Glucose-6-phosphate dehydrogenase deficiency.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect, being present in more than 400 million people worldwide. The global distribution of this disorder is remarkably similar to that of malaria, lending support to the so-called malaria protection hypothesis. G6PD deficiency is an X-linked, hereditary genetic defect due to mutations in the G6PD gene, which cause functional variants with many biochemical and clinical phenotypes. About 140 mutations have been described: most are single base changes, leading to aminoacid substitutions. The most frequent clinical manifestations of G6PD deficiency are neonatal jaundice, and acute haemolytic anaemia, which is usually triggered by an exogenous agent. Some G6PD variants cause chronic haemolysis, leading to congenital non-spherocytic haemolytic anaemia. The most effective management of G6PD deficiency is to prevent haemolysis by avoiding oxidative stress. Screening programmes for the disorder are undertaken, depending on the prevalence of G6PD deficiency in a particular community.

Coagulation and splenectomy: an overview.

Venous thromboembolic events, such as pulmonary embolism, deep venous thrombosis, and portal vein thrombosis, have been observed in adult thalassemia patients, mainly in beta-thalassemia intermedia. The clinical findings are consistent with the observation of several alterations that indicate a state of activation of the hemostatic mechanisms in thalassemias. These alterations have usually been related to high platelet counts due to splenectomy and/or liver dysfunction. In a retrospective study of a large cohort of adults with thalassemia, we found a larger prevalence of venous thromboembolic events in transfusion-independent patients with thalassemia intermedia (29%) than in regularly transfused patients with thalassemia major (2%); moreover, the higher prevalence occurred particularly in splenectomized thalassemia intermedia patients. More recently, a multicenter study involving 56 tertiary referral centers in 7 countries was planned to assess the magnitude of thrombotic risk in thalassemia patients. The total number of patients who had thrombotic events was 146 (1.65%) out of 8860, with a prevalence of 0.9% in thalassemia major and 4% in thalassemia intermedia. The highest prevalence was confirmed in splenectomized patients. The observation that thrombotic events are more frequent in beta-thalassemia patients who are not receiving regular transfusions (thalassemia intermedia or thalassemia major patients in less developed countries with limited transfusion resources) or in thalassemic patients who have undergone splenectomy strongly supports the procoagulant activity of circulating damaged red blood cells.

Alcohol dehydrogenase: an autoantibody target in patients with alcoholic liver disease.

The link between alcohol consumption and liver disease is not direct and several factors including autoimmunity to hepatocyte components have been implicated. We have previously identified alcohol dehydrogenase (ADH) as an autoantigen in autoimmune liver disease and in a proportion of patients with alcoholic liver disease. The aim of the present study is to investigate the association between the presence of anti-ADH antibodies, alcohol consumption and severity of liver damage in alcoholic patients. The presence of antibodies to human ADH beta2 and horse ADH was investigated in 108 patients with documented history of alcohol consumption and alcohol related liver disease, 86 being active alcohol abusers and 22 on sustained alcohol withdrawal, 39 with non-alcohol related disease and 22 normal subjects. Antibodies to either ADH form were more frequently detected in active alcohol abusers (55/86, 64%) than in patients on sustained alcohol withdrawal longer than 6 months (1/8, 13 %, P < 0.005), HBV infection (2/8, 25 %, P=0.03), non-alcohol related disease (9/29, 23 %, P < 0.0001) and in normal controls (3/22, 14 %, P < 0.0001); were more frequent in patients with cirrhosis than in those with steatosis (26/34, 76 % vs 34/64, 53 %, P=0.02); and were associated with elevated levels of ALT (anti-ADH beta2, P < 0.05), immunoglobulin A (P < 0.05) and gamma-glutamyl transpeptidase (P=0.01). Anti-ADH antibody positive serum samples were able to inhibit the enzymatic activity of ADH. These findings suggest that anti-ADH antibodies may be triggered by alcohol consumption and act as a disease activity marker in alcoholic liver disease.

Increased susceptibility to nonalcoholic fatty liver disease in heterozygotes for the mutation responsible for hereditary hemochromatosis.

BACKGROUND: Insulin resistance is a key feature of nonalcoholic fatty liver disease. Patients with hereditary hemochromatosis, a disease characterized by progressive iron overload due, in most cases, to homozygosity for C282Y mutation in the HFE gene, have often decreased insulin sensitivity and release. AIMS: To determine whether increased iron parameters/heterozygosity for the mutations of the HFE gene confer susceptibility to nonalcoholic fatty liver disease. PATIENTS: One hundred and thirty-four consecutive Italian patients with clinical and ultrasonographic diagnosis of nonalcoholic fatty liver disease (82 with hyperferritinemia), half confirmed by liver biopsy. METHODS: Insulin was determined by radioimmunoassay. HFE gene mutations were determined by polymerase chain reaction and restriction fragment length polymorphism analysis. RESULTS: (1) Prevalence of C282Y HFE mutation was significantly higher in patients with nonalcoholic fatty liver disease compared to controls, the difference being more striking in patients with hyperferritinemia than in those without. (2) The presence of mild iron overload was associated with a lower insulin release. (3) Carriers of C282Y mutation developed nonalcoholic fatty liver disease despite lower body mass index and triglycerides. CONCLUSION: The mild iron overload associated with heterozygosity for C282Y HFE mutation confers susceptibility to nonalcoholic fatty liver disease, causing relative insulin deficiency.

Two-vector mechanics.

The conventional orthodontic appliance is not without its limitations for certain types of tooth movements; in particular, if the appliance cannot access the area to elicit the type of force vector for a particular displacement. Examples of such movements are: space closure by translation, uprighting and intrusion of posterior teeth, intrusion with retraction and lingual root torque of anterior teeth. In this paper we describe a mathematical method to design an appliance system that overcomes these difficulties. This system includes two statically determined elements and allows for highly controlled force vector application point and direction. A clinical case of midline discrepancy is shown to demonstrate the clinical use and utility of this method.

Estrogen metabolism in human colorectal cancer cells.

Epidemiological and "in vitro" studies support a direct role of estrogens in the pathogenesis and/or progression of colorectal cancer (CRC). Recent observations suggest a local synthesis of 17beta-estradiol (E(2)). In the present study, the CRC estrogen receptor beta (ERbeta) positive HCT8, HCT116, DLD-1 and LoVo cell lines were evaluated for expression of functional 17beta-hydroxysteroid dehydrogenase (17betaHSD) types 1, 2, 3, and 4. RT-PCR analysis revealed that while 17betaHSD1 and 17betaHSD4 were expressed in all the four cell lines, 17betaHSD2 and 17betaHSD3 were expressed in a cell-specific manner. The interconversion of tritiated estrone (E(1)) or E(2) evaluated by thin layer chromatography of conditioned media revealed that in HCT8, HCT116, and DLD-1 cells both reductive and oxidative activities were present, the latter showing K(m) values (approximately 10 microM) 40-fold higher than the former (approximately 250 nM). On the contrary, in LoVo cells, estrogens were almost (approximately 90%) completely metabolized to hydrophile compounds. Charcoal-dextrane (DC) stripped fetal calf serum (FCS) (10%), E(2) (10nM), Vitamin D(3) (100nM) and the combined E(2) and Vitamin D(3) treatment were evaluated for modulation of 17betaHSD isoenzymes gene expression and activity. Gene expression and activity of 17betaHSD reductive and oxidative isoenzymes were respectively inhibited and enhanced by Vitamin D(3) in HCT8 and LoVo cells. Surprisingly, DC-FCS induced a marked increase of estrogen metabolism toward hydrophile metabolites in all four cell lines. In conclusion, our results clearly show that metabolism of estrogens by 17betaHSD isoenzymes is functional and modulated by external stimuli in continuous neoplastic colonic epithelial cell lines.

Oxidative status and malondialdehyde in beta-thalassaemia patients.

BACKGROUND: In beta-thalassaemia syndromes, decreased or impaired biosynthesis of beta-globin leads to accumulation of unpaired alpha-globin chains. Moreover, the iron overload in beta-thalassaemia patients generates oxygen-free radicals and peroxidative tissue injury. The aim of this study was to detect and correlate iron overload parameters with the oxidative stress and the antioxidant capability in beta-thalassaemia patients. DESIGN: Serum iron, transferrin saturation, serum ferritin, nontransferrin-bound iron (NTBI), levels of serum free and total (free + bound) malondialdehyde (MDA) and total peroxyl radical-trapping antioxidant parameter (TRAP) were evaluated in 21 regularly transfused beta-thalassaemia major (TM) patients, 13 untransfused beta-thalassaemia intermedia (TI) patients and 17 healthy controls. Blood from the TM patients was drawn 48 h after the last desferoxamine (20-40 mg kg(-1)) infusion and just before transfusion. RESULTS: Free and total MDA and NTBI levels were higher in the TM patients than in the TI. In the TM patients the free MDA levels correlated positively with serum iron (r = +0.3, P = 0.0006), whereas the total MDA correlated positively with NTBI (r = +0.45, P = 0.037). However, a negative correlation was observed between TRAP and NTBI (r = -0.4, P = 0.0006). In the TI patients there was no significant correlation between free or total MDA and TRAP or NTBI. CONCLUSIONS: Our results confirm the peroxidative status generated by iron overload in thalassaemia patients and highlight the rapid formation of marked amounts of free MDA despite the chelation therapy in TM patients.

Contrast-enhanced Doppler ultrasonography in the diagnosis of hepatocellular carcinoma and premalignant lesions in patients with cirrhosis.

Hepatocellular carcinogenesis in cirrhosis is a multistage process that includes large regenerative nodules, dysplastic nodules, and hepatocarcinoma. The aim of this study was to establish whether contrast-enhanced Doppler ultrasonography (US) is able to distinguish between early hepatocellular carcinoma (HCC) and small nonmalignant nodules in cirrhosis. Between January 1998 and December 1999, 500 cirrhotic patients with no previous history of HCC or evidence of hepatic focal lesions were enrolled and prospectively followed-up with US every 6 months until December 2000. Sixty-one patients developed focal lesions, 12 multifocal, and 49 monofocal. Biopsy of focal lesions, contrast-enhanced Doppler US, and spiral computed tomography (CT) were performed in 41 consecutive patients with small (<3 cm) monofocal lesions. Twenty nodules were diagnosed as HCC and 21 as nonmalignant (14 large regenerative nodules, 3 low-grade, and 4 high-grade dysplastic nodules) by liver biopsy. Intratumoral arterial blood flow was detected in 19 of 20 (95%) HCC and 6 of 21 (28%) nonmalignant nodules by contrast-enhanced Doppler US (P<.0001). The mean peak resistance and pulsatility indices were 0.82 +/- 0.09 and 1.56 +/- 0.2 in HCC and 0.62 +/- 0.08 and 0.82 +/- 0.08 in dysplastic lesions (P =.002 and.0001), respectively. Spiral CT revealed arterial perfusion in 19 of 20 HCC and in 4 of 21 nonmalignant nodules (high-grade dysplastic nodules). Four of the apparently false-positive nodules at enhanced Doppler US were high-grade dysplastic nodules and 2 evolved to HCC during follow-up. In conclusion, contrast-enhanced Doppler US is a noninvasive, very sensitive technique in differentiating malignant and premalignant lesions from nonmalignant focal lesions in the liver.

Non-transferrin-bound iron in alcohol abusers.

BACKGROUND: Non-transferrin-bound iron, a low-molecular-weight iron complex capable of initiating free radical formation and lipid peroxidation, has been detected in the serum of animals experimentally fed with alcohol, but no data have been reported in alcohol abusers. The purpose of this study was to evaluate whether non-transferrin-bound iron is present in chronic alcohol abusers with liver involvement and whether alcohol plays any part in its appearance. METHODS: We measured non-transferrin-bound iron in a cohort of chronic alcohol abusers with and without liver cirrhosis at presentation, when 43 were active abusers and 33 were abstainers, and in a smaller group during a follow-up period. RESULTS: At presentation, non-transferrin-bound iron was detectable in 83.7% of active abusers but only in 21.2% of abstainers, and within the group of abusers, patients with cirrhosis had significantly higher non-transferrin-bound iron than patients without. Non-transferrin-bound iron was present not only in patients with transferrin saturation >45% but also in those with transferrin saturation < or =45%. Multiple regression analyses revealed that only alcohol intake and total bilirubin were associated independently with non-transferrin-bound iron values. Longitudinal study confirmed the data of the cross-sectional study. CONCLUSIONS: Non-transferrin-bound iron could have a role in initiating or promoting alcohol-induced liver damage.

Liver cancer risk is increased in patients with porphyria cutanea tarda in comparison to matched control patients with chronic liver disease.

BACKGROUND/AIMS: Patients with porphyria and chronic liver disease could be at high risk of developing hepatocellular carcinoma. To define the incidence of primary liver cancer and identify variables associated with the risk of cancer in patients with porphyria cutanea tarda in comparison to control patients. METHODS: Fifty-three patients with porphyria cutanea tarda were enrolled in a prospective study (median follow-up 72 +/- 54.1 months; range 12-216) and matched individually to a control case according to age (+/-5 years), sex, duration of follow up (+/- 5 years), severity of liver disease, and hepatitis C virus infection. RESULTS: During follow-up hepatocellular carcinoma developed in 18 patients with porphyria and in four control patients. Incidence of primary liver cancer was 4.8 and 1.3 x 100 patients/year in the overall series of patients and of controls, respectively. The cumulative probability of being tumor free was significantly lower in porphyria cutanea tarda than in matched controls (75 vs 95%). Variables independently associated with the risk of liver cancer were the presence of porphyria and cirrhosis at enrollment (Odds ratios: 5.3, 95% CI 1.4-19.3 and 3.0, 95% CI 1.2-7.6, respectively). CONCLUSIONS: Patients with porphyria are at higher risk of developing liver cancer than matched control patients.

Mutations in the HFE gene and their interaction with exogenous risk factors in hepatocellular carcinoma.

The possible role of iron in facilitating the development of liver cancer is still debated. The aims of this study were to define the prevalence of the mutations 845G --> A and 187C --> G (C282Y and H63D) in the HFE gene associated with hereditary hemochromatosis in Italian patients with hepatocellular carcinoma occurring in cirrhosis and to analyze the interaction between these mutations and other established risk factors for hepatocellular carcinoma. The HFE gene mutations, performed by polymerase chain reaction, were analyzed in 81 patients (63 males, 18 females) with hepatocellular carcinoma. None of the patients had a phenotype compatible with homozygous hereditary hemochromatosis. Interaction between HFE mutations and exogenous risk factors was analyzed by collecting information on alcohol consumption, hepatitis B and C virus infections, and iron status at the time of diagnosis of chronic liver disease. This analysis was performed only in males to rule out gender influence on patients' iron status by using the case-only approach specifically designed to estimate departure from multiplicative risk ratios under the assumption of independence between genotype and environmental exposure. The prevalence of the C282Y mutation was significantly higher in patients with hepatocellular carcinoma than in normal controls (8.6% vs 1.6%, P < 0.03). At univariate analysis, iron overload was significantly associated with both HFE mutations (P < 0.0001), whereas ongoing hepatitis B virus infection was associated with the C282Y mutation (P < 0.05). By multivariate analysis, a trend for an increased risk of being positive for hepatitis virus markers (OR 2.9, CI 95% 0.9-9.5) and of having been alcohol abusers (OR 3, CI 95% 0.7-14) was observed in patients heterozygous for the HFE mutations. These data indicate that the prevalence of the main mutation associated with hereditary hemochromatosis is significantly higher in cirrhotic Italian patients with hepatocellular carcinoma compared to a normal population and suggest that heterozygotes for HFE mutations exposed to hepatitis virus infections or who had been alcohol abusers could have an increased risk of developing cirrhosis and later liver cancer than people without the mutations exposed to the same risk factors.

Hyperferritinemia, iron overload, and multiple metabolic alterations identify patients at risk for nonalcoholic steatohepatitis.

OBJECTIVE: The aim of this study was to define in patients with hyperferritinemia and normal transferrin saturation the relationships among hyperferritinemia, iron overload, HFE gene mutations, the presence of metabolic alterations, and nonalcoholic steatohepatitis (NASH). METHODS: Forty patients with increased serum ferritin, resistant to dietary restriction and normal transferrin saturation, 90 with ultrasonographic evidence of hepatic steatosis, and 60 obligate heterozygotes for hemochromatosis, all negative for alcohol abuse, hepatitis virus infections, and inflammation were studied. Transferrin saturation, serum ferritin, uric acid, lipids, glucose tolerance, insulin resistance, HFE gene mutations, liver histology, and hepatic iron concentration were analyzed. RESULTS: Of the 40 patients with hyperferritinemia, 29 (72%) had biochemical metabolic abnormalities, 18 of the 26 examined (69%) had insulin resistance, 26 (65%) had the presence of one of the two HFE gene mutations (normal controls, 33 of 128 [26%], p < 0.0001), and all had increased liver iron concentration. Thirty-one patients (77%) had histology compatible with NASH. At univariate analysis, NASH was significantly associated with the presence of metabolic alterations, the C282Y mutation, and severity of fibrosis. At multivariate analysis, NASH was associated with the coexistence of multiple metabolic alterations (odds ratio = 5.2, 95% CI = 0.95-28.7). The risk of having NASH augmented in the presence of higher values of ferritin and liver iron concentration. Among the 90 patients with ultrasonographic evidence of hepatic steatosis, 24 (27%) had increased serum ferritin with normal transferrin saturation, but only six remained hyperferritinemic after dietary restriction. CONCLUSION: Increased ferritin with normal transferrin saturation is frequently found in patients with hepatic steatosis, but it reflects iron overload only in those patients in whom it persists despite an appropriate diet. The simultaneous disorder of iron and glucose and/or lipid metabolism, in most of the cases associated with insulin resistance, is responsible for persistent hyperferritinemia and identifies patients at risk for NASH.

Tumor necrosis factor alpha promoter polymorphisms influence the phenotypic expression of hereditary hemochromatosis.

Severe iron overload usually develops in patients with hereditary hemochromatosis (HHC), but variability in the phenotypic expression of the disease has been reported. This study assessed whether tumor necrosis factor alpha (TNF-alpha) plays a role in phenotypic expression of HHC. Sixty-four patients with HHC and 172 healthy volunteers (controls) were studied. Release of TNF-alpha from stimulated peripheral blood monocytes was measured by enzyme-linked immunosorbent assay, and 308 and 238 TNF-alpha polymorphisms were detected with polymerase chain reaction and restriction fragment-length polymorphism analysis. The relation between TNF-alpha polymorphisms and clinical expression of HHC was evaluated. Patients with HHC released less TNF-alpha than controls, but the difference was significant only in homozygotes for the C282Y mutation. The prevalence of the 308 TNF-alpha polymorphism was similar in patients and controls, whereas the prevalence of the 238 polymorphic allele was significantly lower in patients (3% versus 16%; P =.002). A lower prevalence of cirrhosis was observed in patients with TNF-alpha polymorphism than in those without it (4 of 15 [27%] versus 28 of 49 [57%]), but the difference was not significant (P =.07). In nonhomozygotes for the C282Y mutation, severe liver siderosis was less prevalent in patients with the 308 polymorphism than in those without it (P =.05). Alanine aminotransferase (ALT) values were significantly lower in patients with TNF-alpha polymorphism (P =.006), even when patients with other hepatotoxic factors were excluded. Multivariate analysis showed that TNF-alpha polymorphism was independently associated with ALT values (P =.0008 and P =.045, respectively, in homozygotes and nonhomozygotes for the C282Y mutation) and siderosis in nonhomozygotes (P =.047). Thus, TNF-alpha appears to play a role in HHC by modulating the severity of liver damage. (Blood. 2001;97:3707-3712)

Seven novel point mutations in the uroporphyrinogen decarboxylase (UROD) gene in patients with familial porphyria cutanea tarda (f-PCT).

In this work, we describe seven novel molecular defects in the uroporphyrinogen decarboxylase gene responsible for familial porphyria cutanea tarda in Italian subjects with reduced erythrocyte URO-D activity. Four of these molecular abnormalities (R142Q, L161Q, S219F, P235S) are missense mutations, one (Q206X) is a nonsense mutation, one (IVS8-1 G>C) is a splicing defect causing the exon 9 deletion and one (1107 G>A) is located in the 3' untranslated region of UROD gene. All the amino acid substitutions fall in conserved regions in several organisms suggesting an important role in catalysis or in the protein structure stabilization. Three of these mutations have been detected in more than one subject. These results suggest a molecular heterogeneity at the UROD locus in Italian PCT patients although recurrent mutations have been identified.

Membrane-bound iron contributes to oxidative damage of beta-thalassaemia intermedia erythrocytes.

Iron-dependent oxidative reactions in beta-thalassaemic erythrocyte membranes are involved in premature cell removal and anaemia. We studied 22 beta-thalassaemia intermedia patients (i) to assess if membrane iron accumulation influences the oxidative damage to thalassaemic cells, and (ii) to see whether the mechanisms of haemoglobin destabilization described in vitro have indicators in circulating erythrocytes. Serum non-transferrin-bound iron as potentially toxic iron for erythrocytes was also evaluated. Membrane-bound free iron significantly correlated to bound haemichromes, suggesting a causal relation, but was poorly related to serum non-transferrin iron, which seems to contribute little to damage from outside the cells. The spleen played an important role in the removal of cells with more membrane iron.

TT virus infection in adult beta-thalassemia major patients.

BACKGROUND AND OBJECTIVES: Patients with thalassemia-major are at risk of blood-borne viral infections. TT virus (TTV), a single stranded, circular DNA virus, has recently been found to be associated with acute and chronic hepatitis. The aims of this study were to assess the prevalence of TTV infection in adult patients with transfusion-dependent thalassemia, and to evaluate the clinical significance of TTV. DESIGN AND METHODS: We studied 68 adult patients with thalassemia major, 97% of whom were hepatitis C virus (HCV) antibody positive. TTV DNA was amplified from serum by heminested polymerase chain reaction (PCR). Direct sequencing of PCR products was used to establish TTV genotypes. RESULTS: TTV DNA was detected in 47 patients (69.1%). Sequence analysis of PCR products identified TTV genotype 1b as the most common viral genotype in this group. Patients co-infected by HCV and TTV had a significantly higher histologic grade score than patients with isolated HCV infection (5.1+/-2.7 vs. 2.8+/-1.7, p=0.02) while the stage score was not significantly different. INTERPRETATION AND CONCLUSIONS: TTV is highly prevalent among Italian multiply transfused patients. In these patients TTV viremia appears to affect the necro-inflammatory activity of hepatitis C, though no evidence of an effect on the evolution of fibrosis was found.

Acute intermittent porphyria: heterogeneity of mutations in the hydroxymethylbilane synthase gene in Italy.

Acute intermittent porphyria (AIP) is an autosomal disorder caused by molecular abnormalities in the gene coding for hydroxymethylbilane synthase (HMBS), the third enzyme in the heme biosynthetic pathway. So far, more than 170 different mutations responsible for AIP have been identified worldwide in the HMBS gene. In this study we have performed molecular characterization in 14 patients with suspected diagnosis of AIP and in 29 family members of Italian ancestry. Molecular analysis of the HMBS gene allowed us to identify 13 different mutations among 14 patients with reduced HMBS activity: 5 splicing defects (IVS9+22 G>A, 612 G>T, IVS11-2 delA, IVS12+2 T>C, and IVS13-1 G>A), 1 small insertion (182 insGA), 1 small deletion (730-731 delCT), and 6 missense/nonsense mutations (76 C>T, 295 G>A, 331 G>A, 580 C>T, 673 C>T, and 874 C>T), resulting in single-amino-acid substitutions or protein truncations. Six of these molecular abnormalities had already been described and 7 are new findings. In a previous work on an Italian population we detected 7 different mutations among 8 AIP patients. This study has raised to 18 the number of different mutations so far found among the Italian AIP population, 11 of which are new findings. We can conclude that the mutation screening in the Italian population contributes to improvement of the diagnostic approach of AIP and to establishing possible clustering of mutations in the Mediterranean area.

Venous thromboembolism and hypercoagulability in splenectomized patients with thalassaemia intermedia.

Thromboembolic phenomena have been described in patients with thalassaemia intermedia and major, although there are relatively few epidemiological data on the overall frequency of these complications. To obtain more insight into the risk and mechanism of venous thromboembolism in thalassaemia, the aims of this study were: (i) to establish retrospectively the prevalence of thromboembolic events in a large group of adults with thalassaemia intermedia and major during a follow up period of 10 years; (ii) to measure in subgroups of these patients sensitive markers of activation of coagulation and fibrinolysis enzymes; and (iii) to look for possible procoagulant mechanisms. A high prevalence of thromboembolic events was found, particularly in splenectomized patients with thalassaemia intermedia (29%). These patients had high plasma levels of markers of coagulation and fibrinolysis activation. Furthermore, thalassaemic red cells and erythroid precursors from splenectomized patients with thalassaemia intermedia had an enhanced capacity to generate thrombin. To evaluate the role of splenectomy per se on procoagulant activity, we evaluated the capacity to form thrombin in healthy individuals who had been splenectomized for trauma. They produced the same amount of thrombin as non-splenectomized controls. In conclusion, the results of this study show the existence of a hypercoagulable state in splenectomized patients with thalassaemia intermedia and that their red and erythroid cells are capable of acting as activated platelets in thrombin generation.