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G F Lucas

Publications and source records attributed to G F Lucas.

28 records · Page 2Linked to original sources
PubMed1990

Results of the First International Granulocyte Serology Workshop.

Eleven laboratories participated in the First International Workshop of Granulocyte Serology. Participants were asked to identify any granulocyte-reactive antibodies present in 12 human sera distributed as unknown samples. Granulocyte immunofluorescence and granulocyte micro-agglutination were the most commonly used techniques. The incidence of false-positive and false-negative reactions was 15 and 4%, respectively. Most laboratories were able to distinguish between granulocyte-specific and anti-HLA antibodies using platelet absorption. The identification of the specificity of granulocyte-specific antibodies caused the most problems; these were correctly identified on only 57% of occasions.

Antibody Specificity↗
PubMed1990

A survey of platelet serology in UK laboratories (1987): an assessment of the efficacy of using chloroquine-treated platelets to distinguish between platelet-specific and anti-HLA antibodies. The UK Platelet and Granulocyte Serology Working Group.

This survey was designed to determine the ability of participants to distinguish between platelet specific and anti-HLA antibodies. Four well characterized reference reagents and 10 unknown samples were sent to 29 laboratories affiliated to the UK Platelet and Granulocyte Serology Working Group and to three overseas reference laboratories. Results were obtained from 27 Working Group laboratories and from 2 reference laboratories. Overall, the results indicate that the use of chloroquine-treated platelets alone, without an independent test for anti-HLA antibodies, was insufficiently reliable to elucidate mixtures of platelet specific and anti-HLA antibodies. Laboratories using chloroquine-treated platelets were no more successful in elucidating the antibody composition of sera containing platelet-specific and anti-HLA antibodies than those laboratories which did not use this technique. The results may indicate a lack of experience with the chloroquine technique and suggest that further studies into the performance of the technique are required. The survey also provided insights into other areas of platelet serology: (1) There was a decrease in the incidence of false-positive results compared to earlier UK surveys. [2) All laboratories detected potent platelet-specific antibodies but weakly reactive antibodies were less readily detected. (3) Laboratories using fluorescent antiglobulin techniques recorded fewer errors than laboratories using ELISA techniques. (4) Laboratories using paraformaldehyde (PFA)-treated platelets in fluorescent antiglobulin techniques did not perform better than laboratories using untreated platelets.

Antibody Specificity↗
PubMed1989

A second case of neonatal alloimmune thrombocytopenia associated with anti-PlA2 (Zwb) antibodies.

A case of neonatal alloimmune thrombocytopenia due to fetomaternal incompatibility against the platelet specific antigen PlA2 (Zwb) is described. Anti-PlA2 antibodies were present in the maternal serum together with anti-HLA antibodies. Initial identification of the platelet-specific antibodies was achieved by using chloroquine-treated PlA1(+) and PlA1(-) platelets. Antibody specificity was later confirmed using a panel of platelets of known phenotype.

Adult↗
PubMed1987

The effect of anticoagulant on platelet associated IgG.

Blood anticoagulated with solid K2EDTA had platelet associated IgG (PAIgG) levels five-fold greater than citrated blood when the platelets were harvested by differential centrifugation but identical PAIgG levels when the platelets were harvested by Percoll density gradient. Furthermore, blood anticoagulated with increasing amounts of solid K2EDTA demonstrated a proportionate increase in both PAIgG and haemolysis whereas the same blood sample anticoagulated with aqueous K2EDTA exhibited neither of these effects. Coulter Counter analysis of platelet poor plasma (PPP) prepared from blood anticoagulated with solid K2EDTA revealed particles with a mean volume greater than normal RBC; such particles were not found in the PPP prepared from citrated blood. While some of these particles could be sedimented through plasma, those remaining were sufficiently buoyant to resist sedimentation unless the plasma was diluted with buffer. Studies with FITC conjugated antisera revealed that the particles could be classified into two types. Type I particles reacted strongly with a monoclonal anti-RBC antibody, weakly with anti-IgG antibody and had the appearance of stroma. Type II particles lacked any apparent biological structure, reacted strongly with anti-IgG antibody but not with monoclonal anti-RBC antibody. Thus, the buoyant IgG-rich particles found in blood anticoagulated with solid K2EDTA appear to contribute to the high PAIgG levels associated with this anticoagulant. Consequently, solid K2EDTA should not be used to anticoagulate blood destined for PAIgG measurement.

Anticoagulants↗
PubMed1987

Anti-platelet opsonic activity in alloimmune and autoimmune thrombocytopenia.

A chemiluminescence technique (CLT) has been developed which measures the interaction between human monocytes and antibody-coated (opsonized) platelets. This technique has an objective end-point, is simple to perform and is of comparable sensitivity to the platelet suspension immunofluorescence test (PSIFT) when used to detect anti-platelet allo-antibodies. In contrast, only 4/20 sera from patients with clinically diagnosed autoimmune thrombocytopenia were opsonic in the CLT, while 8/20 of these same sera bound IgG to platelets in the PSIFT. Only one serum gave positive results in both tests.

Antibodies↗
PubMed1987

A survey of anti-platelet antibody detection--report of the UK Platelet and Granulocyte Serology Working Group, 1985.

In 1985, serum samples were distributed to 27 laboratories within the UK and Eire with the objective of determining the current state of anti-platelet antibody detection. The sera included five unknown samples for blind assessment and four well-characterized reference reagents. The laboratories involved used a wide range of different methods but the most commonly used techniques were the fluorescent antiglobulin test and the enzyme-linked immunosorbent assay. In the trial, all responding laboratories were able to detect potent anti-platelet alloantibodies but there was a 43% incidence of 'false positive' results with samples which had been designated as inert. There were no apparent differences in performance between assays using fluorescein- or enzyme-labelled antiglobulin reagents or between assays which utilized PFA-treated rather than untreated platelets.

Antibodies↗
PubMed1984

The effects of amrinone on platelet count, survival and function in patients with congestive cardiac failure.

In a prospective trial, the immediate and long-term haematological effects of amrinone were studied in sixteen patients with refractory cardiac failure. The platelet count was significantly and variably reduced in all patients and the reduction was related to log plasma amrinone concentration. Platelet survival was significantly reduced in those cases studied. No evidence of disseminated intravascular coagulation or intravascular platelet deposition was observed and the reduced platelet survival was not considered to be the result of an immunological process. Evidence of a marrow response to the reduced platelet count and survival was seen. Although no haemorrhagic symptoms were observed in the patients, the haematological side-effects were considered to be of such severity as to limit the use of this drug in clinical practice.

Adult↗
PubMed1982

A double antibody radioassay for the detection of platelet associated IgG.

A double antibody radioimmunoassay has been developed for the detection of platelet associated IgG (PAIgG). The assay employs conventional radioassay technology and, as such, readily may be adopted by laboratories familiar with radioassay techniques. The assay is sensitive to 0.6 ng IgG and can be undertaken on 10(6)-10(7) platelets, or fewer in the case of thrombocytopenia with raised PAIgG. The assay can be completed within 2 working days. Normal PAIgG levels in EDTA blood were 0.8 to 5.7 micrograms IgG/10(9) platelets. However, normal levels depended upon the anticoagulant used for blood collection and were on average five-fold higher for blood taken into EDTA than for blood taken into ACD; normal range 0.1-1.2 micrograms/IgG 10(9) platelets. PAIgG was assayed on blood taken simultaneously into ACD and EDTA from 15 patients with chronic idiopathic thrombocytopenia (ITP). PAIgG was raised in 14 out of 15 EDTA samples, but in only 11 of 15 ACD samples. EDTA was therefore regarded as the anticoagulant of choice. A total of 20 of 23 (87%) patients with chronic ITP had PAIgG values above the normal range. The PAIgG in chronic ITP was weakly related to platelet count, weakly and inversely related to platelet volume, but was independent of serum IgG concentration.

Blood Platelets↗