凝胶微柱法与试管法检测放散液中抗体的比较

目的比较凝胶微柱法和试管法检测红细胞释放液抗体的能力。方法将30例外周血和41例脐血红细胞用两种方法测定直接抗人球蛋白试验(DAT)并进行酸放散,将放散液与三种谱细胞、A1、B细胞反应检测抗体的特异性。71例中12例作为阴性对照样本(DAT均为阴性),其中6例为健康献血者外周血,6例为不发生新生儿溶血病(Heamolytic disease of thenewborn,HDN)的婴儿脐血样本。结果24例外周血放散液中有10例两种方法均阳性,12例均为阴性,2例自身免疫性溶血性贫血(AIHA)患者样本凝胶微柱法阳性而试管凝集法阴性,6例健康捐献者的样本DAT试验阴性且两种方法检测放散液均为阴性;41例脐血样本中33例放散液两种方法均反应,2例放散液在试管法中与A1和B细胞反应而同样的放散液做凝胶微柱法时一个和A1细胞反应,另一个只与B细胞反应。结论两种方法检测放散液结果基本是一致的,检测AIHA患者红细胞释放液抗体时用微柱法比较好,检测脐血细胞释放的同种血凝素时试管凝集法更好—些。     

A preliminary comparison of flow cytometry and tube agglutination assays in detecting red blood cell-associated C3d

This study compared flow cytometric analysis with tube agglutination assays for the detection of red blood cell (RBC)-associated complement and immunoglobulins (Igs). RBCs from 20 patients with reactive tube direct antiglobulin tests (DATs) were evaluated by flow cytometry with anti-C3d, anti-IgG, anti-IgM and anti-IgA. Serial samples were also tested from a patient at risk of passenger lymphocyte haemolysis. Results of flow cytometry and tube assays for anti-IgG were as follows: 12 of 20 samples reactive in both; six of 20 nonreactive in both; two of 20 discordant with a reactive tube and a nonreactive flow cytometry assay. Anti-C3d results showed nine of 20 reactive in both and 11 of 20 discordant with a nonreactive tube and a reactive flow cytometry assay. In the IgM flow cytometry assay, three samples were reactive with anti-IgM. Samples from a group A woman who was transplanted with stem cells from a group B donor showed that on days 3 through 6 post-transplant, the flow cytometry assays for anti-IgG and/or anti-C3d were reactive, whilst the tube assays were nonreactive. In conclusion, flow cytometric analysis is more sensitive than the tube assay for the detection of RBC-associated C3d. Further studies are needed to determine the correlation of C3d levels with clinical sequelae.     

Comparison of DATs using traditional tube agglutination to gel column and affinity column procedures

BACKGROUND: Detection of immunoglobulin or complement bound to RBCs by using the DAT is valuable in the diagnosis of immune-mediated hemolytic anemia. Traditionally, the DAT has been performed by tube agglutination using anti-IgG or anti-C3d. The purpose of this study was to compare the tube agglutination DAT to gel microcolumn, affinity microcolumn, and flow cytometric DATs on RBCs coated in vitro and on patient RBC samples. STUDY DESIGN AND METHODS: RBCs from 84 patients were assessed by tube agglutination DAT, one gel microcolumn DAT, and two affinity microcolumn DATs. One affinity microcolumn assay was unmodified and one was modified by the addition of polyspecific antiglobulin or anti-IgG as a secondary antibody. RBCs from 15 of the 84 patients underwent analysis by flow cytometry with fluorescence-labeled anti-IgG. The assays were also compared by using D+ RBCs sensitized with serially adjusted concentrations of anti-D. RESULTS: Both tube agglutination and gel microcolumn DATs were positive in 49 patient samples; both assays were negative in 20 samples, and the results were discordant in 15. Gel microcolumn DATs were more likely than were tube agglutination DATs to detect IgG on RBCs. Affinity microcolumn DATs were less likely than gel microcolumn or tube agglutination DATs to detect IgG on RBCs. Flow cytometry results were the same as gel microcolumn results in 12 of 15 patient samples and the same as tube agglutination results in 13 of 15. Tube agglutination and both affinity microcolumn assays reacted with RBCs coated with anti-D that was diluted 1-in-100. The gel microcolumn and flow cytometry assays reacted with RBCs coated with anti-D diluted 1-in-400. There was no correlation between tube agglutination and gel microcolumn DATs in detecting bound C3d. CONCLUSION: Detection of IgG bound to RBCs was not consistent with the methods described. Gel microcolumn DATs were more sensitive than tube agglutination and affinity microcolumn DATs. Given the varied results of these assays, reference laboratories should not rely on a single method for DATs. More comprehensive testing should be performed when the tube agglutination DAT is negative in a patient with suspected immune-mediated hemolytic anemia. Further comparisons are necessary to determine the proficiency of flow cytometric assays.     

The evaluation of a positive direct antiglobulin test in pretransfusion testing

The results of serologic studies on 879 blood samples with a positive direct antiglobulin test (DAT) are presented. All blood samples were from patients who were either anemic, for reasons other than blood loss, recently transfused, or had serum antibodies detected during routine pretransfusion tests. Blood samples from only 81 of the patients included in this study had serologically reactive eluates (64 autoantibodies, three antibodies to penicillin and cephalothin treated red blood cells, three passively acquired anti-A antibodies, and 11 transfusion-induced alloantibodies). The eluted antibodies were also detected in the serum by routine pretransfusion tests in 13 of the patients whose red blood cells eluted autoantibodies, and in five of the patients whose red blood cells eluted transfusion-induced alloantibodies. All but one of the 11 transfusion-induced alloantibodies were detected within 14 days posttransfusion. Based on these findings, a cost-effective and safe approach to the management of blood samples with a positive DAT would be to restrict the preparation and testing of eluates to those samples from recently transfused patients. It is the contention of the authors that the incorporation of the DAT in pretransfusion testing should primarily serve to detect alloantibody formation before such antibodies are evident in the serum, and should not be used to screen patients for unsuspected autoimmune hemolytic anemia. Furthermore, the authors question the necessity for blood banks to routinely perform an autocontrol on all blood samples from prospective transfusion recipients.     

False-positive eluate reactivity due to the low-ionic wash solution used with commercial acid-elution kits

BACKGROUND: During the use of commercial red cell (RBC) acid-elution kits for adsorption and elution (adsorption/elution) studies with anti- D, unexpected reactive eluates (anti-D) were obtained from D- RBCs. Such results were not obtained with a parallel xylene method or, historically, with heat and ether methods. STUDY DESIGN AND METHODS: Single-donor and commercial polyclonal anti-D samples were incubated with D+ and D- RBCs. Acid eluates were prepared by the manufacturers' directions. Variations in the wash step of the eluate preparation included the use of commercial kit wash solution versus phosphate- buffered saline versus solutions of various ionic strengths. RESULTS: Anti-D was eluted from 20 of 22 samples of D- RBCs after incubation with commercial polyclonal anti-D (titer 512) and from 2 of 3 samples of D- RBCs incubated with single-donor anti-D (titer 256). With a low- titer (16) single-donor anti-D, 0 of 4 eluates from D- RBCs reacted. When phosphate-buffered saline was substituted for the commercial wash solution, 0 of 11 D- RBC eluates reacted, as compared with 9 of 11 D- RBCs that yielded positive 1+(-)2+ eluates with the commercial wash solution. If the recommended initial phosphate-buffered saline wash was omitted before the use of the commercial wash solution, the eluate reactivity was stronger (2+(-)3+). When low-ionic-strength (< 0.03 M) saline was substituted, anti-D was eluted from D- RBCs. All last washes were nonreactive. Antiglobulin tests on all adsorbing D- were negative. CONCLUSION: Commercial wash solutions used for acid elution are at low ionic strength and commonly yield superior eluates, but in the presence of high-titer antibodies, false-positive eluates can result. It is our belief that the low-ionic-strength wash solution caused aggregation of IgG and nonspecific attachment of IgG on RBCs. Aggregates will contain IgG serum antibodies in proportion to the titer of the antibody. It is this nonspecifically bound antibody that is eluted from antigen- negative RBCs.     

The first example of a patient with etoricoxib‐induced immune hemolytic anemia

BACKGROUND: Etoricoxib, a selective inhibitor of cyclooxygenase 2, is increasingly used in pain relief. Here, we report the first case of etoricoxib‐induced immune hemolytic anemia. STUDY DESIGN AND METHODS: An 84‐year‐old male patient developed anemia 1 week after treatment with etoricoxib. There was no evidence of hemoglobinemia or hemoglobinuria. Administration of the drug was halted, and the patient recovered without further complications. RESULTS: The patient's red blood cells (RBCs) were found to be strongly coated with immunoglobulin G and C3d. Eluted antibodies and dialyzed serum from the patient were not reactive with untreated RBCs, but with etoricoxib‐treated RBCs, RBCs in the presence of etoricoxib, urine containing drug metabolites (ex vivo antigen), and two of four additional COX inhibitor drugs analyzed. DISCUSSION: Although the causative antibodies were drug dependent usually leading to abrupt and intravascular hemolysis, the patient only gradually developed anemia. These findings together with a positive direct and indirect antiglobulin test may lead to confusion with autoimmune hemolytic anemia of warm type. A nonreactive eluate was the key serologic finding in identifying drug‐induced immune hemolytic anemia in this case. CONCLUSION: Etoricoxib should be considered as a risk in the development of immune hemolytic anemia, with the causative antibodies potentially reacting with other COX inhibitors.     

Positive direct and indirect antiglobulin tests associated with oxaliplatin can be due to drug antibody and/or drug-induced nonimmunologic protein adsorption

BACKGROUND: Two patients were suspected of having immune hemolytic anemia (IHA) due to oxaliplatin. A related drug, cisplatin, is known to cause nonimmunologic protein adsorption (NIPA). Studies were performed to determine the presence of oxaliplatin-dependent antibodies in addition to oxaliplatin-induced NIPA.
STUDY DESIGN AND METHODS: Sera and eluates from the two patients were tested against red blood cells (RBCs) treated with oxaliplatin, cisplatin, and carboplatin (another platinum drug). Sera were also tested against untreated RBCs in the presence of the same drugs. Testing with pooled normal sera and anti-human albumin was used to demonstrate the presence of NIPA. Oxaliplatin-treated RBCs sensitized with the patients' sera and pooled normal sera were tested by a monocyte monolayer assay (MMA) to determine potential clinical significance.
RESULTS: Both patients had high-titer antibodies to oxaliplatin in their sera that reacted with oxaliplatin-treated RBCs and with untreated RBCs in the presence of oxaliplatin. RBCs treated with oxaliplatin, cisplatin, and carboplatin all demonstrated NIPA (pooled normal sera and anti-human albumin were reactive to low titers). NIPA was also detected in tests with untreated RBCs in the presence of oxaliplatin and cisplatin. Lower-titer reactivity of both patients' sera with cisplatin may have been due to NIPA and/or cross-reactivity of anti-oxaliplatin with cisplatin. MMAs were weakly positive due to NIPA and more strongly positive due to oxaliplatin antibodies.
CONCLUSION: Two patients with IHA were demonstrated to have oxaliplatin-dependent antibodies. Oxaliplatin was also shown to cause NIPA. The drug-dependent antibody and/or the drug-induced NIPA could have contributed to the patients' hemolytic anemia.     

The protein composition of red cell eluates

BACKGROUND: The protein composition of red cell (RBC) eluates has not been extensively studied. The purpose of this study was to determine the IgG content and protein composition of RBC eluates prepared by the acid and xylene elution methods. STUDY DESIGN AND METHODS: Six samples of group O R1R1 RBCs sensitized with anti-D in vitro, six nonsensitized samples of the same group O R1R1 RBCs, and six samples from patients with warm autoimmune hemolytic anemia (WAIHA) were studied. The eluate protein composition was determined by sodium dodecyl sulfate- polyacrylamide gel electrophoresis, and immunoglobulin concentrations were estimated by an immunoblot technique using horseradish peroxidase- conjugated anti-IgG and 3,3' diaminobenzidine. RESULTS: The protein concentrations of the xylene eluates were significantly greater than those of the acid eluates (37.3 +/− 10.7 and 3.0 +/− 0.4 [SD], respectively; p < 0.005). In all samples, the proportion of IgG was less than 0.13 percent of the total protein content. The acid eluates of sensitized RBCs contained more IgG than the xylene eluates. The antibody titers of eluates from WAIHA RBCs were significantly lower than eluates of in vitro sensitized RBCs (p < 0.005). The estimated molecular weights of the Coomassie blue-stainable protein bands from xylene eluates were 97, 78, 63, 45, 31, 23, and 16 kDa, and those of bands from acid eluates were 97, 78, and 55 kDa. No periodic acid- Schiff reagent-stainable bands were detected. CONCLUSION: These data indicate that IgG represented only a small fraction of the proteins in the eluates and that the protein composition varies with the elution procedure.     

Solid-phase hemadsorption assay for IgM antibody to Treponema pallidum in serum and umbilical cord blood.

A solid-phase hemadsorption assay (SPHA) for Treponema pallidum was evaluated using serum and umbilical cord blood. A total of 133 sera reactive using immunofluorescent antibody assay were tested by SPHA for IgM antibody against T. pallidum. They were categorized into clinical stages of syphilis, including eight sera with primary, 32 sera with secondary, 68 sera with latent, 21 sera with unclassified, and four sera with congenital syphilis. Sera were reactive for 75%, 90.6%, and 33.8% using SPHA in the primary, secondary, and latent phases, respectively. The method gave 57.1% reactivity for the unclassified phase of syphilitic sera and 100% reactive for the congenital syphilitic sera. All 80 immunofluorescent nonreactive sera were nonreactive by SPHA. Of 19 reactive cord blood samples tested, seven samples were reactive by SPHA. However, all 20 nonreactive umbilical cord blood samples were nonreactive by SPHA. The SPHA assay for the determination of IgM antibody to T. pallidum in serum appears to be sensitive for primary, secondary, and congenital syphilis. The SPHA assay in the cord blood is sensitive and specific.     

Altered glycosylation leads to Tr polyagglutination

BACKGROUND: Polyagglutination refers to red blood cells (RBCs) that are agglutinated by a high proportion of ABO-matched adult sera but not by cord sera. Polyagglutinable RBCs have been associated with microbial infection, myeloproliferative disorders, and myelodysplasia. Lectins aid in the identification of polyagglutination. CASE STUDY: A Hispanic male infant with mild hemolytic anemia, a "Bernard-Soulier-like" syndrome, intermittent neutropenia, mitral valve regurgitation, ligament hyperlaxity, and mild mental retardation was studied. The patient's Group O RBCs were polyagglutinable; they were agglutinated by normal human sera, several lectins [including Arachis hypogea, Salvia sclarea, Salvia horminum, Glycine max, Ulex europaeus, Griffonia simplicifolia I, and Gr. simplicifolia II], and some monoclonal antibodies. His RBCs were not agglutinated by cord sera, Dolichos biflorus, or Phaseolus lunatus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis on the RBC membranes followed by staining with periodic acid-Schiff stain showed markedly reduced staining of glycophorins A and B. Staining with Coomassie brilliant blue revealed that Band 3 has a faster mobility than normal. CONCLUSIONS: Collectively, the results suggest that the patient's RBCs have a reduction in N-acetylneuraminic acid on both N- and O-glycans, exposing, respectively, beta1,4-galactosidase and beta1,3-galactosidase. The patient likely has an altered glycosyltransferase that results in defective glycosylation in RBCs and other cell lineages. This type of polyagglutination was named Tr.     

Serologic findings in autoimmune hemolytic anemia associated with immunoglobulin M warm autoantibodies

BACKGROUND: Autoimmune hemolytic anemia (AIHA) associated with immunoglobulin M (IgM) warm autoantibodies is unusual but often severe, with more fatalities than other types of AIHA. Diagnosing this type of AIHA can be difficult because routine serologic data are not always informative.
STUDY DESIGN AND METHODS: Forty-nine cases of IgM warm AIHA in 25 years were studied by serologic methods.
RESULTS: Routine direct antiglobulin tests (DATs) detected red blood cell (RBC)-bound C3 in 90 percent of cases (65% had C3 but no immunoglobulin G [IgG] on their RBCs) and IgG in 24 percent. IgM was detected on 29 of 47 (62%) patients' RBCs; RBC-bound IgM was detected in 14 of 47 cases by a tube DAT method and in an additional 15 of 21 (71%) cases using fluorescein isothiocyanate anti-IgM and flow cytometry. Eighty-one percent of eluates from patients' RBCs reacted. Warm autoagglutinins were present in 94 percent of serum samples; untreated and enzyme-treated RBCs were hemolyzed at 37°C by 13 and 65 percent of serum samples, respectively. Most agglutinins were optimally reactive at 30 to 37°C. Patients' RBCs were spontaneously agglutinated in 78 percent of cases; washing with 37°C saline or treating RBCs with dithiothreitol resolved this problem. Clear specificity of autoantibody was defined in 35 percent of serum samples.
CONCLUSION: IgM warm AIHA can be confused with cold agglutinin syndrome and "mixed/combined"-type AIHA; a serologic workup by a specialist reference laboratory can help with the diagnosis.     

Serologic characteristics of ceftriaxone antibodies in 25 patients with drug-induced immune hemolytic anemia

BACKGROUND: Ceftriaxone, a third‐generation cephalosporin, is commonly used to prevent and treat infections. Since 1987, it has been the second most common cause of drug‐induced immune hemolytic anemia (DIIHA) investigated in our laboratory. STUDY DESIGN AND METHODS: Samples from 79 patients (1987‐2010), suspected of having DIIHA caused by ceftriaxone, were studied for the presence of ceftriaxone antibodies. Direct antiglobulin tests (DATs) and tests with ceftriaxone‐treated red blood cells (RBCs) or untreated and enzyme‐treated RBCs in the presence of ceftriaxone were performed. RESULTS: Twenty‐five (32%) of the 79 patients had antibodies to ceftriaxone detected. Seventeen (68%) of the 25 patients were children; reactions in children were usually dramatic and severe. Nine (36%) of the 25 patients had fatal DIIHA. Nineteen of the 25 samples had DATs performed by our laboratory; 100% of samples were reactive with anti‐C3 and 47% were reactive with anti‐IgG. All 25 sera had ceftriaxone antibodies detected when testing untreated or ficin‐treated RBCs in the presence of ceftriaxone (resulting in agglutination, hemolysis or sensitization of test RBCs). These antibodies were primarily IgM and reactivity was enhanced by testing ficin‐treated RBCs. Sixteen (64%) of the 25 sera reacted with test RBCs when no ceftriaxone was added in vitro; this was most likely due to the transient presence of drug or drug‐immune complexes in the patient's circulation at the time that the blood samples were drawn. CONCLUSION: Ceftriaxone antibodies can cause severe intravascular hemolysis. Complement can usually be detected on the patient's RBCs and IgM antibodies are usually detected in the patient's serum.     

Pancytopenia in a newborn due to maternal piperacillin and human leukocyte antigen antibodies

BackgroundPiperacillin antibody-induced immune hemolytic anemia is not rare in adults, and there have been reports of anti-HLA antibody-induced newborn platelet transfusion refractoriness. However, there has been no report of piperacillin-accompanied anti-HLA antibody-induced newborn pancytopenia.Case ReportWe herein present the case of a newborn with pancytopenia from a mother who carried anti-HLA-B55, anti-HLA-DR11, and piperacillin antibodies. The newborn HLA genotypes were HLA*B55:02 and HLA*DRB1*11:01. IgG antibodies can be transferred to the newborn via the placenta and induce the destruction of the platelet and white blood cells, which carry the corresponding antigens. Piperacillin antibodies coupling with newborn red blood cells (RBCs) led to the destruction of the RBCs and hemolytic anemia.ResultsThe direct anti-globulin test was positive for RBCs in the newborn, and piperacillin antibodies were positive in both the newborn and his mother. Anti-HLA antibodies were positive in the maternal serum, whereas homologous antigens were positive in the newborn. The direct anti-globulin test of platelet was weekly positive in the newborn.ConclusionPiperacillin and anti-HLA antibodies can pass through the placenta, induce incompatible blood cell destruction, and cause a series of clinical syndromes in newborns.     

Is it necessary to add the eluate testing to the direct antiglobulin test to improve the detection of maternal erythrocyte alloantibodies?

BACKGROUNDThe screening of umbilical cord blood samples by the Direct Antiglobulin Test (DAT) is the reference tool for the identification of maternal erythrocyte alloantibodies present in erythrocytes; however, its diagnostic usefulness is controversial.OBJECTIVETo evaluate the diagnostic validity, safety, and efficiency of the eluate testing (detection of antibody in erythrocyte eluates by the Indirect Antiglobulin Test/IAT) in cord blood samples for detection of maternal erythrocyte alloantibodies in comparison with the DAT.MATERIALS AND METHODSEvaluation study of diagnostic tests. DAT and eluate testing were performed in 306 cord blood samples from neonates born to mothers admitted at Clínica Somer in Rionegro, Colombia; then, antibodies present in the eluates were identified with erythrocyte panels. Percentage of positive results by DAT and IAT were compared with the Pearson's chi-square test and the agreement between both assays with the Cohen's kappa coefficient. The diagnostic sensitivity, specificity, safety, and efficiency of the eluate testing were calculated, taking into account the use of DAT as an imperfect reference test.RESULTSThe DAT detected alloantibodies in 6.21% of samples and the eluate testing in 14.1 %; the strength of agreement between both tests was moderate (k = 0.56) due to 25 discrepancies. The eluate testing showed sensitivity and specificity of 98.83 % and 92.31 % respectively, and a negative predictive value of 99.9 %. The diagnostic efficiency was sufficient for detection of maternal erythrocyte alloantibodies. The antibodies identified in the erythrocyte eluates were anti-A or anti-B (79.5 %), anti-D (136%), anti-C (2,3%), and anti-Fya (2,3%).CONCLUSIONThe eluate testing in cord blood samples is a valid, safe, and efficient test for the diagnosis of maternal erythrocyte alloantibodies.     

Immune hemolytic anemia due to cimetidine: the first example of a cimetidine antibody

BACKGROUND: Although there have been a few reports of immune hemolytic anemia (IHA) thought to be due to cimetidine, none of them provided proof (e.g., serologic detection of anti‐cimetidine and/or repeat of IHA upon drug rechallenge). One report used cimetidine as an example of how temporal associations of drug administration and hemolytic anemia are not proof of a cause‐effect relationship. STUDY DESIGN AND METHODS: A 63‐year‐old cancer patient developed IHA on two occasions after receiving cimetidine (with and without chemotherapy). Serologic methods included testing cimetidine‐treated red blood cells (RBCs) as well as testing untreated RBCs in the presence of cimetidine. RESULTS: The patient's direct antiglobulin test was positive (C3 only) and a serum antibody to cimetidine was detected by both testing methods. An eluate from the patient's RBCs was nonreactive. Cimetidine‐treated RBCs were optimally prepared at room temperature and needed to be tested on the day of preparation. CONCLUSIONS: This is the first reported case of IHA due to a cimetidine antibody where a drug‐dependent antibody was demonstrated. The patient had IHA after receiving cimetidine on two separate occasions.     

Hemolytic anemia after kidney transplantation: a prospective analysis

BACKGROUND: Hemolysis may occur in 9% to 40% of patients after solid organ transplantation and be caused by the passenger lymphocyte syndrome (PLS). STUDY DESIGN AND METHODS: We have prospectively examined 217 kidney transplant recipients before (Day ?1) and after (up to Days +10, +20, and +30) surgery. ABO‐identical transplant was performed in 180 (82.9%) patients, while 37 (17.1%) individuals received ABO‐compatible nonidentical grafts. Direct antiglobulin tests (DATs) were performed by tube technique (polyspecific anti‐human globulin [IgG + C3d]), positive DAT samples were further tested by gel agglutination (monospecific anti‐IgG, ‐IgM, ‐IgA, or ‐C3), and eluates were prepared from DAT‐positive red blood cells (RBCs) by the dichloromethane elution test. RESULTS: We observed that 34 of 217 (15.7%) patients developed a positive DAT up to Day +30. The percentage of patients with positive DATs was significantly higher in those having ABO‐compatible nonidentical transplants compared to those that received ABO‐identical grafts (10/37 = 27.0% vs. 24/180 = 13.3%; p = 0.037). Specific RBC antibodies (anti‐A or anti‐B) were found in only 5 of 37 (13.5%) patients having ABO‐compatible nonidentical transplants who presented with clinical hemolysis. We found only three reactive eluates from 24 patients with positive DATs who received ABO‐identical transplants but had no hemolysis. CONCLUSIONS: Our data collected prospectively demonstrated that: 1) positive DATs occurred in 15.7% of all patients up to Day +30 after a kidney transplant; 2) the DAT positivity occurred up to Day +10 in 9.7% of all transplanted patients; 3) the majority of the transplant recipients with a positive DAT had a nonreactive RBC eluate; and 4) PLS was the cause of a positive DAT in 13.5% of patients submitted to ABO‐compatible nonidentical kidney transplants.     

Oxaliplatin-induced immune pancytopenia

BACKGROUND: Oxaliplatin, a third-generation platinum compound, has been implicated in isolated cases of immune hemolytic anemia and/or immune thrombocytopenia. The first case of severe immune pancytopenia related to oxaliplatin is described. PATIENT AND METHODS: A 79-year-old woman with colorectal cancer was initially treated with 5-fluorouracil and she later received oxaliplatin and leucovorin every 2 to 4 weeks. During the 15th and 17th cycles of chemotherapy she developed thrombocytopenia, hemolysis, and neutropenia. No problems occurred during the 16th cycle without oxaliplatin. Serologic testing including detection of drug-dependent antibodies and autoantibodies was performed with standard techniques. RESULTS: Serologic findings included a positive immunoglobulin G direct antiglobulin test; nonreactive red blood cell (RBC) eluates; platelet (PLT)-bound antibodies to glycophorin (GP) IIb-IIIa, GPIb-IX, and GPIa-IIa; and oxaliplatin-dependent antibodies to PLTs, RBCs, and neutrophils. CONCLUSION: Oxaliplatin may lead to the production of ddabs to RBCs, PLTs, and neutrophils. Thus the risk of immune cytopenias should always be considered in patients treated with oxaliplatin.     

IgG red blood cell autoantibodies in autoimmune hemolytic anemia bind to epitopes on red blood cell membrane band 3 glycoprotein.

Red blood cell (RBC) autoantibodies from patients with IgG warm-type autoimmune hemolytic anemia were labeled with iodine 125 and their RBC binding behavior characterized. Epitope-bearing RBC membrane polypeptides were identified after autoantibody immunoprecipitation of labeled membranes and immunoblotting. Immunoaffinity isolation of labeled membrane proteins with 12 different IgG hemolytic autoantibodies with protein A-agarose revealed a major polypeptide at Mr 95 to 110 kd, which coelectrophoresed on sodium dodecylsulfate-polyacrylamide gel electrophoresis with a membrane component isolated with sheep IgG anti-band 3. Immunoprecipitation studies with chymotrypsinized RBCs resulted in the recovery of two labeled membrane polypeptides with molecular weights characteristically resulting from the chymotryptic fragmentation of band 3. Immunoblotting with sheep IgG anti-band 3 of the immunoprecipitated polypeptides confirmed that hemolytic autoantibody binding led to recovery of band 3 or its fragments. Two 125I-labeled IgG hemolytic autoantibodies showed binding behavior consistent with epitope localization on band 3. The labeled RBC autoantibodies bound immunospecifically to all types of human RBC tested, including those of rare Rh type (Rh-null, D--) at a site density of approximately 10(6) per RBC. The 125I-IgG in two labeled autoantibodies was 84% and 92% adsorbable by human and higher nonhuman primate RBCs. Antigen-negative animal RBC bound less than 10% (dog, 2.6%; rhesus monkey, 7.4%), consistent with immunospecific RBC binding. IgG-1 was the major subclass in five autoantibodies tested; one of six fixed complement; and autoantibody IgG appeared polyclonal by isoelectric focusing. We conclude that IgG eluted from RBCs of patients with autoimmune hemolytic anemia consists predominantly of a single totally RBC-adsorbable antibody population that binds to antigenic determinants on band 3. Unlike RBC autoantibodies from antiglobulin-positive normal blood donors, autoantibodies from patients with autoimmune hemolytic anemia did not show Rh-dependent properties as judged by antigen site density, absence of differential binding to RBC of different Rh phenotypes, failure to immunoprecipitate 30 kd Rh-epitope bearing membrane polypeptides, absence of multiple antibody populations, and the lack of a significant nonadsorbable IgG population that has been associated with the presence of antiidiotypic IgG. The absence of antiidiotypic IgG in hemolytic autoantibodies may be a contributory factor in the development of autoimmune hemolytic anemia.     

A new method of antibody elution from red blood cells

A method of antibody elution from red blood cells using xylene is described. It can be completed in 15 minutes after cell washing and requires no special equipment. For warm antibodies, the eluates prepared were more potent than those prepared byRubin's ether method. It was as effective as Landsteiner and Miller's heat elution method in investigations of ABO hemolytic disease of the newborn. The clinical application of this method in the investigation of hemolytic disease of the newborn, delayed transfusion reaction and autoimmune hemolytic anemia was described.     

Anti-i causing acute hemolysis following a negative immediate-spin crossmatch

A unique case of acute hemolysis following transfusion of red cells (RBCs) that were found compatible by immediate-spin (IS) crossmatch technique is reported. Screening tests for unexpected antibodies, using low-ionic-strength saline (LISS), 10 minutes' incubation at 37 degrees C, and anti-IgG, were nonreactive; however, 1 transfused unit was found crossmatch incompatible by indirect antiglobulin technique (IAT). An anti-i (titer 512 at 4 degrees C) that was not an autoantibody was identified in the patient's serum. Unlike the incriminated donor RBCs, most I+ RBCs did not react by LISS-IAT. Variable reactivity was seen with ficin-treated I+ RBCs, and there was marked hemolysis of iadult and icord RBCs. In marked contrast, dominant Lu(a-b-) RBCs, with reduced expression of i, did not react by any test method; nor did autologous I+, Lu(b+) RBCs. The in vivo clinical significance of this anti-i was confirmed by monocyte monolayer assay and RBC survival studies. The patient's i antigen may have been altered, by either chemotherapy or disease, and lacked part of the i antigen-mosaic. Her antibody was directed at epitopes of i that were absent from her RBCs. Those i epitopes missing from her RBCs are also absent on dominant Lu(a-b-) RBCs. This anti-i represents a unique cause of an acute hemolytic transfusion reaction. It also represents a case of acute immune-mediated hemolysis following transfusion of IS crossmatch-compatible blood when screening tests for unexpected antibodies are nonreactive. Because of the rarity of such cases (less than 1/200,000 RBC units transfused), modifications to pretransfusion testing protocols are not proposed.