[Prevention of infections and thromboses after splenectomy or because of functional loss of the spleen]. / Prävention von Infektionen und Thrombosen nach Splenektomie oder bei Funktionsverlust der Milz.

Overwhelming Post-Splenectomy Infection (OPSI or PSS), most frequently caused by encapsulated Gram-positive pathogens, is a complication after splenectomy. Reasons for splenectomy include trauma, or malignant and non-malignant hematologic diseases. OPSI-inducing bacteria are mainly Streptococcus pneumoniae and less frequently Haemophilus influenzae, Neisseria meningitides and Gram-negative bacilli. There exist very efficient--albeit often neglected--strategies, how to prevent infections in patients after splenectomy. These include vaccination, prophylactic antibiotics (always for 3 years during childhood and adolescence) and prompt antibiotic treatment, if an infection is suspected. Patients need to know the nature and likelihood of PSS and they should seek immediate medical attention if they become ill or febrile. Each patient should carry at all times a letter or card documenting the splenectomy. With these measures and precautions, the PSS-risk can be significantly reduced or at best be completely avoided.

Mode of splenectomy and immunogenicity of meningococcal vaccination in patients with hereditary spherocytosis.

BACKGROUND: Splenectomy predisposes patients to invasive disease from pneumococci, meningococci, and Haemophilus influenzae; immunization is mandatory. However, data on the impact of the splenectomy on vaccine immunogenicity are scarce. METHODS: A total of 41 children with hereditary spherocytosis (aged 5.8-14.4 years) had complete (16) or near-total (25) splenectomy. All received one dose of monovalent meningococcal C conjugate vaccine (MCV-C) and, 2 months later, a tetravalent meningococcal polysaccharide vaccine (MPV-ACWY). Serum bactericidal activity and antibodies against serogroups A and C were determined before and after they received MCV-C, and 4 weeks after they received MPV-ACWY. RESULTS: Before vaccination, only four of the 16 children who had a complete splenectomy were protected against serogroup A, compared with 15 of the 25 who had near-total splenectomy (P < 0.050), with the latter responding to immunization with significantly higher serogroup A serum bactericidal activity: geometric mean (95 per cent confidence interval) 1625.5 (49.9 to 3201.1) versus 980.6 (2.00 to 6204.1) (P < 0.050). All patients achieved putative protective serum bactericidal activity titres (at least 8) against serogroup C. CONCLUSION: Near-total splenectomy provides a favourable immunological basis for natural and vaccine-induced protection against meningococcal serogroup A and C infections. Sequential meningococcal vaccination is immunogenic in patients splenectomized for hereditary spherocytosis.

Favorable response of pediatric stem cell recipients to human protein C concentrate substitution for veno-occlusive disease.

Plasminogen activator inhibitor 1 is known to be elevated in patients with hepatic VOD after intensive chemotherapy. To re-establish endogenous fibrinolysis and to inhibit thrombin formation, we used non-APC (zymogen) to normalize PAI-1 levels. As a consequence of thrombin formation inhibition and the consecutive inhibition of the coagulation cascade, this treatment is expected to reduce the elevated D-dimer level. Six pediatric stem cell recipients with moderate or severe VOD after busulfan or total body irradiation conditioning regimen are reported here who were therapy-refractory to defibrotide or rt-PA therapy. All patients had low levels of PC activity (16-39%). The administration of PC (60-240 IU/kg) led to a rapid and sustained rise in PC activity (target level >80%) with near normalization of prothrombin and partial thromboplastin time in all patients. Elevated PAI-1 levels declined. Five of the six patients showed a good clinical response with prompt resolution of clinical, sonographic, and laboratory signs of hepatic blood flow obstruction, while one patient with severe VOD, as well as concomitant liver GVHD and CMV disease, had a slow but detectable response to PC therapy. All patients survived.

[Red cell membrane defects]. / Erythrozytäre Membrankrankheiten.

Genetic defects of red cell membrane proteins constitute in Europe the most common cause of congenital hemolytic anemias. During the past decennium the defects and the pathogenetic mechanisms have been eludicated. Relatively simple hematologic tests allow for differentiation into groups with different severity of the disease. This allows prognostic assessment and careful risk-benefit evaluation for splenectomy.

[Antiinfectious prophylaxis in asplenia]. / Infektionsprophylaxe bei Asplenie.

Asplenia in childhood may be congenital (e.g. Ivemark-syndrome) or acquired (functional hyposplenism in sickle cell disease; after splenectomy or bone marrow transplantation). Hereditary spherocytosis is the most common indication for splenectomy in childhood. Virtually every patient without spleen has a significantly increased risk of severe postsplenectomy infection (mostly caused by Streptococcus pneumoniae). Therefore, vaccinations against pneumococci, haemophilus influenzae and, under certain circumstances, meningococci are recommended. In addition a continuous prophylaxis with antibiotics should be performed for at least three years (or even longer depending on the disease) after splenectomy followed by lifelong interventional application of broad spectrum antibiotics in case of any unclear infection or high fever. This prophylaxis must be started as early as four months of age in sickle cell disease. In future the use of penicillin may be hampered by the growing resistance of pneumococci. Due to this fact the indication for splenectomy in childhood should be restricted to patients with hematologic disease (spherocytosis and other hemolytic anemias, chronic ITP etc.) and moderate to severe symptoms. It is unclear whether partial splenectomy for spherocytosis (and other hemolytic anemias) is an alternative regarding both longlasting reduction of hemolysis and prevention of severe infection. After trauma every effort should be undertaken to preserve a splenic remnant.

Characteristic features of the genotype and phenotype of hereditary spherocytosis in the Japanese population.

Hereditary spherocytosis (HS) is the most common hemolytic anemia of congenital origin in the Japanese population. Among 844 cases of 520 kindred with congenital red cell membrane disorders studied at the Kawasaki Medical School in the last 25 years (1975-1999), 407 cases (48.2%) of 215 kindred had HS. Among the recent 60 kindred with HS, autosomal dominant (AD) transmission was proven in 19. The remaining 41 non-AD HS included 1) homozygous patients with autosomal recessive inheritance, 2) HS patients with de novo gene mutations, and 3) mild HS with AD inheritance. The extent of clinical severity in the non-AD HS cases was nearly identical to that in the AD cases. The incidence of membrane protein abnormalities in our 60 Japanese HS kindred was unique: there were lower ankyrin deficiencies (7%), moderate band 3 deficiencies (20%), and much higher protein 4.2 deficiencies (45%), with 28% of unknown etiology. The incidence of membrane protein deficiencies corresponded to that determined by gene analyses; i.e., mutations mostly in band 3 and/or in protein 4.2 genes and fewer ankyrin gene mutations. In the band 3 gene, 11 mutations pathognomonic for HS were identified (3 frameshift and 8 missense mutations). There were 5 mutations of the protein 4.2 gene (3 missense mutations, 1 nonsense mutation, and 1 splicing mutation) pathognomonic for HS. On the other hand, 2 missense mutations were detected in the ankyrin gene in this study. The genetic abnormalities in our HS patients correlated well with the phenotypic ultrastructural abnormalities of red cell membranes in situ. Ankyrin mutations (ankyrin Marburg and ankyrin Stuttgart with frameshift mutations) were associated mostly with a disrupted cytoskeletal network, and band 3 mutations (band 3 Kagoshima with frameshift mutation) typically demonstrated anomalies of intramembrane particles (IMPs). Protein 4.2 mutations (homozygotes of protein 4.2 Nippon) with complete protein 4.2 deficiency showed abnormalities of both the cytoskeletal network and IMPs.

Frequency of very late fatal sepsis after splenectomy for hereditary spherocytosis: impact of insufficient antibody response to pneumococcal infection.

Very late sepsis in splenectomized patients with hereditary spherocytosis has been seen rarely up to now; the frequency and the immunodeficiency causing it are largely unknown. Within the past 7 years we have learned of four cases of sepsis or meningitis (three fatal) in adult patients with hereditary spherocytosis who had been splenectomized years earlier. The estimated frequency of very late postsplenectomy infections is 0.69 cases of sepsis or meningitis in 1000 patient-years (0.46 deaths in 1000 patient-years). Pneumococci were proven in two patients. The surviving patient showed low antibody titers against pneumococcal serotypes even after pneumococcal meningitis and subsequent vaccination. There have been several reports of an insufficient response to pneumococcal vaccination in patients with severe infections. We recommend determination of pneumococcal antibody titers after immunization in every splenectomized patient: Nonresponders to vaccination may be at high risk for overwhelming postsplenectomy infection. Our data demonstrate that there is a lifelong risk for severe postsplenectomy infections and therefore the lasting need for immediate antibiotic therapy in any case with sudden onset of high fever.

Application of RHD and RHCE genotyping for correct blood group determination in chronically transfused patients.

BACKGROUND: In chronically transfused patients, conventional blood group typing may be impossible because of mixed-field agglutination. STUDY DESIGN AND METHODS: In 27 patients with congenital anemia and lifelong transfusion history, genotyping for D, RHD, and RHCE was performed with polymerase chain reactions. These results were compared with the blood group typing results documented in the medical record. RESULTS: Two of 27 cases had been typed D-negative by serologic tests and D-positive by genotyping. In 20 patients, the CDE formula had been determined serologically according to the medical record; 4 of these patients were Cc by serologic tests and C/C by genotyping. One patient typed ee by serologic tests, and genotyping revealed heterozygosity (E/e). CONCLUSION: In patients with a lifelong transfusion history, serologic blood group determination may be impossible, and pretransfusion test results are not always available or reliable. In whites, Rh-matched transfusions are possible with genotyping. The genetic background of the RH genes has to be elucidated in other ethnic groups, such as in black patients with sickle cell disease, before genotyping can be applied without restriction.

[Postoperative antibiotic therapy of cervical lymphadenitis caused by nontuberculous, atypical mycobacteria]. / Die postoperative antibiotische Therapie von zervikalen Lymphadenitiden durch nichttuberkulöse, atypische Mykobakterien.

BACKGROUND: Cervical lymphadenitis caused by atypical mycobacteria is increasingly observed in immunocompetent children between 1 and 5 years of age. Surgical excision of all affected lymph nodes represents the treatment of choice. However, due to the infiltrative nature of the disease, surgery is occasionally unable to provide a complete cure and is associated with a high risk of recurrence. Such cases might derive benefit from an additional antibiotic therapy. METHODS: The study includes 4 children with demonstrated or clinically suspected nontuberculous mycobacterial lymphadenitis, in whom partial surgery had been performed. Postoperatively, two patients were treated with clarithromycin, rifabutin, and protionamide, the others with clarithromycin alone. Antibiotics were administered orally for 6-12 weeks and were continued four weeks after local signs of inflammation were no longer detectable. RESULTS: In all cases, symptoms of lymphadenitis resolved within 1-2 months and did not recur. One patient was affected by WHO grade I leukopenia after 6 weeks, which soon disappeared after administration of rifabutin and protionamid had been discontinued. CONCLUSIONS: Postoperative antibiotic therapy seems to be an effective approach to treat residual disease following incomplete surgery. It remains to be clarified, however, if such a therapy should comprise combinations of agents or if administration of clarithromycin alone might be sufficient.

Regulation of band 3 rotational mobility by ankyrin in intact human red cells.

Ankyrin mutations and combined spectrin and ankyrin deficiency are prominent features of red blood cells (RBCs) in patients with hereditary spherocytosis (HS). Band 3 is the most abundant integral protein in the human RBC membrane. Previous studies have shown that the lateral mobility, but not the rotational mobility, of band 3 is increased in RBCs from patients with severe autosomal recessive HS and selective spectrin deficiency. These observations are consistent with the steric hindrance model of lateral mobility restriction. Here we use the fluorescence photobleaching recovery and polarized fluorescence depletion techniques to measure the lateral and rotational mobility of band 3 in intact RBCs from six patients with HS, ankyrin mutations, and combined spectrin and ankyrin deficiency. As predicted by the steric hindrance model, the lateral diffusion rate of band 3 is greater in spectrin- and ankyrin-deficient RBCs than in control cells, and the magnitude of the increase correlates with the degree of spectrin deficiency. Unlike RBCs from patients with HS and selective spectrin deficiency, however, HS RBCs with ankyrin mutations exhibit a marked increase in band 3 rotational diffusion. The magnitude of the increase correlates inversely with the ankyrin/band 3 ratio and with the fraction of band 3 retained in the membrane skeleton following detergent extraction. These data suggest that ankyrin deficiency relaxes rotational constraints on the major (slowly rotating) population of band 3 molecules. Increases in band 3 rotation could be due to release of band 3 from low-affinity binding sites on ankyrin.

Ankyrin-1 mutations are a major cause of dominant and recessive hereditary spherocytosis.

Hereditary spherocytosis (HS) is the most common inherited haemolytic anaemia in Northern Europeans. The primary molecular defects reside in the red blood cell (RBC) membrane, particularly in proteins that link the membrane skeleton to the overlying lipid bilayer and its integral membrane constituents. Ankyrin-1 is the predominant linker molecule. It attaches spectrin, the major skeletal protein, to the cytoplasmic domain of band 3, the RBC anion exchanger. Two-thirds of patients with HS have combined spectrin and ankyrin-1 deficiency; deficiency of band 3 occurs in about 15 to 20% (ref.1). These data suggest that ankyrin-1 or band 3 defects may be common in HS. To test this we screened all 42 coding exons plus the 5' untranslated/promoter region of ankyrin-1 and the 19 coding exons of band 3 in 46 HS families. Twelve ankyrin-1 mutations and five band 3 mutations were identified. Missense mutations and a mutation in the putative ankyrin-1 promoter were common in recessive HS. In contrast, ankyrin-1 and band 3 frameshift and nonsense null mutations prevailed in dominant HS. Increased accumulation of the normal protein product partially compensated for the ankyrin-1 or band 3 defects in some of these null mutations. Our findings indicate that ankyrin-1 mutations are a major cause of dominant and recessive HS (approximately 35 to 65%), that band 3 mutations are less common (approximately 15 to 25%), and that the severity of HS is modified by factors other than the primary gene defect.

Thrombo-embolic disease after splenectomy for hereditary stomatocytosis.

Nine cases of hereditary stomatocytosis (HSt) are presented which show documented thrombotic complications after splenectomy. In three cases, patients became severely ill with pulmonary hypertension and a fourth developed portal hypertension. One unsplenectomized affected adult relative had suspected but unconfirmed thrombotic pathology; the six other affected unsplenectomized adults did not. Since splenectomy is of only limited therapeutic benefit in stomatocytosis, it should not be performed without careful consideration. A tendency to iron overload, even without hypertransfusion and irrespective of splenectomy, is evident in many of these patients.

Triosephosphate isomerase deficiency: biochemical and molecular genetic analysis for prenatal diagnosis.

Inherited deficiency of the glycolytic enzyme triosephosphate isomerase leads to a multisystem disorder characterized by progressive neuromuscular dysfunction, chronic nonspherocytic hemolytic anemia and increased susceptibility to severe infections. Most patients die within the first 6 years. We examined a family with severe triosephosphate isomerase deficiency. The 1-year-old index patient suffered from hemolytic anemia, neuromuscular impairment and pneumonias, with the necessity of intermitten mechanical ventilation. Triosephosphate isomerase activity in erythrocytes was reduced to about 20% of normal. Heat stability of the enzyme was strongly reduced; concentration of the physiological substrate, dihydroxyacetone phosphate was increased 20-fold due to the metabolic block. Direct sequencing of the triosephosphate isomerase gene revealed homozygosity for the formerly described GAG-->GAC-mutation changing 104 Glu-->Asp. During a 2nd pregnancy we examined a cord blood sample obtained in the 19th gestational week. The biochemical data on enzyme activity, heat stability of the enzyme and concentration of dihydroxyacetone phosphate were in the normal range. The molecular genetic analysis confirmed the presence of the normal triosephosphate isomerase alleles. Pregnancy was continued, resulting in the delivery of an unaffected, healthy newborn.

Combined ankyrin and spectrin deficiency in hereditary spherocytosis.

Hereditary spherocytosis is characterized by a reduced spectrin content of the erythrocytes. However, the underlying primary defect remains unclear in the majority of cases. Genetic studies have revealed a linkage to the gene for ankyrin in some families. By means of ELISA we measured the ankyrin, spectrin, and band-3 contents in erythrocytes of 45 patients with typical spherocytosis. They were classified as having mild or moderate spherocytosis, according to clinical severity. Sixteen patients with mild spherocytosis showed slight reductions of ankyrin and spectrin contents. In contrast, 29 patients with moderate spherocytosis exhibited a clear reduction of both ankyrin and spectrin to about 60% of normal. Band 3 and lipid phosphorus, as measures for membrane surface area, were only slightly reduced to 85%. Our results, together with the molecular genetic data indicating the linkage between spherocytosis and the gene for ankyrin, suggest an ankyrin defect or deficiency as the primary lesion in most cases of spherocytosis.

[Hemolytic-uremic syndrome in pneumococcal meningitis and infection. Importance of T-transformation]. / Hämolytisch-urämisches Syndrom bei Pneumokokken-meningitis und -sepsis. Bedeutung der T-Transformation.

A 4 month old girl developed a severe hemolytic uremic syndrome (HUS) following pneumococcal sepsis and meningitis. As a result of the hemolytic anemia and thrombocytopenia with associated gastrointestinal bleeding several red blood cell and thrombocyte transfusions became necessary. No plasma was transfused to the patient and all cellular blood components to be transfused were washed thoroughly in order to avoid the administration of eventually dangerous donor anti-T antibodies. Continuous peritoneal dialysis was performed for 23 days until sufficient spontaneous urine production was resumed. From the start of increased hemolysis T-transformation of the patient's red blood cells could be shown; bacterial neuraminidase was proven in the patient's serum, which could be neutralized in vitro by a commercial intravenous IgG preparation. The direct Coombs-Test was negative and no significant amounts of anti-T antibodies were detectable in the patient's serum at any stage of the disease. Our observation suggest that the T-transformation itself has caused the increased hemolysis and not an antigen-antibody (T-anti-T) reaction. In cases of HUS und proven T-transformation, intravenous IgG preparations should be tried therapeutically to inhibit the bacterial neuraminidase.

Prevalence of increased osmotic fragility of erythrocytes in German blood donors: screening using a modified glycerol lysis test.

We screened for increased osmotic fragility of erythrocytes in 1464 healthy German blood donors. The osmotic fragility was determined by an acidified glycerol lysis test (AGLT) using glycerol-sodium phosphate-buffered NaCl solution. Since the original test described by Zanella et al. [23] showed only low specificity for hereditary spherocytosis, we used a modification with 0.0093 M sodium phosphate-buffered glycerol-saline solution, pH 6.90, instead of the original 0.0053 M sodium phosphate buffer, pH 6.85. Sixteen of the donors (1.1%) had a "pathologic result," similar to that of 32 patients with hereditary spherocytosis: AGLT 50 less than 5 min ("half-time of AGLT, defining normal and pathologic results). The osmotic fragility of the erythrocytes from 12 of these donors was further investigated using the conventional test with hypotonic NaCl solutions. With one exception, increased osmotic fragility was verified in all of them by both tests. Further hematologic data showed a mild reticulocytosis (2% and 2.6%) in two of the donors. One donor had a moderate reticulocytosis of 6.5%, probably due to a mild, previously undiagnosed spherocytosis; 99 of the donors had an intermediate result (AGLT 50: 5-30 min). Hypotonic lysis of their erythrocytes by the conventional method showed a normal result; there were no signs of increased hemolysis. Thus they are not definitely regarded as having increased osmotic fragility of their erythrocytes. Erythrocyte osmotic fragility shows a wide distribution range in the normal population and might be normally distributed. Thus the blood donors with "pathologic AGLT (less than 5 min)" probably represent only one end of a continuum of salt-dependent hemolysis, and not a separate entity. However, they did show additional minor signs of a functional defect of the erythrocyte membrane and therefore could be carriers of a spherocytosis trait. The frequency of carriers of an erythrocyte membrane defect (possible spherocytosis trait) could be as high as 1.1% in the general population and would distinctly exceed the prevalence of patients with apparent spherocytosis (0.02%).