Fulvia Frau

Deferoxamine-induced growth retardation in patients with thalassemia major

In the retrospective study reported here, we compared the longitudinal growth in three groups of children with thalassemia major who received a similar transfusion program but different schedules of chelation treatment. In those patients who initiated deferoxamine (DF) administration by daily subcutaneous infusion (50 to 80 mg/kg/day) simultaneously with the beginning of transfusion (at 8 +/- 6 months), mean height at 2 to 6 years of age was significantly reduced in comparison (1) with those patients who initiated DF subcutaneous treatment after 3 years at similar doses and (2) with those who were treated intramuscularly with small doses. In the patients treated at an early stage, those with more marked stunted growth had a clinical and radiologic ricketslike syndrome associated with joint stiffness. Mineral metabolism studies in these patients showed a reduction of hair and leukocyte zinc levels and leukocyte alkaline phosphatase activity. Our findings indicate that DF administration at high doses by continuous infusion before iron overload has been established adversely affects longitudinal growth. By contrast, after 3 years of age, even large doses (in the order of 100/mg/kg/day) did not result in growth retardation. The growth retardation observed may be related to chelation of other trace elements, including zinc, in the presence of low iron burden, to the direct toxic effect of unchelated DF by interference with critical iron-dependent enzymes, or both. These results indicate that in patients with thalassemia major, DF administration should be initiated only after iron accumulation is established, namely, around 3 years of age, after 20 to 30 transfusions, which are usually associated with ferritin levels in the range of 800 to 1000 ng/ml. At this age, deferoxamine doses should be established on the basis of iron balance studies and dose response curves. Doses higher than 50 to 60 mg/kg do not adversely affect growth but produce toxic side effects on acoustic and visual pathways and therefore should not be used. Longitudinal growth monitoring of DF-treated patients is warranted.

Effect of iron overload on the response to recombinant interferon-alfa treatment in transfusion-dependent patients with thalassemia major and chronic hepatitis C

The purpose of this study was to determine whether interferon-alfa (IFN-alpha) therapy benefits patients with transfusion-dependent thalassemia and chronic active hepatitis C, and whether their iron burden modifies the response to this therapy. We conducted a controlled trial of recombinant IFN-alpha (3 million units per square meter of body surface area, three times a week for 15 months) in 65 patients with thalassaemia major and chronic active hepatitis C; 14 of them were untreated control subjects. In 21 of the 51 treated patients, alanine aminotransferase values returned to normal within 6 months, and hepatitis C virus ribonucleic acid was no longer detected in serum; no changes were detected among control subjects. The response to IFN-alpha therapy was inversely related (p < 0.002) to the liver iron burden as assessed by atomic absorption, the histologic semiquantitative method, or both methods. During 3 years of follow-up, two responder patients had relapses. We conclude that IFN-alpha represents a useful therapeutic option for children with transfusion-dependent thalassemia and chronic active hepatitis C with a mild to moderate iron burden.

Combinations of specific DRB1, DQA1, DQB1 haplotypes are associated with insulin-dependent diabetes mellitus in sardinia

The Sardinian population has an extremely high incidence of IDDM (30.2 of 100.000 in the age group of 0-14 years). This study reports the molecular characterization of HLA class II genes in 120 IDDM sporadic patients and 89 healthy subjects of Sardinian origin. Compared with other Caucasians, both Sardinian patients and controls had an unusual distribution of haplotypes and genotypes. In particular, there was a high gene frequency of the DRB1*0301, DQA1*0501, DQB1*0201 susceptibility haplotype both in patients (0.58) and controls (0.23) while a reduction of the DRB1*1501, DQA1*0102, DQB1*0602 protective haplotype (0.03) was observed in the healthy population. This distribution may partially explain the high incidence of IDDM reported in Sardinia. The analysis of the DQ beta 57 and DQ alpha 52 residues showed that the absence of Asp 57 and the presence of Arg 52 were associated with IDDM in a dose-response manner. On the other hand, we found that (a) a very similar distribution of these residues was found when comparing Sardinians with another healthy Caucasian population from the same latitude but with a lower rate of IDDM incidence; (b) several genotypes encoding the identical DQ alpha 52/DQ beta 57 phenotype carried very different relative risks; and (c) the DRB1*0403, DQA1*0301, DQB1*0304 haplotype (DQ beta 57 Asp-neg and DQ alpha 52 Arg-pos) was found in 40% of the DR4-positive controls but not in patients (p = 0.00034), while the DRB1*0405, DQA1*0301, and DQB1*0302 haplotype carrying the same residues at the same positions was found in 70% of the DR4-positive patients and in only one control (p = 0.00003). These findings suggest that IDDM susceptibility cannot be completely explained by the model in which only DQ alpha 52 and DQ beta 57 residues are taken into account.

Two cytochromes P450 are major hepatocellular autoantigens in autoimmune polyglandular syndrome type 1

BACKGROUND & AIMS Liver disease has been described in 10%-15% of patients with autoimmune polyglandular syndrome type 1 (APS-1). After the discovery of cytochrome P450 1A2 (CYP1A2) as a hepatocellular autoantigen in liver-kidney microsomal autoantibody (LKM)-positive patients with APS-1, the investigation of antiliver antibodies was extended to 11 Sardinian patients with APS-1. METHODS Indirect immunofluorescence and Western blotting analysis were performed to study the antiliver antibodies. RESULTS Immunofluorescence revealed LKM antibodies in 3 patients with APS-1, 1 of whom died of fulminant hepatitis. Western blotting showed a liver microsomal protein band of approximately 51 kilodaltons in the LKM-positive sera of these 3 patients. Western blotting performed with recombinant cytochrome P450 enzymes allowed the identification of CYP2A6 as a specific target antigen. CONCLUSIONS LKM antibodies in APS-1 sera are specifically directed against CYP1A2 or CYP2A6, but their diagnostic and prognostic significance for liver disease remain to be determined.

Immune reaction against the cytoskeleton in coeliac disease.

BACKGROUND The cytoskeleton actin network of intestinal microvilli has been found to be rapidly impaired after gluten challenge in coeliac disease (CD). The aim of this study was to investigate the presence of an immune reaction towards cytoskeleton structures such as actin filaments in CD. METHODS Eighty three antiendomysial antibody positive CD patients (52 children and 31 adults) were studied at our outpatient clinics from 1996 to 1998 using indirect immunofluorescence, ELISA, and western blotting for antiactin (AAA) and antitissue transglutaminase (TGA) antibodies before and after a gluten free diet (GFD). Sixteen patients with smooth muscle antibody positive autoimmune hepatitis, 21 with inflammatory bowel diseases, seven with small bowel bacterial overgrowth, and 60 healthy subjects were studied as controls. RESULTS Fifty nine of 83 CD patients (28/31 adults (90.3%); 31/52 children (59.6%)) were positive for IgA and/or IgG AAA. Seventy seven (92.7%) were positive for IgA TGA. IgA AAA were strongly correlated with more severe degrees of intestinal villous atrophy (p<0.0001; relative risk 86.17). After a GFD, AAA became undetectable within five months. CONCLUSIONS Apart from the immune reaction against the extracellular matrix, we have described an immune reaction against the cytoskeleton in both children and adults with CD. As AAA are strongly associated with more severe degrees of villous atrophy, they may represent a useful serological marker of severe intestinal atrophy in CD.

A gene dosage effect of the DQA1*0501/DQB1*0201 allelic combination influences the clinical heterogeneity of Celiac disease

This study reports the HLA-DR and DQ molecular characterization of 62 CD patients of Sardinian descent. Patients were divided in two groups (36 in group I and 26 in group II) according to the clinical features at the disease onset. Among the patients of group I, having the fully expressed form of CD and a mean age of 3 years at disease onset, a significant increase of DRB1*0301, DQA1*0501, DQB1*0201 homozygotes, encoding in cis two DQ (alpha 1*0501, beta 1*0201) susceptibility heterodimers, was observed when compared either with the patients of group II (pIII < 0.012) or with healthy individuals (pI < 10(-6)). On the other hand, in the patients of group II, presenting oligosymptomatic forms and a mean age of 5.7 years at the disease onset, the haplotype combinations encoding in cis or in trans only one DQ (alpha 1*0501, beta 1*0201) heterodimer were significantly increased in comparison either with the patients of group I (pIII < 0.026) or with controls (pII < 10(-6)). These findings suggest that a double dose of DQA1*0501, DQB1*0201 genes may predispose a person to an earlier onset and to more severe disease manifestations. Genotype analysis showed that only three patients (all in group I) failed to form in trans or in cis the DQ (alpha 1*0501, beta 1*0201) heterodimer and carried the DQA1*0101,DQB1*0501 haplotype, suggesting its possible role in CD susceptibility. In addition, a significant increment of DQB1*0501 gene (pc < 0.0065) was found comparing the frequency of DQB1 alleles in CD patients and healthy controls, after exclusion of DQB1*0201 chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitissue Transglutaminase Antibodies Outside Celiac Disease

Background Tissue transglutaminase enzyme-linked immunosorbent assay (tTG-ELISA) has recently been proposed as a simple and fast screening test for celiac disease (CD). The rate of false-positive and false-negative tests with tTG-ELISA, however, has not been definitively established. Therefore, the aim of our study was to investigate anti-tTG antibodies (TGA) not only in untreated patients with CD and in healthy controls, but also in a large group of patients with other autoimmune diseases. Methods The presence of TGA was investigated in sera from 111 patients with untreated CD, 96 patients with other autoimmune conditions (28 with autoimmune liver disease, 46 with insulin-dependent diabetes mellitus, 10 with inflammatory bowel syndrome, 12 with type 1 polyglandular syndrome) and from 100 healthy controls using guinea pig tTG-ELISA (gp-TG/ELISA) and highly purified recombinant human tTG-ELISA (h-TG/ELISA). Western blotting with guinea pig tTG was also performed. Results Ninety-four patients with CD who tested positive for antiendomysial antibodies (AEA) and one who tested negative for AEA showed antibodies against the gp-TG. Among the controls, 50% of patients with autoimmune liver disease and 6.5% of patients with insulin-dependent diabetes mellitus tested positive with gp-TG/ELISA. Western blotting experiments revealed that the high rate of positive tests observed using ELISA among the control group sera is attributable to impurities in the gp-TG preparation. However, h-TG/ELISA tests were positive for the sera from all patients who tested positive for AEA and from one control who tested negative for AEA, whereas h-TG/ELISA tests were negative for all CD patients who tested negative for AEA and for other controls who tested negative for AEA. Conclusions The frequency of false-negative and false-positive tests represents the major limit to the use of gp-tTG/ELISA. However, because h-TG/ELISA is both simple and fast, it could be used in large screening programs for CD.

Iron overload and desferrioxamine chelation therapy in β-thalassemia intermedia

This study on serum ferritin levels ind urinary iron excretion after 12h subcutaneous infusion of desferrioxamine in 10 thalassemia intermedia patients shows that even nontransfusion-dependent patients may have positive iron balance resulting in iron overload from 5 years of age. However, the iron overload found in these patients appears to be much lower than in age matched patients with transfusion-dependent thalassemia major. Iron overload increases with advancing age, as shown by increasing serum ferritin levels and desferrioxamine-induced urinary iron elimination. After a six month trial of 12h continuous subcutaneous desferrioxamine administration there was a significant decline in serum ferritin levels.From this study it seems that iron chelation is indicated in thalassemia intermedia patients over 5 years of age in order to prevent iron accumulation. However, the appropriate treatment schedule should be tailored to the individual needs of each patients, established by close monitoring of serum ferritin levels and desferrioxamine-induced urinary iron elimination.

Jagged-1 mutation analysis in Italian Alagille syndrome patients

Alagille syndrome (AGS) is an autosomal dominant disorder with developmental abnormalities affecting the liver, heart, eyes, vertebrae, and craniofacial region. The Jagged‐1 (JAG1) gene, which encodes a ligand of Notch, has recently been found mutated in AGS. In this study, mutation analysis of the JAG1 gene performed on 20 Italian AGS patients led to the identification of 15 different JAG1 mutations, including a large deletion of the 20p12 region, six frameshift, three nonsense, three splice‐site, and two missense mutations. The two novel missense mutations were clustered in the 5′ region, while the remaining mutations were scattered throughout the gene. The spectrum of mutations in Italian patients was similar to that previously reported. We also studied in detail a complex splice site mutation, 3332dupl8bp, which was shown to lead to an abnormal JAG1 mRNA, resulting in a premature stop codon. With the exception of the missense mutations, the majority of the JAG1 mutations are therefore likely to produce truncated proteins. Since the phenotype of the patient with a complete deletion of the JAG1 gene is indistinguishable from that of patients with intragenic mutations, our study further supports the hypothesis that haploinsufficiency is the most common mechanism involved in AGS pathogenesis. Furthermore, our data confirmed the absence of a correlation between the genotype of the JAG1 gene and the AGS phenotype. Hum Mutat 14:394–400, 1999.

Evaluation of IgA deficiency in Sardinians indicates a susceptibility gene is encoded within the HLA class III region

IgA deficiency (IgA‐D) has been associated with the HLA region, in particular with the North European haplotype HLA‐A1, ‐B8, ‐DR3, but the exact location of the susceptibility gene(s) is unknown. Some reports suggest that a susceptibility gene is encoded in the class II region, while others implicate the class III region. We exploited differences between the common Sardinian and North European HLA‐DR3 haplotypes to help localize the IgA‐D susceptibility gene(s). With the knowledge that approximately 13% of HLA‐DR3 homozygous individuals of North European origin are IgA‐D, we examined 43 HLA‐DR3 homozygous Sardinians to find that all had normal serum IgA, IgG and IgM levels. A detailed analysis of their MHC haplotypes indicated a common Sardinian HLA‐DR3 haplotype TAP1A, TAP2A, HLA‐DQB1*0201, ‐DQA1*0501, ‐DRB1*0301, LH1‐(Z  +  2), D3A‐(Z  +  2), C4B‐0, C4A‐L, G11‐15, Bf‐0.4, C2‐a, HSP70‐7.5, 9N3‐(Z  +  10), 82I‐(Z  −  2), TNFα‐9, 62‐(Z  −  20), HLA‐B18, ‐Cw5, ‐A30 which diverges from the common North European HLA‐DR3 haplotype telomeric to the HLA‐DR region. In parallel studies of five Sardinians with IgA‐D, two of the 10 HLA haplotypes (20%) contained HLA‐DR3, a frequency similar to that observed in the background population. One of these was the HLA‐DR3‐ B8 North European haplotype, which occurs rarely in Sardinia. Our data favour the hypothesis that a class III region allele, present on the common North European but not on the Sardinian HLA‐DR3 haplotype, confers susceptibility to IgA‐D.