Leg ulcers in hereditary spherocytosis

Refractory leg ulcers in two patients healed following splenectomy. Neither patient had the ethnic background or family history of haematological abnormalities to suggest a haemoglobinopathy.

Alteration of the erythrocyte membrane skeletal ultrastructure in hereditary spherocytosis, hereditary elliptocytosis, and pyropoikilocytosis

The membrane skeleton of normal erythrocytes is largely organized into a hexagonal lattice of junctional complexes (JC) crosslinked by spectrin tetramers, and occasional double tetramers and hexamers. To explore possible skeletal alterations in hereditary spherocytosis (HS), elliptocytosis (HE), and pyropoikilocytosis (HPP), we have studied the ultrastructure of the spread membrane skeletons from a subpopulation of HS patients with a partial spectrin deficiency ranging from 43% to 86% of normal levels, and in patients with HPP who, in addition to a mild spectrin deficiency, also carried a mutant spectrin that was dysfunctional, thus reducing the ability of spectrin dimers to assemble into tetramers. Membrane skeletons derived from Triton-treated erythrocyte ghosts were examined by negative staining electron microscopy. HS membrane skeletons contained structural elements, consisting of JC and spectrin filaments similar to the normal skeleton. However, less spectrin filaments interconnected the JC, and the decrease of spectrin filaments attached to JC appeared to correlate with the severity of spectrin deficiency. Only in severe HS associated with severe spectrin deficiency was the loss of spectrin sufficient enough to disrupt the overall skeletal architecture. In contrast, membrane skeletons prepared from red blood cells (RBCs) of subjects with HPP were strikingly different from HS RBCs with a comparable degree of spectrin deficiency. Although HPP RBCs were only mildly deficient in spectrin, their skeletal lattice was grossly disrupted, in contrast to only mild ultrastructural abnormalities of HS membrane skeletons with a nearly identical degree of spectrin deficiency. Skeletons from patients with common mild HE or asymptomatic carriers, carrying the mutant spectrin but having normal spectrin content, exhibited a moderate disruption of the skeletal lattice. We propose that the above differences in skeletal ultrastructure may underlie differences in the biomechanical properties and morphology of HS, HE, and HPP RBCs.

Ultracentrifugal analysis of the junction complexes of the red cell membrane cytoskeletal network: application to hereditary spherocytosis and metabolically depleted cells

A method has been developed for the assessment of the number of spectrin dimer units associated with each actin protofilament junction, in the membrane cytoskeletal network (i.e. the degree of branching) of the red cell. Ghosts are first exposed to elevated temperature at low ionic strength to dissociate some 65% of the spectrin tetramers (that link the network junctions) into dimers, without causing their release from the actin filaments. Non-ionic detergent is then added to solubilize the membrane itself with its intrinsic proteins, so as to liberate the cytoskeletal material, and the mixture is immediately examined in the analytical ultracentrifuge. The predominant components observed are isolated junctions (20 S), free spectrin dimers and the residual undissociated cytoskeletal material, with very minor components, probably corresponding to multiple junctions, linked by spectrin tetramers. The junction boundary is homogeneous within the accuracy of measurement and is taken to correspond to a complex containing six spectrin dimers, known to predominate in situ. About 17% of the total network is liberated in this form and 12% as free spectrin dimers. In hereditary spherocytosis both the size of the junction complex (as reflected by its sedimentation coefficient) and the proportion of the complex and of free spectrin liberated are indistinguishable from normal values. We conclude that the reported deficit of spectrin in hereditary spherocytosis is not reflected by a lower degree of branching of the network, and, if the membrane area is not correspondingly reduced, this must mean that the junctions are more widely spaced and the spectrin tetramers therefore more extended. In metabolically depleted cells, in which the cytoskeletal proteins are known to be extensively dephosphorylated, there is no change in the sedimentation pattern and thus no detectable loss of spectrin from the junctions or weakening in the cohesion of the cytoskeletal network.

[Usefulness of cytometry based on the diffraction of a laser beam in evaluating spherocytosis]

Thirty four cases of hereditary spherocytosis were studied by means of laser diffraction cytometry. The cases were grouped for study in accordance to previous splenectomy or not, familial involvement or not, and, in patients not subjected to splenectomy, severity of the clinical course. The values used to assess the presence of spherocytosis were those measuring the haemoglobin concentration within red cells, such as CH (directly estimated mean corpuscular haemoglobin), HDW (standard deviation of the distribution according to haemoglobin concentration) and % hyper (percentage of cells with haemoglobin concentration higher than 41 g/dL). The variables attained were statistically analysed by means of non-parametric tests. In patients with spherocytosis, MCV, MCHC, RDW, HDW, % hyper, and CH were significantly different from the normal group. This method points to the presence of spherocytosis by means of CH, HDW and % hyper. A reduction of the limit of haemoglobin concentration used to define % hyper (41 g/dL) could improve the sensitivity of the instrument for the diagnosis of the mild forms, which is often more difficult.

Fine architecture of the splenic terminal vascular bed as revealed by arterial and venous pressure-loading perfusion fixation

The three-dimensional fine architecture of the red pulp of human and animal spleens, which as fixed by a modified version of the arterial and venous pressure-loading perfusion fixation (AVPL perfusion fixation) method, is demonstrated by scanning and transmission electron microscopy. In the human spleen, changes in splenomegalias associated with hereditary spherocytosis and chronic portal hypertension are also introduced in addition to the normal architecture of the red pulp of spleens removed from patients with stomach cancer. The AVPL perfusion fixation of these spleens clearly visualized complicated three-dimensional fine architecture of the red pulp and provided much important information on in situ morphology and dynamic change of the terminal vascular bed, including venous pressure-dependent size change of the stomata and three-dimensional shapes of the capillary terminal, with positive proof of their opening into the cordal reticular tissue. In studies of the spleen associated with portal hypertension, the AVPL perfusion fixation is considered a necessary technique for analysis of the structural deviation closely relating to a very high venous pressure.

Morphologic and morphometric light and electron microscopic studies of the spleen in patients with hereditary spherocytosis and autoimmune haemolytic anaemia

With the aim of contributing to a better understanding of the haemolytic function of the spleen, a morphologic and morphometric study of this organ fixed by arterial perfusion was performed in nine patients with hereditary spherocytosis (HS), three with autoimmune haemolytic anaemia (AHA) and six with Hodgkin's disease without splenic involvement (controls). The spleen weight in HS and AHA (621 +/- 429 g, mean +/- SD) was significantly increased with respect to controls (168 +/- 36 g) (P = 0.003). In HS the red cell retention in the cords of Billroth was significantly increased (203 +/- 68 per 10(4) microns 2) with respect to the cases with AHA (93 +/- 35 per 10(4) microns 2) and to the controls (57 +/- 28 per 10(4) microns 2) (P = 0.004). In HS and AHA the number of macrophages per 10(4) microns 2 of red pulp was significantly increased (5.41 +/- 1.10 and 7.52 +/- 2.91, respectively) with respect to the controls (3.25 +/- 0.58) (P less than 0.003). There was no statistically significant difference between the number of macrophages in HS and AHA. The transmission (TEM) and scanning electron microscopy (SEM) studies demonstrated predominantly red cell retention in the cords of HS spleens, red cell phagocytosis by cordal macrophages in AHA spleens and in a lesser intensity in HS spleens, and phagocytosis of haematic corpuscles by sinus endothelial cells (SEC) in the cases of HS. These quantitative studies allow a better understanding of splenic red cell destruction in haemolytic syndromes.

Evaluation of stem cell reserve using serial bone marrow transplantation and competitive repopulation in a murine model of chronic hemolytic anemia

Serial transplantation and competitive repopulation were used to evaluate any loss of self-replicative capacity of bone marrow stem cells in a mouse model with increased and persistent hemopoietic demands. Congenic marrows from old control and from young and old mice with hereditary spherocytic anemia (sphha/sphha) were serially transplanted at 35-day intervals into normal irradiated recipients. Old anemic marrow failed or reverted to recipient karyotype at a mean of 3.5 transplants, and young anemic marrow reverted at a mean of 4.0 transplants, whereas controls did so at a mean of 5.0 transplants. In a competitive assay in which a mixture of anemic and control marrow was transplanted, the anemic marrow persisted to 10 months following transplantation; anemic marrow repopulation was greater if anemic marrow sex matched with the host. It is possible that lifelong stress of severe anemia decreases stem cell reserve in the anemic sphha/sphha mouse marrow. However, marginal differences in serial transplantation number and the maintenance of anemic marrow in a competition assay would suggest that marrow stem cells, under prolonged stress, are capable of exhibiting good repopulating and self-replicating abilities.

Decreased membrane mechanical stability and in vivo loss of surface area reflect spectrin deficiencies in hereditary spherocytosis

Whereas marked variations in the clinical manifestations of hereditary spherocytosis have long been recognized, we have only recently begun to define the molecular basis for this heterogeneity. An important unanswered question is whether decreased spectrin results in reduced membrane mechanical stability, and if this reduction in membrane mechanical stability can be related to in vivo surface area loss. Using the ektacytometer, we quantitated membrane surface area and stability in erythrocytes from 18 individuals with hereditary spherocytosis and deficiencies of spectrin (30-80% of normal spectrin level). Membrane mechanical stability was reduced and the magnitude of the reductions correlated with the spectrin content. Moreover, the reductions in mechanical stability correlated with in vivo loss of membrane surface area. These data indicate that decreased spectrin content results in reduced membrane mechanical stability and surface area loss in vivo. We conclude that partial deficiencies of spectrin, reductions in membrane mechanical stability, and loss of membrane surface area are directly related and are major features determining the heterogeneous clinical manifestations of hereditary spherocytosis.

Reductions of erythrocyte membrane viscoelastic coefficients reflect spectrin deficiencies in hereditary spherocytosis

Hereditary spherocytosis is a common hemolytic anemia associated with deficiencies in spectrin, the principal structural protein of the erythrocyte membrane-skeleton. We have examined 20 different individuals from 10 spherocytosis kindreds and 2 elliptocytosis kindreds to determine the effects of different levels of spectrin deficiency on the viscoelastic properties of the erythrocyte membrane. Micropipettes were used to perform single-cell micromechanical measurements of approximately 1,000 individual cells to determine the membrane elastic shear modulus, the apparent membrane bending stiffness, and whole cell recovery time constant for the different cell populations. The membrane viscosity was calculated by the product of the shear modulus and the recovery time constant. Results show correlation between the fractional reduction in shear modulus and the fractional reduction in spectrin content (determined by spectrin radioimmunoassay) and spectrin density (determined by the ratios of spectrin to band 3 on electrophoresis gels) suggesting that membrane shear elasticity is directly proportional to the surface density of spectrin on the membrane (P less than 0.001). The apparent membrane bending stiffness is also reduced in proportion to the density of spectrin (P less than 0.001). The membrane viscosity is reduced relative to control (P less than 0.001), but the nature of the relationship between spectrin density and membrane viscosity is less clearly defined. These studies document striking relationships between partial deficiencies of erythrocyte spectrin and specific viscoelastic properties of the mutant membranes.

Abnormal oxidant sensitivity and beta-chain structure of spectrin in hereditary spherocytosis associated with defective spectrin-protein 4.1 binding

Hereditary spherocytosis (HS) is an inherited disorder of erythrocyte shape associated with spectrin deficiency and hemolytic anemia. In a subset of patients with the autosomal dominant form of HS, spectrin displays a reduced capacity to bind protein 4.1 and, therefore, actin; both functions that are critical to the membrane skeleton. A specific structural defect has not been identified in the spectrin from these patients. Chymotryptic digestion of the isolated spectrin chains shows impaired cleavage of the distal peptide of the beta subunit, the beta IV domain. In previous work, we have shown that mild oxidation markedly diminishes the binding capacity of normal spectrin for protein 4.1. Here we observe that chemical reduction of freshly isolated, untreated HS spectrin dramatically improves its function. Thus, a primary structural defect in the beta subunit of spectrin in this subtype of HS may lead to oxidant sensitivity, and secondarily, to a functional defect in the binding of spectrin to protein 4.1 and actin.

Red pulp of the spleen in autoimmune haemolytic anaemia and hereditary spherocytosis: morphometric light and electron microscopy studies

Morphometric light and electron microscopy studies on perfusion-fixed spleens from 6 patients with autoimmune haemolytic anaemia and 18 patients with hereditary spherocytosis showed increased relative (and absolute) volumes of red pulp and absolute volumes of pulp cords when compared to 10 controls and 16 patients with immune thrombocytopenia without haemolysis. The mean erythrocyte volume density of the red pulp and mean erythrocyte area were significantly increased, and more of the erythrocytes' profiles were closer to being circular than in the controls. The changes within the splenic red pulp were qualitatively identical in the 2 cases of haemolytic disease, being quantitatively more pronounced, however, in hereditary spherocytosis than in autoimmune haemolytic anaemia.

Hereditary spherocytosis. Recent experience and current concepts of pathophysiology

Hereditary spherocytosis is a clinically heterogeneous, genetically determined red blood cell membrane disorder resulting in hemolytic anemia. A deficiency of spectrin, the largest and most abundant structural protein of the erythrocyte membrane skeleton, results in the formation of spherocytes which lack the strength, durability, and flexibility to withstand the stresses of the circulation. Clinical manifestations of the disease are primarily dependent on the severity of hemolysis, which additionally results in an increased incidence of pigment gallstones. The likelihood of cholelithiasis is directly related to patient age and is uncommon before 10 years of age. Splenectomy is indicated in virtually every patient. When the disease is diagnosed in early childhood, the risk of overwhelming postsplenectomy sepsis makes it advisable to delay splenectomy until after 6 years of age if possible. At the time of splenectomy, it is important to identify and remove any accessory spleens. If gallstones are present, cholecystectomy should be performed. Although spherocytosis persists following splenectomy, hemolysis is alleviated and clinical cure of the anemia is achieved for most patients. Patients with recessively inherited spherocytosis are exceptions. Although they are significantly benefited by splenectomy, their anemia is not completely corrected. Splenectomy reduces hemolysis in all patients and thereby decreases the risk for development of pigment gallstones. Excision of an enlarged spleen removes the danger of traumatic rupture.

The human spleen; a histological study in splenectomy specimens embedded in methylmethacrylate

In a series of 316 surgically removed spleens, a histological and supportive immunohistological study was performed on methylmethacrylate sections. The structure of the human white and red pulp differs from the rat spleen in many respects, e.g. the human lacks the marginal sinus and the architecture of the periarteriolar lymph sheath seen in the rat. In man, the lymphoid compartment is in both white and red pulps. In the white pulp separate periarteriolar T-cell areas contain a large lymph-vessel plexus, which was reconstructed in serial sections. The circulation in the red pulp is discussed. The area between the red and white pulp, the perifollicular zone, is not the equivalent of the marginal sinus in the rat. Its anatomy in man suggests that it is an area formed from red pulp during the expansion of new follicles. The micro-anatomy was analysed in 119 controls. In cases of traumatic rupture the white pulp showed evidence of stimulation. A pathognomonic histological picture was not found in idiopathic thrombocytopenic purpura. In haemolytic anaemia the pulp cords were engorged by erythrocytes accompanied by a decreased B/T cell ratio in autoimmune haemolytic anaemia and by an increased B/T cell ratio in congenital spherocytosis.

Angioid streaks associated with hereditary spherocytosis

We examined members of a family in whom hereditary spherocytosis had appeared in three generations. Angioid streaks were confirmed in the second generation and presumed to exist in the first generation. A woman in the third generation with hereditary spherocytosis did not have angioid streaks but these are age-related and may develop later. The one individual in the second generation without hereditary spherocytosis did not have angioid streaks. Angioid streaks associated with hereditary spherocytosis in this family did not appear to be coincidental. Patients with hereditary spherocytosis should be examined for angioid streaks because of the implications for their vision.

An autopsy case of hemochromatosis and hepatoma combined with hereditary spherocytosis

A case of hemochromatosis and hepatocellular carcinoma secondary to hereditary spherocytosis is very rare and this is only the second case reported in an English language bulletin. When the patient, a 56 years old man, was admitted for receiving cholecystectomy for cholelithiasis, a diagnosis of hemochromatosis secondary to hereditary spherocytosis was made by liver biopsy and hematological examination data. The patient did not receive a blood transfusion nor was administered iron during the entire duration of the illness. Hepatoma was suspected at the time of splenectomy which was performed in 1981 because of severe anemia. Eight months later he died of massive abdominal cavity bleeding and subsequent autopsy findings were consistent with the disease mentioned above. Clinical and postmortem examinations suggested that conspicuously enhanced erythropoiesis in the bone marrow and unknown factors may be responsible for an increase in iron absorption from the gut and in the amount of stored body iron, leading to the development of hemochromatosis.

The amount of white pulp in the spleen; a morphometrical study done in methacrylate-embedded splenectomy specimens

This report deals with a morphometrical study on 92 surgically removed human spleens, to investigate the composition of spleens which are considered to be normal, i.e. spleens which had ruptured in traffic accidents or which had been incidentally removed during abdominal operations. A comparison was made with 16 spleens with hypersequestration of platelets and to 11 with hyper-sequestration of erythrocytes. Methyl-methacrylate embedding was used because of the superiority of this technique over conventional paraffin embedding. Significant differences were found between both 'normal' groups as to the absolute and relative amount of white pulp as well as the perifollicular red pulp zone. Based also on the few morphometrical reported studies in the literature, spleens removed during abdominal surgery form the best control group. Traumatic rupture of the spleen in traffic accidents might specifically occur in spleens which already contained a stimulated lymphatic compartment. A probably non-specific increase of white pulp was found in splenomegaly of varied aetiology. An expected influence of age on weight and composition of the spleen was not found in our study. The spleen changes in weight and composition only up to 5 years of age. Significant involution at older age was not found in ours nor in other reported larger series.

The influence of membrane skeleton on red cell deformability, membrane material properties, and shape

A membrane skeleton consisting of a structural matrix of spectrin, actin, and band 4.1 linked to band 3 in the fluid bilayer through ankyrin appears to be responsible for many of the material properties of the red cell membrane. In response to externally applied forces, the membrane behaves as a solid, a semisolid, or a liquid, depending on the magnitude and duration of the applied forces. Under physiologic conditions, the normal skeleton permits the red cells to undergo marked reversible deformations as a viscoelastic material. Perturbations of this skeletal assembly, as a result of molecular defects in skeletal components, lead to various altered membrane material properties and altered behavior in the circulation. The altered material properties include increased elastic shear modulus, irreversible membrane flow, or even membrane yield, resulting in cell fragmentation. These alterations in turn lead to changes in cellular deformability either as a result of increased membrane rigidity or decreased surface-area-to-volume ratio, secondary to cell fragmentation. As cellular deformability is one of the major parameters that determines red cell life span, skeletal dysfunction leading to decreases in deformability can account for increased red cell destruction in many congenital and hereditary hemolytic anemias.

Erythrocyte membrane skeleton abnormalities in hereditary spherocytosis

Erythrocyte ghosts from eight individuals with hereditary spherocytosis have been compared with respect to their protein compositions as judged by SDS gel electrophoresis, their ease of spectrin extractability, and their freeze-etch electron microscopic appearance after incubation in condition designed to promote aggregation of the intramembrane particles. Four of these HS cases were unrelated, while the other four represented two generations from a single family, including a pair of identical twins, one of whom had not undergone splenectomy when this investigation was initiated. Of the four unrelated cases, one showed no departures from normal under the conditions of this investigation, whereas the other three exhibited features which suggested a membrane skeleton lesion. In one of these there was a reduced proportion of spectrin tetramers relative to dimers in 4 degrees C extracts, while the two remaining cases exhibited abnormal intramembrane particle aggregation. The four related cases had almost identical variations from normal. Spectrin was not extractable from their ghost membranes during a mild extraction incubation which removed spectrin from normal control ghosts. However, the intramembrane particle aggregation subsequently induced in these ghosts was of a degree unobtainable in normal ghosts without such spectrin extraction. In addition the ghosts from one twin, the only one of these patients who had not undergone splenectomy at the start of this investigation, showed a reduced amount of band 4.2. However, when this patient's blood was re-tested after splenectomy, this protein was found to be at normal levels. Our results support the view that hereditary spherocytosis is not a single disease, but is rather a term used to describe a variety of different molecular lesions of the erythrocyte membrane skeleton with similar clinical manifestations.

Isolation and characterization of mucoid and non-mucoid Salmonella oranienburg isolated from pleural effusion of a patient with hemolytic anemia

Salmonella oranienburg, mucoid and non-mucoid strains, were simultaneously isolated as causative agents from the pleural effusion of a patient with hereditary spherocytosis. The mucoid-typed Salmonella oranienburg was characterized by serological examination, taking advantage of the high frequency of mucoid (M) to non-mucoid (N) variation.