA binds to certain MHC class II molecules in a way that prevents MHC-TCR interactions.

Antigens, Bacterial↗
PubMed1993

The National Marrow Donor Program.

As the number of successful marrow transplants has increased, the lack of HLA-identical sibling donors for 60 to 70 percent of transplant candidates has become a serious problem. Pilot studies established that marrow transplantation between phenotypically HLA-identical, unrelated individuals can be accomplished successfully. Therefore, the National Marrow Donor Program was established to develop a large file of volunteer marrow donors and to serve as a center for the coordination of the donor search and donor-recipient matching processes. By November 1991, 63 months after the program was established, 457,205 potential marrow donors typed for HLA-A and -B antigens had agreed to be listed in the marrow donor registry. A donor search had been initiated for 8481 patients. At least one potential donor matched for at least three of the four HLA-A and -B antigens was located for 99.8 percent of patients. Among the 3156 searches that were completed, 940 (29.8%) resulted in a transplant. The median time in which to locate a matched donor, complete all predonation evaluations, and obtain donor consent was 208 days. The most common diagnosis in patients who underwent transplantation was chronic myelogenous leukemia (42.0%). When this analysis was completed in November 1991, the National Marrow Donor Program was operating a national network of 99 donor centers and 53 transplant centers. The donor file was increasing rapidly, and a follow-up system was in place to determine the effects of donation on the donors and the outcome in the patients who underwent transplantation. This national network of donor and transplant centers exists and is now facilitating unrelated-donor marrow transplants. The National Marrow Donor Program made it possible to locate donors for many patients in need of a transplant and helped to determine the role of unrelated-donor marrow transplants in the treatment of many diseases.

Blood Component Removal↗
PubMed1993

Immunosuppressive therapy as a determinant of transplantation outcomes.

Although surgical proficiency is essential to the immediate outcome of transplantation, long-term success depends upon how adequately the transplantation recipient is managed. Immunosuppression, the most critical aspect of after care, is subject to wide variation. In January 1990, a survey was sent to the directors of all transplant programs in the United States performing one or more kidney, heart, liver, heart-lung, or pancreas transplant in 1988. Detailed data were obtained on both the drugs and methods used for induction and maintenance immunosuppression, as well as the treatment of rejection. Each program director was asked to rank each immunosuppressive approach according to its perceived impact on patient outcomes. Over 85% of all eligible program directors completed the survey. There is no evidence of survey respondent bias. The use of polyclonal and monoclonal agents for induction immunosuppression was favored most by pancreas program directors (72-76%). These agents were least preferred by liver transplant programs (35-37%). About half of kidney, heart, and heart-lung program directors preferred these agents. Triple-drug therapy consisting of CsA, PRED, and AZA was considered the most preferable maintenance protocol for all transplants (i.e., kidney, 89%; heart, 94%; liver, 88%; heart-lung, 86%; pancreas, 96%). Either i.v. steroids or OKT3 were regarded as the preferred approaches for the treatment of acute or resistant rejection. Finally, the acceptability of outpatient treatment of rejection varied by transplant type (i.e., kidney, 9%; heart, 58%; liver, 5%; heart-lung, 29%; pancreas, 8%). Although there are similarities in the ratings of various aspects of immunosuppressive therapy, there are important differences. This information is critical to anticipate the implications of new immunosuppressive agents and to evaluate changes in the use of existing drugs and therapeutic approaches.

Data Collection↗
PubMed1993

Recombinant granulocyte-macrophage colony stimulating factor followed by immunosuppressive therapy for aplastic anaemia.

Seventeen patients with aplastic anaemia were treated with recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) for 14 d. Nonresponding patients were then treated with anti-human thymocyte globulin (ATG), methylprednisolone and oxymetholone. Side-effects of rhGM-CSF included fever, nausea and vomiting, diarrhoea, bone pain, headache and chills. Two patients had sustained trilineage haemopoietic recovery after receiving only rhGM-CSF. Of 11 patients who received immunosuppressive therapy, there was one complete response, two partial responses, one minimal response, and seven nonresponses. Actuarial survival at 2 years is 64%. Early administration of rhGM-CSF had no apparent effect on subsequent response to immunosuppressive therapy.

Adolescent↗
PubMed1993

A comparative study of HLA-DRB1 typing by standard serology and hybridization of non-radioactive sequence-specific oligonucleotide probes to PCR-amplified DNA.

A double-blind study was carried out to evaluate the relative performance and reliability of the PCR/SSOP assay compared to conventional serological typing in identifying HLA-DR alleles. A total of 268 consecutive samples were entered into the study. In 14 (5.2%) of the cases, HLA-DR serology could not be performed due to poor cell viability, while in seven (2.6%) of the cases, PCR/SSOP typing could not be performed due to poor amplification or to contamination with exogenous DNA. Among samples that were successfully typed by both methods, serologic typing correctly identified 455/465 (97.9%) DR antigens, while PCR/SSOP correctly identified 464/465 (99.8%) DR alleles (p = 0.0117, McNemar's test). The majority of discrepancies in serologic typing resulted from a lack of discriminative alloantisera to identify DR6 or DR103. For the overall sample set (N = 268), serology provided accurate results in 244 (91.0%) cases, while PCR/SSOP provided accurate results in 260 (97.0%) cases (p = 0.0037). The results of this study demonstrate that PCR/SSOP typing for HLA-DRB1 alleles provides results that are equal to or surpass serological typing for HLA-DR antigens. In addition, the PCR/SSOP approach offers the advantages of better reagent availability, lower cost, more rapid turn-around time, and greater accuracy, all of which would warrant its use as an HLA typing method of choice.

Alleles↗
PubMed1993

The MLC assay as a test for HLA-D region compatibility between patients and unrelated donors: results of a national marrow donor program involving multiple centers.

Mixed lymphocyte culture (MLC) assays from 763 patients and prospective unrelated marrow transplant donors identified through the National Marrow Donor Program (NMDP) were analyzed for their overall utility in measuring HLA-D region compatibility. The assays were performed at 31 different transplant centers (range, 1 to 197; median, 9 assays per center). A total of 325/763 (42.6%) of the tests were judged to be uninterpretable, either due to lack of sufficient control cells included in the assay (89 tests) or to insufficient reactivity by patient and/or donor cells (236 tests). Among the 438 tests that could be interpreted, HLA-Dw phenotyping with HLA-D homozygous cells was performed for a subset of 190. The relative response (RR) values from these 190 tests, however, were not clearly separable into distinct populations; i.e., RR values corresponding to Dw identity versus nonidentity between patient and donor could not be reliably discriminated. The predictive value of a nonreactive MLC for Dw identity was calculated to be 0.91 for RRs of < or = 20%, while the predictive value of a reactive MLC for Dw nonidentity was 0.35 for RRs of > 20%. These results, based on an analysis of data submitted from multiple transplant centers testing patients who had a variety of hematologic disorders, suggest that the MLC assay is a relatively imprecise method for determining HLA-D region compatibility between patient and prospective unrelated marrow donor.

Bone Marrow Transplantation↗
PubMed1993

Second allogeneic marrow transplantation for patients with recurrent leukemia after initial transplant with total-body irradiation-containing regimens.

PURPOSE: The impact of a second marrow transplant on long-term disease-free survival (DFS) was evaluated for 77 consecutive patients aged 2 to 51 years who relapsed subsequent to allogeneic marrow transplantation after high-dose chemotherapy and total-body irradiation (TBI). PATIENTS AND METHODS: Patients received a second transplant for recurrent chronic myelogenous leukemia (CML) (n = 28), acute myelogenous leukemia (AML) (n = 32), and acute lymphoblastic leukemia (ALL) (n = 15) or lymphoma (n = 2) that used the same marrow donor as the initial transplant. High-dose chemotherapy of busulfan (BU) and cyclophosphamide (CY), or CY, carmustine (BCNU), and etoposide (VP-16), was used as a preparative regimen for the second transplant. Graft-versus-host disease (GVHD) prophylaxis consisted of the following: no prophylaxis (n = 8), T-cell depletion (n = 36), methotrexate (MTX) only (n = 21), cyclosporine (CSP) only (n = 1), MTX and CSP (n = 9), or anti-thymocyte globulin (ATG) and prednisone (n = 2). RESULTS: Engraftment occurred in the 74 assessable patients. Severe veno-occlusive disease (VOD) was the most frequent cause of grades 3 and 4 regimen-related toxicity (RRT); it occurred in 20 patients. The probability of death before day 100 from nonleukemic causes was 36%. The probability of relapse after second transplant was 70%, and the DFS rate was 14% (median DFS, 36 months; range, 22 to 87). The DFS rates for ALL, AML, and CML were 8%, 10%, and 25%, respectively. Multivariate analysis showed that the risk of relapse was inversely associated with acute GVHD (relative risk [RR] of relapse = 0.2; P = .0009). No other factor was associated with relapse. DFS was associated with the presence of acute GVHD (RR of treatment failure = 0.5; P = .0085), and a reduction of DFS was associated with severe VOD (RR = 10.6; P = .0001) and those patients older than 10 years (RR = 2.5; P = .0337). CONCLUSION: These data show that some patients may benefit from a second marrow transplant for recurrent leukemia after an initial marrow transplant. Younger patients and patients with CML especially should be considered as potential candidates for a second transplant.

Adolescent↗
PubMed1993

Association of PAH-DNA adducts in peripheral white blood cells with dietary exposure to polyaromatic hydrocarbons.

Previous investigations suggest that dietary sources of polycyclic aromatic hydrocarbons (PAHs) contribute to the PAH-DNA adduct load in peripheral white blood cells (WBCs). In the current study, we measured PAH-DNA adducts by enzyme-linked immunosorbent assay in WBCs obtained from 47 California wildland (forest) firefighters at two time points (early and late) during an active forest fire season. PAH-DNA adduct levels were not associated with recent firefighting activity, but were positively associated with frequency of charbroiled food consumption in the previous 2 weeks. In addition, adduct levels declined with time since last ingestion of charbroiled food. These studies indicate that recent consumption of charbroiled food contributes to the PAH-DNA adduct load in peripheral WBCs.

Adolescent↗