Identification of homozygous hemochromatosis subjects by measurement of hepatic iron index

The value of measurement of hepatic iron concentration and determination of the hepatic iron index in distinguishing homozygotes from heterozygotes for hemochromatosis was examined. The study group included 42 homozygotes with an unequivocal diagnosis of hemochromatosis and six individuals who had initial equivocal results but were established as homozygous after extensive follow-up. These were compared with 15 heterozygotes with no sign of increasing body iron stores who had undergone liver biopsy because of an initial suspicion of raised iron levels. In these subjects a hepatic iron concentration of greater than 75 mumol/gm dry weight was clearly indicative of homozygous hemochromatosis. Body iron accumulation was age-related both in homozygotes and in these heterozygotes with mild biochemical abnormalities (r = 0.476; p = 0.001 and r = 0.689; p = 0.01, respectively), with a rate of accretion of approximately 5 mumol/gm dry weight/year in homozygotes and 0.9 mumol/gm dry weight/year in heterozygotes. Thus, lower values in young subjects may be consistent with homozygosity, and higher values in older individuals are consistent with heterozygosity. To overcome this problem, the hepatic iron index (hepatic iron concentration divided by age in years) was analyzed and found to separate the two groups effectively, with no homozygote having an index of less than 1.9 and no heterozygote having an index of greater than 1.5. These results in a series of patients who have been followed for a median of 3 yr (range = 1 to 30 yr) validate the use of the hepatic iron index to discriminate hemochromatosis homozygotes from heterozygotes with raised levels of serum ferritin, transferrin saturation or both.     

Value of hepatic iron measurements in early hemochromatosis and determination of the critical iron level associated with fibrosis

The role of the measurement of hepatic iron in the diagnosis of genetic hemochromatosis was studied, with particular reference to the differentiation of early hemochromatosis from alcoholic siderosis and the critical hepatic iron concentration associated with fibrosis in hemochromatosis. Hepatic iron was measured in 30 homozygous relatives of 17 hemochromatosis probands, 8 heterozygous relatives, 51 patients with alcoholic liver disease and 40 control subjects. Hepatic iron concentrations were greatly increased in the majority of homozygous hemochromatosis subjects, and there was little overlap with the other groups. In the absence of alcoholism, fibrosis or cirrhosis in hemochromatosis was present only with hepatic iron concentrations above a threshold of approximately 400 mumoles per gm (22.3 mg per gm) dry weight. In some heterozygous hemochromatosis subjects and in some alcoholic patients, hepatic iron concentrations were in the range seen in young homozygous subjects. However, an age-related rise in hepatic iron was seen only in hemochromatosis homozygotes, and calculation of an hepatic iron index (hepatic iron/age) resulted in a clear distinction between homozygotes and the other three groups. It is concluded: that chemical measurement of hepatic iron concentration, when corrected for the age of the subject, reliably distinguishes early hemochromatosis from alcoholic siderosis, and, that there appears to be a threshold level of hepatic iron above which there is a high risk of fibrosis.     

Hepatic ferritin uptake and hepatic iron

The effect of hepatic iron on the uptake of ferritin was studied by perfusing livers from normal, iron-deficient and iron-loaded rats with 125I-labeled ferritin. Unlabeled ferritin with tracer doses of labeled ferritin in concentrations of 0.02 to 2,700 nmol/L were studied. Rats were made iron deficient by feeding an established iron-deficient diet for 3 wk. Rats were iron loaded by injection of iron dextran (50 mg/wk) for 3 wk. The mean percentage of uptake of ferritin was similar for doses ranging from 0.22 to 22.2 nmol/L of 125I-labeled ferritin. Uptake of ferritin in the normal animal was saturable, with an apparent maximal velocity of uptake of approximately 9.1 pmol/gm/min and a Michaelis-Menten constant of approximately 5 nmol/L at 37 degrees C. Uptake was minimal at 4 degrees C. The mean uptake of ferritin was 78% +/- 10% in the iron-deficient rats (mean hepatic iron = 1.5 mumol/gm), 79% +/- 10% in the normal animals (mean hepatic iron = 9.2 mumol/gm) and 78% +/- 8% in the iron-loaded animals (mean hepatic iron = 192 mumol/gm). In this experimental system, modulation of hepatic iron did not affect uptake of ferritin, suggesting that regulation of the hepatic ferritin receptor may not depend on hepatic iron content. The rapid uptake of ferritin by the liver despite iron overload is consistent with other observations of the nonregulation of non-transferrin-bound iron by hepatic iron and may play a role in the progressive iron overload seen in hemochromatosis.     

Liver fibrosis in genetic hemochromatosis. Respective roles of iron and non-iron-related factors in 127 homozygous patients.

A retrospective study of 127 patients with untreated homozygous genetic hemochromatosis (HGH) was conducted to evaluate the respective roles of iron overload and non-iron-related factors in the development of hepatic fibrosis in HGH. Twenty-seven percent of the patients had cirrhosis, 21% had liver fibrosis and 52% had no fibrosis (prefibrotic group). The mean value of liver iron concentration was increased significantly (p < 0.001) in cirrhotic (378 +/- 144 mumol/g dry wt.) and in fibrotic (331 +/- 168) subjects compared to prefibrotic (237 +/- 108) patients. Of 13 patients with liver iron concentration > or = 500, 12 had liver fibrosis or cirrhosis, versus 48/134 with liver iron concentration < 500. Chronic alcoholic men exhibited hepatic fibrosis or cirrhosis more frequently than non-alcoholic men (p < 0.001). Non-alcoholic men had hepatic fibrosis or cirrhosis more often than non-alcoholic women (p < 0.05). Cirrhotic and fibrotic patients were significantly older than prefibrotic patients whilst a significant correlation between age and liver iron concentration was found in younger patients only. These results suggest that the iron overload threshold necessary to induce fibrosis is modulated by non-iron-related factors such as alcoholism, sex and age. The development of fibrosis in HGH with liver iron concentration < 500 mumol/g is frequent and must lead to a search for associated non-iron-related fibrogenic factors.     

Saturability of hepatic iron deposits in genetic hemochromatosis.

The relationship of pretreatment serum ferritin and hepatic iron concentration to body iron removed by venesections was evaluated in 33 patients with genetic hemochromatosis. The median values of the three variables considered were 1,950 micrograms/L (range = 255 to 10,000), 1,175 micrograms/100 mg dry weight (range = 270 to 4,310) and 10 gm (range = 2 to 41), respectively. At basal liver biopsy 18 patients had cirrhosis, 6 patients had fibrosis and 9 patients had a normal pattern; siderosis was degree 3 in 6 patients and degree 4 in 27 patients. The results of fitting a polynomial regression of second degree showed that the curve of serum ferritin on iron removed was a straight line (R2 = 0.79, with a significant coefficient of linearity, p less than 0.01, and a nonsignificant coefficient of curvature), whereas that of hepatic iron concentration on iron removed showed a curvature (R2 = 0.62, with significant coefficient of linearity and curvature, p less than 0.01) and reached a plateau. The sigmoid model fit the curve of hepatic iron concentration on iron removed (R2 = 0.61), which suggested a saturation of hepatic iron storage capability; the asymptote corresponded to a hepatic iron concentration of about 2,000 micrograms/100 mg. In alcoholic patients (17 cases) the location of the sigmoid was greater than in nonalcoholic patients. Our results suggest that iron deposition occurs in the liver before other organs are involved and that with massive iron overload hepatic deposits reach saturation, after which hepatic iron concentration does not always reflect the amount of total stores. Alcohol consumption could slow the saturation of hepatic iron deposits.     

Evaluation of computed tomography in the assessment of liver iron overload. A study of 46 cases of idiopathic hemochromatosis

The aim of the present study was to evaluate the effectiveness of single-energy computed tomography in determining iron overload in idiopathic hemochromatosis, with special reference to slightly overloaded cases. Liver attenuation was determined in 100 patients (46 cases of idiopathic hemochromatosis, 32 cases of chronic liver disease, and 22 normal controls). The iron load was determined for the first two groups by biochemical determination of liver iron concentration (performed in all but 12 subjects in the chronic liver disease group) and hepatic histologic grading. The main results for liver attenuation (upper normal limit, 72 Hounsfield units) showed that despite a high specificity (0.96), this parameter was of low sensitivity (0.63). Although mean liver attenuation in idiopathic hemochromatosis (77 +/- 14) was significantly higher than in chronic liver diseases (53 +/- 17; p less than 10(-4) and normal controls (66 +/- 3; p less than 10(-3], and despite an overall good correlation between liver attenuation and liver iron concentration (r = 0.72; p less than 10(-3], liver attenuation was unable to detect moderate iron overload. Fourteen of 18 patients with a liver iron concentration of less than 150 mumol/g dry liver wt had liver attenuation values of less than 72. Moreover, 3 of 18 subjects with a liver iron concentration of greater than 150 had a liver attenuation of less than 72. Of these 17 false-negatives, only 7 could be attributed to associated steatosis. On the whole, single-energy computed tomography, when used on a routine basis for diagnosing iron overload, is of limited clinical value in idiopathic hemochromatosis due to its poor sensitivity. Hepatic histologic examination together with biochemical determination remains the most accurate means to assess liver iron.     

Regulation of hepatic transferrin, transferrin receptor and ferritin genes in human siderosis

Although many studies have examined the regulation of transferrin, transferrin receptor and ferritin subunit gene expression in experimental systems, no molecular biological data in humans have been documented to date. In this study we simultaneously analyzed the hepatic content of transferrin, transferrin receptor and heavy and light ferritin subunit messenger RNAs in tissue samples obtained from subjects with normal iron balance and patients with primary or secondary iron overload. Steady-state levels of transferrin messenger RNA were not depressed by iron overload. On the contrary, they were increased (p less than 0.001) in patients with severe hepatic siderosis (liver iron content greater than 200 mumol/gm dry wt) as compared with the control group. This indicates that, as already suggested by our previous data in experimental siderosis, iron maintains the ability to induce transferrin gene activity even when cellular iron content is significantly increased. Transferrin receptor gene expression was found to respond in the same manner to any cause of iron-tissue load, regardless of the cause. In fact, a lower signal for transferrin receptor messenger RNA was consistently detected in iron-overloaded patients vs. control subjects, particularly in patients with thalassemia major and idiopathic hemochromatosis (p less than 0.001). Ferritin light-subunit messenger RNA accumulation was significantly increased in those patients with severe siderosis (idiopathic hemochromatosis and thalassemia major = liver iron between 200 and 600 mumol/gm dry wt). The fact that no significant change in hepatic ferritin heavy-subunit gene expression was detected in iron-loaded patients confirms preferential production of light-subunit--enriched ferritins in long-term iron overload.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gender-related variations in iron metabolism and liver diseases

The regulation of iron metabolism involves multiple organs including the duodenum, liver and bone marrow. The recent discoveries of novel iron-regulatory proteins have brought the liver to the forefront of iron homeostasis. The iron overload disorder, genetic hemochromatosis, is one of the most prevalent genetic diseases in individuals of Caucasian origin. Furthermore, patients with non-hemochromatotic liver diseases, such as alcoholic liver disease, chronic hepatitis C or nonalcoholic steatohepatitis, often exhibit elevated serum iron indices (ferritin, transferrin saturation) and mild to moderate hepatic iron overload. Clinical data indicate significant differences between men and women regarding liver injury in patients with alcoholic liver disease, chronic hepatitis C or nonalcoholic steatohepatitis. The penetrance of genetic hemochromatosis also varies between men and women. Hepcidin has been suggested to act as a modifier gene in genetic hemochromatosis. Hepcidin is a circulatory antimicrobial peptide synthesized by the liver. It plays a pivotal role in the regulation of iron homeostasis. Hepcidin has been shown to be regulated by iron, inflammation, oxidative stress, hypoxia, alcohol, hepatitis C and obesity. Sex and genetic background have also been shown to modulate hepcidin expression in mice. The role of gender in the regulation of human hepcidin gene expression in the liver is unknown. However, hepcidin may play a role in gender-based differences in iron metabolism and liver diseases. Better understanding of the mechanisms associated with gender-related differences in iron metabolism and chronic liver diseases may enable the development of new treatment strategies.     

Evaluation of liver iron content by computed tomography: its value in the follow-up of treatment in patients with idiopathic hemochromatosis

The therapeutic management of patients with idiopathic hemochromatosis (IH) implies the evaluation of excess hepatic iron. This work was undertaken to confirm the value of computed tomography for the assessment of liver iron overload in such patients and to evaluate this technique during the course of treatment by phlebotomy. The study included 24 patients with initially untreated IH and 7 patients previously treated by phlebotomy for 10 months to 7 years. Follow-up was obtained in 15 subjects. In patients with untreated IH, liver attenuation coefficient (LAC) was always markedly increased (92.4 +/- 7.1 Hounsfield units) as compared with LAC of subjects with normal liver (60.2 +/- 3.1 Hounsfield units) and that of patients with chronic liver disease (53.8 +/- 4.8 Hounsfield units), and was found to be specific for liver iron overload. LAC decreased progressively during phlebotomy, and this diminution was correlated with the amount of mobilized iron (r = 0.79, p less than 0.001); it returned to normal values only after complete removal of iron overload. LAC was closely correlated with liver iron concentration (r = 0.83, p less than 0.001), better than usual biochemical parameters, especially serum ferritin (r = 0.70, p less than 0.01). This study confirms that the determination of LAC on computed tomography provides a reliable index of hepatic iron stores in patients with IH, without requiring a liver biopsy, and shows that this noninvasive method is of particular interest for the follow-up of patients treated by phlebotomy.     

Association of hepatic iron deposition and serum iron indices with hepatic inflammation and fibrosis stage in nonalcoholic fatty liver disease]

BACKGROUND/AIMS: Nonalcoholic steatohepatitis can develop from nonalcoholic fatty liver and progress to severe liver disease such as cirrhosis. The mechanism determining the progression from fatty liver to steatohepatitis is unknown. Iron is suspected to enhance hepatic damage associated with nonalcoholic fatty liver disease (NAFLD). The aims of this study were to evaluate the relationship of serum iron indices and hepatic iron deposition with hepatic fibrosis or inflammation, and to assess whether the increased hepatic iron deposition is an independent predictor of progression to liver injury. METHODS: The biochemical and histopathological data of thirty-nine patients with NAFLD were analyzed. Liver biopsy findings were graded according to the method described by Brunt, et al. Hepatic iron concentration was available in 29 of 39 patients. RESULTS: The mean hepatic iron concentration and hepatic iron indices were 1,349+/-1,188 microg/g dry weight and 0.9+/-0.7 microg/g/age. Serum ferritin and body mass indices were associated with hepatic inflammation (p=0.001, p=0.006) and fibrosis (p=0.005, p=0.013). Hepatic iron concentration and hepatic iron index were not associated with hepatic inflammation and fibrosis. Multivariate analysis did not identify serum ferritin or body mass index as an independent predictor of liver injury. CONCLUSIONS: Hepatic iron deposition shows no association with the degree of hepatic inflammation or fibrosis. Hepatic iron is not an independent predictor of hepatic injury in patients with NAFLD.     

Usefulness and limitations of laboratory and hepatic imaging studies in iron-storage disease

Liver biopsy with measurement of hepatic iron concentration is the most certain procedure for evaluation of iron-storage disease, although use of computed tomography and magnetic resonance imaging procedures recently have been proposed as alternative, noninvasive methods for estimating the degree of iron overload. The results of these imaging procedures were compared with those of other noninvasive techniques and liver biopsies in 48 patients. Final diagnoses, based on synthesis of clinical and laboratory data, included (a) primary hemochromatosis (n = 25; 19 homozygous, 6 heterozygous); (b) secondary hemochromatosis (n = 7); (c) alcoholic liver disease (n = 11); (d) chronic active hepatitis (n = 3); and (e) other (n = 2). Serum ferritin and computed tomography or magnetic resonance scanning had 100% sensitivity in detecting hepatic iron overload more than fivefold above the upper limit of normal (greater than 10.7 mumol Fe/100 mg dry liver) but did not detect lesser degrees of iron overload reliably, including those found in 6 of 13 patients with untreated homozygous primary hemochromatosis and 3 of 7 with secondary hemochromatosis. Computed tomography and magnetic resonance imaging were more specific than ferritin (64% and 92% vs. 21%) in the detection of iron excess, more than five times the upper limit of normal. Among magnetic resonance imaging measures, the ratio of the second echo signal intensities of liver to paraspinous muscle was the most sensitive and most specific for detection of this degree of iron overload. The degree of correlation between hepatic iron concentration and results of noninvasive laboratory or imaging studies were insufficient to permit prediction of hepatic iron content by noninvasive studies alone. It is concluded that computed tomography or magnetic resonance scanning as currently usually used is not cost-effective in routine evaluation of iron overload, although these imaging procedures may play a role in patients in whom liver biopsy is contraindicated. Because of their low cost and ready availability, serum ferritin and transferrin saturation tests remain the preferred screening studies for iron overload. Liver biopsy with quantitative iron measurement remains the study of choice for the definitive diagnosis of hemochromatosis.     

Retinol and retinyl esters in patients with alcoholic liver disease

Liver retinoid levels and the retinyl esters were examined in liver biopsy specimens from 70 patients with alcoholic and nonalcoholic liver diseases. There was a wide variation in the liver retinoid levels. The liver retinoid level was statistically significantly lower in 15 patients with alcoholic liver disease and a depressed Normotest (NT) value of less than 65% compared with patients with alcoholic liver disease and a normal NT value of greater than 65% (P less than 0.01). The mean serum retinol level in patients with alcoholic cirrhosis was 0.68 +/- 0.38 mumol/l compared with 1.99 +/- 1.14 mumol/l in patients with alcoholic fatty liver (P less than 0.03). The relative amount of retinyl oleate was increased in the alcoholic fatty liver compared with the nonalcoholic fatty liver (P less than 0.001).     

Significance of the iron and copper content of the liver for the differential diagnosis of chronic liver diseases

Liver iron and copper concentrations were estimated in 395 patients undergoing hepatological examination. Relations to clinical, morphological and laboratory data were evaluated. Liver iron concentrations were not significantly different in chronic hepatitis of viral, toxic or immunological origin. Liver iron levels exceeding 100 mg/100 g dry liver tissue (normal range up to 300 mg/100 g) were only found in idiopathic hemochromatosis (n = 8), in a patient with prophyria cutanea tarda and in a multiple transfused patient who suffered from aplastic anemia. Liver copper content was significantly increased in primary biliary cirrhosis compared to chronic hepatitis of other origin. Apart from untreated Wilson's disease (n = 3) copper levels higher than 25 mg/100 g dry liver tissue (normal range up to 6 mg/100 g) were measured in chronic active hepatitis B (n = 2), primary biliary cirrhosis (n = 9) and in chronic hepatitis of uncertain origin (n = 3). Therefore excess accumulation of copper in the liver was typical of Wilson's disease but less diagnostic than severely elevated liver iron stores of idiopathic hemochromatosis.     

Alcoholic liver injury： Pathological features and models—Role of alcohol in the regulation of iron metabolism

Patients with alcoholic liver disease frequently exhibit increased body iron stores, as reflected by elevated serum iron indices (transferrin saturation, ferritin) and hepatic iron concentration. Even mild to moderate alcohol consumption has been shown to increase the prevalence of iron overload. Moreover, increased hepatic iron content is associated with greater mortality from alcoholic cirrhosis, suggesting a pathogenic role for iron in alcoholic liver disease. Alcohol increases the severity of disease in patients with genetic hemochromatosis, an iron overload disorder common in the Caucasian population. Both iron and alcohol individually cause oxidative stress and lipid peroxidation, which culminates in liver injury. Despite these observations, the underlying mechanisms of iron accumulation and the source of the excess iron observed in alcoholic liver disease remain unclear. Over the last decade, several novel iron-regulatory proteins have been identified and these have greatly enhanced our understanding of iron metabolism. For example, hepcidin, a circulatory antimicrobial peptide synthesized by the hepatocytes of the liver is now known to play a central role in the regulation of iron homeostasis. This review attempts to describe the interaction of alcohol and iron-regulatory molecules. Understanding these molecular mechanisms is of considerable clinical importance because both alcoholic liver disease and genetic hemochromatosis are common diseases, in which alcohol and iron appear to act synergistically to cause liver injury.     

Hepatic iron stores and markers of iron overload in alcoholics and patients with idiopathic hemochromatosis

Liver iron concentrations were determined in 60 alcoholics with liver disease of varying severity, 15 patients with untreated idiopathic hemochromatosis, and 16 control subjects with biliary tract disease. Mean liver iron concentrations (g/100 mg dry weight) were significantly greater in the alcoholics (156.4±7.8 (sem);P<0.05) and in patients with idiopathic hemochromatosis (2094.5±230.7;P<0.01) than in control subjects (53.0±7.0). Liver iron concentrations of >140 g/100 mg were found in 17 alcoholics (29%) and in all 15 patients with idiopathic hemochromatosis. Liver iron concentrations >1000 g/100 mg were found in all patients with idiopathic hemochromatosis but in none of the alcoholics. In the alcoholics no relationship existed between liver iron concentrations and the amount of alcohol consumed daily, the length of the drinking history, the amount of beverage iron consumed daily, or the severity of the liver disease. Serum ferritin concentrations reflected iron stores in patients with hemochromatosis and in alcoholics with minimal liver disease. However, in alcoholics with significant liver disease serum ferritin concentrations did not reflect iron stores accurately, although with normal values iron overload is unlikely. Serum iron concentration and percentage saturation of total iron-binding capacity were of little value in assessing iron status in either alcoholics or patients with hemochromatosis. Measurement of the liver iron concentration clearly differentiates between alcoholics with significant siderosis and patients with idiopathic hemochromatosis.R. W. Chapman was Watson-Smith Fellow of the Royal College of Physicians of London.     

Room-temperature susceptometry predicts biopsy-determined hepatic iron in patients with elevated serum ferritin

Background. There is an ongoing clinical need for novel methods to measure hepatic iron content (HIC) noninvasively. Both magnetic resonance imaging (MRI) and superconducting quantum interference device (SQUID) methods have previously shown promise for estimation of HIC, but these methods can be expensive and are not widely available. Room-temperature susceptometry (RTS) represents an inexpensive alternative and was previously found to be strongly correlated with HIC estimated by SQUID measurements among patients with transfusional iron overload related to thalassemia. Aim. The goal of the current study was to examine the relationship between RTS and biochemical HIC measured in liver biopsy specimens in a more varied patient cohort.Material and methods. Susceptometry was performed in a diverse group of patients with hyperferritinemia due to hereditary hemochromatosis (HHC) (n = 2), secondary iron overload (n = 3), nonalcoholic fatty liver disease (NAFLD) (n = 2), and chronic viral hepatitis (n = 3) within one month of liver biopsy in the absence of iron depletion therapy.Results. The correlation coefficient between HIC estimated by susceptometry and by biochemical iron measurement in liver tissue was 0.71 (p = 0.022). Variance between liver iron measurement and susceptometry measurement was primarily related to reliance on the patient’s body-mass index (BMI) to estimate the magnetic susceptibility of tissue overlying the liver.Conclusions. We believe RTS holds promise for noninvasive measurement of HIC. Improved measurement techniques, including more accurate overlayer correction, may further improve the accuracy of liver susceptometry in patients with liver disease.     

Magnetic resonance imaging and assessment of liver iron content in genetic hemochromatosis

Computed tomography (CT) scanning is not highly sensitive in the assessment of liver iron content and magnetic resonance imaging (MRI) appears to be more efficient. The aim of this study was to determine the effectiveness of MRI in the evaluation of liver iron content using a standard spin-echo technique. The study included 23 patients with genetic hemochromatosis and 24 non-iron-overloaded patients as controls. A comparison was made of: (a) MRI signal intensity of liver, spleen, paravertebral muscles and subcutaneous adipose tissue using two different spin-echo sequences (SE 500/28; SE 2000/28,56); (b) liver attenuation determined by a single energy CT scan; and (c) a biochemical determination of hepatic iron. There was a significant decrease in liver signal intensity in the genetic hemochromatosis group (256 +/- 201, mean +/- S.D.) compared with the control group (801 +/- 413, p less than 0.001), but there was no correlation with liver iron concentration. However, such a correlation was found and was even more highly significant than in CT when the ratio between the liver and another organ was taken into account. For a lower limit of liver/spleen ratio calculated at 0.46 (mean 2 S.D. in the control group), the specificity (0.96) of MRI was satisfactory, but the sensitivity (0.78) remained insufficient (MRI being unable to detect an iron overload of up to 125 mumol/g). Hopefully, these results might be improved in the near future by using more sensitive sequences such as gradient echo sequences.     

Confirmation of the efficacy of hepatic tissue iron index in differentiating genetic haemochromatosis from alcoholic liver disease complicated by alcoholic haemosiderosis.

The hepatic tissue iron index proposed by Bassett et al was evaluated in 35 patients with homozygous genetic haemochromatosis, 67 patients with alcoholic liver disease, and 18 patients with other forms of chronic liver disease with and without cirrhosis. In patients with cirrhosis hepatic tissue iron concentration reliably differentiated alcoholic liver disease from genetic haemochromatosis. Although mean iron concentration was greater in patients with prefibrotic haemochromatosis than in those with prefibrotic alcoholic liver disease, some overlap occurred and complete differentiation of the two conditions was not possible. This overlap was particularly evident in some young patients with haemochromatosis in whom the tissue iron concentration grade fell in the range commonly seen in alcoholic haemosiderosis. Inability to differentiate early genetic haemochromatosis from alcoholic liver disease complicated by haemosiderosis was also a problem with standard Perls's staining. When the hepatic tissue iron index was calculated (hepatic tissue iron concentration/patient's age in years), clear differentiation of genetic haemochromatosis from both alcoholic liver disease and other forms of chronic liver disease was obtained in both cirrhotic and precirrhotic patients. This study confirms that the hepatic tissue iron index is a useful means of differentiating patients with genetic haemochromatosis from those with alcoholic liver disease. We suggest that biochemical estimation of tissue iron concentration and calculation of the tissue iron index in all patients in whom genetic haemochromatosis is a possible diagnosis will reduce the likelihood of misdiagnosing this as alcoholic liver disease.     

Biliary excretion of iron and ferritin in idiopathic hemochromatosis

The role of biliary excretion of iron and ferritin in iron overload was studied and evaluated. Ten patients with idiopathic hemochromatosis and two groups of controls (14 gallstone patients and 16 healthy subjects) were included. Liver tissue (obtained by percutaneous or operative biopsy) was investigated with light microscopy and transmission electron microscopy in combination with x-ray microanalysis. Fasting bile samples were obtained through duodenal aspiration or at cholecystectomy. Iron was determined in liver tissue and bile using atomic absorption spectroscopy, and ferritin was determined in serum and bile with a radioimmunoassay technique. All patients with hemochromatosis had iron-positive staining as seen in light microscopy. Electron microscopy showed iron-containing proteins in the lysosomes and cytosol of liver parenchymal cells, and this observation was supported by x-ray microanalysis. Hepatic iron concentration was increased about eightfold in the patients with hemochromatosis (p less than 0.001). Biliary iron concentration, expressed per millimole of bile acid, was increased about twofold (p less than 0.05) and biliary ferritin concentration about fivefold (p less than 0.001) in hemochromatosis. Four of the patients with hemochromatosis were reexamined after completed treatment with venesection; this resulted in normalized biliary concentrations of iron and ferritin. We conclude that biliary secretion of ferritin occurs in humans and that both iron and ferritin excretion are enhanced in hepatic iron overload. The apparently limited capacity of biliary iron excretion may be of importance for the hepatic iron accumulation in hemochromatosis.     

Characteristics of serum IgA and liver IgA deposits in alcoholic liver disease

Patients with alcoholic liver disease frequently reveal an increase in IgA serum concentration and IgA deposits in a continuous pattern along hepatic sinusoids. We investigated whether the hepatic IgA deposits are a passive reflection of changes in concentration or composition of IgA in the circulation, or represent a distinct effect of alcohol on the liver. Forty-one patients with alcoholic liver disease (daily alcohol intake at least 50 gm for more than five consecutive years) were compared with 41 patients with nonalcoholic liver disease. Patients in both groups were matched for serum IgA and histopathological changes in the liver biopsy. IgA deposits in the liver were found in 78% of the alcoholic patients and in 12% of the nonalcoholic patients. The presence of deposits was not related to histopathological changes in the liver or to the serum IgA concentration. In serum IgA subclass distribution, alcoholic patients differed from nonalcoholic patients by a slight but significant shift to IgA2; in contrast, the hepatic IgA deposits in alcoholic patients were almost of the IgA1 subclass. Serum secretory component (which is an equivalent of serum secretory IgA) was elevated in both alcoholic and nonalcoholic patients; patients with a liver biopsy revealing hepatitis showed the highest level. In contrast, the hepatic deposits did not contain secretory component. We conclude that the continuous deposits of IgA along liver sinusoids are not a passive reflection of changes in concentration or composition of circulating IgA, but may represent a distinct effect of alcohol on the liver related to the role of this organ in IgA metabolism.