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Biomedical subjects

G Garratty

Publications and source records attributed to G Garratty.

At least 91 records · Page 5Linked to original sources
PubMed1990

Correlation between in vivo hemolysis and the amount of red cell-bound IgG measured by flow cytometry.

A flow cytometry method was used to compare the amount of red cell (RBC)-bound IgG in 73 patients with and without immune hemolytic anemia (IHA). The positive results in 10 of the direct antiglobulin tests (DATs) were idiopathic, and those in 25 were due to methyldopa therapy; 38 of the 73 DAT-positive patients were babies born to women with IgG alloantibodies of potential clinical significance. Normal blood donors with (n = 30) and without (n = 121) positive DATs were also tested. RBCs that had been strongly sensitized (4+ indirect antiglobulin test) in vitro with different quantities of IgG anti-D, but that had similar antiglobulin test (AGT) titration scores, could easily be differentiated by flow cytometry. The mean percent fluorescence of RBCs, incubated with fluorescein-labeled anti-IgG, from neonatal patients with IHA was higher than that of RBCs from those without IHA, but there was no statistical difference in the other groups. There was considerable overlap in the respective ranges of percent fluorescence of RBCs from patients with and without IHA in all groups. It was not possible to define a clear quantitative threshold differentiating patients with IHA from those without. Although flow cytometry was more precise and reproducible than standard serology (e.g., AGT titration scores), correlations of the amount of RBC-bound IgG and in vivo hemolysis were similar.

Anemia, Hemolytic, Autoimmune↗
PubMed1990

A simple method for inhibiting ABO antibodies in sera used for platelet crossmatching.

Sometimes it is necessary to crossmatch and transfuse ABO-incompatible platelets As IgG anti-A and anti-B sometimes react with platelets from group A or B donors, these reactions can confuse the interpretation of crossmatching, which is designed to detect HLA or platelet-specific antibodies. Methods previously described to overcome this problem have been complex. Neutr-ABR, which contains A and B blood group substances from porcine and equine sources, can be used to neutralize anti-A and/or anti-B in sera used to crossmatch ABO-incompatible platelets. This simple technique has been used for many years in red blood cell (RBC) serology and involves simply adding 1 volume of Neutr-AB to 5 volumes of serum and incubating at room temperature for 5 minutes. In this study, 13 of 65 (20%) random group O donor sera reacted against random group A platelets and 6 of 67 (9%) random group O donor sera reacted against random group R platelets. All of the anti-A and anti-B reactions were inhibited by Neutr-AB when tested against group A or B platelets by solid-phase ELISA. The amount of A antigen on platelets and the levels of anti-A in group B or O sera can vary considerably, so we investigated the extent of the problem in platelet crossmatching. Sixty percent of 20 random group O sera reacted with platelets from a donor, who was selected because of the strong A antigen present on the platelets. Eighty-six percent of randomly selected group A platelets reacted with a group O serum containing strong anti-A. Neutr-AB was found not to inhibit 1 anti-P1A1 and 6 anti-HLA.

Journal Article↗
PubMed1989

Isoimmunization to Cromer antigen in pregnancy.

Pregnancy in a woman isoimmunized to Cromer antigen, a high-frequency antigen, is reported. Neither of her two Cromer antigen-positive infants was affected with hemolytic disease of the newborn. Autologous blood or that from a compatible Cromer antigen-negative relative may be frozen and stored for possible transfusion in a pregnant woman with anti-Cromer antigen antibodies.

Adult↗
PubMed1989

Investigations of the potential for five beta-lactam antibiotics to elicit type II hypersensitivity reactions in rats and monkeys.

Immunologic reactions are occasionally elicited in patients by various beta-lactam antibiotics (e.g., penicillins and cephalosporins). A relatively rare reaction (type II hypersensitivity) may involve antibody-mediated destruction of erythrocytes, leukocytes, and/or platelets. During the safety evaluation of several modified beta-lactam compounds (carbapenems), hemolytic anemia and/or neutropenia were observed in rhesus monkeys, and anemia, neutropenia, and thrombocytopenia in rats, after approximately 2 weeks of intravenous administration. Antiglobulin tests and other clinicopathologic findings indicated an immune basis for the cytopenias. A review of summaries of the preclinical data for numerous marketed beta-lactam antibiotics revealed that various cytopenias of unknown etiology were commonly seen in animals given high doses of these compounds. To determine whether these hematologic abnormalities were related to those produced by the above carbapenems, we investigated the potential of five widely used beta-lactam antibiotics (penicillin G, cephalothin, cefazolin, cefoperazone, and cefamandole) to elicit immune-mediated cytopenias in rhesus monkeys and Sprague-Dawley rats when given intravenously. After approximately 1 month of administration of these compounds at a dose level of 500 mg/kg/day, slight anemia occurred in several drug-treated monkeys; however, direct and indirect antiglobulin tests were negative for all animals, indicating that the anemias were not immune-mediated. In rats, no drug-induced hematologic changes were observed after 1 month of intravenous administration of 500 and 1000 mg/kg/day of each of the beta-lactams. In addition, direct antiglobulin tests were negative in rats. Therefore, it appears that the ability of certain carbapenem antibiotics to produce a high incidence of type II hypersensitivity reactions in animals is not typical of beta-lactam compounds in general.

Animals↗
PubMed1989

Quantitation of fetal-maternal hemorrhage by flow cytometry. A simple and accurate method.

A simple and objective assay was developed for the detection and quantitation of fetal-maternal hemorrhage with the use of flow cytometry. In vitro prepared control mixtures of 10%, 2%, 1%, 0.5%, 0.25%, 0.125%, and 0.06% D+ RBCs in D- RBCs were tested (8-11) different times by flow cytometry and gave mean % D+ results of 11.10%, 1.90%, 0.92%, 0.45%, 0.24%, 0.11%, and 0.05%. The coefficient of variation of preparing and testing these mixtures ranged from 11.0 to 15.9% for the 10-0.125% mixtures. Thus, flow cytometry was accurate, reproducible, and sensitive. Flow cytometry was compared with Du tests, rosette tests, and acid elution. The Du test was highly variable because it was not sensitive enough to detect a significant bleed (approximately 0.6%) in some cases and too sensitive (necessitating quantitation of an insignificant bleed) in others. The rosette test was too sensitive. Acid elution and flow cytometry results did not always agree; acid elution results were approximately twice as high as flow cytometry. The authors believe flow cytometric detection of D+ red blood cells to be more accurate than the detection of fetal hemoglobin by acid elution techniques, which is known to have poor reproducibility. Postpartum samples from 56 D- women who delivered D+ babies were tested. Fifty-two had fetal bleeds less than 0.3% by acid elution and flow cytometry; all had negative Du test results, but there were two false positive results with the use of the rosette technique. Four had significant bleeds (greater than or equal to 0.6%); in all four cases the flow cytometry results were lower than the acid elution results. The authors were able to quantitate a bleed of fetal RBCs, which were D+ only by the Du test, in a D- mother with the use of flow cytometry, and D+ RBCs in a mother whose RBCs were of the rare DVI mosaic phenotype. This would not have been possible with the use of the standard Du or rosette techniques.

Erythrocyte Count↗
PubMed1989

Monocyte monolayer assay: an efficient noninvasive technique for predicting the severity of hemolytic disease of the newborn.

The authors performed monocyte monolayer assays (MMAs) with the use of normal donor monocytes, and homologous reagent red blood cells, sensitized in vitro, with antibodies in maternal sera. The sera were from 16 pregnant women with Rh antibodies, drawn at the time of amniotic fluid analysis. They compared the predictive value (PV) of the MMAs and the delta OD 450 of amniotic fluid in forecasting the need for transfusing the infant. The PV of the delta OD 450 result in Liley zone mid II-III was 100%, but in zones 0 to low II it was only 60% (13 samples from ten women were in these zones but four babies required transfusion). In contrast, the PV of a positive (greater than 20% reactivity) MMA was 91% (one false positive result) and the PV of a negative MMA was 100%. Thus, the MMA was more efficient than amniotic fluid analysis at predicting hemolytic disease of the newborn severe enough to require transfusion. The noninvasive MMA could be used as a screening test, reducing the number of amniocenteses or ultrasound evaluations performed on Rh-sensitized women.

Amniotic Fluid↗
PubMed1988

Erythromycin-induced immune hemolytic anemia.

A 3-year-old female receiving Pediazole (erythromycin ethylsuccinate and sulfisoxazole) for tonsillitis and otitis media developed severe hemolytic anemia. No serum drug-dependent antibodies could be demonstrated with an in vitro 'immune-complex' method using Pediazole, pure erythromycin ethylsuccinate or pure sulfisoxazole. However, a method using red cells coated with erythromycin base showed in vitro lysis of the erythromycin-coated red cells. This is only the second case of immune hemolytic anemia associated with erythromycin and the first where in vitro drug-dependent hemolysis was demonstrable.

Anemia, Hemolytic↗
PubMed1987

Application of flow cytometry to immunohematology.

A method is described for applying flow cytometry to the analysis of populations of red blood cells that have been sensitized, in vivo or in vitro, with IgG antibody. Specific instrument settings and details of the method are given with sufficient explanation for practical use in immunohematologic investigations.

Antigen-Antibody Reactions↗
PubMed1987

A new potentiator of red blood cell antigen-antibody reactions.

A new technic using polyethylene glycol (PEG) was developed to detect and enhance weak red blood cell/antibody reactions. Twenty percent PEG of 4,000 molecular weight was found to be optimal. Weakly reactive antibodies (n = 25) were tested by PEG, Polybrene, and low ionic strength saline (LISS); 64% were strongest in PEG, 28% reacted equally in PEG as in Polybrene or LISS, 8% reacted weaker in PEG than in Polybrene or LISS. Stronger antibodies (n = 11) were titrated and compared in the three technics; in 10 of 11 titrations, PEG was better or equal to Polybrene and LISS. The false positive rate with the use of PEG and anti-IgG was 1.5% with the use of random sera. Sera from patients (n = 24) with hemolytic transfusion reactions and no detectable antibody by routine technics were tested; two sera had specific antibodies by the PEG technic. This new technic should be a valuable aid in the detection and identification of weak antibodies.

Antigen-Antibody Reactions↗
PubMed1987

Acquired loss of red cell Kell antigens.

A 19-year-old patient with a long history of idiopathic thrombocytopenic purpura developed a potent antibody against a high-incidence antigen in the Kell blood group system. The direct antiglobulin test on his red cells was negative. His cells exhibited profound depression of Kell blood group antigens, but antigens of other blood groups were normal. Transfusion of incompatible blood was well tolerated and differential agglutination tests, using selected Rh antisera, showed in vivo survival of the transfused red cells for more than 8 weeks. However, the transfused red cells also showed acquired loss of Kell antigens. Five months after the initial findings, Kell-related antibody disappeared and Kell antigens reappeared on his red cells. The patient's serum stored from the initial investigation now reacted with his freshly collected red cells. These data suggest that an environmental agent in the patient's plasma was responsible for the temporary loss of Kell antigens from red cells in his circulation.

Adult↗
PubMed1987

Immunospecific red cell binding of iodine 125-labeled immunoglobulin G erythrocyte autoantibodies.

The primary interaction of autoantibodies with red cells has been studied by using labeled autoantibodies. Immunoglobulin G red cell autoantibodies obtained from IgG antiglobulin-positive normal blood donors were labeled with radioactive iodine and compared with alloanti-D with respect to their properties and binding behavior. Iodine 125-labeled IgG autoantibody migrated as a single homogeneous peak with the same relative mobility as human IgG on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric focusing pattern of labeled autoantibodies varied from donor to donor but was similar to that of alloanti-D, consisting of multiple IgG populations with isoelectric points in the neutral to alkaline range. 125I-autoantibody bound to all human red cells of common Rh phenotypes. Evidence for immunospecific antibody binding of the labeled autoantibody was based on variation in equilibrium binding to nonhuman and human red cells of common and rare phenotypes, enhanced binding after red cell protease modification, antiglobulin reactivity of cell-bound IgG comparable to that of cell-bound anti-D, and saturation binding in autoantibody excess. Scatchard analysis of two 125I-autoantibody preparations yielded site numbers of 41,500 and 53,300 with equilibrium constants of 3.7 and 2.1 X 10(8) L X mol-1. Dog, rabbit, rhesus monkey, and baboon red cells were antigen(s) negative by quantitative adsorption studies adsorbing less than 3% of the labeled autoantibody. Reduced ability of rare human D--red blood cells to adsorb the autoantibody and identification of donor autoantibodies that bind to Rh null red blood cells indicated that eluates contained multiple antibody populations of complex specificities in contrast to anti-D, which consists of a monospecific antibody population. Another difference is that less than 70% of the autoantibody IgG was adsorbed by maximum binding red blood cells as compared with greater than 85% for alloanti-D. Evidence obtained indicates that the red blood cell nonadsorbable IgG, some 30%, consists of other IgG populations, one of which represents IgG autoanti-idiotypes to the autoantibody.

Agglutination Tests↗
PubMed1986

Two examples of low ionic strength-dependent autoagglutinins with anti-Pr1 specificity.

Two low ionic strength-dependent autoagglutinins were studied and found to have anti-Pr1 specificity. This specificity was determined by studies with enzyme-treated and neuraminidase-treated human red blood cells (RBCs), animal RBCs and chemically-modified sialoglycoproteins, all suspended in a low ionic strength solution (LISS). Both IgM complement-binding cold agglutinins had a wide thermal range and caused in vitro hemolysis of some LISS-suspended RBCs at 37 degrees C. Compatible blood was found for these patients by using techniques that did not employ LISS.

Agglutination Tests↗