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P Lalezari

Publications and source records attributed to P Lalezari.

68 records · Page 4Linked to original sources
PubMed1971

NB1, a new neutrophil-specific antigen involved in the pathogenesis of neonatal neutropenia.

A new human antigen is reported which is present only on blood neutrophils. A neutrophil-specific antigen, designated NA1, has previously been identified in two unrelated families, and was shown to be involved in fetomaternal incompatibility and the development of isoimmune neonatal neutropenia in five newborns. In the present paper, a second antigen, designated NB1, is identified in four families with seven affected children. Antibodies that react with this second antigen are shown to produce selective agglutination of neutrophils but not other blood cells. They are neither absorbed by cells prepared from solid tissues nor by non-neutrophilic blood cells. By family and population studies, NB is shown to be distinct from NA, representing an independent genetic locus. 68% of the New York population are homozygous for NB1, 29% heterozygous, and 3% negative. The NB locus is shown to be independent from those of HL-A and other known leukocyte antigens. No evidence for linkage between NA, NB, and red cell antigens was obtained.

Agranulocytosis↗
PubMedDate not supplied

The manual polybrene test: a simple and rapid procedure for detection of red cell antibodies.

A rapid manual Polybrene test for detection of red blood cell antibodies have been devised which uses standard laboratory equipment. Red blood cells are incubated with the test sera in a low ionic medium at room temperature for one minute. Polybrene, a quaternary ammonium polymer, is then introduced to cause nonspecific red blood cell aggregation. The test tubes are centrifuged, the cell free supernatant fluid decanted, and the Polybrene effect on the cells is neutralized by adding a dilute sodium citrate-glucose solution. The hemagglutination results are evaluated macroscopically and microscopically. The entire procedure is completed in less than three minutes. In the Rh system, the test is 10--160-fold more sensitive than the antiglobulin reaction. In other systems tested, except for the Kell, a high sensitivity is achieved. The sensitivity for the Kell system is markedly increased, however, by performing a supplementary antiglobulin reaction on the sensitized, Polybrene-treated, red blood cells. The antiglobulin reagent used for this purpose should lack anti-C4 and anti-C3 activities. Sensitivity for cold reactive antibodies is augmented by cooling the cells for 30 seconds before citrate-glucose reagent is added.

ABO Blood-Group System↗
PubMedDate not supplied

A comparison of methods for detecting leukocyte antibodies in autoimmune neutropenia.

A six-month-old girl and an 18-month-old boy with autoimmune neutropenia due to anti-NA1 are described. The antibodies were detected by granulocyte microagglutination, and their disappearance in the girl coincided with a return of a normal neutrophil count. The autoantibodies in both patients also reacted in the granulocyte cytotoxicity (GC) assay, and in one patient, in the staphylococcal protein A (SPA) assay. However, neither the GC nor the SPA assays showed the anti-NA1 specificity found by agglutination, and the presence of GC and SPA antibodies did not coincide with neutropenia. These three leukocyte antibody techniques may detect different antibodies and have different clinical significances. This report provides additional evidence of the existence of autoimmune neutropenia and indicates that the clinical role of neutrophil antibodies detected by different serologic techniques is not yet established. Antibodies detected by granulocyte agglutination were clinically significant in these two patients with autoimmune neutropenia, while the results of testing with GC and SPA were not.

Absorption↗
PubMedDate not supplied

The manual hexadimethrine bromide (Polybrene) test. Effects of serum proteins and practical applications.

Serum proteins affect the performance of the manual hexadimethrine bromide (Polybrene) test. Red cells suspended in the low-ionic medium adhere to the surface of test tubes when centrifuged. This adherence is prevented by serum components apoprotein B, fibronectin, von Willebrand factor, or serum diluted less than 75-fold, but not by serum albumin or immunoglobulin fractions. A high concentration of serum reduces the sensitivity of the test and destabilizes antibody-dependent aggregation. Disaggregation time (DT), defined as the time required for antibody-dependent aggregates to disperse, was used as an indicator of agglutination stability. DT was often shortened when antibodies were in native serums, but could be prolonged if serums were diluted with 0.85 percent saline. Other factors that influenced DT included antibody concentration, temperature, specificity, and sources of antibodies within specificities. When antibodies were present in a mixture, they produced various DTs related to individual specificities. Determination of these differences allowed the successful identification of multiple antibodies. The procedure, called differential disaggregation time, was also used for typing red cells coated by autoantibodies. Additional modifications improved the performance of the antiglobulin phase.

Antibody Specificity↗