Roberta Galavotti

Association of a Lymphotoxin alpha gene polymorphism and atopy in Italian families.

Tumour necrosis factor (TNF) is a proinflammatory cytokine that increases human airway tissue responsiveness and is considered a candidate gene for asthma. Two common polymorphisms (LTαNcoI and TNFα-308) in the TNF gene complex were studied in 600 subjects from 131 Italian families with atopic asthmatic children. Skin prick test (SPT), total IgE levels, atopy (defined as increased IgE levels or SPT positivity or both), bronchial hyperresponsiveness, and clinical asthma were investigated. The observed distribution of the identical by descent alleles at the LTαNcoI locus was different from expected for SPT and atopy (p=0.015). The LTαNcoI genotype distribution for increased IgE levels was different between males and females (p=0.0011), and an association of the 2.2 genotype with increased IgE levels was observed in females (p=0.0032). The results indicate that the LTα gene, or a closely linked locus, is associated with atopy, and suggest a sex difference in the effect of the gene.

Chromosome 7p linkage and GPR154 gene association in Italian families with allergic asthma.

Background Several genome scans have reported linkage of markers on chromosome 7p with asthma and related phenotypes in different populations. A fine mapping in Finnish and French‐Canadian populations has associated the GPR154 gene (also known as G‐protein‐coupled receptor for asthma susceptibility, GPRA) with elevated IgE or asthma.

Linkage to atopy on chromosome 19 in north-eastern Italian families with allergic asthma

Background Allergic asthma is a multifactorial disease for which there is a widely assessed, although poorly understood, genetic involvement. Genome‐wide screens reported evidence for linkage of allergic asthma‐related phenotypes to several chromosomal locations. Markers on chromosome 19 have been linked to allergic asthma phenotypes in different populations in independent studies.

Association of childhood allergic asthma with markers flanking the IL33 gene in Italian families

To the Editor: Two recent, independent, large-scale genome-wide association studies described the association of asthma with single nucleotide polymorphisms (SNPs) mapping on chromosome 9 in a region flanking the IL33 gene. No family-based association study has yet been reported to confirm the association that was found in the case-control studies. We have previously reported the preliminary results of a genome-wide linkage study conducted on a sample of Italian asthmatic families that indicated linkage to the microsatellite marker D9S286, which is located in an extended region of chromosome 9p24 that includes the IL33 gene. We have now investigated whether the SNPs rs1342326 and rs928413,which showed association in the recent study byMoffatt et al, are associated with childhood asthma or related phenotypes in the abovementioned Italian families. The SNP rs928413 is in absolute linkage disequilibrium (LD; http://www.hapmap.org, rel#24) with rs3939286, which was associated to atopic asthma in the study by Gudbjartsson et al. Therefore this last marker was not genotyped because it is tagged by the marker rs928413. A family-based association study was performed in 137 family trios (father, mother, and asthmatic child) from northeastern Italy ascertained through an allergic asthmatic child. Details of the enrollment criteria were given elsewhere. Association analysis was conducted by using the transmission disequilibrium test (TDT) with the computer program PLINK. The following phenotypes were investigated: doctor-diagnosed asthma according to the Global Initiative for Asthma criteria, increased total serum IgE levels (defined as a qualitative trait with serum concentrations >200 kU/L for adults and >90th percentile in an age-adjusted standard curve value for subjects aged <10 years), bronchial hyperresponsiveness (BHR) to methacholine, positive skin prick test (SPT) responses to common aeroallergens, positive SPT responses to house dust mites, and positive SPT responses to graminae. Table I reports the phenotype distribution in asthmatic/atopic children and in their parents. Genotype data were available for all subjects (parents and offspring), and therefore missing parental genotypes did not represent an issue in this study. The SNPs rs1342326 and rs928413 were in Hardy-Weinberg equilibrium and LD with each other (D9 5 0.95, R 5 0.59). The observed minor allele frequency was 23% (minor allele, G; major allele, T) and 31% (minor allele, G; major allele, A) for rs1342326 and 928413, respectively. TDT analysis showed a preferential transmission of the rs928413 G allele to subjects with positive SPT responses (transmitted, 65; not transmitted, 43; P 5 .034) and in particular with positive SPT responses to graminae (transmitted, 54; not transmitted, 33; P 5 .024) but not with positive SPT responses to house dust mite (transmitted, 41; not transmitted, 33; P 5 .353). No significant association was observed between rs928413 and the other phenotypes or between rs1342326 and any of the phenotypes investigated. Even if the study had a limited dimension that might affect statistical power, we emphasize that the families were enriched for the genetic risk factor because they were in linkage with the 9p24 marker. A 2-loci haplotype TDT was performed. Table II reports the haplotype frequencies observed. Haplotype rs1342326rs928413/T-A was the most frequent haplotype observed (Table II). Table III shows the result of the haplotype association test. Haplotype rs1342326-rs928413/T-G was preferentially transmitted to children affected by asthma (P5 .018), BHR to methacholine (P 5 .006), increased IgE levels (P 5 .022), or positive SPT responses (P 5 .015), particularly positive SPT responses to graminae (P 5 .006). The TDT performed on 2 loci confirms the association found in the rs928413 analysis and adds the information that the rs1342326-rs928413/T-G haplotype (frequency, 8.8%) is associated to allergic phenotypes. This haplotype can therefore be considered the at-risk haplotype, and it might contain the susceptibility allele for the phenotypes investigated. It is worth noting that haplotype analysis showed a significant association for 5 of the 6 phenotypes, and this is far superior to what would be expected by chance (P5 .00002 when considering 5 associated phenotypes of the 6 phenotypes or P5 .001 for 5 significant results of 18 tests). It is therefore reasonable to conclude that the excess of associations might indicate the presence of a true association. These results are therefore in agreement with the previous studies because Moffatt et al indicated association with the rs938413 allele G and Gudbjartsson et al with the rs3939286 allele A, which is tagged by the rs928413 allele G. It is noteworthy that we observe a significant association of rs928413with positive SPT responses but not with asthma, and Gudbjartsson et al reported the association of rs3939286 with atopic asthma but not with nonatopic asthma. This could suggest that rs928413 (and rs3939286) could be mainly associated with the atopic component of the disease. The association to the most common aeroallergens was in particular because of positive SPT response to graminae, suggesting that rs928413 might be associated with the atopic component of seasonal epidemic asthma. We could not exclude that association with positive SPT responses is independent from asthmatic status because all the children were asthmatic. The 2 studied SNPsmap in an intergenic region, and the closest gene is IL33; the 59 side is located in an LD block containing the SNP rs928413 (http://www.hapmap.org, rel#24). No significant association was observed between genetic markers and total serum IgE levels by using the family-based association test statistic. We can speculate that SNP rs928413 might be in LD with variants affecting gene expression. For its characteristics and functions, IL33 represents an attractive candidate gene for the association with allergic asthma–related traits. The IL33 gene, a member of the IL-1 family, is an inducer of TH2 cytokine immunity and systemic inflammation through a complex including the membrane-bound ST2 protein. Binding of IL-33 to its receptor, which is present on mast cells, basophils, eosinophils, natural killer cells, and natural killer T cells, triggers the release of several proinflammatory mediators, induces systemic TH2-type inflammation in vivo, and contributes to allergen-induced airway inflammation and hyperresponsiveness. In conclusion, the results of this family-based association study in an Italian population extends the previously described asthma

Detection of a large deletion in the P-selectin (SELP) gene

P-selectin is an adhesion molecule involved in the pathogenesis of inflammation, thrombosis, and oncogenesis. In this study of 51 polymorphisms in candidate genes for cardiovascular disease in 1561 individuals, we identified a new allelic variant of the SELP gene, g.18196_20704del, that determined the lack of genotyping for one polymorphism in one individual. It is a deletion of 2509 nucleotides which starts in intron 6 and ends in intron 8. Re-genotyping of 1023 apparent homozygotes indicated an overall allele frequency of 0.27%. The inclusion of this allelic variant in genetic association studies will avoid genotyping errors and marginally improve the sensitivity.

Haploidentical hematopoietic stem cell transplantation in a myelofibrosis patient with primary graft failure

The prognosis of patients affected by myelofibrosis (MF) is usually dismal and allogeneic hematopoietic stem cell transplantation (HSCT) remains the only cure. The number of HSCTs in MF patients has recently increased. However, a major obstacle is still represented by primary graft failure (PGF). Currently there are no definitive guidelines for the treatment of PGF and a second HSCT can be performed only when an allogeneic donor is rapidly available. Herein we report on a MF patient with PGF after an unrelated HSCT, who was rescued by a non-myeloablative, unmanipulated, haploidentical HSCT that resulted in persistent engraftment and bone-marrow fibrosis regression, but not in a long-term disease control. Based on this experience we briefly review the role of different conditioning regimens and hematopoietic stem cell sources in the setting of HSCT for MF patients with PGF. The role of haploidentical donors in MF patients lacking HLAmatched relatives is also discussed.