Agglutination Of Erythrocytes Research Articles

ABH-Glycan Microarray Characterizes ABO Subtype Antibodies: Fine Specificity of Immune Tolerance After ABO-Incompatible Transplantation.

Organ transplantation from ABO blood group-incompatible (ABOi) donors requires accurate detection, effective removal and subsequent surveillance of antidonor antibodies. Because ABH antigen subtypes are expressed differently in various cells and organs, measurement of antibodies specific for the antigen subtypes in the graft is essential. Erythrocyte agglutination, the century-old assay used clinically, does not discriminate subtype-specific ABO antibodies and provides limited information on antibody isotypes. We designed and created an ABO-glycan microarray and demonstrated the precise assessment of both the presence and, importantly, the absence of donor-specific antibodies in an international study of pediatric heart transplant patients. Specific IgM, IgG, and IgA isotype antibodies to nonself ABH subtypes were detected in control participants and recipients of ABO-compatible transplants. Conversely, in children who received ABOi transplants, antibodies specific for A subtype II and/or B subtype II antigens-the only ABH antigen subtypes expressed in heart tissue-were absent, demonstrating the fine specificity of B cell tolerance to donor/graft blood group antigens. In contrast to the hemagglutination assay, the ABO-glycan microarray allows detailed characterization of donor-specific antibodies necessary for effective transplant management, representing a major step forward in precise ABO antibody detection.

Detection of Leishmania infantum in Peripheral Blood Smear and Lymph Node of a Domestic Feline

Background: Cats can become infected and develop feline visceral leishmaniasis (LVF) and manifest variable clinical signs. The diagnosis of the disease in this species has been made more frequently by means of serological and molecular techniques. Different from what happens with dogs, the use of parasitological analysis of lymph node, in clinical practice, for agent detection in felines are infrequent. Therefore, the aim of this study was to disclose the diagnosis of visceral leishmaniasis in a domestic cat from the blood smear analysis and aspiration cytology of lymph node.Case: An adult mixed breed queen, from the city of Campo Grande, Mato Grosso do Sul state, Brazil was referred for clinical care due to the presence of a nodule, with approximately 4 cm, near the inguinal breast. Other parameters, on physical examination, are within the normal range for the specie. For the investigation, additional tests were requested. Eosinophilia was found in a complete blood count (CBC). The association between macroscopic characteristics and cyto­logical findings allowed the diagnosis of inguinal lymph node hyperplastic. Furthermore, amastigotes of Leishmania sp. were visualized both in the peripheral blood sample and in the analyzed material mass. The diagnosis of visceral leishmani­asis and identification of specie of Leishmania was performed by PCR technique (Polymerase Chain Reaction), from the detection of genetic material from Leishmania infantum. After diagnosis of the disease, the owner opted for the conduct of animal euthanasia in the Zoonosis Control Center (CCZ), making impossible the realization of post-mortem examination.Discussion: Hematologic changes described for cats with feline visceral leishmaniasis may be absent or multiple and vari­able, such as for example, anemia, agglutination of erythrocytes, leukocytosis, leukopenia and thrombocytopenia, however, isolated eosinophilia, identified in this report, has not been observed by other authors. The viewing of the amastigote forms in blood smears is considered unusual. A study in which there were examined 1438 samples of dogs, the agent detection did not exceed 0.28%. In cats, there is only one report, of a pancytopenic feline, describing this finding and corroborates for the rarity of the observation of amastigote forms in peripheral blood feline of this report. The use of serologic and mo­lecular methods for the diagnosis of disease in felids has been most frequently used, however, high titers of anti-Leishmania antibodies associated with protective humoral immune response and degenerated genetic material of the amastigotes can be detected by PCR techniques, not identifying active infection. The parasitological diagnosis by means of cytological evaluation of lymph nodes is fast, low cost, presents high specificity and is frequently used in research of canine visceral leishmaniasis, however, the use of this technique for the diagnosis of the disease in cats is still restricted to academic environment. The identification of amastigotes in peripheral blood and lymph nodes, detected in this study, indicates the possibility of using the blood test and, especially, the cytological examination of lymph node for parasitological research of feline visceral leishmaniasis and highlights the need of studies to determine the sensitivity of these tests in this species.Keywords: cat, diagnosis, leishmaniasis, complete blood count, cytology.

An acousto-optical method for registration of erythrocytes’ agglutination reaction—sera color influence on the resolving power

The absorption spectra of agglutinating sera were used to determine blood groups. It was shown experimentally that the sera color significantly affects the resolving power of the acousto-optical method of blood typing. In order to increase the resolving power of the method and produce an invariance of the method for sera color, we suggested introducing a probing light beam individually for different sera. The proposed technique not only improves the resolving power of the method, but also reduces the risk of false interpretation of the experimental results and, hence, error in determining the blood group of the sample. The latter is especially important for the typing of blood samples with weak agglutination of erythrocytes. This study can be used in the development of an instrument for instrumental human blood group typing based on the acousto-optical method.

Molecular serological characteristics of weak D antigen types of the Rhesus system

to estimate the spread of weak D antigen types of the Rhesus system in the citizens of the Russian Federation and a possibility of serologically identifying these types. The red blood cells and DNA of people with weakened expression of D antigen were investigated using erythrocyte agglutination reaction in salt medium (2 methods); agglutination reaction in the gel columns containing IgM + IgG anti-D antibodies, indirect antiglobulin test with IgG anti-D antibodies (2 methods); polymerase chain reaction to establish the type of weak D. A rhesus phenotype was determined in 5100 people in 2014-2015. The weakened agglutinable properties of red blood cells were detected in 102 (2%) examinees. 63 examinees underwent genotyping to identify the variants of the weak D antigen, which identified 6 weak D types. There were the most common weak D types 3 (n=31 (49.2%)) and weak D type 1 (n=18 (28.6%)), including weak D type 1.1 in one (1.6%) case. The other 4 weak D antigen types were as follows: weak D type 2 (14.3% (n=9)), weak D type 15 (4.8% (n=3)), weak D type 4.2 (DAR) (1.6% (n=1)) and weak D type 6 (1.6% (n=1)). The antiglobulin test in the gel column containing antiglobulin serum was the most sensitive serological assay to identify the weak D antigen. Only a molecular test could establish weak D type 15 in 2 samples of red blood cells with Ccdee and ccdEe phenotypes. The weak D antigen could be serologically identified in 96.8% of cases. When testing for weak D, particular attention should be given to people with the D-negative phenotype who had the C or E antigens. Our investigations conducted for the first time in Russia will be able to improve the immunological safety of red blood cell-containing medium transfusions for patients.

Adrenalin modulated time of start of human erythrocyte agglutination depending on agglutination inducer, sex and stage of reproductive process in the case of women

Adrenalin modulated time of start of human erythrocyte agglutination depending on agglutination inducer, sex and stage of reproductive process in the case of women

PolySTAT-modified chitosan gauzes for improved hemostasis in external hemorrhage

Positively-charged chitosan gauzes stop bleeding from wounds by electrostatically interacting with negatively-charged cell membranes of erythrocytes to cause erythrocyte agglutination and by sealing wounds through tissue adhesion. In the following work, nonwoven chitosan gauze was impregnated with PolySTAT, a synthetic polymer that enhances coagulation by cross-linking fibrin, to generate PolySTAT/chitosan gauzes with improved hemostatic efficacy. When comparing nonwoven chitosan and PolySTAT/chitosan to a commercially-available chitosan-containing gauze (Celox® Rapid), no appreciable differences were observed in fiber size, morphology, and pore size. However, PolySTAT/chitosan demonstrated more rapid blood absorption compared to Celox® Rapid. In a rat model of femoral artery injury, PolySTAT/chitosan gauzes reduced blood loss and improved survival rate compared to non-hemostatic controls and Celox® Rapid. While Celox® Rapid had stronger adherence to tissues compared to PolySTAT/chitosan gauzes, blood loss was greater due to hematoma formation under the Celox® dressing. Animals treated with PolySTAT/chitosan gauzes required less saline infusion to restore and maintain blood pressure above the target blood pressure (60mmHg) while other treatment groups required more saline due to continued bleeding from the wound. These results suggest that PolySTAT/chitosan gauzes are able to improve blood clotting and withstand increasing arterial pressure with the addition of a fibrin cross-linking hemostatic mechanism. Statement of significanceBlood loss remains one of the leading causes of death after traumatic injury in civilian populations and on the battlefield. Advanced biomaterials that interact with blood components and/or accelerate the clotting process to form a hemostatic plug are necessary to staunch bleeding after injury. Chitosan-based gauzes, which stop bleeding by causing red blood cell aggregation, are currently used on the battlefield and have shown variable performance under high pressure arterial blood flow in animal studies, suggesting that red blood cell aggregates require further mechanical stabilization for more reliable performance. In this work, we investigate the binding and cross-linking of fibrin, a major component in blood clots, on chitosan gauze fiber surfaces to structurally reinforce red blood cell aggregates.

A novel vasorelaxant lectin purified from seeds of Clathrotropis nitida: partial characterization and immobilization in chitosan beads

A novel lectin from seeds of Clathrotropis nitida (CNA) was purified and characterized. CNA is a glycoprotein containing approximately 3.3% carbohydrates in its structure. CNA promoted intense agglutination of rabbit erythrocytes, which was inhibited by galactosides and porcine stomach mucin (PSM). The lectin maintained its hemagglutinating activity after incubation in a wide range of temperatures (30–60 °C) and pH (6.0–7.0), and its binding activity was dependent on divalent cations (Ca+2 and Mg+2). SDS-PAGE showed an electrophoretic profile consisting of a single band of 28 kDa, as confirmed by electrospray ionization mass spectrometry, which indicated an average molecular mass of 27,406 ± 2 Da and the possible presence of isoforms and glycoforms. In addition, CNA exhibited no toxicity to Artemia sp. nauplii and elicited reversible and dose-dependent vasorelaxation in precontracted aortic rings. CNA was successfully immobilized on chitosan beads and was able to capture PSM in solution. This study demonstrated that CNA is a lectin that has potential as a biotechnological tool in glycomics and glycoproteomics applications.

Haemostatic chitosan coated gauze: in vitro interaction with human blood and in-vivo effectiveness.

BackgroundChitosan and its derivates are widely used for biomedical application due to antioxidative, anti-inflammatory, antimicrobial and tissue repair induced properties. Chitosan-based materials also used as a haemostatic agent but influence of different molecular weight and concentration of chitosan on biological response of blood cells is still not clear.The aim of this research was to evaluate interaction between human blood cells and various forms of chitosan-based materials with different molecular weight and chitosan concentration and prove their effectiveness on in-vivo model.MethodsWe used chitosan with molecular weight 200, 500 and 700 kDa and deacetylation rate 80-82 %. For chitosan impregnation of gauze chitosan solutions in 1 % acetic acid with different concentrations (1, 2, 3, 5 %) were used. We used scanning electron microscopy to obtain information about chitosan distribution on cotton surface; Erythrocyte agglutination test and Complete blood count test – for evaluation of interaction between blood cells and chitosan-based materials with different compound. In-vivo studies was performed in 20 Wistar rats to evaluate effectiveness of new dressing.ResultsOur data shown that chitosan can bind erythrocytes in concentration-depend manner that does not depend on its molecular weight. In addition, chitosan-based materials affect selectively human blood cells. Composition of chitosan with cotton materials does not change erythrocyte shape and does not cause agglutination.ConclusionsСotton-chitosan materials have higher adhesive properties to platelets that depend on molecular weight and concentration of chitosan. These materials also change platelets’ shape that probable is one of the most important mechanisms of haemostatic effect. In-vivo studies have shown high effectiveness of 2 % 200 kDa chitosan for stop bleeding from arteries of large diameter.

Yeast expressed ArtinM shares structure, carbohydrate recognition, and biological effects with native ArtinM

Recent advances in glycobiology have revealed the essential role of lectins in deciphering the glycocodes at the cell surface to generate important biological signaling responses. ArtinM, a d-mannose-binding lectin isolated from the seeds of jackfruit (Artocarpus heterophyllus), is composed of 16kDa subunits that are associated to form a homotetramer. Native ArtinM (n-ArtinM) exerts immunomodulatory and regenerative effects, but the potential pharmaceutical applicability of the lectin is highly limited by the fact that its production is expensive, laborious, and impossible to be scaled up. This led us to characterize a recombinant form of the lectin obtained by expression in Saccharomyces cerevisiae (y-ArtinM). In the present study, we demonstrated that y-ArtinM is similar to n-ArtinM in subunit arrangement, oligomerization and carbohydrate binding specificity. We showed that y-ArtinM can exert n-ArtinM biological activities such as erythrocyte agglutination, stimulation of neutrophil migration and degranulation, mast cell degranulation, and induction of interleukin-12 and interleukin-10 production by macrophages. In summary, the expression of ArtinM in yeast resulted in successful production of an active, recombinant form of ArtinM that is potentially useful for pharmaceutical application.

Algal Lectins and their Potential Uses

Lectins (hemagglutinins), or carbohydrate-binding proteins, are ubiquitous in nature and play important roles in many biological processes. They bind mono- and oligosaccharides reversibly with high specificity, but are devoid of catalytic activity, and in contrast to antibodies, are not products of an immune response. The erythrocyte agglutination or hemagglutination activity of lectins is a major attribute of these proteins and is used routinely for their detection and characterization. Due to their biochemical and biological properties, lectins attract a great deal of attention in the fields of medicine, molecular biology, biochemistry, and glycobiology. Lectins have been isolated and characterized from marine algae. Many of algal lectins generally have common characteristics of low molecular weight, no divalent cations requirements for their activity, and have an affinity for glycoproteins but not for monosaccharides. These properties imply that they may possess molecular structures and carbohydrate-binding specificities distinct from known lectins from other sources. Recent investigations revealed that algal lectins have the strict binding specificity to some definite oligosaccharide structures and are grouped into several types on the basis of oligosaccharide-binding specificity. Thus, marine algae are promising sources of novel lectin molecules for basic research and application. In spite of the progress made in biochemical characterization of algal lectins, additional information are still needed for a more comprehensive understanding of their molecular structures and possible biological functions for the future applications.

Membrane perturbations induced by the interactions of zinc ions with band 3 in human erythrocytes

Of group 12 metals, zinc is an essential element to maintain our life, but other metals such as cadmium and mercury are toxic in cellular activities. Interactions of these metals with biomembranes are important to understand their effects on our living cells. Here, we describe the membrane perturbations induced by these metals in human erythrocytes. Of these metals, Zn2+ ions only induced the erythrocyte agglutination. Histidine residues in extracellular domains of band 3 participated in Zn2+-induced agglutination. Interestingly, it was found that band 3-cytoskeleton interactions play an important role in Zn2+-induced agglutination. In contrast with Hg2+ and Cd2+ ions, Zn2+ ions greatly suppressed pressure-induced hemolysis by cell agglutination. Such a suppression was removed upon dissociation of agglutinated erythrocytes by washing, indicating the reversible interactions of Zn2+ ions with erythrocyte membranes. Excimer fluorescence of pyrene indicated that spectrin is denatured by a pressure of 200MPa irrespective of hemolysis suppression. Taken together, these results suggest that the agglutination of erythrocytes due to the interactions of Zn2+ ions with band 3 is stable under pressure, but spectrin, cytoskeletal protein, is denatured by pressure

Isolation of a novel lectin from the dorsal spines of the devil stinger, Inimicus japonicus

A novel lectin was purified from the dorsal spines of the devil stinger, Inimicus japonicus using a combination of affinity chromatography techniques. A single band was detected on a native PAGE gel with a relative molecular mass of 97 kDa. The N-terminal partial amino acid of the intact 75 kDa subunit of the 97 kDa lectin was found to be DHEDS. The agglutination of rabbit erythrocytes by the 97 kDa lectin was inhibited most effectively by methyl α-D-mannoside. The 97 kDa lectin stimulated mitogenesis in murine splenocytes. This is the first study to examine the dorsal lectin of I. japonicus and one of the very few studies on venom lectins from venomous scorpaeniform fish. These results suggest that the devil stinger, I. japonicus, may be a novel resource for biologically active substances.

Immunomodulatory Activity of Atalantia monophylla DC. roots

Objective: The objective of the present study was to evaluate the immunomodulatory activity of the roots of Atalantia monophylla. In the present study Pet. Ether, Chloroform and Methanolic fractions of the ethanolic extract of the roots of Atalantia monophylla, were administered orally, in the doses of 10 mg/kg and 30 mg/kg, to evaluate the immunomodulatory activity. Materials and Methods: The Methanolic fraction showed most significant effect when compared with control group, in the dose of 30 mg/kg, in the E.Coli induced abdominal sepsis and Carbon Clearence Test as models for non-specific immune response. In the models of the Specific immune response, cell mediated immune response to SRBC - delayed type of hypersensitivity (DTH) the methanolic fraction in the dose 30 mg/kg, when compared with control group, showed most significant effect on decrease in footpad edema after treatment. Results: Humoral immune response was assessed by Sheep erythrocyte agglutination test, in which the Methanolic fraction of Atalantia monophylla in the dose of 30 mg/kg showed most significant (p<0.05) increase in antibody titer after treatment when compared with control group. Conclusion: The present investigation reports that the Methanolic fraction of the ethanolic extract of the roots of Atalantia monophylla, in the dose of 30 mg/kg showed most significant immunomodulatory activity.

The carbohydrate-binding promiscuity of Euonymus europaeus lectin is predicted to involve a single binding site.

Euonymus europaeus lectin (EEL) is a carbohydrate-binding protein derived from the fruit of the European spindle tree. EEL was first identified for its erythrocyte agglutinating properties and specificity for B and H blood groups. However, a detailed molecular picture of the structural basis of carbohydrate recognition by EEL remains to be developed. In this study, we performed fluorescence titrations of a range of carbohydrates against EEL. Binding of EEL to a wide range of carbohydrates was observed, including a series of blood group-related carbohydrates, mannosides, chitotriose and sialic acid. Affinity was strongest for carbohydrates with H-related structures and the B trisaccharide. A homology model of EEL was produced from templates identified using the HHPred server, which employs hidden Markov models (HMMs) to identify templates. The HMM approach identified that the best templates for EEL were proteins featuring a ricin B-like (R-type) fold. Separate templates were used to model the core and binding site regions of the lectin. Through the use of constrained docking and spatial comparison with a template ligand, binding modes for the carbohydrate ligands were predicted. A relationship between the experimental binding energies and the computed binding energies of the selected docked poses was determined and optimized. Collectively, our results suggest that EEL utilizes a single site for recognition of carbohydrates terminating in a variety of monosaccharides.

Effect of propranolol, histidine, and trimethylhydrazine propionate on the capacity of epinephrine to change the rate of erythrocyte agglutination.

We studied the effects of analogues of endogenous sensitizer of β-adrenergic receptors histidine (10(-4) g/ml) and mildronate (10(-5) g/ml) and endogenous β-adrenoreceptor blocker propranolol (10(-6) g/ml) on adrenoreactivity of erythrocytes in men assessed by changes in the rate of erythrocyte agglutination under the influence of epinephrine (10(-10)-10(-6) g/ml). Epinephrine increased the rate of agglutination, which attested to predominance of α1-adrenoceptors. Propranolol enhanced the effect of epinephrine, while histidine and mildronate reduced it. Hence, endogenous modulators of adrenoceptors can modify adrenoreactivity of erythrocytes and probably other cells, and erythrocytes can serve as indicator of instant adrenoreactivity of body cells.

Biodegradable nanoparticles composed of dendrigraft poly-l-lysine for gene delivery

We developed novel gene vectors composed of dendrigraft poly-l-lysine (DGL). The transgene expression efficiency of the pDNA/DGL complexes (DGL complexes) was markedly higher than that of the control pDNA/poly-l-lysine complex. However, the DGL complexes caused cytotoxicity and erythrocyte agglutination at high doses. Therefore, γ-polyglutamic acid (γ-PGA), which is a biodegradable anionic polymer, was added to the DGL complexes to decrease their toxicity. The resultant ternary complexes (DGL/γ-PGA complexes) were shown to be stable nanoparticles, and those with γ-PGA to pDNA charge ratios of >8 had anionic surface charges. The transgene expression efficiency of the DGL/γ-PGA complexes was similar to that of the DGL complexes; however, they exhibited lower cytotoxicity and did not induce erythrocyte agglutination at high doses. After being intravenously administered to mice, the DGL6 complex demonstrated high transfection efficiency in the liver, lungs, and spleen, whereas the DGL6/γ-PGA8 complex only displayed high transfection efficiency in the spleen. Future studies should examine the utility of DGL and DGL/γ-PGA complexes for clinical gene therapy.

Quantifying the bioadhesive properties of surface-modified polyurethane-urea nanoparticles in the vascular network

Nanomedicine research is currently requiring new standard methods to quantify the biocompatibility and bioadhesivity of emerging biomaterials designed to be used in contact with blood or soft tissues. In this study, we used biotinylated polyurethane-urea nanoparticles as a model to examine the applicabitility of an adapted hemagglutination assay to quantify the bioadhesive potential of these nanoparticles to red blood cells and, in turn, to extrapolate this data to vascular endothelial cells. We demonstrated that biotinylated nanoparticles adsorb to human erythrocytes and preferentially gather in erythrocyte contact areas. Moreover, these nanoparticles promoted a higher percentage of pig and human erythrocyte agglutination than naked polyurethane-urea nanoparticles in a biotin concentration-dependent manner. Conversely, pegylated nanoparticles were used as a negative control of the technique thus showing decreasing hemagglutination values as compared to naked nanoparticles until a minimum threshold. Furthermore, hemagglutination assay demonstrated an excellent positive correlation with bioadhesion quantification in human endothelial cells and the endothelial layer of pig aorta thus validating the hemagglutination assay described here as a useful method for predicting nanoparticle bioadhesivity to vascular endothelium. Therefore, the methodology described here is a versatile and straightforward method that allows evaluating the bioadhesive features of surface-modified polyurethane-urea nanoparticles in contact with blood and the vascular network and appears as a powerful tool to better design any drug delivery systems or implantable devices for biomedical applications.

Expression, purification and characterization of galectin-1 in Escherichia coli

As a member of beta-galactoside-binding proteins family, Galectin-1 (Gal-1) contains a single carbohydrate recognition domain, by means of which it can bind glycans both as a monomer and as a homodimer. Gal-1 is implicated in modulating cell–cell and cell–matrix interactions and may act as an autocrine negative growth factor that regulates cell proliferation. Besides, it can also suppress TH1 and TH17 cells by regulating dendritic cell differentiation or suppress inflammation via IL-10 and IL-27. In the present study, Gal-1 monomer and concatemer (Gal-1②), which can resemble Gal-1 homodimer, were expressed in Escherichia coli and their bioactivities were analyzed. The results of this indicate that both Gal-1 and Gal-1② were expressed in E. coli in soluble forms with a purity of over 95% after purifying with ion-exchange chromatography. Clearly, both Gal-1 and Gal-1② can effectively promote erythrocyte agglutination in hemagglutinating activity assays and inhibit Jurkat cell proliferation in MTT assays. All these data demonstrate that bacterially-expressed Gal-1 and Gal-1② have activities similar to those of wild type human Gal-1 whereas the bioactivity of concatemer Gal-1② was stronger than those of the bacterially-expressed and wild type human Gal.

Rheumatoid factor in idiotypic regulation of autoimmunity

Rheumatoid factor (RF) is known to be heterogeneous, and RFs detected by various methods exhibit different characteristics. In addition to interacting with the Fc region of immunoglobulin G (IgG), certain RFs are able to recognize idiotypes of antibodies. Given the important role of idiotypic interactions in regulating autoimmunity, we hypothesize that RF is involved in regulation of lymphocyte activity against autoimmune disease-inducing antigens via idiotype-anti-idiotype interactions with these lymphocytes. RF level and the existence of idiotype-anti-idiotype interactions between RF and antibodies to autoimmunity-inducing antigens were studied in rats resistant and sensitive to collagen-induced arthritis, encephalomyelitis and atherosclerosis. RF was assayed by agglutination of tanned IgG-loaded erythrocytes. Rat resistance to autoimmune disease is associated with high RF production during the initiation of the immune response, and a low RF level during this period may be a preclinical marker of experimental autoimmune disease manifestation. RF-containing sera compete with an antigen if the RF-containing sera were obtained from rats immunized with that antigen, and they non-specifically inhibit binding of different antigen-antibody pairs. This suggests that RFs are anti-idiotypic antibodies that carry two kinds of paratopes: a particular paratope that recognizes the antigen-binding sites of antibodies, and a shared paratope that serves to recognize the recurrent idiotype on antibodies. Antigenic epitopes for the shared RF paratope can be created in the hinge region of Fc fragments of homologous IgG. RF detected by agglutination of tanned IgG-loaded erythrocytes is involved in negative idiotypic regulation of lymphocytes specific to autoimmunity-inducing antigens.

Erythrocyte Agglutination in a Child with Neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in children. Here we present a 4- year-old boy diagnosed with neuroblastoma, showing erythrocyte agglutination on blood smear six days after intensive chemotherapy. Total blood count showed a significant discrepancy between hemoglobin and hematocrit values. Mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) values were elevated. Erythrocyte agglutination was disappeared after the sample was warmed at 37 0 C. Cold agglutination reaction was found to be positive whereas direct Coombs test was found to be negative. Follow-up total blood counts were back to reference range after cyclophosphamide, etoposide and cisplatin therapy. To our knowledge, this is the first report in the literature in which erythrocyte (red blood cell) agglutination due to cold agglutinins was detected in a child diagnosed with neuroblastoma.