Immune Hemolysis Research Articles

Human Heme Oxygenase-1 Deficiency Presenting with Hemolysis, Bleeding, Nephritis, Asplenia and Inflammation.

Abstract 3013Poster Board II-989 Introduction:Heme oxygenase-1 (HO-1) is a stress induced enzyme that catalyses the oxidation of heme to biliverdin and bilirubin. HO-1 is not constitutively produced and has been shown to be an endogenous factor against inflammation. Deficiency of HO-1 in HO-1 knockout mice as well as in one human case has been found to have a pro-inflammatory phenotype. To the best of our knowledge, previously there is only one published case of human HO-1 deficiency in literature. We report a patient who presented with massive hemolysis, bleeding, nephritis and inflammation and was proved to have HO-1 deficiency. Case report:A 15-year-old previously well girl presented with high-grade fever for 2 weeks and cervical and axillary lymphadenopathy. She had an insignificant family history and had no growth or developmental retardation. Initial evaluation was unremarkable except for thrombocytosis noted from first week of fever and asplenia that was noted on CT scan. There was no past history of any major infection or thrombocytosis. She developed intravascular hemolysis from the second week of illness followed by nephritis as evidenced by hematuria, proteinuria (2950 mg over 24 hr), hyaline cast with hypertension. C3 levels were normal. IgA levels were increased to 502 mg/dl. Her blood was agglutinating at room temperature and serum could be separated with great difficulty. Workup for hemolysis showed evidence of cold antibody mediated immune hemolysis. Her direct combs test was positive. LDH was 9262 IU/l. Urine was positive for hemoglobinuria. Her serum ferritin was 4219 ng/ml, ESR was 75mm/1st hr, platelets were increased to 1200,000/ul and interleukin-6 levels were increased to 139 pg/ml. Blood cultures were negative repetitively. However etiology including infections, lymphoreticular malignancies was ruled out. She was started on treatment with methylprednisolone (20 mg/kg x 3 days) followed by oral prednisolone at 2mg/kg/day. A month later, she developed vasculitic skin rash. In renal biopsy, glomeruli showed normal cellularity with mild focal mesangeal prominence, normal basement membrane and open capillary loops compatible with IgA nephropathy or minimal change disease. Immunoflourescence was non-contributory due to absence of any glomerulus. Bone marrow was normal and skin biopsy was non-contributory. Hemolysis persisted despite giving steroids. She developed bleeding diathesis in the form of uncontrolled epistaxis, diffuse alveolar hemorrhage and skin bleeds. Evaluation for coagulopathy showed high platelet count and normal PT (14.9 sec), INR 1.24 and APTT (32 sec). Von Willebrand antigen was raised to 308 %; Fibrinogen was 2.4 g/l and FDP level was increased to 8.0 mg/l by screening method. Epistaxis was controlled with repeated transfusion of fresh plasma. In view of hemolysis and nephritis non-responsive to steroids, she received a pulse of cyclophosphamide (500mg/m2) followed by two doses of Rituximab (375 mg/m2 each). Her condition deteriorated further over the next few weeks. She developed intracranial hemorrhage in right parietal lobe and required Factor VIIa for control of bleeding. She died with fungal sepsis (Trichosporon asahii) after prolonged hospitalization within 5 months from onset of the illness. Atypical features noticed in this case were near normal serum bilirubin despite severe intravascular hemolysis and presence of asplenia. In view of a similar case with hemolysis, asplenia and nephritis reported from Japan as the first case of human HO-1 deficiency, our patient's DNA was sent to the same lab for HO-1 gene mutation. Mutation analysis revealed homozygous mutations in exon 2 (R44X) on chromosome 22q12 which would result in absence of functional protein HO. Renal biopsy for HO-1 immunostaining showed little if any detectable HO-1 in renal tubules, despite the presence of massive hemolysis. Conclusion:HO-1 has been found to have cytoprotective effect against stress mediated organ damage. Inhibition of HO-1 has been shown to increase the vulnerability of an individual to stressful stimuli like infections. Lack of this enzyme might explain the varied clinical features and exaggerated response to stress noted in our patient. However it is not clear whether the entire spectrum of manifestations noted in our patient can be explained solely by HO-1 deficiency. Further cases are required to characterize the clinical and pathological manifestations of HO-1 deficiency. Disclosures:Off Label Use: Use of activated factor VII for control of intracranial hemorrhage.

Early Detection of Isohemagglutinin From Donor Lymphocytes Has Impact On Acute Graft-Versus-Host Disease After Minor ABO-Incompatible Hematopoietic Stem Cell Transplantation.

Abstract 1150Poster Board I-172 IntroductionABO-incompatibility is not generally considered to be a risk factor of hematopoietic stem cell transplantation (HSCT). However, in our single-institute study of 568 patients, the incidence of acute GVHD was higher in minor-ABO incompatible HSCT than others (45.3% vs 35.2%, p=0.019). We made a hypothesis that there is a potential association between donor-derived isohemagglutinin (IH) and the outcomes of minor-ABO incompatible HSCT. Patients and methodThere were 1052 patients undergone HSCT between 1988 and 2009 at Komagome hospital. We analyzed 130 of 1052 patients (12.4%), who had received minor- ABO incompatible HSCT. Blood type and anti-A/B antibody titers were evaluated at least weekly in first one month after HSCT, and were repeated monthly until blood type had completely changed to the donor type. Our analysis was especially focused on the impact of IH on the outcome of minor-ABO incompatible HSCT. ResultMinor ABO-incompatible HSCT were 130 cases that included AML (n=40), ALL (n=28), CML (n=27), MDS (n=15), SAA (n=9), NHL (n=7), MM (n=2) and ATL (n=2). Median age was 37 (range: 16-67) years old. Seventy-seven patients were male, 53 were female. Stem cell sources were bone marrow (n=96), peripheral blood (n=16) and umbilical cord blood (n=18). Eleven cases were HLA-matched and 9 were HLA-mismatched transplants. Anti-host IgG and IgM IH had been detected in 20 of 130 transplants undergoing minor ABO-incompatible HSCT (15.4%). Median time to IH detection was 13 days after HSCT (12-39days). There was a higher incidence of IH production in the HLA-mismatched group than in the HLA-matched group (p=0.007).There was also a higher incidence of IH production in the unrelated transplants group than in the related transplants group. (p=0.021). None of 18 patients receiving umbilical cord blood transplantation showed evidence of IH production. The incidence of grade II-IV acute GVHD was significantly higher (90% vs 60%, p <0.001) and the severity of target organs was higher in the group with IH (IH group). Onset of acute GVHD was significantly earlier (median: 9 days vs 20 days, p<0.001) in IH group compared to non-IH group. The incidence of chronic GVHD was higher in IH group (69% vs 55%, p=0.036). No statistically significant differences were observed between IH group and non-IH group in time to engraftment, transplantation related mortality (63% vs 65%, p=0.666), disease-free survival (49.5% vs 37.6%,p=0.277) and overall survival (44.9% vs 37.6%,p=0.348). Immune hemolysis called passenger lymphocyte syndrome occurred in 2 cases of IH group. Their onset of acute GVHD was on Day 7 and 8 after HSCT, and IH was detected on Day 11 and 12 that were almost at the same time as hemolysis. Their WBC engraftment occurred on Day14 and 15. In both of 2 cases, hemolysis was resolved without specific treatment. Discussion and ConclusionOur study showed that IH production had association with HLA-mismatched and unrelated transplants in minor-ABO incompatible HSCT. We also showed that early detection of IH was related with the onset of grade II-IV acute GVHD. These findings indicate that strong allo-immunity induces not only severe acute GVHD caused by T lymphocytes but also antibody-production by B lymphocytes. In conclusion, we suggest that early detection of IH has impact on severity of acute GVHD. DisclosuresNo relevant conflicts of interest to declare.

Inhibition of complement-mediated hemolysis in gel by rheumatoid factors.

When subjected to a hemolysis in gel (HIG) assay for the detection of complement deficiency, 9 of 37 sera from patients with classical rheumatoid arthritis produced impaired lysis of sensitized sheep erythrocytes. All sera were normal in a test for the alternative pathway and no major abnormalities were found within the complement system. Using a two-step HIG technique, with guinea-pig serum as the complement source, all sera were shown to inhibit lysis of sheep erythrocytes sensitized with rabbit IgG. Lysis of IgM-coated erythrocytes was not inhibited. The agglutination titers in a Waaler-Rose test, and the areas of inhibition in the two-step HIG assay with IgG-sensitized erythrocytes, were correlated (r = 0.80, p less than 0.001). Absorption of serum with rabbit IgG coupled to Sepharose 4B, reduced the capacity to inhibit immune hemolysis. The eluate from IgG-Sepharose contained rheumatoid factors and also inhibited immune hemolysis. The findings suggested that rheumatoid factors in serum were responsible for inhibition in the HIG assays used.

Acute hemolysis after receiving oxaliplatin treatment: a case report and literature review

To report a case of immune mediated hemolysis occurring after oxaliplatin infusion in a patient with rectal cancer. We report a 69 year old male patient who presented with acute onset anemia after infusion of oxaliplatin as chemotherapy. A positive direct Coombs test and good response to steroids treatment underlined the diagnosis of immune related hemolytic anemia. The patient was switched to irinotecan-based chemotherapy regimen for further treatment. To our knowledge, there has been less than 10 cases of hemolysis occurring after oxaliplatin treatment in the medical literature. In all cases, immune mediated hemolysis has been proven with a positive coombs test. As oxaliplatin based chemotherapy regimen has become a standardized first line treatment for metastatic colorectal adenocarcinoma, this phenomenon warrants a higher level of physician awareness. Oxaliplatin related hemolytic anemia is a rare reported phenomenon. Patient under oxaliplatin treatment presenting with sudden hemoglobin decrease should prompt further investigation of hemolysis.

Diagnostic utility of the pre-incubated acidified glycerol lysis test in haemolytic and non-haemolytic anaemias

The usefulness of the pre-incubated acidified glycerol lysis test (AGLT), a laboratory test for spherocytosis, has been investigated in a selected hospital population of 348 patients with haemolytic and non-haemolytic anaemia. The AGLT was positive in 58 out of 59 patients with hereditary spherocytosis. In all 32 patients with other types of hereditary haemolytic anaemia the AGLT was normal or equivocal, but clearly different from spherocytosis. Adults with a positive AGLT, but without hereditary spherocytosis, had auto-immune haemolytic anaemia, myelodysplastic syndrome or were pregnant women. In newborn infants the AGLT was positive, in the first week of life, in those babies having hereditary spherocytosis or immune haemolysis due to blood group incompatibility; no positive AGLT results were seen if no haematological explanation for neonatal hyperbilirubinaemia could be found. At the optimal cut-off point the sensitivity of the AGLT for hereditary spherocytosis was 98.3% and the specificity 91.1%, under the most unfavourable conditions. The AGLT is a very useful and simple test for the diagnosis of hereditary spherocytosis.

Erratum to: Micafungin-induced immune hemolysis attacks

Erratum to: Micafungin-induced immune hemolysis attacks

The role of nanoparticle size in hemocompatibility

It is expected that nanoparticular matters will be increasingly used for industrial and medical applications. Since it is known that nanoparticles exhibit unique and potential hazardous properties due to their small size, toxicity studies, risk assessment and risk management are of great interest. We focussed on adverse effects on human blood. Processes which warrant special attention are clotting, reactions triggering inflammatory and immune responses and hemolysis. Starting with the determination of size and surface charge in different media we assessed the effect of size and surface charge on induction of coagulation, thrombocyte activation, complement activation, granulocyte activation and hemolysis. We used polystyrene particles as model because they are available in different sizes but constant surface charges. The presence of salts and of protein in the dispersion solution increased particle size and neutralized surface charge. Positively charged particles formed aggregates in buffered solution. Interference of the particles with assays based on fluorescence associated cell sorting was identified. Positive surface charge induced activation of complement. Small size caused thrombocyte and granulocyte activation, and hemolysis. A characterization of particle size and surface charge in the solutions used for the experiments appears important for interpretation of the results. The size dependency of adverse effects in human blood is not linear; negatively charged particles larger than 60 nm hydrodynamic diameter appear to be considerably less hematotoxic than smaller ones.

Micafungin-induced immune hemolysis attacks

The echinocandins provide an attractive new option for prophylactic and empirical treatment of invasive fungal infections in patients with neutropenia after intensive cytotoxic chemotherapy or hematopoietic stem cell transplantation. We present two patients with hematological diseases who experienced massive intravascular hemolysis followed by renal failure after administration of micafungin. In indirect antiglobulin test, significant agglutination was observed when red blood cells were exposed to the mixture of micafungin and either of the patients' plasma samples, indicating that production of antibodies directed against both micafungin and red blood cell membrane induced hemolysis attack. Micafungin-mediated immune hemolysis represents an uncommon but life-threatening adverse reaction leading to renal failure.

Immune hemolytic anemia—selected topics

Autoimmune hemolytic anemia (AIHA) is most often idiopathic. However, in recent years, AIHA has been noted with increased incidence in patients receiving purine nucleoside analogues for hematologic malignancies; it has also been described as a complication of blood transfusion in patients who have also had alloimmunization. As the technology of hematopoietic stem cell transplantation has become more widespread, immune hemolysis in the recipients of ABO-mismatched products has become better recognized. The syndrome is caused by passenger lymphocytes transferred from the donor and, although transient, can be quite severe. A similar syndrome has been observed in recipients of solid organ transplants when there is ABO-incompatibility between donor and recipient. Venous thromboembolism is a little-recognized, though likely common, complication of AIHA, and may in some instances be related to coexistent antiphospholipid antibodies. While AIHA is a well-documented complication of malignant lymphoproliferative disorders, lymphoproliferative disorders may also paradoxically appear as a consequence of AIHA. A number of newer options are available for treatment of AIHA in patients refractory to corticosteroids and splenectomy. Newer immunosuppressives such as mycophenolate mofetil may have a role in such cases. Considerable experience has been accumulating in the last few years with monoclonal antibody therapy, mainly rituximab, in difficult AIHA cases; it appears to be a safe and effective option.

Immune Hemolytic Anemia: A Report of Two Cases

The transfusion-medicine specialists and physicians are often in a difficult situation when the patient has severe worsening anemia and all the blood is mismatched. This situation can arise in patients with red cell autoantibodies or alloantibodies due to previous transfusions. We report two cases of immune hemolysis – one due to warm auto antibodies and the second due to alloimmunization from multiple transfusions.

Autoantibody formation after alloimmunization inducing bystander immune hemolysis

Abstract The development of RBC autoantibodies resulting from or associated with allogeneic blood transfusions is not an easily determined complication of RBC transfusions. This report discusses one patient who developed RBC autoantibodies in association with an allogeneic blood transfusion and alloimmunization leading to a temporary bystander immune hemolysis. A 72-year-old woman was hospitalized as a result of severe anemia and received two units of ABO- and D-compatible RBCs. She had a history of two pregnancies 40 years before, but no history of RBC transfusion, and her antibody screen was negative. On the tenth day after transfusion her hemoglobin dropped, and alloanti-c was identified in her serum and eluate. At this time she received another two units of compatible blood according to her phenotype (group O, R1R1, K:-1). After 48 hours, she developed joint pain, pyrexia, and hemoglobinuria, and her Hb dropped from 9.2 g/dL to 5.3 g/dL. The direct antiglobulin test was positive, an IgG autoantibody was present in the eluate, and the antibody investigation revealed the presence of anti-Jkb in addition to the previously identified alloanti-c. Her genotype was determined, and, based on the findings, two additional units were selected, found to be compatible, and transfused without incident. Transfusions were discontinued, and she was treated with IVIG and corticosteroids. Her Hb increased to 9.7 g/dL, and the patient made an uneventful recovery. It was concluded that transfusion of incompatible RBCs induced the formation of an autoantibody in this patient, resulting in lysis of bystander RBCs. The need for additional blood transfusion was successfully avoided by treatment with IVIG, steroid therapy, and rituximab. Immunohematology 2009;25:9–12.

The James Blundell Award Lecture 2007: Do we really understand immune red cell destruction?

We have learned a great deal about immune red blood cell (RBC) destruction since the elaboration of biochemical/immunological interactions of antibodies, complement and macrophages during the past 50 years. We first learned about the direct lysis of RBCs involving complement. We then learned of the role of the macrophage (particularly in the spleen and the liver) in initiating phagocytosis and antibody-dependent cytotoxicity of antibody-coated RBCs. Later, as the complexities of the human complement system were unravelled, we learned that complement-coated RBCs that were not directly haemolysed could interact with macrophages and that specific complement molecules on the RBC membrane could lead to a phagocytic event or the RBC (although heavily coated with complement) could survive normally. The application of isotope-labelling procedures (e.g. (51)Cr) for RBC survival (starting in the 1950s) advanced our knowledge considerably. Advances in knowledge in immunology helped us understand the complexity of the immunoglobulins (e.g. subclasses) and the specific receptors on macrophages and their role in immune haemolysis. Nevertheless, after more than 30 years researching this area, I am sometimes embarrassed to realize how much I cannot explain. Why do some patients have severe haemolytic transfusion reactions because of antibodies that are only detectable by one technique or not detectable by any? How do we explain autoimmune haemolytic anaemia with negative direct antiglobulin tests (DATs)? Why do RBCs strongly coated with immunoglobulin (Ig)G1 or IgG3 sometimes have normal survival? Are cells, other than macrophages, involved in immune RBC destruction? Could the relative amount of cytotoxicity vs. phagocytosis explain different clinical findings and response to treatment? How do we explain 'hyperhaemolysis' in sickle cell disease? Could novel mechanisms involving IgG glycosylation, CD47, 'armed' macrophages, bystander lysis, antibody activated reactive oxygen species, natural killer cells or antibody perturbation of RBC membrane be involved? Why do RBCs die after circulating for 100-120 days in healthy individuals? How should we define a 'clinically significant' antibody; how do we evaluate this? So many questions, so little time!

Alloimmunization Does Not Modify the Clinical Profile of Sickle Cell Disease Patients from Salvador-Brazil

Introduction: The hemoglobinopathies are the most common monogenic disorders known. A mutation in the gene for β globin gave origin to hemoglobin S, an abnormal hemoglobin originated in Africa. Sickle cell disease (SCD) is characterized by the presence of hemoglobin S, which results in vasoocclusion episodes and hemolytic anemia throughout patients life. Vascular occlusion leads to acute events and progressive disabling organ damage. Sickle cell anemia is the homozygous state SS, while hemoglobinopathy SC is a doubly heterozygous state, where hemoglobin S occurs in combination with hemoglobin C. Brazil has a prominent African ancestry and SCD is highly prevalent in some regions of the country. In Bahia State, for example, neonatal screening data have shown that, from every 650 children born alive, one has SCD, mostly homozygous SS. Among other therapeutic measures, packed red blood cells (RBC) play a prominent role in SCD management. In situations such as acute chest syndrome (ACS), primary and secondary prevention of stroke, splenic or hepatic sequestration crisis, severe anemia, complicated pregnancy, isquemic organ damages and others, the transfusions may save lives. Although RBC may contribute to reduce morbidity and improve quality of life in SCD patients, there still are risks. Among other risk categories, alloimmunization may result from transfusions and occurs in 5 % to 50 % of SCD patients. It is still not known whether allosensibilization significantly affects the clinical outcomes in SCD.Objecive: The purpose of this study was to compare the clinical profile of multitransfused adult SCD patients who developed alloantibodies (ALO) to patients with the same disease, coming from the same population who did not become alloimmunized (non-ALO).Methods: This is a cross sectional study where medical records of SCD patients, referred to a reference center of Salvador, the capital of Bahia State, Brazil, were reviewed. Only SCD patients 18 years of age or older were included. They had received at least 3 RBC transfusions from 2004 to 2007, or had any alloantibody identified during this period. Patient characteristics, clinical findings, number of transfusions, frequency and specificity of alloantibodies, laboratory data, and the main clinical outcomes were reviewed.Results: a hundred and eight patients were included: 105 SS and 3 SC. The pre-transfusional RBC matching was done to ABH, D,C,c,E,e and Kell antigens. 56 patients developed alloantibodies (53 SS and 3 SC). Anti-E, anti-K, and anti-C were the most prevalent alloantibodies identified (39,3 %, 21,4 % and 16,1 %, respectively). Among the variables addressed in this study, age (higher in non-ALO, .041) and antiglobulin test positivity, more prevalente in ALO (.0001), depicted statistically significant difference. A few patients developed immune hemolysis, controlled successfully with corticosteroids. Alloimmunization was more prevalent among women, although no statistically significant difference was reached between ALO and non-ALO Other variables such as number of transfusions, hematological profile, biochemical data and complications such as stroke, leg ulcers, osteonecrosis, renal disease, abnormal cardiac features, and pulmonary hypertension did not show significant difference between both groups.Conclusion: his study shows that, although alloimmunization is a potential dangerous consequence of RBC transfusions, it did not modify the clinical profile of SCD alloimmunized patients. The concomitance of allosensibilization and autoantibodies in SCD leads to additional difficulties in the RBC matching for transfusion and may exacerbate hemolysis. In order to address autoimmunity in SCD, prospective studies with larger samples are needed.

A Rare Cause of Anemia in Inflammatory Bowel Diseases: A Case Report and Review of Literature

Introduction: Anemia is a common problem in patients with inflammatory bowel diseases (IBD), and its etiology is usually multifactorial. It can be produced by chronic blood loss, nutritional deficiencies, and drugs such as salazopyrine; however it can also due to auto immune hemolysis, which is a rare complication of IBD. We report a case of coombs positive autoimmune hemolytic anemia associated with ulcerative colitis both diagnosed at the same presentation.Case Report: A 32 year old man with no significant past medical history presented with complaint of dark colored urine, jaundiced skin and fatigue for 4 weeks. He also reported diarrhea mixed intermittently with blood for last few months. Physical exam was consistent with jaundice and anemia (pallor and icterus) with slightly palpable spleen. Initial lab work up showed Hb of 3.8 with normal platelet and WBC count, high reticulocytes count of 7% .LFT showed serum bilirubin of 3.6 (direct 0.4) with normal serum ALT and AST levels .Serum LDH was high (1032 U/l) while serum haptoglobin was low (0.11 mg/dl). Peripheral smear showed anisopoikilocytosis & spherocytosis. (See Figure 1) Further investigations revealed a positive direct Coombs test consistent with diagnosis of autoimmune hemolytic anemia. CT abdomen and pelvis showed mild splenomegaly & non-specific enlarged mesenteric lymph nodes. Colonoscopy revealed ulcerative pancolitis confirmed by histological findings of biopsies taken. Patient received PRBC transfusions and was started on steroids and mesalamine and was discharged on maintenance dose. His symptoms resolved in 4 weeks and Hb remained stable with no evidence of further hemolysis at 4 month follow up .Repeated CT abdomen & pelvis showed resolution of the lymphadenopathy. [Display omitted] Discussion: Autoimmune hemolytic anemia (AIHA) is a rare complication of IBD. The exact underlying pathogenesis of this association remains obscure; however it has been attributed to the production of cross reacting anti erythrocyte antibodies. In AIHA associated with IBD, corticosteroids are considered to be first line therapy and often cause remission of hemolysis along with treatment for IBD Immunomodulators and splenectomy has been used for patients with refractory AIHA. Colectomy done for fulminant colitis has also been reported to induce remission of AIHA. Further studies for long term follow up and pathogenesis of this association are warranted.

Harmful algal toxins of the Florida red tide (Karenia brevis): natural chemical stressors in South Florida coastal ecosystems.

The Florida red tide is a descriptive name for high concentrations of the harmful marine alga, Karenia brevis. Although most prevalent along the south-west Florida coast, periodic blooms have occurred throughout the entire US and Mexico Gulf coasts and the Atlantic coast to North Carolina. This dinoflagellate produces a suite of polyether neurotoxins, called brevetoxins, that cause severe impacts to natural resources, as well as public health. These naturally produced biotoxins may represent one of the most common chemical stressors impacting South Florida coastal and marine ecosystems. Impacts include massive fish kills, marine mammal, sea turtle and sea bird mortalities, benthic community die-off and public health effects from shellfish contamination and inhalation of air-borne toxins. The primary mode of action is binding to voltage-gated sodium channels causing depolarization of nerve cells, thus interfering with nerve transmission. Other effects include immune depression, bronchial constriction and haemolysis. Parent algal toxins are synthesized within the unicellular organism, others are produced as metabolic products. Recent studies into the composition of brevetoxins in cells, water, air and organisms have shown PbTx-2 to be the primary intracellular brevetoxin that is converted over time to PbTx-3 when the cells are ruptured, releasing extracellular brevetoxins into the environment. Brevetoxins become aerosolized by bubble-mediated transport of extracellular toxins, the composition of which varies depending on the composition in the source water. Bivalved molluscs rapidly accumulate brevetoxins as they filter feed on K. brevis cells. However, the parent algal toxins are rapidly metabolized to other compounds, some of which are responsible for neurotoxic shellfish poisoning (NSP). These results provide new insight into the distribution, persistence and impacts of red tide toxins to south-west Florida ecosystems.

PREVALENCE OF CEFTRIAXONE-INDUCED RED BLOOD CELL ANTIBODIES IN PEDIATRIC PATIENTS WITH SICKLE CELL DISEASE AND HUMAN IMMUNODEFICIENCY VIRUS INFECTION

Ceftriaxone can be associated with catastrophic immune hemolysis in pediatric patients, particularly those with underlying diseases such as sickle cell disease and human immunodeficiency virus infection. We designed a study to screen for ceftriaxone-induced RBC antibodies in these 2 pediatric populations. The prevalence of anticeftriaxone antibody was 12.5% (8 of 64). Two of these 8 patients with the antibody experienced hemolysis; 1 case was fatal.

Autoantibodies and drug-or metabolite-dependent antibodies in patients with diclofenac-induced immune haemolysis

Two patients with acute immune haemolytic anaemia caused by diclofenac are described. Both patients had developed IgG drug-independent autoantibodies and drug-dependent antibodies. The drug-dependent antibodies in one patient reacted with red blood cells (RBC) only in the presence of urine from patients receiving diclofenac (ex vivo antigen) but not in the presence of the drug itself or its known metabolites. This antibody appeared to recognize a trace metabolite which has not yet been identified. The drug-dependent antibodies in the second patient reacted with RBC in the presence of urine as ex vivo antigen as well as in the presence of the drug itself and its main metabolites. Incorrect diagnosis of such cases often is due to the occurrence of autoantibodies and/or unusual drug metabolism and excretion.

Kreislaufstörungen der Milz

Splenic vascular disturbances mainly affect the red pulp and can involve the venous or arterial blood flow. The venous blood flow may be impaired by congestion and morphologically shows dilated splenic sinuses. Disturbances of the arterial blood flow may occur in connection with anomalies of the erythrocyte membrane or in immune haemolysis and usually are characterized by narrow splenic sinuses. Infarction of the spleen is usually caused by arterial embolism.

317: Impact of Prophylactic Red Blood Cell Exchange for Prevention of Severe Immune Hemolysis in Pediatric Minor ABO-Mismatched Allogeneic Peripheral Blood Progenitor Cell Transplantation

The presence of minor ABO incompatibility between donor and recipient is common in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Delayed severe immune hemolysis due to donor-derived passenger lymphocytes has been reported in minor and/or bidirectional ABO-mismatched transplants. To evaluate the impact of RBC exchange procedure in pediatric patients on the morbidity and outcome we analyzed 29 pediatric cases undergoing minor ABO-incompatible allo-HSCT from January 2000 to January 2007. First group (RBC exchange) included sixteen patients who underwent prophylactic red cell exchange. Six patients received grafts from HLA identical siblings, ten patients – from HLA matched unrelated donors. Eleven patients received bone marrow transplant (BMT), five patients received peripheral stem cell transplant (PBSC). Patient's age was 10 ± 5.3 years old.Second group (No – RBC exchange) included thirteen patients who did not undergo prophylactic red cell exchange, but the stem cell product was plasma depleted according to the institutional guidelines. Six patients received grafts from HLA identical siblings, three patients from HLA matched unrelated donors, and four patients form unrelated cord blood. Four patients received BMT, five patients received PBSC, four patients received cord blood transplant. Patient's age was 7.6 ± 5.4 years old.No incidence of immune mediated hemolysis was documented in both groups. No patients developed pure red cell aplasia. RBC engraftment was not different in both groups (23.2 ± 4.2 vs. 22 ± 4.2 days). Neutrophil engraftment was similar in both groups (21.0 ± 5.4 vs. 21.02 ± 4.0 days). No significant difference was found among the groups in the incidence of acute graft vs. host disease (GVHD). The incidence of chronic GVHD was insignificantly higher in patients with no RBC exchange (72% vs. 60%). The relapse rate and overall outcome were not influence.In conclusion these results suggest that RBC exchange does not have a significant impact in pediatric patients. Further investigations are required to identify the best clinical transfusion practice in pediatric patients with minor ABO incompatibility. The presence of minor ABO incompatibility between donor and recipient is common in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Delayed severe immune hemolysis due to donor-derived passenger lymphocytes has been reported in minor and/or bidirectional ABO-mismatched transplants. To evaluate the impact of RBC exchange procedure in pediatric patients on the morbidity and outcome we analyzed 29 pediatric cases undergoing minor ABO-incompatible allo-HSCT from January 2000 to January 2007. First group (RBC exchange) included sixteen patients who underwent prophylactic red cell exchange. Six patients received grafts from HLA identical siblings, ten patients – from HLA matched unrelated donors. Eleven patients received bone marrow transplant (BMT), five patients received peripheral stem cell transplant (PBSC). Patient's age was 10 ± 5.3 years old. Second group (No – RBC exchange) included thirteen patients who did not undergo prophylactic red cell exchange, but the stem cell product was plasma depleted according to the institutional guidelines. Six patients received grafts from HLA identical siblings, three patients from HLA matched unrelated donors, and four patients form unrelated cord blood. Four patients received BMT, five patients received PBSC, four patients received cord blood transplant. Patient's age was 7.6 ± 5.4 years old. No incidence of immune mediated hemolysis was documented in both groups. No patients developed pure red cell aplasia. RBC engraftment was not different in both groups (23.2 ± 4.2 vs. 22 ± 4.2 days). Neutrophil engraftment was similar in both groups (21.0 ± 5.4 vs. 21.02 ± 4.0 days). No significant difference was found among the groups in the incidence of acute graft vs. host disease (GVHD). The incidence of chronic GVHD was insignificantly higher in patients with no RBC exchange (72% vs. 60%). The relapse rate and overall outcome were not influence. In conclusion these results suggest that RBC exchange does not have a significant impact in pediatric patients. Further investigations are required to identify the best clinical transfusion practice in pediatric patients with minor ABO incompatibility.

A Case of Plasmodium vivax Malaria Associated with Autoimmune Hemolytic Anemia

Anemia associated with P. vivax malaria occurs as a result of the lysis of red cells by schizonts, bone marrow suppression, and splenic sequestration(1). In Plasmodium falciparum (P. falciparum) malaria, the extent of hemolysis is much greater than what we experience in other parasite induced hemolysis and combined mechanism with immune mediated hemolysis has been suggested(3). Positive results in DAGT were been found only in a minority of patients and it was suggested that complement or immunoglobulin-mediated immune complex formation contribute to hemolysis in P. falciparum malaria infection(4). But P. vivax malaria with direct antiglobulin reaction has not been reported. We encountered a patient with P. vivax malaria associated with