Rosanna Lampis

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.

The distribution of DR4 haplotypes in sardinia suggests a primary association of type I diabetes with DRB1 and DQB1 loci

The contribution of genetic variation at HLA class II loci to the susceptibility to and protection from IDDM was investigated by analyzing the distribution of HLA-DRB1*04 haplotypes in 630 Sardinian newborns and 155 Sardinian IDDM patients. The different RRs and ARs of the various DR4-DQB1*0302 haplotypes, significantly ranging from the strongly associated DRB1*0405, DQB1*0302 to the protective DRB1*0403, DQB1*0302 haplotypes, provides clearcut evidence that the DRB1 locus is crucial in conferring IDDM predisposition or protection. Also, the DQB1 locus influences IDDM predisposition or protection by restricting the disease-positive association to DRB1*0405 haplotypes carrying the susceptibility DQB1*0302 or DQB1*0201 alleles but not the protective DQB1*0301 allele. Haplotype analysis not only suggests that the DRB1 and DQB1 loci influence IDDM risk in the same way, but also that the HLA-linked protection is dominant compared with susceptibility. These results, obtained from a population with one of the highest IDDM incidences in the world, define more clearly the contribution of the various HLA loci to IDDM protection or susceptibility and allow a more precise calculation of AR.

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)

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‐(Zu2003u2003+u2003u20032), D3A‐(Zu2003u2003+u2003u20032), C4B‐0, C4A‐L, G11‐15, Bf‐0.4, C2‐a, HSP70‐7.5, 9N3‐(Zu2003u2003+u2003u200310), 82I‐(Zu2003u2003−u2003u20032), TNFα‐9, 62‐(Zu2003u2003−u2003u200320), 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.

HLA-DQB1*0305 and -DQB1*0304 alleles among Sardinians: evolutionary and practical implications for oligotyping

This study, performed in individuals of Sardinian descent, reports an epidemiologic and molecular analysis of the recently identified DQB1*0304 and DQB1*0305 alleles. These two alleles having a gene frequency of 0.017 and 0.005, respectively, are not uncommon in Sardinia and are distributed fairly uniformly on the island. The analysis of DQB1 second and third exons of the two alleles revealed that although they have always been found included within the same DRB1*0403-DQA1*03 haplotype, they had a different origin. The sequence pattern of DQB1*0305 confirmed that it originated from the DQB1*0302 recipient gene by the insertion of a DQB1*0402 nucleotide stretch, within its beta-sheet region, while that of DQB1*0304 suggested that it originated from the DQB1*0301 gene, either by a single point mutation at codon 57 (GCC instead of GAC) or, alternatively, by a segmental transfer of a DQB1*0302 motif, including codon 57, within its alpha-helic region. Independently from the mechanism of generation, the fact that DQB1*0304 originated from DQB1*0301 allele was intriguing considering that, in over 1500 HLA class II Sardinian haplotypes examined, neither the putative parental DRB1*0403-DQA1*03-DQB1*0301 haplotypes were found. Finally, since the assignment of DQB1*0305 may be inaccurate with the traditional panel of probes commonly used for DQB1 oligotyping, the use of an additional oligonucleotide probe is recommended.

High frequency of low-risk human leukocyte antigen class II genotypes in latent celiac disease.

Human leukocyte antigen (HLA) class II genotypes in latent celiac disease, a clinical variant of celiac disease (CD) have been scarcely studied. The aim of this work was to investigate whether latent CD and CD share similar frequencies of HLA class II genotypes. HLA class II genotypes of CD patients compared with controls were subdivided in the following at-risk groups: DQB1*02/DQB1*02 (43.0%, odds ratio [OR] 8.02, p < 0.0001), DQB1*0302/DQB1*02 (12.2%, OR 2.77, p = 0.0002), DQB1*02/DQB1*X (39.2%, OR 1.23, p = 0.1903), DQB1*0302/DQB1*X (3.4%, OR 0.35, p = 0.0064) and DQB1*X/DQB1*X (0.8%, OR 0.01, p = 0.0001) where X is neither DQB1*0302 nor DQB1*02. Next, HLA class II genotypes of 21 latent CD patients were compared with the above at-risk groups. Only one latent CD patient (4.8%) was found in the high risk DQB1*02/DQB1*02 group, three (14.3%) were DQB1*0302/DQB1*02, one (4.8%) was DQB1*0302/DQB1*X and the remaining 16 (76.2%) showed the DQB1*02/DQB1*X genotype. Noteworthy, the only 1 patient with the DQB1*02/DQB1*02 high risk genotype did not carry the DR3-DQB1*02/DR3-DQB1*02 or the DR3-DQB1*02/DR7-DQB1*02 but the uncommon DR3-DQB1*02/DR4-DQB1*02 genotype. These data suggest that latent CD is prevalently associated with low-risk HLA class II genotypes.