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Resume La spherocytose hereditaire (SH) est la maladie constitutionnelle du globule rouge (GR) la plus frequente en Europe du Nord et en Amerique du Nord. Elle se manifeste par une anemie regenerative de gravite tres variable selon les individus. Sa transmission est dominante dans 75 % des cas. Son diagnostic est aise lorsqu’il existe des antecedents familiaux associes a une anemie regenerative hemolytique avec presence de spherocytes et un exces de cellules hyperdenses. Un test specifique de confirmation du diagnostic est necessaire en cas : (1) d’antecedent familial de SH si le decompte des cellules hyperdenses n’est pas realisable ; (2) en l’absence d’histoire familiale, devant toute atypie du frottis ; (3) chez le nouveau-ne et avant splenectomie, notamment pour eliminer le diagnostic de stomatocytose hereditaire, contre-indiquant formellement la splenectomie. L’indication de la splenectomie depend de l’importance de l’anemie et de sa tolerance clinique.

Resume But de l’etude La grossesse chez la femme drepanocytaire est a haut risque maternel et fœtal. Notre objectif etait d’evaluer l’interet d’un programme transfusionnel prophylactique adapte, soit par des transfusions de globules rouges, soit par des echanges erythrocytaires automatises, chez des patientes drepanocytaires ayant des antecedents de complications obstetricales et/ou vaso-occlusives severes. Patientes et methodes Nous avons suivi 18 grossesses chez 14 patientes (12 SS, 1 SC, 1S/β-thalassemie). Sept avaient eu une ou plusieurs grossesses anterieures avec, dans neuf cas sur dix, des complications maternofœtales graves. Sept ont ete prises en charge des leur premiere grossesse en raison d’antecedents de complications drepanocytaires severes. Le but etait d’obtenir un taux d’hemoglobine anormale (hemoglobine S ou S + C) inferieur a 50 % et un taux d’hemoglobine entre 9 et 11 g/dL. Le choix entre transfusions simples et echanges erythrocytaires etait fonction du taux d’hemoglobine. Les echanges erythrocytaires ont ete realises a l’aide d’un separateur de cellules (Com. Tec, Laboratoires Fresenius). Dans dix cas, les patientes n’ont eu que des echanges erythrocytaires. Dans cinq cas, seules des transfusions simples ont ete realisees. Dans trois cas, les patientes ont beneficie successivement de transfusions et d’echanges erythrocytaires. Resultats Aucune complication maternelle grave et aucune mort fœtale ou perinatale n’ont ete observees. Dans un cas, l’accouchement a ete declenche a 36 semaines d’amenorrhee du fait d’une souffrance fœtale avec hypotrophie. Conclusion Les femmes atteintes d’un syndrome drepanocytaire majeur peuvent, meme en cas d’antecedents obstetricaux severes, mener a terme une grossesse sans grave complication obstetricale grâce a l’association d’une prise en charge precoce par une equipe multidisciplinaire et d’une politique transfusionnelle preventive adaptee.

Dehydrated hereditary stomatocytosis (DHS) is a rare dominant form of hereditary haemolytic anaemia. In some families, pseudohyperkalaemia accompanies DHS. Familial hyperkalaemic hypertension (FHHt), a rare autosomal dominant form of arterial hypertension, is associated with genuine hyperkalaemia. We present a large French family in which DHS and FHHt were diagnosed independently in two separate branches. In branch A, mild DHS accompanied by pseudohyperkalaemia was found. In branch B, the proband and her daughter were initially diagnosed with FHHt, based on the coincidence of high blood pressure and hyperkalaemia. After finding out that branches A and B were related, reinvestigation of the affected members of branch B lead to the diagnosis of DHS, yielding the largest DHS kindred known in France. This allowed extensive linkage analysis based on 19 microsatellites markers in 12 affected and 10 unaffected members at 16q24.1qter, where one known DHS locus maps to. A maximal two-point LOD score (4.71 at theta = 0) was obtained for markers D16S3074 and D16S476. Haplotype analysis led to the definition of a new 11.5 cM disease interval with an upper limit at microsatellite D16S3037.

We report a patient in whom hepatosiderosis was diagnosed at the age of 55 years and who has since been treated by regular bleeding. The H63D mutation was found in the heterozygous state in the HFE gene. No mutation was recorded in the SLC11A3 gene (ferroportin). Hepatosiderosis did not seem primary, nevertheless its cause long remained elusive. Only 2 years ago did we find the responsible condition, a very mildly expressed form of dehydrated hereditary stomatocytosis (DHS). This genetic disease is a strongly iron-loading condition. Haemolysis was fully compensated. Kalaemia was slightly elevated, suggesting a pseudohyperkalaemia that may be associated with DHS. Osmotic gradient ektacytometry allowed to assess the diagnosis of DHS. The red cell monovalent Na+ and K+ concentrations were moderately elevated and reduced respectively. The temperature dependence of the ouabain + bumetanide-resistant K+ influx produced a shallow slope, above and parallel to the control curve. These features were consistent with the diagnosis of DHS. The pronounced hepatosiderosis contrasted with the mildly expressed DHS, and with the ferritinaemia that was slightly elevated, if at all, prior to bleeding. Bleeding caused ferritinaemia to decrease and hepatosiderosis to recede. The whole picture accounts for a misleading presentation of DHS, in which the primary condition long remained hidden behind one of its remotest complications, hepatosiderosis.

Dehydrated hereditary stomatocytosis (DHS) is a rare congenital hemolytic anemia mapping to 16q23-q24. We showed recently that it is part of a pleiotropic syndrome likely to display pseudohyperkalemia and/or different forms of fetal and placental fluid collections. Here, we report a woman with DHS. She had two consecutive pregnancies associated with severe fetal hydrops. Hydrops would probably have been lethal in the absence of appropriate removal of ascites and excess amniotic fluid. In utero exchange transfusion, performed once, was useless, because anemia was not pronounced enough to be the cause of the hydrops. In both newborns, ascites resolved within a week following birth and never recurred. The association of hydrops and hemolytic anemia suggests the possibility of DHS. Symptomatic treatment of the hydrops assists survival until spontaneous resorption occurs.

Dehydrated hereditary stomatocytosis (DHS) belongs to the heterogeneous class of hemolytic anemias with leaky red cell membranes. Splenectomy is a highly deleterious treatment, because it favors, with virtually no exception, the occurrence of thrombo‐embolic disease. We describe here the extreme case of a patient with DHS and an associated sickle cell trait. Splenectomy was carried out due to a splenic infarction that occurred during an airplane journey. About 12 years later, the patient noticed an exertional dyspnea, which gradually worsened to such a degree that she became severely incapacitated within 5 years. Eventually, the patient developed a cor pulmonale associated with chronic thrombo‐embolic pulmonary hypertension (CTEPH) and successfully underwent a heart–lung transplant operation. This case ranks as one of the most severe examples ever recorded of the effect that splenectomy may have in DHS patients. Nonetheless, it represents the first case to receive a heart–lung transplant.

We studied a recessive hereditary spherocytosis (HS) family from Norway in which all four children had haemolytic spherocytosis while spectrin (Sp) deficiency was detected in the proband. Molecular analysis demonstrated that all affected children had inherited the low expression alpha-Sp allele LEPRA (Low Expressed PRAgue) from the father. Haplotyping with a polymorphic dinucleotide repeat for the alpha-Sp gene (alphaVNTR) located in the 3' untranslated region of mRNA showed that all recessive children had inherited the same maternal alpha-spectrin allele. The paternal Sp-alphaLEPRA allele was found in cis of the polymorphic alpha-Sp Bughill allele (alphaBH) characterized by the A970D point mutation in the Sp alpha-chain. This mutation was identified on two-dimensional electrophoresis of Sp tryptic digests as an acidic shift of the alphaII tryptic domains (spots alphaIIa). Analyses of the relative expression of the paternal alpha-Sp Bughill polymorphism in the proband showed that the product of the maternal alpha-Sp gene is almost completely absent from the mature erythrocyte membrane. Comparative analysis between alphaVNTR PCR-amplified from genomic DNA and from cDNA showed that the maternal low expression alpha-Sp allele is associated with a decreased amount of mRNA. Results from molecular and biochemical studies showed that all the affected children of this family are compound heterozygous for two different low expression alpha-Sp alleles: an uncharacterized defective alpha-Sp allele on the maternal side and an alphaLEPRA allele tagged by the alphaIIa polymorphism on the paternal side.

Resume Le globule rouge est deformable et elastique et ces proprietes garantissent sa survie dans la circulation. Dans la spherocytose hereditaire, la plus frequente des anemies hemolytiques constitutionnelles en Europe, les capacites physiques du globule rouge sont limitees par des anomalies genetiques concernant diverses proteines du squelette membranaire, le plus souvent l'ankyrine, la bande 3, la proteine 4.2, la chaine α ou β de la spectrine. L'expression clinique est variable, d'une hemolyse bien compensee a une anemie severe. Le diagnostic repose sur des signes cliniques et biologiques d'hemolyse chronique associes a un faisceau d'arguments etiologiques : exces de globules rouges denses, augmentation de la fragilite osmotique, presence de spherocytes sur les frottis sanguins. L'ektacytometrie en gradient osmolaire permet d'obtenir des courbes de deformabilite typique, quoique non specifiques. L'electrophorese des proteines de la membrane erythrocytaire et la genetique moleculaire peuvent identifier la proteine et l'anomalie responsables de la maladie. Le traitement essentiel reste la splenectomie totale ou, mieux, subtotale.

Although hereditary spherocytosis (HS) is a common disorder of the red cell membrane, its clinical and biologic expression at birth and in early infancy has received little attention. In order to obtain insights into the natural history of HS during infancy, we studied 46 neonates, 39 from families in which 1 of the parents had previously been given a diagnosis of HS and 7 presenting with nonimmune hemolytic anemia and no family history of HS. Of these 46 neonates, 23 were subsequently confirmed to have HS and 23 were found to be healthy. The hematologic and biologic analyses carried out in this cohort of 46 newborns enabled us to develop guidelines for early diagnosis of HS. A careful clinical follow-up of 34 HS patients during the first year of life allowed us to define several important clinical features of HS during this period. Hemoglobin values are usually normal at birth but decrease sharply during the subsequent 20 days, which leads, in many cases, to a transient and severe anemia. The anemia is severe enough to warrant blood transfusions in a large number of infants with HS (26 of 34 in our series). The aggravation of anemia appears to be related to the inability of these infants to mount an appropriate erythropoietic response to anemia and to the development of splenic filtering function. These findings indicate that careful monitoring of infants with HS during the first 6 months of life is important for appropriate clinical management.

Hereditary spherocytosis (HS) is the commonest inherited disorder of the erythrocyte membrane in Northern Europe and North America. It is marked by a regenerative anemia which varies widely from asymptomatic patients to severe hemolysis. In 75% of HS patients, inheritance is autosomal dominant. The diagnosis of HS is easily made when there are a family history, hemolytic anemia, reticulocytosis, spherocytes and increased hyperdense cells. Specialized testing to clarify the nature of membrane disorder is required when the film appearance is atypical without a positive family history, in the absence of a family history, in the newborn and before the splenectomy, to rule out the stomatocytosis which is contraindicated. The indication for splenectomy is dependent on the degree of anemia and its clinical manifestation.

Intracellular polymerization and sickling depend markedly on the cellular concentration of sickle hemoglobin (Hb S). A possible therapeutic strategy for sickle cell disease is based on reducing the cellular concentration of Hb S through prevention of erythrocyte dehydration. The K-Cl cotransporter is a major determinant of sickle cell dehydration and is inhibited by increasing erythrocyte Mg content. We studied 10 patients with sickle cell disease before treatment and after 2 and 4 wk of treatment with oral Mg supplements (0.6 meq/kg/d Mg pidolate). Hematological parameters, erythrocyte Na, K, and Mg content, erythrocyte density, membrane transport of Na and K, and osmotic gradient ektacytometry were measured. We found significant increases in sickle erythrocyte Mg and K content and reduction in the number of dense sickle erythrocytes. Erythrocyte K-Cl cotransport was reduced significantly. We also observed a significant reduction in the absolute reticulocyte count and in the number of immature reticulocytes. Ektacytometric analysis showed changes indicative of improved hydration of the erythrocytes. There were no laboratory or clinical signs of hypermagnesemia. Mild, transient diarrhea was the only reported side effect. We conclude that oral Mg supplementation reduces the number of dense erythrocytes and improves the erythrocyte membrane transport abnormalities of patients with sickle cell disease.

Resume Les auteurs rapportent leur experience personnelle de la spherocytose hereditaire (SH) a partir d'une serie de 88 patients (dont 74 enfants) sulvis entre les annees 1980 et 1994. Patients and methodes. — La gravite clinique est tres variable, allant des formes asymptomatiques aux formes severes necessitant des transfusion iteratives. Un retentissement sur la croissance est observe dans quatre cas et une fatigue chronique dans 30 cas. Quatre-vingt-dix-hult pour cent des enfants etudies ont un pourcentage anormalement eleve (>4%) de globules rouges (GR) hyperdenses (CCMH s 41 g/dL). L'etude en ektacytometrie revel, une courbe typique de SH avec une diminution constante de l'index de deformabilite maximale en isotomie, liee a la diminution de surface globulaire. La frequence des lithiases biliaires recherchee systematiquement en echographie est de 24%. Resultats. — Vingt-quatre des 30 patients splenectomises ont co une splenectomie subtotale, ne laissant en place qu'environ 25% du volume splenique normal pour l'age. L'amelioratiion postoperatoire a ete constante. marquee per une diminution franche de l'hemolyse avec allongement de la duree de vie des GR et augmentation significative de l'hemoglobine. Les fonctions phagocytaires de la rate restame paraissent conservees a en juger par le taux des pitted erythrocytes et la bonne captation du technetium 99m par le moignon splenique en scintigraphie. Cependant, un certain degre d'hemolyse persistait apres l'intervention et deux cas ont necessite secondairement une splenectomie totale; le risque de developper une lithiase billaire n a pas ete completement prevenu (trois cas). Conclusion. — La splenectommie subtotale nous parait representer une alternative interessante a la splenectomie totale. Elle permet d'obtenir des resultats hematologiques satisfaisants tout en protegeant a la fois des risques potentiels transfusionnels et des risques infectieux qui persistent toute leur vie chez les sujets ayant eu une splenectomie totale.

Maternal and fetal risk is often high during pregnancy in sickle cell disease. Our objective was to evaluate the benefits of a transfusion program adapted to each pregnant patient, either by red cell transfusion or by automated red cell exchange, in sickle cell patients with a history of serious obstetrical and/or sickling complications.We managed 18 pregnancies in 14 patients (12 SS, 1 SC, 1 S/b-thalassemia), seven of whom had a history of one or more pregnancies, with severe maternofetal complications in nine out of 10 cases. The other seven patients were pregnant for the first time and were in care because of a history of severe sickling complications. The aim was to achieve a proportion of abnormal hemoglobin (hemoglobin S or S+C) below 50% and a hemoglobin level between 9 and 11 g/dL. The choice between transfusion and red cell exchange was made in the light of the hemoglobin level. Red cell exchange was done using a Fresenius Com. Tec blood cell separator. Patients had red cell exchange in 10 cases, and transfusions in five cases. In three cases, patients had successive transfusions and red cell exchange.No serious maternal complication was observed. No fetal or perinatal death occurred. In one case, delivery was induced at 36 weeks of gestation because of fetal distress and hypotrophy.Our study suggests that women with severe sickle cell disease, even if they have a serious obstetrical history, can carry their pregnancy to term, without major obstetric complications, through a combination of early management by a multidisciplinary team and a suitable policy of prophylactic transfusion or automated red cell exchange.

Hereditary spherocytosis (HS) is the commonest inherited disorder of the erythrocyte membrane in Northern Europe and North America. It is marked by a regenerative anemia which varies widely from asymptomatic patients to severe hemolysis. In 75% of HS patients, inheritance is autosomal dominant. The diagnosis of HS is easily made when there are a family history, hemolytic anemia, reticulocytosis, spherocytes and increased hyperdense cells. Specialized testing to clarify the nature of membrane disorder is required when the film appearance is atypical without a positive family history, in the absence of a family history, in the newborn and before the splenectomy, to rule out the stomatocytosis which is contraindicated. The indication for splenectomy is dependent on the degree of anemia and its clinical manifestation.

The family of two siblings with severe hereditary spherocytosis was investigated. The decrease was evident on both the alpha- and the beta-chains. The parents were haematologically normal. The mother was heterozygous for the low-expression polymorphic allele alphaLEPRA. The father was heterozygous for a novel combination in which one allele showed the alpha-spectrin low expression polymorphic allele alphaLELY, while his other allele showed the alphaLELY polymorphism in cis with a G--A substitution, named Bicêtre, found at the extreme 3' end of exon 51. This combination was designated alpha(LELY-Bicêtre). The children were compound heterozygotes for alleles alphaLEPRA and alpha(LELY-Bicêtre). Reverse transcription polymerase chain reaction detected only trace amounts of the mRNA coding for alpha(LELY-Bicêtre). Mutation is therefore an essentially null mutation with no functional protein product. The lack of disease in the alphaLELY/(LELY-Bicêtre) father compared with the marked haemolysis in the alphaLEPRA/alpha(LELY-Bicêtre) children showed that expression of allele alphaLELY is not low enough to expose null alpha-spectrin alleles on the other chromosome. Quantitative estimations from these findings suggest that, to evoke spherocytosis, it is necessary that alpha-spectrin expression must be reduced to less than 25% of normal, while a reduction to 8% is sufficient.

The appearance of schistocytes in a peripheral blood film is considered to be an important diagnostic marker for thrombotic microangiopathy. However, the morphological analysis of schistocytes remains uneasy. To determine practice patterns in the biological management of schistocytosis, the French Group of Cellular Hematology from the French Society of Hematology conducted a survey on the approach of the diagnosis of microangiopathy. A guideline is proposed in order to cancel the substantial variation among biologists.

The case is reported of a mother and baby with dehydrated hereditary stomatocytosis and perinatal ascites, an autosomal dominant condition not previously reported in Britain. Recognition is important for the management of pregnancy and for avoidance of splenectomy which, if performed, can predispose the patient to fatal thromboembolic events.

We studied a recessive hereditary spherocytosis (HS) family from Norway in which all four children had haemolytic spherocytosis while spectrin (Sp) deficiency was detected in the proband. Molecular analysis demonstrated that all affected children had inherited the low expression alpha-Sp allele LEPRA (Low Expressed PRAgue) from the father. Haplotyping with a polymorphic dinucleotide repeat for the alpha-Sp gene (alphaVNTR) located in the 3' untranslated region of mRNA showed that all recessive children had inherited the same maternal alpha-spectrin allele. The paternal Sp-alphaLEPRA allele was found in cis of the polymorphic alpha-Sp Bughill allele (alphaBH) characterized by the A970D point mutation in the Sp alpha-chain. This mutation was identified on two-dimensional electrophoresis of Sp tryptic digests as an acidic shift of the alphaII tryptic domains (spots alphaIIa). Analyses of the relative expression of the paternal alpha-Sp Bughill polymorphism in the proband showed that the product of the maternal alpha-Sp gene is almost completely absent from the mature erythrocyte membrane. Comparative analysis between alphaVNTR PCR-amplified from genomic DNA and from cDNA showed that the maternal low expression alpha-Sp allele is associated with a decreased amount of mRNA. Results from molecular and biochemical studies showed that all the affected children of this family are compound heterozygous for two different low expression alpha-Sp alleles: an uncharacterized defective alpha-Sp allele on the maternal side and an alphaLEPRA allele tagged by the alphaIIa polymorphism on the paternal side.

Dehydrated hereditary stomatocytosis (DHS) is a rare genetic disorder of red cell permeability to cations, leading to a well-compensated hemolytic anemia. DHS was shown previously to be associated in some families with a particular form of perinatal edema, which resolves in the weeks following birth and, in addition, with pseudohyperkalemia in one kindred. The latter condition was hitherto regarded as the separate entity, "familial pseudohyperkalemia." DHS and familial pseudohyperkalemia are thought to stem from the same gene, mapping to 16q23-q24. This study screened 8 French and 2 American families with DHS. DHS appeared to be part of a pleiotropic syndrome in some families: DHS + perinatal edema, DHS + pseudohyperkalemia, or DHS + perinatal edema + pseudohyperkalemia. If adequately attended to, the perinatal edema resolved spontaneously after birth. Logistic regression showed that increased mean corpuscular volume and mean corpuscular hemoglobin concentration were the parameters best related to DHS. In patients in whom cation fluxes were investigated, the temperature dependence of the monovalent cation leak exhibited comparable curves. Specific recombination events consistently suggested that the responsible gene lies between markers D16S402 and D16S3037 (16q23-q24). The 95% confidence limits (Z(max)/= 3.02) spanned almost the complete 9-cM interval between these 2 markers.

Prevention of erythrocyte dehydration by specific blockade of the transport pathways promoting loss of potassium (K) is a potential therapeutic strategy for sickle cell (SS) disease. Dietary magnesium (Mg) pidolate supplementation over a 4-week period has been shown to inhibit K-Cl co-transport and reduce dehydration. We report here the results in 17 of 20 patients with SS disease treated in an open-label unblinded study of the effects of long-term (6 months) oral Mg pidolate administration (540 mg Mg/d). A significant decrease (P0.0025) was observed with Mg therapy in the distribution widths for red cell mean cell haemoglobin concentration (MCHC) (haemoglobin distribution width; HDW), reticulocyte mean cell volume (red cell distribution width of reticulocytes; RDWr) and MCHC (reticulocyte HDW; HDWr), activity of red cell K-Cl co-transport, Na/Mg exchanger and Ca2+-activated (Gardos) K+ channel, whereas red cell K and Mg contents were significantly increased. Hb levels and absolute reticulocyte counts did not change with Mg therapy. Two patients did not complete the trial because of diarrhoea and one did not complete the trial for unrelated reasons. Although the median number of painful days in a 6-month period decreased from 15 (range 0-60) in the year before the trial to 1 (range 0-18; P0.0005) during the period of Mg therapy, no firm conclusion on therapeutic efficacy could be drawn from this unblinded open-label trial.

We describe two White persons, a girl and her mother, presenting with Southeast Asian ovalocytosis. The child was evaluated for scoliosis. The red cell indices were normal but the cell counter triggered an alarm due to a high fraction of hyperdense red cells. Blood smears showed ovalocytes and ovalostomatocytes. Red cells exhibited a total lack of deformability upon osmotic gradient ektacytometry performed immediately after blood drawing. Analysis of nucleic acids and proteins ascertained a 27 nucleotide deletion, resulting in the loss of amino acids 400 to 408, and the presence in cis of the Memphis I polymorphism. The sulfate transport was diminished by more than 50%. There was no acidosis. In vitro invasion of ovalocytes by Plasmodium falciparum was decreased. The mother presented with the same hematological picture. On the whole, the condition was Southeast Asian ovalocytosis in all respects. The present kindred had ancestors who had inhabited islands in the Southwestern Indian Ocean.

Dehydrated hereditary stomatocytosis is a haemolytic anaemia with an underlying impairment of monovalent cation transport. It is sometimes associated with pseudohyperkalaemia (e.g. an increase of kalaemia when blood is left at room temperature) or with perinatal ascites. We report a case in which dehydrated hereditary stomatocytosis, pseudohyperkalaemia and perinatal oedema coexisted, and were transmitted en bloc in a dominant fashion. Transfusions did not cure the oedema, that spontaneously receded after a few months. We assume that the various manifestations stemmed from one single altered locus, yet to be determined.

Effectiveness of subtotal splenectomy, a procedure recently advocated as an alternative treatment to total splenectomy for patients with hereditary spherocytosis (HS), has been evaluated.Eighty-eight patients (74 children) with HS were included in this series. Clinical presentations ranged from asymptomatic cases to severe transfusion-dependent forms. Stunting of growth occurred in four cases; chronic fatigue was observed in 30 cases and cholelithiasis in 21 cases. Among the red cell indices measured by laser light scattering on Technicon H2, the most reliable for diagnosis was the abnormal percentage of hyperdense red cells (98% of HS patients). Osmotic gradient ektacytometry, used to measure membrane deformability and impairment of maximal deformability due to a reduction of erythrocyte surface, always showed the characteristic curves of HS.Subtotal splenectomy was performed in 24 patients leading to a remnant spleen of about 25% of normal for age volume. This decreased the hemolytic rate while adequately sustaining the phagocytic function of the spleen (assessed by percentage of "pitted erythrocytes" and technetium 99n scans of the remnant). However, the observed reduction in hemolytic rate was not as extensive as that observed after total splenectomy (six cases) and subtotal splenectomy did not entirely prevent risk of cholethiasis (three cases).This subtotal splenectomy (+/-cholecystectomy) has to be particularly considered for children with transfusion-dependent forms of HS, in order to obtain the benefits of increased hemoglobin levels without the pending risk throughout life of overwhelming post-splenectomy infections.

Hereditary spherocytosis (HS) is an inherited hemolytic anemia characterized by the presence of dense spherocytic red cells. In HS patients, red cell membrane protein gel electrophoresis has identified different subsets of abnormalities: isolated spectrin deficiency, combined spectrin and ankyrin deficiency, band 3 deficiency. To direct the search for the molecular defect in 9 families with dominant HS, we developed microsatellite markers specific for the membrane protein encoding genes possibly involved in HS (alpha- and beta-spectrin, ankyrin and band 3 genes) and genotyped each family. In 5 families with isolated spectrin deficiency, the beta-spectrin gene was designated as candidate. In one family with combined spectrin/ankyrin deficiency, only the ankyrin gene was not excluded, whereas in the 3 HS families with band 3 deficiency, only the band 3 gene was not excluded. This work allowed development of a reliable methodology to search for candidate genes in HS and showed the frequent involvement of the beta-spectrin gene in HS with isolated spectrin deficiency.

In sickle cell disease (SCD), vaso-occlusion is a complex process involving cellular, vascular and humoral factors and possibly thrombotic events. We studied three physiological inhibitors of the coagulation system, antithrombin III (AT III), protein C (PC) and protein S (PS), in three groups of subjects: 27 homozygous patients observed either in crisis or in a steady state, 23 heterozygous patients and 30 healthy subjects. PS study included the measurement of total and free PS antigen, PS activity and C4bBP antigen. In heterozygous subjects the results were similar to those of controls, but in homozygous subjects abnormalities of PS and to a lesser extent PC were observed. Values of PC were extremely variable with 10 cases lower than the normal range (2 SD of the mean) and 17 others within this range. In all cases total PS antigen was slightly reduced (77 +/- 18%, M +/- SD) with a more marked decrease of free antigen (59 +/- 17%) and normal values of C4bBP. Levels of PS activity were greatly reduced and lower than those of free antigen with a mean ratio of PS activity to free antigen of 0.6. These abnormalities were associated with significantly high concentrations of fibrinogen D-dimers. PS deficiency in SCD may be at least partly due to adsorption of free PS to aminophospholipids abnormally expressed on sickle cells membranes, microvesicles and activated platelets, while the discrepancy between PS activity and free antigen could reflect proteolytic inactivation of PS by traces of thrombin.