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Biomedical subjects

H Chaplin

Publications and source records attributed to H Chaplin.

At least 19 recordsLinked to original sources
PubMed1999

Prevalence of HLA sensitization in female apheresis donors.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a serious complication of plasma-containing blood components. Studies have implicated HLA antibodies along with biologically active lipids in stored blood in the pathogenesis of TRALI. It has been proposed that the exclusion of HLA-untested, multiparous donors of plasma-rich components, including plasma and single-donor apheresis platelets, would substantially reduce the risk of TRALI. STUDY DESIGN AND METHODS: To investigate the feasibility of such an exclusion, 332 female plateletpheresis donors with a record of over 9000 donations, none of which were associated with TRALI, were studied. RESULTS: Seventeen percent of female donors demonstrated HLA sensitization. Parity and HLA sensitization were significantly correlated (p<0.0001), with sensitized donors having an average of 2.9 (+/- 0.6 95% CI) prior pregnancies and unsensitized donors having an average of 1.8 (+/- 0.2 95% CI) prior pregnancies. The percentage of HLA-sensitized women with 0, 1 to 2, and > or = 3 pregnancies was 7.8, 14.6, and 26.3, respectively. CONCLUSION: These findings confirm the hypothesis that multiparous women (> or = 3 pregnancies) represent an increased potential risk for TRALI. However, the exclusion of multiparous plateletpheresis donors would eliminate one-third of our female donor pool. Screening such donors for HLA sensitization may represent the optimal approach for identifying donors at risk for causing TRALI, but this still would result in the deferral of 8 percent of female plateletpheresis donors. At present, prospective screening to identify donors at risk for causing TRALI is not justified.

Adult↗
PubMed1994

Low retention of white cell fragments by polyester fiber white cell-reduction platelet filters.

BACKGROUND: There is intense interest in the potential of current white cell (WBC)-reduction filters to prevent the alloimmunization of patients by the residual donor WBCs in filtered blood components transfused to them. Little attention has been paid to the capacity of current synthetic fiber filters to remove WBC membrane fragments bearing detectable leukocyte antigens. STUDY DESIGN AND METHODS: Fluorescein isothiocyanate-conjugated monoclonal antibody to a universal WBC membrane antigen (CD45) and high-speed centrifugation coupled with ficoll-hypaque differential sedimentation were used to quantitate low-density WBC fragments in single-donor platelet components before and after filtration to determine if a polyester fiber filter retained WBC fragments. RESULTS: Prefiltration measurements in 25 single-donor platelet components indicated that WBC fragments increased with length of storage up to 5 days at room temperature (p < 0.0001). When fragments in eight components were measured before and after filtration, absolute values for differences were insignificant (p = 0.15). CONCLUSION: WBC fragments were poorly retained by these polyester fiber WBC-reduction filters. The antigenicity of WBC fragments could contribute to the WBC alloimmunization of some recipients of WBC-reduced blood components.

Antibodies, Monoclonal↗
PubMed1994

Fatal outcome in a patient with autoimmune hemolytic anemia associated with an IgM bithermic anti-ITP.

BACKGROUND: Several cold autoantibodies (usually IgG) with IT specificity have been reported previously, as have autoantibodies with joint I and P blood group specificities (IP1, ITP1, iP1, IP). A fatal outcome associated with an IgM cold autoantibody of ITP specificity is reported. CASE REPORT: A 54-year-old man suffered from progressively severe cold autoimmune hemolytic anemia for 9 months. Hemoglobin concentration ranged from 6 to 7 g per dL (60-70 g/L) and reticulocytes from 3 to 5 percent (0.030-0.050). The direct antiglobulin test was weakly positive for IgM and strongly positive for C3d. The serum contained a cold agglutinin that reacted strongest with cord i red cells (RBCs) > adult I RBCs > adult i RBCs, which is consistent with IT specificity. The Donath-Landsteiner test was positive; the reaction was neutralized by globoside. The serum reacted weakly or was negative with RBCs from five group p blood donors, which suggests anti-ITP specificity. Dithiothreitol treatment of the serum abolished the cold agglutinin reactivity, which suggests that the anti-IT was IgM. The patient received > 40 RBC transfusions and failed to respond to oral steroids, oral cytoxan, high-dose pulse intravenous steroids, and plasma exchange at room temperature and at 35 degrees C. He died of sepsis following an unsuccessful trial of chlorambucil. Autopsy revealed unsuspected disseminated non-Hodgkin's lymphoma. CONCLUSION: Serologic studies are consistent with our patient's having a single IgM cold autoantibody with IT and P specificities (anti-ITP) and requiring both specificities on the same RBC to permit maximal antibody expression.

Adsorption↗
PubMed1992

Refractory immune hemolytic anemia with a high thermal amplitude, low affinity IgG anti-Pra cold autoantibody.

A 54 y.o. woman presented with acute Coombs-negative hemolytic anemia at an outside hospital where she received 25 RBC transfusions and did not respond to prednisone or splenectomy. On transfer to our hospital, routine DAT and IAT were weakly positive, occasionally negative. When a modified "cold" antiglobulin test was employed, the result was strongly positive for IgG, weakly positive for C3d. Cold agglutinin titer was 32, and the Donath-Landsteiner test was negative. The autoantibody exhibited Pra specificity. The patient failed IV-IgG, high dose IV pulse steroids and cyclophosphamide, and continued to require daily transfusions. She responded 21 days after receiving daily plasma exchange (x3), with pulse cyclophosphamide on the third day, followed by escalating daily oral cyclophosphamide.

Agglutinins↗
PubMed1991

Experience of a combined apheresis, blood collection, and blood transfusion unit in a large tertiary care medical center.

The Barnes Hospital Apheresis Blood Collection and Blood Transfusion Unit is part of Barns Hospital Blood Bank. Because of its size and complexity, we report our experience which may be useful to administrators and physicians involved in the planning or management of similar services. From 1985 through 1988 we collected platelets from 1,976 different donors, the majority of which (87%) were community donors. Sixty-nine percent of 1,976 donors donated in 1988 an average of 4.9 times. Of 6,568 apheresis products collected. 1.1% were discarded because of positive screening tests and 0.7% were discarded because of outdating or presence of fibrin clot. In 1988 a total of nine cell separators were used. All donor apheresis were done with seven blood separators, and on average a separator produced an apheresis product every 4.5 worked hours. All therapeutic apheresis (338) were done on two separators. Most of them (88%) were performed during work hours. In 1988 donor and therapeutic apheresis were done by 17 1/2 full-time employees (FTEs) during work hours. Considering the Workload Unit Value per procedure given by the College of American Pathologists (CAP) and that each FTE worked 1,864 hours per year, the worked hour productivity for donor and therapeutic apheresis was 78.2%. Blood collections, therapeutic bleeds, and outpatient transfusions (1,127, 114 and 1,745 respectively) were accomplished by two FTEs, for a worked hour productivity of 35.5%. Because 95.1% of total worked units was produced by efficient donor and therapeutic apheresis activities, overall efficiency remained high at 73.8%.

Blood Banks↗
PubMed1990

Invalidation of antiglobulin tests by a high thermal amplitude cryoglobulin.

A multiply transfused patient was referred for evaluation of a transfusion reaction. The direct and indirect antiglobulin tests (DAT, IAT) for alloantibody were negative. However, IgG-coated control cells failed to agglutinate in the negative reactions, casting doubt on their validity. At 4 degrees C, the patient's serum exhibited a large cryoprecipitate (2.9 mg/mL), made up predominantly of an IgG kappa paraprotein and having trace amounts of IgM and C3. Clear serum separated at 37 degrees C became cloudy within 10 minutes at room temperature (RT); within 4 hours, approximately 60 percent of the total precipitable cryoprotein had precipitated. Red cells (RBCs) incubated in fresh serum that had cooled to RT or RBCs obtained from RT or refrigerated samples contained cryoprecipitate that sedimented with the RBCs during washing with RT saline. On resuspension, enough IgG cryoglobulin redissolved to neutralize completely the commercial anti-IgG reagents. If the patient's samples were maintained at 37 degrees C, cryoprecipitate did not form, and RBCs washed four times at 37 degrees C gave valid DAT and IAT reactions. The removal of all cryoprecipitate from the patient's serum by centrifugation after overnight incubation at 4 degrees C also made possible valid antibody screening and compatibility tests.

Blood Grouping and Crossmatching↗
PubMed1989

Multiple plasma exchanges successfully maintain a young adult patient with Crigler-Najjar syndrome type I.

Plasmapheresis has been shown to reduce total and free bilirubin levels in acute exacerbations of Crigler-Najjar syndrome, type I (CNS-TI), but its effectiveness in long-term management has not been reported. An 18-year-old (yo) male with CNS-TI, who required prolonged daily high-intensity phototherapy to prevent cerebral nervous system symptoms, developed increasingly frequent bouts of confusion, nausea, and vomiting associated with free bilirubin concentrations (fbcs) greater than 10-15 nmol/L. Pending consideration of orthotopic liver transplantation, plasma exchange (approximately 3 liters per procedure) was begun in 12/84 using the IBM/COBE 2997 with 5% albumin as replacement fluid. Frequency of treatments was guided by twice weekly fbcs, with plasma exchange for fbc greater than 10-15 nmol/L. Pre-exchange and postexchange fbcs ranged from 27.5 to 11 nmol/L and 9.2 to 2 nmol/L, respectively. Seventy-two exchanges were performed over a 28 month period. Irreversible CNS damage did not occur, and the patient underwent successful liver transplantation in April of 1987, with complete correction of his metabolic disorder. He remains well 18 months following transplantation.

Adolescent↗
PubMed1989

Effect of ABO mismatching on a radioimmunoassay for platelet compatibility. Successful adsorption of ABO alloantibodies with synthetic A and B substance.

IgG and IgM anti-A and/or -B agglutinin titers were determined on 17 serum samples (5 group 0, 7 group A, 5 group B) to range from 8 to 1024. The presence of hemolysins was also evaluated. Single adsorptions with solid-state synthetic A and B substances greatly reduced or eliminated anti-A and -B titers but did not adsorb known platelet antibodies. Unadsorbed and adsorbed serum samples were crossmatched with ABO-compatible and -incompatible platelets by a radioimmunoassay employing 125I-labeled monoclonal antibodies specific for human gamma, mu, and C3d antigens. IgG and IgM crossmatch incompatibility was directly related to ABO alloantibody titers greater than or equal to 64. The use of adsorbed serum in the crossmatch eliminated or greatly reduced incompatible results that were due to ABO alloagglutinins alone, thus allowing the reliable detection of platelet and/or HLA antibodies.

ABO Blood-Group System↗
PubMed1989

Effectiveness of two synthetic fiber filters for removing white cells from AS-1 red cells.

Two commercially available synthetic fiber filters were studied for their effectiveness at removing white cells (WBCs) from AS-1-preserved red cells (RBCs) stored less than or equal to 14 days. In all, 65 filtrations were performed. An automated microprocessor-controlled hydraulic system designed for use with cellulose acetate fiber filters was employed to prepare filtered RBCs before release for transfusion. Studies were also carried out on polyester fiber filters, which are designed to be used in-line during transfusion. Residual WBCs were below the accurate counting range of Coulter counters and of conventional manual chamber counts. An isosmotic ammonium chloride RBC lysis method, plus a modified chamber counting technique, permitted a 270-fold increase over the number of WBCs counted by the conventional manual method. For the polyester fiber-filtered products, residual WBCs per unit were not affected by speed of filtration, prior length of storage, or mechanical tapping during filtration. The effectiveness of WBC removal (mean 99.7%), total residual WBCs (means, 4.8 and 5.5 x 10(6], and RBC recovery (mean, 93%) was the same for both filters. The majority of residual WBCs were lymphocytes. WBC removal and RBC recovery were strikingly superior to results reported with nonfiltration methods.

Adenine↗
PubMed1989

Severe paravalvular mechanical hemolysis with a normal blood smear.

A 74-year-old white female presented with clinical and laboratory evidence of severe hemolysis caused by paravalular leakage around a prosthetic mitral valve. The unique aspect of ther case is the absence of red blood cell fragments in the peripheral smear. Red blood cell transfusions, which averaged three to four units per week, were no longer required after operative repair of the primary suture line. All evidence for hemolysis disappeared; hematologic values returned to normal and remained so during the subsequent six months.

Acute Disease↗
PubMed1989

Preliminary trial of minidose heparin prophylaxis for painful sickle cell crises.

Four patients with well-documented severe recurrent painful sickle cell crises received 12-month courses of self-administered minidose heparin (5000-7500 units every 12 hours). Patients were evaluated weekly or bi-weekly for symptoms and signs of sickle crises. The observations were compared with identical observations during 12 months off heparin (control). Prior to starting heparin, baseline laboratory values were established, including hematocrits, platelet counts, and plasma coagulation factors. Bone density was evaluated by radiologic measurement of metacarpal cortical width and by forearm transmission osteodensitometry. Laboratory values were repeated at each visit; bone density was reevaluated every 6 months. At each visit clinical status for the preceding 1-2 weeks was classified as: no pain (I), minor pain controllable by non-prescription medications (II), pain requiring office or emergency room admissions for parenteral narcotics (III), hospitalized for about 3 days for pain crisis (IV). One patient completed a single 2-year cycle; one patient completed 2 cycles (followed 4 years), and 2 patients have undertaken 3 cycles (followed greater than or equal to 6 years). No treatment-related complications occurred requiring discontinuation of heparin. Thrombocytopenia was not observed. There was no evidence of progressive osteopenia. All patients improved while receiving heparin; 1 moderately, 3 markedly. Cumulative data (8.7 patient years on heparin, 12 control years) revealed a 73% reduction in days of hospitalization per year and 74% reduction in hours spent in emergency rooms per year during heparin administration. Pretreatment pain patterns recurred when heparin was discontinued.

Adult↗
PubMed1987

Anti-B-mediated rejection of an ABO-incompatible cardiac allograft despite aggressive plasma exchange transfusion.

A group A recipient received a group B cardiac allograft. Aggressive plasma exchange with replacement by group AB FFP initially reduced the recipient's anti-B titer to a low level. Once a secondary anti-B response was mounted, plasma exchange was ineffective and IgM and IgG anti-B titers rose to high levels. Associated with the increased anti-B titers, cardiac function deteriorated and on day 13 the group B heart was replaced by a group A allograft. The compatible allograft functioned well initially but was eventually rejected, and the patient died 51 days after the initial transplantation. Histologic examination of the first allograft revealed a delayed form of typical antibody-mediated rejection with destruction of the microvasculature associated with antibody deposition and acute inflammation. By contrast, the histopathology of the second compatible allograft was typical of cell-mediated allograft rejection. Extracts of myocardium from the incompatible heart contained IgM and IgG anti-B, while no anti-B alloantibody was demonstrable in the extracts of the ABO-compatible allograft and a control heart. The utility of plasma exchange with group AB FFP replacement in such a circumstance requires further study.

ABO Blood-Group System↗