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Biomedical subjects

D H Pamphilon

Publications and source records attributed to D H Pamphilon.

At least 55 records · Page 3Linked to original sources
PubMed1996

A prospective, randomized study of the use of platelet concentrates irradiated with ultraviolet-B light in patients with hematologic malignancy.

BACKGROUND: Irradiation of platelet concentrates (PCs) with ultraviolet-B (UVB) light inactivates the contaminating white cells and might be an alternative to filtration for the prevention of alloimmunization to HLA antigens and subsequent refractoriness to further platelet transfusions in multiply transfused patients with bone marrow failure. STUDY DESIGN AND METHODS: Patients with hematologic malignancy, mainly acute myeloid leukemia, were prospectively assigned in a random manner to receive either UVB-irradiated or control, nonirradiated PCs. All patients were given red cells that were white cell reduced by filtration. Transfusion efficacy and alloimmunization were assessed by means of corrected count increments, requirement for red cells and PCs, and measurement of lymphocyte-reactive antibodies. RESULTS: UVB-irradiated PCs had a clinical efficacy similar to controls as judged by corrected count increments at 1 to 6 and 12 to 24 hours and by the median requirement for red cell and platelet transfusions. Alloimmunization determined by measurements of lymphocyte-reactive antibodies using both conventional and antiglobulin-augmented lymphocytotoxicity techniques was not abolished in recipients of UVB-irradiated PCs (4/30, 13%) but was less than that in controls (5/20, 25%; p = NS). The mean number of platelet transfusion episodes prior to the occurrence of alloimmunization was greater in the control group (27 vs. 10; p = 0.017). CONCLUSION: In this trial, UVB irradiation did not diminish the clinical efficacy of platelet transfusions. There was a small but nonsignificant reduction alloimmunization, but no difference in refractoriness of the two groups was observed. Larger prospective randomized studies are required to confirm these findings and to compare UVB irradiation with white cell reduction.

Adolescent↗
PubMed1996

Comparative clinical studies of platelet concentrates: effects on clinical outcome and the use of healthcare resources. NBS Platelet Study Group.

The Platelet Study Group are developing proposals to conduct a prospective randomised trial of different platelet products in the transfusion support of patients with haematological malignancy. All patients will receive prestorage leucodepleted red cells and will be randomised to receive either multiple donor non-apheresis buffy coat platelets which are non-leucodepleted (BCP), single donor apheresis platelets non-leucocyte depleted (SDP) or single donor (LD-SDP). All leucocyte depleted products will contain fewer than 5 x 10(6) WBC/transfusion. The primary objective of the study is to compare clinical efficacy, the incidence of adverse reactions treatment outcome and the use of healthcare resources.

Adult↗
PubMed1996

PCR amplification of short tandem repeat sequences allows serial studies of chimaerism/engraftment following BMT in rodents.

Animal models of bone marrow transplantation (BMT) allow evaluation of new experimental treatment strategies. One potential strategy involves the treatment of donor marrow with ultra-violet B light to allow transplantation across histocompatibility boundaries without an increase in graft rejection or graft-versus-host disease. A major requirement for a new experimental protocol, particularly if it involves manipulation of the donor marrow, is that the manipulated marrow gives rise to long-term multilineage engraftment. DNA based methodologies are now routinely used by many centres to evaluate engraftment and degree of chimaerism post-BMT in humans. We report the adaptation of this methodology to the serial study of engraftment in rodents. Conditions have been defined which allow analysis of serial tail vein samples using PCR of short tandem repeat sequences (STR-PCR). These markers have been used to evaluate the contribution of ultraviolet B treated marrow to engraftment following BMT in rodents without compromising the health of the animals under study. Chimaerism data from sequential tail vein samples and bone marrow from selected sacrificed animals showed excellent correlation, thus confirming the validity of this approach in analysing haemopoietic tissue. Thus the use of this assay may facilitate experimental studies in animal BMT.

Animals↗
PubMed1996

Transplantation of peripheral blood progenitor cells from unrelated donors.

Six patients with high risk haematological malignancies received peripheral blood progenitor cells (PBPC) from unrelated donors. Four patients received PBPC as primary treatment and 2 following graft failure. Five donors were HLA-A, -B and -DR identical and one had a one antigen mismatch. PBPC were mobilised by treatment with G-CSF for 4-6 days. The patients received a range of 3.4 to 11.4 x 10(8) mononuclear cells/kg and 1.0 to 15.0 x 10(6) CD34 positive cells/kg. Four patients were given Campath 1G and 2 ATG prior to transplantation. The patient with one antigen mismatch received in vitro T-cell depleted PBPC using Campath 1M. All received cyclosporin and 5 in addition methotrexate. All recipients were given G-CSF and all engrafted. The patients developed no or mild acute GVHD. Two patients had limited chronic GVHD of the skin. The recipient of the mismatched graft died from extensive chronic GVHD. Three patients have had a relapse and two are alive and free of leukaemia.

Adolescent↗
PubMed1995

Human Rh D monoclonal antibodies (BRAD-3 and BRAD-5) cause accelerated clearance of Rh D+ red blood cells and suppression of Rh D immunization in Rh D- volunteers.

The use of prophylactic anti-D to prevent Rh D immunization in Rh D- women and subsequent hemolytic disease in Rh D+ infants is widespread, but has led to shortages of the anti-D Ig. With the aim of substituting monoclonal anti-D for Rh D prophylaxis, we have compared the abilities of monoclonal and polyclonal anti-D to clear Rh D+ red blood cells (RBCs) infused into Rh D- male volunteers and to suppress Rh D immunization. Two human monoclonal antibodies (MoAbs), BRAD-3 (IgG3) and BRAD-5 (IgG1), produced from stable Epstein-Barr virus-transformed B-lymphoblastoid cell lines, were selected because of their proven in vitro activity in promoting RBC lysis in antibody-dependent cell-mediated cytotoxicity assays. RBC clearance was assessed by intravenous injection of 3 mL of 51chromium-labeled D+ RBCs into 27 volunteers 48 hours after intramuscular injection of monoclonal or polyclonal anti-D. Further 3-mL injections of unlabeled D+ cells were administered at 6 and 9 months to induce immunization. Blood samples were taken throughout the 12-month period of study for the serologic detection of anti-D. The mean half-life (t50%) of RBCs in 7 recipients of 300 micrograms BRAD-5 (5.9 hours) was similar to that in 8 recipients of 500 IU polyclonal anti-D (5.0 hours), whereas D+ cells were cleared more slowly in some of the 8 subjects injected with 300 micrograms BRAD-3 (mean t50% 12.7 hours) and in 1 individual administered 100 micrograms BRAD-3 (t50% 41.0 hours). The rate of RBC clearance in both groups administered 300 micrograms monoclonal anti-D correlated with the amount of antibody bound per cell, determined by flow cytometry. There was no evidence of primary immunization having occurred in any subject after 6 months of follow-up. Five of 24 subjects produced anti-D after one or two further injections of RBCs, confirming that they were responders who had been protected by the monoclonal or polyclonal anti-D administered initially. Four of these responders were recipients of monoclonal anti-D (3 BRAD-3, 1 BRAD-5). One individual who received BRAD-5 produced accelerated clearance of D+ RBCs at the third unprotected RBC challenge but did not seroconvert. This study shows that the human MoAbs BRAD-3 and BRAD-5 can prevent Rh D immunization, and indicates that they may be suitable replacements for the polyclonal anti-D presently used in prophylaxis of Rh D hemolytic disease of the newborn.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Prestorage white cell reduction in saline-adenine-glucose-mannitol red cells by use of an integral filter: evaluation of storage values and invivo recovery.

BACKGROUND: Prestorage white cell (WBC) reduction in blood components may decrease the incidence of adverse reactions and improve component quality. A bottom-and-top system with an integral third-generation WBC-reduction filter has been studied. STUDY DESIGN AND METHODS: Whole blood was collected from 30 healthy donors: from 20 by using a blood container system with an integral filter and from 10 controls by using a standard blood container system. Ten test units were buffy coat-depleted, stored for 72 hours at 4 degrees C, and then filtered, while an additional 10 test units were buffy coat-depleted and filtered at room temperature within 8 hours of collection. All units were stored at 4 degrees C for 42 days and sampled weekly. RESULTS: The mean WBC content of the 72-hour, 4 degrees C units was 0.33 x 10(6), that of the room-temperature units was 2.6 x 10(6), and that of the buffy coat-depleted controls was 460 x 10(6) (p < 0.0005). No significant differences were found among lactate, glucose, sodium, potassium, and plasma hemoglobin levels in the three groups. ATP and 2,3 DPG levels were significantly better preserved in control units than in 72-hour, 4 degrees C units (p = 0.016 and p = 0.032, respectively), but not better than in the room-temperature units. Significant differences were observed between pH values in filtered units and both groups of test units (p = 0.016). In biologic terms however, these differences were small. Red cells from an additional eight healthy volunteer donors were processed by an 8-hour room-temperature method and stored for 35 days. Studies in vivo 24-hour recovery of autologous red cells were performed by transfusing a radiolabeled (51Cr plus 131I-albumin) aliquot after 35 days' storage. Good recovery (mean > 80%) was found by both the single- and double-isotope-label methods. Recovery was significantly greater when calculated by the single-isotope method (p = 0.02). CONCLUSION: The combination of buffy coat removal and filtration in the blood container system with an integral filter achieved effective WBC reduction (> or = 3 log10 reduction from whole blood) without biologically significant detriment to in vitro or in vivo storage values.

Adenine↗
PubMed1995

In vitro demonstration of a fundamental difference in the proliferation of murine and human bone marrow and lymphocytes following ultraviolet irradiation: relevance to bone marrow transplantation.

Exposure of rodent allogeneic donor marrow and splenocyte grafts to ultraviolet radiation (UVR) has been shown to permit durable engraftment at doses that abolish graft-versus-host disease (GVHD) and graft rejection. We have compared both murine and human alloreactive and mitogen-induced lymphoid responses and bone marrow proliferation in mixed lymphocyte culture (MLC), phytohemagglutinin (PHA)-induced proliferation and colony-forming unit-granulocyte/macrophage (CFU-GM) assays using germicidal UVC (200-290 nm), broadband and narrowband UVB (290-320 nm) and UVA (320-400 nm) sources. Our data show a wavelength and dose-dependent reduction in lymphoid proliferation in the mouse with CFU-GM survival of 50-75% of control at doses required to abolish allogeneic lymphocyte responses for all lamps. In contrast, human lymphocyte responses are more resistant to UVC with CFU-GM proliferation reduced to zero when allostimulation is abolished. Mitogen-induced lymphoid responses show a similar wavelength-dependent sensitivity. Abolition of response in MLC using UV-irradiated stimulator cells was less sensitive than proliferation with UV-irradiated responder cells at all wavelengths in both species. With all sources, murine CFU-GM proliferation is less susceptible to UVR than human marrow at doses required to abolish lymphoid responses.

Animals↗
PubMed1994

Randomised trial of intravenous immunoglobulin as prophylaxis against infection in plateau-phase multiple myeloma. The UK Group for Immunoglobulin Replacement Therapy in Multiple Myeloma.

Patients with plateau-phase multiple myeloma have an increased risk of life-threatening bacterial infections and polyclonal humoral immune suppression. We conducted a randomised, double-blind, placebo-controlled, multicentre trial of intravenous immunoglobulin (IVIg) as prophylaxis against infection. 82 patients with stable multiple myeloma received monthly infusions of IVIg at 0.4 g/kg body weight or an equivalent volume of placebo (0.4% albumin) intravenously for 1 year. Other interventions, including chemotherapy, were not affected; no patient received prophylactic antibiotics. There were no differences at entry or on study in clinical or laboratory variables between patients in the two groups. There were no episodes of septicaemia or pneumonia in patients receiving IVIg compared with 10 in placebo patients (p = 0.002). There were 57 serious infections; 38 occurred in 470 patient-months on placebo, compared with 19 in 449 patient-months on IVIg (p = 0.019). IVIg also protected against recurrent infections (p = 0.021) in 60 patients who completed a year. Before treatment, 54 patients were immunised with Pneumovax and specific IgG responses were measured. A poor pneumococcal IgG antibody response (less than 2-fold increase) identified patients who had maximum benefit from IVIg. Mild adverse reactions were noted in 12% of IVIg infusions and 5% of placebo infusions. IVIg can be given safely to plateau-phase myeloma patients. It protects against life-threatening infections and significantly reduces the risk of recurrent infections. The individuals who benefit most can be identified prospectively by measuring IgG antibody responses to pneumococcal immunisation.

Aged↗
PubMed1994

A comparison of four ultraviolet sources to alter graft-versus-host responses.

Graft-versus-host disease (GVHD) is a major contributor to the morbidity and mortality associated with allogeneic bone marrow transplantation. Direct ultraviolet B (UVB) irradiation of bone marrow and spleen cell allografts in mice using broadband lamps is known to abolish alloreactive responses which would normally cause GVHD. Using a histoincompatible murine model, we have extended these observations by comparing the physical spectrum of four UV sources (the Philips TUV8W, TL12 and TL01, and the Spectronics XX15B) with in vitro assessment of bone marrow progenitor cell damage and suppression of lymphocyte proliferation and in vivo comparison of the effect on GVHD of the TL12 and XX15B and on the rate of engraftment with the TL12. At doses of uv found to abolish lymphocyte proliferation (2.5, 7, 12 and 1000 J m(-2) with the TUV8W, XX15B, TL12 and TL01 lamps) colony-forming unit granulocyte-macrophage (CFU-GM) proliferation was reduced to 81%, 71%, 79% and 62%, respectively. At an optimal dose found to suppress GVHD (100 J m(-2) integrated radiant energy from 200-320 nm for the TL12 and XX15B) CFU-GM proliferation showed a reduction of 98% with the XX15B and 86% with the TL12. At this radiant energy with the TL12, the rate of bone marrow engraftment was impaired with 72% marrow cellularity at 2 weeks, decreasing to 48% after 200 J m(-2). Our results with this model demonstrate that broadband UVB irradiation of bone marrow permits transplantation across a major histocompatibility barrier. Furthermore we have provided in vitro evidence that narrowband UVB or UVC might potentially be applied to this model.

Animals↗
PubMed1994

Ultraviolet irradiation for the prevention of graft-versus-host disease and graft rejection in bone marrow transplantation.

This review describes an approach to the prevention of graft-versus-host disease (GVHD) and graft rejection following allogeneic BMT that differs from conventional methods. Ultraviolet (UV) irradiation inhibits the proliferative responses of lymphoid cells to mitogens and alloantigens by inactivation of T lymphocytes and dendritic cells, and in animal models this can prevent both GVHD and graft rejection. It is important that the marrow repopulating capacity of haemopoietic stem cells is not damaged by the irradiation process. We have found that polymorphic microsatellite markers are a sensitive way of assessing the impact of UV irradiation on chimerism after BMT in rodents.

Antigen-Presenting Cells↗
PubMed1993

Quality of platelet concentrates irradiated with UVB light: effect of UV dose and dose rate on glycocalicin release and correlation with other markers of the platelet storage lesion.

The amount of membrane-associated glycoprotein Ib in platelet concentrates (PCs) irradiated with a high dose of UVB light has been shown to be significantly reduced after 48 h storage. We recently corroborated this finding when we noted an increase in the supernatant levels of glycocalicin (GC, a major segment of glycoprotein Ib) in UVB-treated PCs during storage. The aim of the present study was to determine whether GC release was related to both the UV dose and the rate of dose delivery. Plateletpheresis concentrates obtained from five donors were pooled and split into five equal parts. Four of these were treated with 7500 and 15,000 mJ/cm2 UVB using two prototype UV sources with differing rates of dose delivery; namely, Baxter (BAT) and British Aerospace (BAC) cabinets, with the latter having the slower rate of delivery. On days 1 and 5 of storage, GC levels in the supernatants of PCs were determined by ELISA. Moreover, the following parameters were also assessed: platelet and WBC count; hypotonic shock response (HSR) and platelet aggregation response to ADP, ADP+collagen, ADP+arachidonic acid and ristocetin; pH; supernatant levels of lactate, glucose, von Willebrand factor (vWf) and beta-thromboglobulin (beta TG). The results revealed an association of GC release with UVB dose using both UV sources, although this was more apparent in the BAC system, in which glycocalicin release at day 5 of storage was as follows (microgram/ml, mean +/- SD): 4.8 +/- 0.3 and 9.5 +/- 3.6 at 7500 and 15,000 mJ/cm2 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1993

Antibodies to platelet glycoprotein V in polytransfused patients with haematological disease.

Polytransfused patients often develop platelet-reactive antibodies (PRAb). These give positive reactions in the platelet immunofluorescence test (PIFT) and may be either lymphocytotoxic (LCTAb) or platelet-specific antibodies (PSAb). The latter may be detected in the PIFT using chloroquine-treated platelets (Chl-PIFT) or by immunoblotting. Serial samples from 106 multiply transfused patients with bone marrow failure were screened by PIFT using a microplate method and flow-cytometric analysis. PSAb activity was confirmed by Chl-PIFT. In 45 (42%) of the patients studied PSAb were detected; 37 (35%) formed LCTAb and 19 (51%) had co-existent PSAb. Sera from 25 of 27 patients with a positive Chl-PIFT, retested by immunoblotting, recognised determinants of Mr 82-160 kD on whole platelets. A large group became sensitised to a component of Mr 105-115 kD reduced (99 kD non-reduced) with similar electrophoretic mobility to GPIIIa using a monoclonal anti-GPIIIa and two human polyclonal anti-HPA-1a sera; some also produced anti-GPIIb. The largest group recognised a determinant of Mr 80-83 kD, probably glycoprotein V (GPV). Three sera were immunoblotted against thrombin-treated platelets and the results confirmed GPV specificity.

Adolescent↗
PubMed1993

Immune reconstitution after BMT in children.

Serial assessment of peripheral blood T and B cell recovery and serum immunoglobulins was performed in 19 children for the first year following BMT and compared with normal values established from healthy children. Immunophenotypic analysis on bone marrow was performed in selected cases by Southern blotting of the immunoglobulin heavy chain (IgH) gene. We found no significant differences between T cell-replete or depleted allogeneic bone marrow transplants. Lymphocyte numbers were low until 9 months post-BMT. T cell numbers (CD2, CD3, CD5) were also low until 12 months but B cell numbers (CD19) became normal at 3 months. Both CD4+ and CD8+ T cell subsets were low post-BMT with depression of CD4+ greater and more prolonged than that of CD8+. No overshoot of CD8+ was seen. The principal effect of GVHD or its treatment was further depression of CD4+ cells but with no increase in CD8+; recovery of B cells was also delayed. Recovery of IgG was slow with only six of 11 children reaching an age-adjusted normal level by 1 year, whereas there was more rapid recovery of IgM and IgA. Several children had an increase in lymphocytes of immature appearance in their bone marrow at varying times post-BMT with increased cells of phenotype CD19+, CD10+, HLA-DR+ and TdT+. In each case Southern blotting showed a germline pattern of the IgH indicating a polyclonal early B cell regenerative population.

Adolescent↗
PubMed1993

Successful second unrelated donor BMT in a child with juvenile chronic myeloid leukaemia: documentation of chimaerism using the polymerase chain reaction.

A 3-year old child with juvenile chronic myeloid leukaemia received a T cell-depleted BMT from a male unrelated donor. There was early graft failure associated with increasing splenomegaly and hypersplenism. Splenectomy was performed 53 days post-transplant and was followed by autologous marrow recovery with return of leukaemia. A second unrelated donor BMT was performed 9 months later using T cell-replete marrow from a similarly matched female donor. Grade 2 GVHD involving the skin and gut responded to treatment with steroids. Chimaerism was assessed using Y-specific polymerase chain reaction (PCR) and microsatellites. Samples taken at the time of splenectomy showed no donor marrow engraftment but there was significant engraftment in the spleen. Following the second transplant, donor-type haematopoiesis was documented using a panel of microsatellite probes. The patient remains well 6 months after transplant. Splenectomy should be considered prior to transplant in patients with significant splenomegaly and hypersplenism. Partial chimaerism in the spleen, but not bone marrow, post-BMT, has not previously been documented. PCR technology is a useful and highly sensitive way to assess chimaerism post-BMT and is informative in sex-matched cases, whilst the small amount of material required is advantageous in paediatric patients.

Bone Marrow Transplantation↗
PubMed1992

Accessory cell damage and loss of overall white cell viability inhibit lymphocyte responses after ultraviolet-B irradiation but without evidence of in vitro suppression.

The effect of different doses of ultraviolet B irradiation (UVR) on the proliferative responses of Balb/c spleen cells has been tested. In 72-hour cultures, there was dose-dependent suppression of proliferation in response to phytohemagglutinin (PHA). Cell viability after UVR was found to be reduced in a dose- and time-dependent manner. Proliferation increased by greater than 100 percent after low-dose (20 J/m2) UVR when either normal or gamma-irradiated peritoneal cells were added to the cultures, but not at higher doses. Delaying UVR until 24 hours after stimulation of cultures with PHA did not substantially increase [3H]-thymidine uptake. Stimulation of mixtures of UV-irradiated and control cells or incorporation of medium conditioned with UV-irradiated cells provided no evidence of suppression of proliferation. The accessory cell population is an important target for UVR, but cells are physically damaged to the extent that, at higher doses, the response to PHA stimulation cannot be restored.

Animals↗