Sickle Cell Anemia - Red Blood Cell Exchange

3/03/2005

Question:  When should red blood cell exchange be used in patients with sickle cell disease?

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15908276.ui or 15114592.ui or 15095397.ui or 15004333.ui or 14967885.ui or 12877891.ui or 11886573.ui or 11206958.ui or 10831921.ui or 10342068.ui or 10174684.ui or 9163584.ui or 8866138.ui or 8411432.ui or 1593347.ui or 2228996.ui or 2166162.ui or 7131475.ui

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15908276[PMID] OR 15114592[PMID] OR 15095397[PMID] OR 15004333[PMID] OR 14967885[PMID] OR 12877891[PMID] OR 11886573[PMID] OR 11206958[PMID] OR 10831921[PMID] OR 10342068[PMID] OR 10174684[PMID] OR 9163584[PMID] OR 8866138[PMID] OR 8411432[PMID] OR 1593347[PMID] OR 2228996[PMID] OR 2166162[PMID] OR 7131475.[PMID]

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<1>

Unique Identifier [PMID]: 15908276

Authors: Cabibbo S. Fidone C. Garozzo G. Antolino A. Manenti GO. Bennardello F. Licitra V. Calabrese S. Costantino F. Travali S. Distefano R. Bonomo P.

Institution: Centro diagnosi e Cura della Talassemia, Azienda Ospedaliera, Civile-M.P. Arezzo P.zza Igea 1 97100 Ragusa, Italy. scabibbo@ospedaleragusa.it

Title: Chronic red blood cell exchange to prevent clinical complications in sickle cell disease.

Source: Transfusion & Apheresis Science. 32(3):315-21, 2005 Jun.

Abstract: We tracked the results of 394 manual or automatic red blood cell exchanges done with a cell separator in 20 sickle cell patients at high risk for recurrent complications. Over an average of 6 years, none of the patients developed complications related to the procedure or to the increased blood use. It was safe and effective in preventing complications of sickle cell disease, and if done automatically, reduced iron overload. Ferritin levels also decreased in patients treated with automatic red blood cell exchange. Furthermore, using Single Donor Red Blood Cell units (SDRC) we reduced the potential exposure to transfusion transmitted infectious diseases (TTI).

Publication Type: Journal Article.

<2>

Unique Identifier [PMID]: 15114592

Authors: Liem RI. O'Gorman MR. Brown DL.

Institution: Department of Pediatrics, Children's Memorial Hospital, Chicago, Illinois, USA. Rliem1@jhmi.edu

Title: Effect of red cell exchange transfusion on plasma levels of inflammatory mediators in sickle cell patients with acute chest syndrome.

Source: American Journal of Hematology. 76(1):19-25, 2004 May.

Abstract: Red cell exchange transfusion is the recommended therapy for patients with sickle cell disease (SCD) who have severe, progressive acute chest syndrome (ACS). A double-volume red cell exchange transfusion decreases the percentage of hemoglobin S (Hgb S) containing red blood cells to less than 20%, improving vascular perfusion. We speculated that reduction of pro-inflammatory mediators might also contribute to the therapeutic effect of an exchange transfusion. We measured white blood cell count (WBC), absolute neutrophil count (ANC), platelet concentration as well as plasma levels of interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), and soluble vascular cell adhesion molecule-1 (sVCAM-1) in 8 sickle cell patients with 9 episodes of ACS who received a manual, double-volume exchange transfusion. Six patients with SCD seen during a routine clinic visit were used as controls. The mean number of hospitalization days was 6, with an average of 2 days in the intensive care unit. All patients recovered without complication. Sickle cell patients with ACS had a higher WBC and ANC at baseline but lower sVCAM-1 levels compared to controls. TNF-alpha, IL-1alpha, IL-1beta, and IL-8 levels were not significantly different from controls. WBC, ANC, platelet, and sVCAM-1 measurements were significantly decreased immediately post-exchange in patients with ACS; however, this effect was not persistent as levels trended towards pre-exchange values by 24 hr post-exchange. Due to wide inter-individual variability, a consistent pattern was not seen for TNF-alpha, IL-1alpha, IL-1beta, or IL-8. We conclude that in sickle cell patients with ACS, a manual, double-volume exchange transfusion lowers WBC, ANC, platelets, and sVCAM-1 levels, but the effect is short-lived. Copyright 2004 Wiley-Liss, Inc.

Publication Type: Clinical Trial. Journal Article.

<3>

Unique Identifier [PMID]: 15095397

Authors: Tiftik N. Altintas E. Kiykim A. Ucbilek E. Sezgin O.

Institution: Department of Hematology, Mersin University Medical School, Mersin, Turkey. tiftikenaci@hotmail.com

Title: Long-term red blood cell exchange can be used to successfully treat sickle cell intrahepatic cholestasis: a case report.

Source: Journal of Clinical Apheresis. 19(1):17-9, 2004.

Publication Type: Case Reports. Journal Article.

<4>

Unique Identifier [PMID]: 15004333

Authors: Thurston GB. Henderson NM. Jeng M.

Institution: Rheology Laboratory, Department of Mechanical Engineering, University of Texas at Austin, TX 78716, USA.

Title: Effects of erythrocytapheresis transfusion on the viscoelasticity of sickle cell blood.

Source: Clinical Hemorheology & Microcirculation. 30(2):83-97, 2004.

Abstract: Red blood cells containing hemoglobin S are less deformable than normal erythrocytes and have a major effect on the viscoelasticity of blood. This alteration in rheology increases the impedance to flow, leading to an increase in RBC aggregation and reduction in oxygen saturation, which induces further sickling and occlusions in the microcirculation. Patients with sickle cell disease (SCD) can experience severe complications, such as acute pain and stroke. Automated red blood cell exchange transfusion, or erythrocytapheresis, is used with homozygous SCD (Hb SS) to replace sickled cells with normal cells, thereby decreasing the percentage of sickle hemoglobin (%Hb S) and maintaining a net balance in iron accumulation. These patients received monthly erythrocytapheresis with a goal to maintain a pre-pheresis %Hb S at less than 30%. In this study, viscoelastic parameters were used to quantify the effectiveness of this therapy for six patients undergoing chronic erythrocytapheresis. Whole blood viscosity, elasticity and relaxation time at oscillatory strains of 0.2, 1 and 5, and hematocrit and %Hb S were measured prior to erythrocytapheresis and 15 minutes after completion and compared with normal reference values at the patient's hematocrit. This study confirms the beneficial effects on viscosity, elasticity, and relaxation time of erythrocytapheresis.

Publication Type: Evaluation Studies. Journal Article.

<5>

Unique Identifier [PMID]: 14967885

Authors: Thurston GB. Henderson NM. Jeng M.

Institution: Rheology Laboratory, Department of Mechanical Engineering, University of Texas at Austin, TX, USA.

Title: Effects of erythrocytapheresis transfusion on the viscoelasticity of sickle cell blood.

Source: Clinical Hemorheology & Microcirculation. 30(1):61-75, 2004.

Abstract: Red blood cells containing hemoglobin S are less deformable than normal erythrocytes and have a major effect on the viscoelasticity of blood. This alteration in rheology increases the impedance to flow, leading to an increase in RBC aggregation and reduction in oxygen saturation, which induces further sickling and occlusions in the microcirculation. Patients with sickle cell disease (SCD) can experience severe complications, such as acute pain and stroke. Automated red blood cell exchange transfusion, or erythrocytapheresis, is used in homozygous SCD (Hb SS) to replace sickled cells with normal cells, thereby decreasing the percentage of sickle hemoglobin (%Hb S) and maintaining a net balance in iron accumulation. These patients received monthly erythrocytapheresis with a goal to maintain a pre-pheresis %Hb S at less than 30%. In this study, viscoelastic parameters were used to quantify the effectiveness of this therapy for six patients undergoing chronic erythrocytapheresis. Whole blood viscosity, elasticity and relaxation time at oscillatory strains of 0.2, 1 and 5, and hematocrit and %Hb S were measured prior to erythrocytapheresis and 15 minutes after completion and compared with normal reference values at the patient's hematocrit. This study confirms the beneficial effects on viscosity, elasticity, and relaxation time of erythrocytapheresis.

Publication Type: Case Reports. Journal Article.

<6>

Unique Identifier [PMID]: 12877891

Authors: Lombardo T. Rosso R. La Ferla A. Ferro MG. Ximenes B. Frontini V. Pennisi S.

Institution: Servizio di Thalassemia, Ospedale Santo Bambino, via Tindaro 1, 95124 Catania, Italy. servthalassemia@virgilio.it

Title: Acute Chest Syndrome: the role of erythro-exchange in patients with sickle cell disease in Sicily.

Source: Transfusion & Apheresis Science. 29(1):39-44, 2003 Aug.

Abstract: Acute Chest Syndrome (ACS) describes a syndrome characterized by the presence of a new pulmonary infiltrate on a chest X-ray, fever, and respiratory symptoms and is the leading cause of death and hospitalization in sickle cell disease (SCD). We studied 21 patients affected by SCD (13 HbSbeta+, 4 HbS beta(o), 4 HbSS, mean age 38.2 years). Six out of the 21 patients developed one episode of ACS (two patients had positive blood cultures, for Mycoplasma pneumoniae and Haemophilus influenzae respectively). The aim of our study was to evaluate the therapeutic efficacy of red cell-exchange during ACS. This procedure decreases HbS levels. The patients who underwent erythro-exchange showed a dramatic clinical and radiographic improvement with stabilized HbS levels between 20% and 30%. During follow up (14-32 months), none of the 6 patients developed viral complications related to transfusion therapy, alloimmunization or recurrence of ACS. In conclusion, in regard to the pre- and post-red cell-exchange clinical and laboratory data, we can say that red cell-exchange provides a dramatic resolution of the episode of ACS, minimizes the development of iron overload, and rapidly decreases HbS and hematocrit levels. In light of our results, we hypothesize that ACS episodes are secondary to pulmonary damage and to a gradual worsening related to age, and that there is some evidence that individuals affected by SCD in the third to fourth decade of life are more susceptible to ACS and/or other severe disease-related complications, needing repeated and strict clinical follow up.

Publication Type: Journal Article.

<7>

Unique Identifier [PMID]: 11886573

Authors: Danielson CF.

Institution: Department of Pathology, Indiana University Hospital, Indianapolis, Indiana 46202, USA.

Title: The role of red blood cell exchange transfusion in the treatment and prevention of complications of sickle cell disease. [Review] [113 refs]

Source: Therapeutic Apheresis. 6(1):24-31, 2002 Feb.

Abstract: Patients with sickle cell disease have abnormal red blood cells (RBCs). This can cause chronic hemolytic anemia and vaso-occlusion leading to tissue hypoxemia and organ dysfunction. RBC exchange transfusion can, without increasing the whole-blood viscosity, quickly replace abnormal erythrocytes with normal and raise the hematocrit resulting in improved delivery of oxygen to hypoxic tissues. Unfortunately, transfusion can also be associated with complications. This paper reviews the role of transfusion, both simple and exchange, in the treatment and prevention of sickle-related complications. The benefits of exchange versus simple transfusion and transfusion versus alternative therapies are discussed. [References: 113]

Publication Type: Journal Article. Review.

<8>

Unique Identifier [PMID]: 11206958

Authors: Eckman JR.

Institution: Georgia Comprehensive Sickle Center, Emory University School of Medicine, Atlanta 30303, USA.

Title: Techniques for blood administration in sickle cell patients. [Review] [50 refs]

Source: Seminars in Hematology. 38(1 Suppl 1):23-9, 2001 Jan.

Abstract: Transfusion therapy provides many benefits to Individuals with sickle cell disease but may lead to cardiovascular complications, alloimmunization, exposure to infection, and iron overload. Simple transfusion is used to increase oxygen-carrying capacity. Chronic simple transfusion is useful in preventing a number of complications in sickle cell disease. Acute erthrocyte exchange transfusion can reduce the percentage of cells containing sickle hemoglobin while decreasing volume overload and minimizing hyperviscosity. Chronic erythrocyte exchange transfusion reduces iron loading but Increases donor exposure. Directed odnation may reduce alloimmunization and exposure to infection. [References: 50]

Publication Type: Journal Article. Review.

<9>

Unique Identifier [PMID]: 10831921

Authors: Valbonesi M. Bruni R.

Institution: Immunohematology Services, San Martino University Hospital, Largo Rosana Benzi 10, 16132, Genoa, Italy.

Title: Clinical application of therapeutic erythrocytapheresis (TEA). [Review] [79 refs]

Source: Transfusion Science. 22(3):183-94, 2000 Jun.

Abstract: Therapeutic erythrocytapheresis (TEA) has been used in different diseases such as polycythemia vera (PV), secondary erythrocytosis or hemochromatosis as a process of the less cumbersome but more expensive phlebotomy. TEA is preferred in emergency conditions such as thrombocytosis or in conditions such as porphyria cutanea tarda (PCT) or erythropoietic porphyria when plasma exchange (PEX) is often combined with TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity. TEA is often combined with drug therapy that varies from etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce iron stores in hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for TEA, there is no standard protocol and, clinical experience with this therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe anemia in thalassemia patients thereby preventing iron overload. It has also been used for the management of complications of sickle cell disease such as priapism, chest syndrome, stroke, retinal, bone, splenic and hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated apheresis has also favored the use of TREX in conditions such as paroxysmal nocturnal hemoglobinuria and aniline poisoning, arsenic poisoning, Na chlorate intoxications and CO intoxications, hemoglobinopathies, autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible bone marrow transplantation or for preventing anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic parasite infections such as malaria and babesiosis. Application of TREX may be wide but its real use remains limited. In our personal experience, in 16 years, only 167 TREX procedures have been carried out in a total of 13,747 therapeutic procedures. This represents only 1.21% of the total. [References: 79]

Publication Type: Journal Article. Review.

<10>

Unique Identifier [PMID]: 10342068

Authors: Lawson SE. Oakley S. Smith NA. Bareford D.

Institution: Department of Haematology, Birmingham Children's Hospital NHS Trust, UK.

Title: Red cell exchange in sickle cell disease.

Source: Clinical & Laboratory Haematology. 21(2):99-102, 1999 Apr.

Abstract: Red cell exchange transfusion is frequently of use in the management of patients with sickle cell disease either electively or therapeutically. Modern cell separators allow this procedure to be performed rapidly, effectively and safely. These machines have a number of advantages over manual exchange procedures. The patient remains isovolaemic, there is little loss of plasma or platelets, the procedure is relatively short and in elective circumstances can be performed on an outpatient basis. In this series 66 exchanges were performed on 21 patients with an overall increase in HbA of 70%. The COBE Spectra gave a mean increase in HbA of 77%, with the majority of patients achieving an HbA of > 90% post exchange. Automated redcell exchange was well tolerated by most patients, and adverse effects were limited to symptoms of hypocalcaemia which were easily treated, and to transfusion reactions. Cell separators can therefore be recommended for exchange transfusion in patients with sickle cell disease, who require an increase in HbA levels either prophylactically or therapeutically. They are safe, effective, easy and quick to use.

Publication Type: Journal Article.

<11>

Unique Identifier [PMID]: 10174684

Authors: Robertson PB. Danielson CF. McCarthy LJ.

Institution: Department of Pathology and Laboratory Medicine, Indiana University Medical Center, Indianapolis 46202, USA.

Title: Unexpected hemoglobin electrophoresis results following red cell exchange in a sickle cell anemia patient with acute chest syndrome.

Source: Transfusion Science. 18(2):195-8, 1997 Jun.

Abstract: Acute chest syndrome is a well described complication of sickle cell anemia. It is characterized by fever, pulmonary infiltrates, pleuritic chest pain and abnormal pulmonary auscultation. Transfusion therapy, either simple transfusion of red blood cells or a total red blood cell exchange, is a cornerstone therapy for these patients. Exchange transfusion is preferred when an acute reduction of the hemoglobin S (HbS) concentration is the therapeutic goal since it allows one to rapidly reduce the percent HbS without increasing blood viscosity or volume (Wayne, Kevy and Nathan, Blood 1993; 81:1109-1123). Hemoglobin electrophoresis may be used to monitor the effectiveness of the exchange in decreasing HbS. The post-exchange HbS electrophoresis results which were obtained in this case initially caused confusion. In this report we discuss the findings and the reasons why such results may be occasionally expected in future similar situations.

Publication Type: Case Reports. Journal Article.

<12>

Unique Identifier [PMID]: 9163584

Authors: Janes SL. Pocock M. Bishop E. Bevan DH.

Institution: Department of Haematology, St George's Hospital Medical School, London.

Title: Automated red cell exchange in sickle cell disease.[see comment].

Comments Comment in: Br J Haematol. 1997 Oct;99(1):237; PMID: 9359530

Source: British Journal of Haematology. 97(2):256-8, 1997 May.

Abstract: Red cell exchange is important in the care of acutely ill sickle-cell patients, and may be life-saving. An automated red cell exchange technique has been developed using a Baxter blood cell separator, enabling an isovolaemic exchange to be performed within 2.5 h. A total of 20 procedures have been performed in 15 patients, including one woman in the third trimester of pregnancy, with a mean decrease of 72% in the circulating sickle haemoglobin (HbS) level. This method enables almost all adult patients with sickle cell anaemia to have their HbS reduced to safe levels by only one procedure. The procedure was well tolerated by all patients, including those who were acutely ill. This technique provides an effective procedure for reducing the percentage of circulating HbS rapidly in acutely ill patients with complications of sickle cell anaemia.

Publication Type: Journal Article.

<13>

Unique Identifier [PMID]: 8866138

Authors: McCready CE. Doughty HA. Pearson TC.

Institution: Department of Haematology, St Thomas' Hospital, London, UK.

Title: Experience with the Port-A-Cath in sickle cell disease.

Source: Clinical & Laboratory Haematology. 18(2):79-82, 1996 Jun.

Abstract: Peripheral vein access is often a problem in patients with sickle cell disease (SCD). Totally implantable venous access devices (TIVAD) have offered other groups of patients safe long-term venous access. We reviewed our own experience with the use of a Port-A-Cath device in five patients with SCD undergoing exchange transfusion programmes. All five lines required removal due to infection associated with SBE, septic arthritis, pulmonary embolus and axillary vein thrombosis. The organisms involved were Staphylococcus aureus (3), Staphylococcus epidermidis (1) and Streptococcus sp. (1). The median working life of the catheters was 240 days (range 61-428). The median length of time from presentation to the diagnosis of a line-associated infection was 29 days (range 1-58). The rate of complications (0.4 per 100 patient days) in this small group of patients contrasts with the lower rates in patients with HIV and malignancy (0-0.1 per 100 patient days). Our results suggest that patients with SCD suffer an unacceptable incidence of infective complications associated with the Port-A-Cath. Bone infection is more common where there is pre-existing infarcted tissue. While these systems provide a valuable tool, our experience has led us to discontinue the use of TIVADs in SCD.

Publication Type: Case Reports. Journal Article.

<14>

Unique Identifier [PMID]: 8411432

Authors: Siegel JF. Rich MA. Brock WA.

Institution: Department of Urology, Schneider Children's Hospital, Long Island Jewish Medical Center, New Hyde Park, New York.

Title: Association of sickle cell disease, priapism, exchange transfusion and neurological events: ASPEN syndrome. [Review] [22 refs]

Source: Journal of Urology. 150(5 Pt 1):1480-2, 1993 Nov.

Abstract: Priapism and acute neurological events are believed to be unrelated complications of sickle cell hemoglobinopathy. We describe a syndrome based on our experience and a review of the literature of significant neurological events after partial exchange transfusion to treat priapism in sicklemic patients. Severe headache is often the initiating symptom of this complex. The ensuing neurological events range from seizure activity to obtundation requiring ventilatory support. The proposed pathophysiology of these neurological events is related to cerebral ischemia after an acute increase in per cent total hemoglobin, concomitant decrease in per cent hemoglobin S and subsequent release of vasoactive substances during penile detumescence. We have termed this constellation of events the ASPEN syndrome, an eponym for association of sickle cell disease, priapism, exchange transfusion and neurological events. Early recognition and aggressive medical management resulted in complete reversal of neurological sequela. [References: 22]

Publication Type: Case Reports. Journal Article. Review.

<15>

Unique Identifier [PMID]: 1593347

Authors: Rackoff WR. Ohene-Frempong K. Month S. Scott JP. Neahring B. Cohen AR.

Institution: Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia.

Title: Neurologic events after partial exchange transfusion for priapism in sickle cell disease.[see comment].

Comments Comment in: J Pediatr. 1992 Nov;121(5 Pt 1):838; PMID: 1432448

Source: Journal of Pediatrics. 120(6):882-5, 1992 Jun.

Abstract: We describe six boys with homozygous sickle cell disease, aged 7 to 13 years, in whom acute, severe neurologic abnormalities developed 1 to 11 days after partial exchange transfusion was performed to treat priapism that was unresponsive to more conservative therapy. Hemoglobin levels were 10.5 to 13.4 gm/dl (mean 12.1 gm/dl), and hemoglobin S levels were 18% to 33% (mean 27%) before the onset of neurologic complications. Severe headache was the initial finding in five patients, four of whom had increased intracranial pressure and three of whom required tracheal intubation and hyperventilation. Four patients had seizures; three had focal neurologic deficits for more than 24 hours. Cerebral arteriography demonstrated vascular abnormalities, including irregularity, stenosis, and complete occlusion of vessels. Patients treated with regular erythrocyte transfusions had no recurrence of neurologic signs or symptoms when hemoglobin S levels were kept at 30% to 50%. The occurrence of serious neurologic complications after partial exchange transfusion in patients with homozygous sickle cell disease from three centers indicates the possibility of a causal relationship between the events. Early and thorough investigation of neurologic symptoms, especially severe headache, is warranted in this clinical setting.

Publication Type: Case Reports. Journal Article.

<16>

Unique Identifier [PMID]: 2228996

Authors: Talacki CA. Ballas SK.

Institution: Cardeza Foundation for Hematologic Research, Thomas Jefferson University Hospital Blood Bank, Philadelphia, Pennsylvania 19107.

Title: Modified method of exchange transfusion in sickle cell disease.

Source: Journal of Clinical Apheresis. 5(4):183-7, 1990.

Abstract: The treatment of various complications of sickle cell disease has included red cell exchange in the past, and the development of automated pheresis equipment has greatly simplified such exchanges. Traditionally, the patient's red cells have been exchanged while their plasma was returned to them. Recently, plasma factors have been thought to play a role in the pathogenesis of vasoocclusive events. Therefore, we performed whole blood exchange, which consisted of replacement of the patient's plasma with albumin and saline in addition to the usual replacement of erythrocytes. A total of 32 whole blood exchanges were performed on 12 patients with a variety of complications of their disease. The procedure was done using standard pheresis equipment and was relatively simple to perform. There were no serious complications and the clinical outcome was good with 10 out of 12 patients experiencing improvement.

Publication Type: Journal Article.

<17>

Unique Identifier [PMID]: 2166162

Authors: Canessa M. Fabry ME. Suzuka SM. Morgan K. Nagel RL.

Institution: Endocrine-Hypertension Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.

Title: Na+/H+ exchange is increased in sickle cell anemia and young normal red cells.

Source: Journal of Membrane Biology. 116(2):107-15, 1990 Jun.

Abstract: Red cell volume regulation is important in sickle cell anemia because the rate and extent of HbS polymerization are strongly dependent on initial hemoglobin concentration. We have demonstrated that volume-sensitive K:Cl cotransport is highly active in SS whole blood and is capable of increasing MCHC. We now report that Na+/H+ exchange (Na/H EXC), which is capable of decreasing the MCHC of erythrocytes with pHi less than 7.2, is also very active in the blood of patients homozygous for HbS. The activity of Na/H EXC (maximum rate) was determined by measuring net Na+ influx (mmol/liter cell.hr = FU) driven by an outward H+ gradient in oxygenated, acid-loaded (pHi6.0), DIDS-treated SS cells. The Na/H EXC activity was 33 +/- 3 FU (mean +/- SE) (n = 19) in AA whites, 37 +/- 8 FU (n = 8) in AA blacks, and 85 +/- 15 FU (n = 14) in SS patients (P less than 0.005). Separation of SS cells into four density-defined fractions by density gradient revealed mean values of Na/H EXC four to five times higher in reticulocytes (SS1), discocytes (SS2) and dense discocytes (SS3), than in the fraction containing irreversibly sickled cells and dense discocytes (SS4). In contrast to K:Cl cotransport, which dramatically decreases after reticulocyte maturation, Na/H EXC persists well after reticulocyte maturation. In density-defined, normal AA red cells, Na/H EXC decreased monotonically as cell density increased. In SS and AA red cells, the magnitude of stimulation of Na/H EXC by cell shrinkage varied from individual to individual.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Type: Journal Article.

<18>

Unique Identifier [PMID]: 7131475

Authors: Van de Pette JE. Pearson TC. Slater NG.

Title: Exchange transfusion in life-threatening sickling crises.

Source: Journal of the Royal Society of Medicine. 75(10):777-80, 1982 Oct.

Publication Type: Case Reports. Journal Article.