Clinical and immunohematological characterization of autoimmune hemolytic anemia in children

Autoimmune Hemolytic Anemia (AIHA) in childhood is uncommon and estimated to be three per million annually under 18 years of age. Detailed immunohematological and clinical characterizations are essential for correct diagnosis of the disease and its management. In this study we described AIHA in children with regards to patient demography, underlying etiology, disease classification, antibody characterization, clinical features, degree of in vivo hemolysis and transfusion management. The prospective observational study was conducted over a period of 6 years and included 29 children with newly diagnosed AIHA. Patient details were obtained from the hospital information system and patient treatment file. The median age of the children was 12 years with a female preponderance. Secondary AIHA was observed in 62.1% patients. The mean hemoglobin and reticulocyte were 7.1 gm/dL and 8.8 percentages respectively. The median polyspecific direct antiglobulin test (DAT) grading was 3+. Red cell bound multiple autoantibodies were found in 27.6% children. Free serum autoantibodies were present in 62.1% patients. Twenty six of the 42 units transfused were “best match” or “least incompatible”. Follow-up of 21 children showed clinical and laboratory improvement with DAT still positive at the end of 9 months. AIHA in childhood requires advanced and efficient clinical, immunohematological and transfusion support. Detailed characterization of AIHA is important, as they determine degree of in vivo hemolysis, disease severity, serological incompatibility and necessity of blood transfusion. Although blood transfusion in AIHA is a challenge but it should not be withheld in critically ill patients.     

直接抗人球蛋白试验阳性的类型鉴别及临床意义

目的　通过直接抗人球蛋白试验 (DAT)阳性的类型鉴别 ,有助于临床对自身免疫性溶血性贫血 (AIHA)的正确诊断 ;对血库交叉配血不合的处理有指导意义。方法　DAT阳性标本分AIHA组和非AIHA组 ,进行免疫分型 ,然后把IgG或IgG C3的标本进行放散试验 ,利用放散液与标准抗体筛查细胞进行间接抗人球蛋白试验 (IAT)。结果　AIHA组患者的放散液均同标准抗体筛查细胞反应 ,非AIHA组除了 1例SLE患者外均为阴性反应。结论　DAT阳性患者可以分为两类 :自身抗体引起和免疫复合物引起     

Clinical application of a flow cytometric direct antiglobulin test

BACKGROUND: The clinical application of flow cytometric direct antiglobulin test (FC-DAT) has rarely been evaluated for patients with various diseases including immune and nonimmune hemolytic anemia.
STUDY DESIGN AND METHODS: Blood samples from 380 patients with a variety of diseases were studied using the tube direct DAT and FC-DAT. The results of tube DAT and FC-DAT were compared. The predictive values of DAT for hemolysis were evaluated.
RESULTS: Of 57 patients with autoimmune hemolytic anemia (AIHA), 6 of the 17 with a negative tube DAT (immunoglobulin G [IgG]) had a positive FC-DAT (IgG) and 23 of the 36 patients with a negative tube DAT (complement 3d [C3d]) had a positive FC-DAT (C3d). In 57 patients with AIHA, the incidence of positive results of FC-DAT (IgG) and tube DAT (IgG) were similar (42 positive vs. 40 positive); but in 323 patients without AIHA, the incidence of positive FC-DATs (IgG) was higher than that of tube DAT (IgG; 47 positive vs. 9 positive). The higher incidence of positive FC-DAT (C3d) than that of tube DAT (C3d) was seen in patients with AIHA (42 positive vs. 21 positive) as well as in patients without AIHA (61 positive vs. 5 positive). Both DAT (IgG) and DAT (C3d) positive has highest positive predictive value for hemolysis, followed by DAT (IgG) alone positive and DAT (C3d) alone positive.
CONCLUSIONS: FC-DAT is a complementary test for diagnosing AIHA. There is a synergistic effect of the red blood cell–bound IgG and complement in predicting hemolysis.     

Quantitation of immunoglobulin classes and subclasses of autoantibodies bound to red cells in patients with and without hemolysis

The concentration of IgG, IgA, and IgM, as well as IgG subclasses, was measured by an enzyme-linked immunosorbent assay in autoantibodies eluted from red cells (RBCs); the number of molecules of each isotype per RBC was calculated. Three groups were analyzed: Group 1 included 23 patients with autoimmune hemolytic anemia (AIHA) associated with warm autoantibodies of IgG class; Group 2 included 11 patients without anemia but with a positive direct antiglobulin test (DAT); Group 3 included 10 healthy DAT-negative subjects. The mean number of IgG molecules per RBC in Group 1 (920) was about three times that in Group 2 (306) and about 17 times that in Group 3 (54). The range of RBC-bound IgG showed an overlap between the two groups of patients. The mean number of IgM and IgA molecules per RBC was low in the three groups. IgG1 predominated in all groups except in two patients with AIHA, in whom IgG3 made up at least 50 percent of total IgG. The mean number of IgG1, IgG2, and IgG4 molecules per RBC in Group 1 was about three times that in Group 2, whereas the mean number of IgG3 molecules per RBC was 10 times as high (p < 0.001). It follows that IgG3 was more common in patients of Group 1, but it was also detected in patients of Group 2.     

A dual antiglobulin test for the detection of weak or nonagglutinating immunoglobulin M warm autoantibodies

BACKGROUND: Immunoglobulin (Ig)M warm autoantibodies (AABs) usually cause severe autoimmune hemolytic anemia (AIHA) and, in some cases, red blood cell (RBC)‐bound IgM cannot be detected. We describe a simple dual antiglobulin test (DDAT) for diagnosing such cases. STUDY DESIGN AND METHODS: A patient with erroneously suspected cold agglutinin syndrome was investigated. The direct antiglobulin test (DAT) was performed using standard techniques and dual (two stages) antiglobulin reagents (IgG rabbit anti‐human IgM, IgG goat anti‐rabbit IgG). RESULTS: A cold agglutinin syndrome was diagnosed initially, as the patient's serum was reactive with RBCs at a temperature of 28°C or less, and the DAT was strongly positive with anti‐C₃d. Six months later, the patient was reexamined at this hospital due to progressive hemolysis. His RBCs were found to be coated with IgM warm AABs that only became detectable using a DDAT, and his serum contained only a weak cold agglutinin. The hemolysis remained refractory to treatment with prednisolone and also prednisolone plus azathioprine, but gradually improved after treatment with prednisolone plus cyclophosphamide. CONCLUSION: Weak or nonagglutinating RBC‐bound IgM warm antibodies can be identified by the presented DDAT.     

IgA-mediated autoimmune hemolytic anemia in an infant

Autoimmune Hemolytic anemia (AIHA) a relatively uncommon form of hemolytic anemia in children, occurs due to the premature destruction of red blood cells caused by presence of autoantibodies directed against antigens on RBCs. Warm reactive AIHA is the most common form due to IgG isotype of immunoglobulin class binding to autologous RBCs at 37⁰C and confirmed with a positive DAT screening. We present a case of DAT-negative primary warm AIHA in an infant due to IgA antibody. A 10 month old male infant presented with dark colored urine and irritability for past two months, with associated history of fever, diarrhea and vomiting. He had received one red cell transfusion 10 days prior. On physical examination he had pallor with tachycardia without splenomegaly. On investigation his hemoglobin was 5.8 g/dl, WBC 25.9 × 10³/mm³ and normal platelets counts. Peripheral blood smear had spherocytes and biochemical values showed high bilirubin and LDH. Immunohematological work up revelaed polyspecific DAT was negative but monospecific DAT screening showed strong (4+) positivity for IgA and a weak IgG positivity. The patient was diagnosed as IgA-mediated Warm AIHA and was started on prednisolone at 2 mg/kg/day following which hemoglobin improved over the next 2 months. After 2 weeks, prednisolone was tapered and stopped by the end of 3 months. Patients with clinical and laboratory evidence of acute hemolysis, an additional screening for IgA antibody may be done even in cases where poly-specific DAT is negative. Early detection helps in avoiding further investigations and provide efficient management.     

Severe autoimmune hemolytic anemia caused by a warm IgA autoantibody directed against the third loop of band 3 (RBC anion-exchange protein 1)

BACKGROUND: Autoimmune hemolytic anemia associated with only IgA autoantibodies reacting optimally at 37 degrees C (WAIHA) is exceedingly rare. When identified, warm IgA autoantibodies specificities are usually directed to antigens of the Rh system. However, like IgG autoantibodies, the specificity of the majority of these antibodies is not identified. CASE REPORT: A case of a 3-year-old boy in whom a life-threatening IgA WAIHA occurred suddenly is reported. Following initial RBC transfusions and treatment with steroids at a dose of 3 mg per kg, which was slowly tapered, stabilization to a state of compensated hemolysis was achieved, persisting 4 months before complete resolution. There was no recurrence within a 16-month follow-up. STUDY DESIGN AND METHODS: The standard DAT in a gel column method with anti-IgG and anticomplement reagents was negative. However, the same method with an anti-IgA was strongly positive. RESULTS: The serum and the eluate obtained after acid elution reacted with all normal RBCs tested. Enzymatic treatment of panel RBCs by alpha-chymotrypsin and pronase abolished the reactivity. The reaction was completely inhibited by RBC incubation with four different MoAbs directed against the third extracellular loop of band 3, the RBC anion-exchange protein 1 (AE1), whereas MoAbs against other specificities showed no effect. CONCLUSIONS: This is the first report of an IgA autoantibody directed against the band 3 (AE1) protein and, more specifically, against the third loop. Moreover, this case underlines the importance of including IgA research in the initial diagnostic evaluation when a hemolytic anemia is suspected to be autoimmune and when IgG and complement are not detected on the patient's RBCs.     

Do patients with autoantibodies or clinically insignificant alloantibodies require an indirect antiglobulin test crossmatch?

BACKGROUND: Compatibility testing is the standard protocol that identifies suitable blood for patients requiring transfusion. If the antibody screen is negative or no clinically significant antibodies are detected, BCSH guidelines and AABB standards allow an immediate-spin crossmatch (IS XM) or even electronic issue. The testing requirement is less clear where autoantibodies or non-clinically significant alloantibodies compromise the indirect antiglobulin test crossmatch (IAT XM). Performing an IAT XM will give a mismatched result anyway, delays the supply of blood to the patient, and provides no additional benefit or safety. STUDY DESIGN AND METHODS: From January 2002 to April 2006, the provision of blood for autoimmune hemolytic anemia (AIHA) patients with autoantibodies and no alloantibodies as well as patients with alloantibodies that exhibited a "high-titer, low-avidity" (HTLA) mode of reactivity was reviewed. RESULTS: A total of 222 AIHA patients (428 samples) with autoantibodies had 1585 units of red cells supplied after IAT XM; 1308 (82.5%) were mismatched. In 50 patients (80 samples) with HTLA-like antibodies, 286 units of 328 (87.2%) were mismatched by IAT XM. CONCLUSION: No adverse reactions were reported for the study groups where "suitable" blood was provided after a serologically mismatched IAT XM. No additional benefit for these patients can be claimed by performing an IAT XM over an IS XM, as a check of ABO match. The IAT XM is both costly and time-consuming. It is proposed that for these study group patients, a reduction to an IS XM can be applied and can be beneficial.     

β内酰胺类抗生素导致药源性溶血的初步研究

本研究的目的是初步探讨β内酰胺类药物诱导患者溶血性贫血的机理.对2004年6例肺部感染且不明原因贫血分析的患者的基础疾病、治疗用药、感染病原体等信息进行归纳,对患者外周血进行白细胞计数（WBC）、网织红细胞计数、总胆红素（TB）、直接胆红素（DB）、血糖（Glu）检测,对患者的红细胞进行直接抗人球蛋白试验（DAT）、补体结合实验、细胞培养与涂片镜检,对患者血浆中的抗体进行间接抗人球蛋白试验（IAT）.结果发现：6例患者的临床治疗的药物都属于β内酰胺类;住院期间患者的WBC、TB、DB、Glu的检测结果出现异常,红细胞的DAT试验结果均为阳性,IAT试验结果均为阴性;将DAT阳性的红细胞进行补体结合实验时,结果为阴性;细胞涂片见部分红细胞表面有颗粒状物质附着,细胞培养见部分红细胞被白细胞识别、黏附;改用其它抗生素后,患者的上述化验指标恢复到正常值范围内,DAT试验结果转为阴性.结论：β内酰胺类抗生素引起患者溶血性贫血的原因可能是某些蛋白在红细胞表面的非特异性吸附,这些物质很可能是导致患者出现药物性溶血的直接原因.     

Coombs' negative immune hemolytic anemia with anti-E occurring in the red blood cell eluate of an E-negative patient

A previously untransfused 20-year-old man presented with a seven day history of malaise, fatigue, jaundice, dark urine and splenomegaly. Hemolytic anemia was indicated by a hemoglobin of 8.7 mg/dl, reticulocyte count 8 per cent, Lactic dehydrogenase 389 iu/L, bilirubin 4.3 mg/dl (direct 0.1 mg/dl), and undetectable haptoglobins. Tests for nonimmunologic mediated hemolytic anemia were negative. The direct antiglobulin test (DAT) was repeatedly negative with polyspecific, anti-IgG, -IgA, -IgM and anti-C3 antisera. The patient's serum contained a weak anti-I, anti-E strongly reactive by indirect antiglobulin test (IAT) and an antibody reactive against all cells tested. The latter antibody reacted weakly by the IAT but strongly against enzyme-treated cells (Titer 160). Eluates from the patient's red blood cells only reacted with E+ red blood cells. The patient typed E negative. He was treated for warm autoimmune hemolytic anemia (AIHA) with high doses of prednisone. By the twelfth day his response allowed the medication to be tapered and by one month from the onset of treatment laboratory studies had returned to normal. The DAT remained negative, however, following recovery, anti-E could not be eluted from the red blood cells. Anti-E remained in his serum and the titer of the enzyme reactive antibody had decreased to 16. It is suggested that the anti-“E-like” antibody may represent auto anti-Hr preferentially reacting with E+ red blood cells. A unique feature in the case is the presence of a specific antibody eluted from cells that appear to lack that antigen in a DAT-negative patient with AIHA.     

12例急性自身免疫性溶血性贫血患者体外溶血试验配血与输血研究

本研究采用体外溶血试验配血方法,为微柱凝胶抗人球蛋白法配血困难的急性自身免疫性溶血性贫血（AIHA）患者筛查配血相容的红细胞。对照组选择26例AIHA患者,采用微柱凝胶抗人球蛋白法,确定配血结果凝集强度最弱的同型供血者红细胞输注。实验组为12例微柱凝胶抗人球蛋白法配血困难的急性AIHA患者,采用体外溶血试验配血法,选取配血结果出现不溶血的同型供血者红细胞输注。结果表明,体外溶血试验法输血组与微柱凝胶抗人球蛋白法配血组输血效果相比较,差异有显著性意义（P〈0.01）。实验组患者平均每次输注去白细胞红细胞悬液2.26单位,输血后患者血红蛋白、网织红细胞及总胆红素等指标变化与输血前相比较,差异有显著性意义（P〈0.01）。结论：在微柱凝胶抗人球法配血困难时,采取体外溶血试配血可以顺利为AIHA患者筛查到相容红细胞。     

Removing IgG antibodies from intact red cells: comparison of acid and EDTA, heat, and chloroquine elution methods

BACKGROUND: To accurately phenotype red cell from patients with a positive direct antiglobulin test (DAT), nonlytic elution procedures were assessed for their ability to dissociate IgG from antibody-coated red cells without altering red cell antigen expression. STUDY DESIGN AND METHODS: Antibodies coating red cells that were sensitized in vivo (warm-reactive autoantibodies: 8 patients) or in vitro (42 alloantibodies) were eluted by using glycine-HCl and EDTA (acid/ EDTA), heat (56 degrees C, 10 min), or chloroquine method. RESULTS: Acid/EDTA elution gave the best results, reducing DAT positivity to microscopic levels or rendering the DAT negative in 48 of 50 instances, whereas 4 samples remained resistant to heat elution and 24 to chloroquine. Standard DAT agglutination scores demonstrated that both acid/EDTA and heat elution were superior to the chloroquine method (p < 0.0001). With the gel low-ionic-strength saline indirect antiglobulin test, acid/ EDTA was superior to heat (p < 0.001). Overall, acid/ EDTA elution dissociated more antibodies than heat (p < 0.0001), especially for Kell system (K, k, Kpa, Kpb) alloantibodies. Common red cell antigens, other than Kell system antigens, were unaffected by acid/EDTA elution. In contrast, the expression of most blood group antigens was diminished after heat elution. However, it was possible to type red cell antigens by using gel low-ionic-strength saline indirect antiglobulin tests or tube agglutination methods. CONCLUSION: Although heat elution may be used on a limited basis, the acid/EDTA method appears to be the procedure of choice for typing red cell coated with warm-reactive IgG alloantibodies or autoantibodies.     

Finding the elusive and causative autoantibody: An atypical case of autoimmune hemolytic anemia

An isolated IgA‐mediated autoimmune hemolytic anemia can present a diagnostic challenge. When a routine direct antiglobulin test (DAT) is negative but clinical suspicion remains high, further testing with monospecific antisera should be performed. As with IgG‐mediated WAIHA, steroids are first‐line treatment, though splenectomy is often required to achieve a durable treatment response.     

84例自身免疫性溶血性贫血IgG抗体亚型与临床意义的分析

目的　研究温抗体型自身免疫性溶血性贫血ＩｇＧ亚型及其临床意义。方法　回顾性分析８４ 例患者ＩｇＧ亚型与临床特点的关系。结果　８４ 例患者中ＩｇＧ１ ＋ＩｇＧ３ ＋ Ｃ３ｄ 型占４５．０％ ,ＩｇＧ１ ＋ＩｇＧ３型占１５ ．５％ ,ＩｇＧ１ ＋ Ｃ３ｄ型占１１．０％ ,Ｃ３ｄ型占１０ ．７％ ,ＩｇＧ１ 型占９．５％ ,ＩｇＧ３ ＋ Ｃ３ｄ占８．３ ％ 。各型中均以女性为主,合计占６９ ．５％ 。ＩｇＧ３ 阳性各型的临床表现相似,各项临床指标异常最严重;ＩｇＧ１ 阳性的各型次之;Ｃ３ｄ 型最轻。Ｈｂ＜６０ ｇ／Ｌ、总胆红素＞ ４０ μｍｏｌ／Ｌ、ＦＨｂ＞ ６０ ｍｇ／Ｌ的患者百分率三组间比较,差异有显著性（Ｐ＜０ ．０５） 。ＩｇＧ１ 型与ＩｇＧ３ 型都随Ｃｏｏｍｂｓ 试验积分增高,其临床表现及溶血程度加重。ＩｇＧ３ 阳性的患者治疗有效率为６８ ．２％ ,ＩｇＧ１ 阳性患者有效率为１００％ 。结论　ＩｇＧ 亚型中以ＩｇＧ１ ＋ＩｇＧ３ 为主。ＩｇＧ３ 阳性的患者临床表现及溶血程度严重,治疗效果差     

A newly developed gel centrifugation test for quantification of RBC-bound IgG antibodies and their subclasses IgG1 and IgG3: comparison with flow cytometry

BACKGROUND: Novel gel centrifugation test (GCT) cards were evaluated with respect to their ability to estimate the quantity of IgG on RBCs and the determination of the IgG subclasses IgG1 and IgG3. STUDY DESIGN AND METHODS: In 65 patients with a positive DAT, the amount of IgG-gamma-, IgG1, and IgG3 on RBCs was examined by use of GCT cards and flow cytometry (FC) in parallel. The results were correlated with the presence or absence of hemolysis. In addition, D+ RBCs were studied after sensitization with anti-D sera from 22 alloimmunized pregnant women. RESULTS: The amount of IgG on the RBCs as determined by GCT dilution cards correlated with FC (r=0.70, p < 0.0001). IgG subclass results as determined by GCT IgG subclass cards were confirmed by FC in 14 cases with an anti-IgG-gamma-chain titer > or =300, whereas IgG subclass cards were not suitable in cases with anti-IgG-gamma-chain titers less than 300. In 44 patients with 2+ or 3+ DAT in the GCT and anti-IgG-gamma-chain titer < or =30, no hemolysis was observed, whereas hemolysis occurred in 13 of 14 patients with an anti-IgG-gamma-chain titer > or =300. GCT data obtained by IATs with anti-D sera were concordant with FC results. CONCLUSION: There is a correlation between the amount of RBC-bound IgG and immune hemolysis. The GCT cards that detect the anti-IgG-gamma-chain may be useful to predict hemolysis in patients with a 2+ or 3+ DAT in the GCT. The diagnostic value of GCT cards for IgG subclass testing should be investigated further.     

Evidence suggesting the occurrence of C3-independent intravascular immune hemolysis. Reactive hemolysis in vivo

The authors present circumstantial evidence for the involvement of reactive hemolysis, i.e., C3-independent binding of the cytolytic C5b-9 complement complex to bystander red cells (RBC), in a case of intravascular immune hemolysis. Fresh serum obtained from a 6-year-old patient during the hemolytic episode, but not obtained thereafter, induced C5b-9-dependent hemolysis of human RBCs but the indirect C3 antiglobulin test remained negative. Particles (presumably RBC ghosts) isolated from the patient's plasma anticoagulated with EDTA at the peak of hemolysis were coated with C5b-9 complexes, whereas the direct antiglobulin test was strongly positive for IgA, only weakly positive for IgG, and negative for C3. Moreover, neither the autoantibodies isolated by elution (IgG plus IgA), nor free serum autoantibodies (IgA alone) activated complement in vitro. Additionally, serum samples collected later during the 12-month period of observation contained normal levels of C3, C4, C8, and C9, but markedly reduced levels of C7. These serums all produced strong reactive lysis in agarose plates, but not in test tubes. These results appear compatible with the working hypothesis that the intravascular hemolytic episode in this patient might have arisen through a local initiation of complement activation with subsequent C3-independent binding of C5b-9 to and hemolysis of bystander RBCs.     

Hypergammaglobulinemia can be associated with a positive direct antiglobulin test, a nonreactive eluate, and no evidence of hemolysis

To determine the cause of a positive direct antiglobulin test (DAT), blood banks routinely perform serologic tests on eluates prepared from DAT-positive red cells. Negative eluates traditionally have been suspected to be associated with drug reactions. This report confirms that the most frequent cause of a positive DAT and a nonreactive eluate is hypergammaglobulinemia. The results of 74 patient samples with positive DATs were analyzed retrospectively. Eluates prepared from the red cells of 54 patients (72.9%) reacted; eluates from 20 patients (27.1%) did not react. This latter group had identical serologic and clinical findings, suggesting that they made up a homogeneous group. In particular, the patients had a positive DAT, a negative indirect antiglobulin test, and a negative eluate; an increased serum concentration of IgG; and no evidence of hemolysis. In a subsequent study, DATs were performed prospectively on red cells from 44 consecutive patients with elevated serum IgG levels. The serum IgG concentration was highest in the three patients whose red cells had a positive DAT. The DAT also became positive in two patients treated with high-dose intravenous gammaglobulin (IV IgG). These studies indicate that a negative eluate from red cells with a positive DAT, a common serologic finding, is often caused by hypergammaglobulinemia. The authors postulate that IgG binds nonspecifically to the red cells because of the hypergammaglobulinemia.     

Clinical significance of serologic markers related to red blood cell autoantibodies production after red blood cell transfusion—severe autoimmune hemolytic anemia occurring after transfusion and alloimmunization: successful treatment with rituximab

BACKGROUND: The association of autoantibody formation with blood transfusion was previously noted. Severe autoimmune hemolytic anemia (AIHA) diagnosed after red blood cell (RBC) transfusion determined us to undertake this study and investigate the incidence and clinical significance of autoantibodies occurring after transfusion by a retrospective review of blood bank and medical records.
STUDY DESIGN AND METHODS: We report a lymphoma patient who developed severe autohemolysis after blood transfusion and alloantibody production. The hemolysis was refractory to steroids and chemotherapy and ceased after rituximab. We also retrospectively assessed the blood bank records for a 2-year period to identify the patients who developed autoantibodies after blood transfusion and examined laboratory, clinical features, and outcome.
RESULTS: From January 2005 through December 2006, 375 direct antiglobulin tests (DATs) and 3409 indirect antiglobulin tests (IATs) were found to be positive. Thirty-eight patients with positive DATs and IATs had demonstrable RBC warm-type autoantibodies occurring after blood transfusion; 27 of them had also one or more alloantibodies. Clinical and laboratory signs of hemolysis were absent in all patients (except the case reported). In another 5 patients alloantibodies were retrieved from RBC eluate and serum without evidence of autoantibodies; therefore, a delayed serologic transfusion reaction was diagnosed.
CONCLUSION: RBC autoantibodies are quite commonly found after blood transfusion. Nevertheless, clinically significant AIHA is a rare but at times a life-threatening phenomenon. We describe a first case of successful treatment with rituximab of refractory posttransfusion AIHA. Rituximab must be further evaluated for this indication.     

与免疫相关的血细胞减少患者骨髓造血细胞自身抗体的研究

目的　了解与免疫相关的血细胞减少患者骨髓造血细胞结合的自身抗体的类型、分布、数量及临床意义 ,考察骨髓单个核细胞直接抗人球蛋白试验 (BMMNC Coombs)的敏感性。方法　对 32例临床疑诊为免疫性全血细胞减少的患者进行BMMNC Coombs试验和流式细胞术 (FACS)双标法检测骨髓造血干 祖细胞、有核红细胞、粒细胞结合的自身抗体的种类及结合率。结果　FACS双标法检出的骨髓造血细胞自身抗体的阳性率为 90 .6 %,BMMNC Coombs试验检出的阳性率为 5 0 .0 %,前者显著高于后者 ( χ2 =12 .6 5 ,P <0 .0 5 )。FACS检测自身抗体阳性的 2 9例患者中IgG型占 6 .9%,IgM型占13 .8%,IgG +IgA型占 3 .4%,IgG +IgM型占 31.0 %,IgG +IgM +IgA型占 44 .8%;2 9例中含IgG型 2 5例 ,占 86 .2 %,含IgM型 2 6例 ,占 89.7%,含IgA型 14例 ,占 48.3 %。IgG型血红蛋白减少得最严重 ,含IgM型的患者可有血管内溶血的实验室发现 ,IgM和IgM +IgG型组治疗的起效时间明显短于其他组。91.3 %的患者可检出造血干 祖细胞上有自身抗体 ,而且多表现为全血细胞减少 ;约 5 0 .0 %的患者红、粒系细胞上有自身抗体 ,13例BMMNC Coombs试验阴性而FACS检测阳性的患者中有 11例在造血干细胞上有自身抗体。与有核红细胞和造血干 祖细胞结合的三种抗体     

The gel test: some problems and solutions

The gel centrifugation test (GT) is a method of transfusion serology, based on the fact that, after centrifugation, unagglutinated red blood cells (RBC) pass easily through a gel, while agglutinated RBC do not. The introduction of the GT to our blood bank transfusion routine [strictly following the manufacturer's instructions (DiaMed ID Micro Typing System)] resulted in problems with the interpretation of the results. These were overcome after the introduction of modifications, which included: (1) the systematic use of 1% RBC suspensions; (2) the use of 50 microliters of 1% RBC suspensions and 25 microliters of serum in all tests; (3) the control of all negative indirect antiglobulin tests (IAT) and direct antiglobulin tests (DAT) by the addition of 50 microliters of a 1% IgG coated RBC suspension followed by centrifugation; and (4) the systematic use of saline-suspended RBC for ABO typing in patients with positive DAT.