Endoscopy waiting times and impact of the two week wait scheme on diagnosis and outcome of upper gastrointestinal cancer.

The NHS has introduced the two week wait scheme to detect upper gastrointestinal cancers at an early stage and improve survival rates The aim of this study was to assess the impact of this scheme and changes in endoscopy waiting times on tumour stage and resection rates over a four year period. Data were analysed prospectively for all patients diagnosed with oesophagogastric cancer between September 1998 and September 2002 and from those referred under the two week wait scheme since its introduction in 2000. Of those tumours diagnosed by this scheme (15%) only 5% were early disease (stage 1 or 2). Patients with early cancer, mainly diagnosed by routine gastroscopy, do not present with symptoms meeting the two week wait criteria. An increase in the resection rates for early disease will most probably be seen with a reduction in routine endoscopy waiting times.

The gluten-host interaction.

Work continues to progress in the unravelling of the molecular interactions involved in the pathogenesis of coeliac disease. The immunogenetics of the disease implicate certain HLA DQ alleles as necessary for subsequent disease development. These HLA molecules have been shown to be necessary in the binding and presentation of gliadin peptides to antigen-specific T cells. Current work is examining the precise HLA-antigen interaction that may lead to the development of antigen-blocking agents. The isolation of antigen-specific T cells has led to the confirmation of a toxic T-cell epitope of the gliadin protein (residues 31-49) and it would appear likely that additional toxic epitopes may be similarly characterized in the near future. No common TCR motifs have so far been detected, although these may become apparent as this work progresses. The gliadin peptide sequence, residues 31-49, has now been demonstrated to be toxic in vivo. Additional toxic T-cell epitopes may also be present within gliadins, but this identification of a toxic gliadin sequence for the first time raises the possibility of future manipulation of the wheat genome (and other toxic cereals) that could lead to the development of new graminae cereals with the properties of wheat, but which do not induce toxicity in patients with coeliac disease.

An analysis of HLA class II gene polymorphism in British and Greek idiopathic membranous nephropathy patients.

Fifty-two British and 29 Greek idiopathic membranous nephropathy (IMN) patients were analysed for DRB, DQA1, DQB1 and DPB1 gene polymorphism using second exon amplification and sequence-specific oligonucleotides (SSO). In addition 100 British and 92 Greek controls were analysed. A highly significant increased frequency of the DRB1*0301 allele was found in IMN patients from Britain (80%), when compared to controls (27%, OR 10.6, P = 0.000004). A lower frequency of DRB1*0301 was observed in Greek IMN patients (33%), but this was just significant before correction, when compared to Greek controls (15%, OR 3, P = 0.02). The DRB3 allele most often associated with DRB1*0301 was DRB3*0101 (OR 4.2, P = 0.00025) in British patients and DRB3*0201/2 (OR 11, P = 0.006) in Greek patients. In Greek IMN patients a decrease in DR16 was found (OR 0.08, P = 0.004), and the overall incidence of DR2 was significantly lowered when both sets of IMN patients were combined (OR 0.21, chi 2 17.6, P = 0.00013). The incidence of DQA1*0501 was raised in both Greek (96% vs. 66%, OR 9.7, chi 2 6.9, P = 0.009) and British IMN (85% vs. 45%, OR 7.4, chi 2 20, P = 0.00007) patients. This gives some support to a proposal for a major role for this allele in IMN.(ABSTRACT TRUNCATED AT 250 WORDS)

Pitfalls in diagnosing coeliac disease.

AIMS: To highlight the pitfalls in the diagnosis of coeliac disease and to make recommendations for its diagnosis and the management of refractory cases with equivocal histology. METHODS: Six patients, referred since 1989 with a diagnosis of coeliac disease based on duodenal biopsy specimens taken at endoscopy, and who failed to respond to a gluten-free diet were studied. All patients were subjected to peroral jejunal biopsy. Morphometric analysis of villus height:crypt depth ratios, surface enterocyte cell heights, and intraepithelial counts was used to aid in the assessment of equivocal histology. RESULTS: Subsequent small intestinal biopsy specimens both taken when the patients were following a gluten-free diet and after gluten challenge were normal in all cases. Morphometric analysis and intraepithelial counts were normal. CONCLUSIONS: Misinterpretation of the original slides was often due to poor sample quality and tangential sectioning. Failure to respond to a gluten-free diet should always raise doubt regarding the initial diagnosis, especially when the findings are normal. For correct diagnosis at least three distal duodenal biopsy specimens should be taken simultaneously, and these should be of an adequate size and correctly orientated. Review by a histopathologist experienced in gastrointestinal diagnosis is essential in difficult cases. Quantitative morphometric analysis is helpful in equivocal cases, and jejunal suction biopsy, following a gluten challenge, may be necessary in patients refractory to treatment.

Associations between alleles of the major histocompatibility complex-encoded ABC transporter gene TAP2, HLA class II alleles, and celiac disease susceptibility.

The study of celiac disease among Southern European populations has confirmed the hypothesis from Northern Europe that a close association exists between disease susceptibility and a combination of polymorphic alleles at the HLA-DQ loci (DQA1*0501-DQB1*0201) arranged either in a cis- or a trans-configuration. Attempts to identify additional genetic influences have been inconclusive, although many studies have raised possibilities of further major histocompatibility complex (MHC)-linked susceptibility genes. This study examines the disease associations of polymorphisms of a recently discovered gene located close to the DQ loci, TAP2, whose products are thought to be involved in the transport of antigen peptides across the endoplasmic reticulum for binding to HLA class I molecules. Like the products of the DQ loci, the product of TAP2 forms part of a heterodimeric molecule with products of a second genetic locus, TAP1, which is located centromerically to TAP2. The populations studied were central Italians from Rome and Ashkenazi Jews from Rehovot, Israel. HLA studies demonstrate that the Roman celiac group has a high proportion of people with DR3-negative celiac disease in whom the combination DR5/7 is frequently found. In Israel, 20% of celiac patients lack the DQ susceptibility markers but are DR4 positive. The polymorphic substitutions of TAP2 studied encode amino acid changes in the trans-membrane region (position 379) and the ATP-binding cassette region (positions 565 and 665) of the protein. No TAP2-specific disease associations were found in any HLA subgroup.(ABSTRACT TRUNCATED AT 250 WORDS)

Celiac disease among Ashkenazi Jews from Israel. A study of the HLA class II alleles and their associations with disease susceptibility.

The immunogenetics of celiac disease demonstrates a highly significant association with the HLA class II alleles DQA1*0501 DQB1*0201 encoded in either a cis- or trans-configuration. In Northern Europe, these alleles are found in linkage disequilibrium with DRB1*0301 while in Southern Europe an additional secondary association through linkage disequilibrium is seen with the combination DRB1*1101/0701. This study examines 34 Ashkenazi Jews with celiac disease and 36 ethnically matched controls to determine alleles at the DRB, DQA1, DQB1, and DPB1 loci using SSO probes in conjunction with gene amplification by the PCR. The results confirm a highly significant association with the DQA1*0501 DQB1*0201 allelic combination (71% celiac vs 8% control individuals; p = 0.00005; chi 2 = 21.4). Of celiac subjects, 29% were negative for the proposed DQ susceptibility alleles, the majority of whom were DRB1*0402 positive (20% overall celiac group). No additional susceptibility was associated at the DRB3 and DPB loci. This study confirms that the MHC-linked celiac disease susceptibility among Ashkenazi Jews is closely associated with the presence of the combination of alleles DQA1*0501 DQB1*0201. However, within this population of relatively high-prevalence celiac disease, 30% of celiac patients do not carry these alleles and are therefore not covered by a single "unifying" hypothesis.

HLA class II alleles associated with celiac disease susceptibility in a southern European population.

Susceptibility to celiac disease in Northern Europe is associated with the human leukocyte antigens (HLA) B8, DR3 and DQ2, which exist together on an extended haplotype. The strong predominance of this haplotype within the Northern European celiac populations, together with the linkage disequilibrium which occurs between these loci, does not allow identification of the gene(s) primarily associated with disease susceptibility. Studies from Southern Europe using both serology and examination of restriction fragment length polymorphisms (RFLP) have demonstrated associations with DR3, DR7 and DQ2, suggesting that the DQ locus is primarily involved. We investigated 43 celiac patients and 41 healthy controls from Rome, Italy, using sequence-specific oligonucleotide (SSO) probes, in conjunction with gene amplification by the polymerase chain reaction (PCR), to determine alleles at the DRB, DQA1, DQB1 and DPB1 loci: 19% of celiac patients possessed the alleles DRB1*0301 DRB3*0101, 33% DRB1*0301 DRB3*0201 and 33% of celiac patients were heterozygous for DRB1*1101-1201/DRB1*0701. The strongest association with celiac disease susceptibility was the combination of alleles DQA1*0501 DQB1*0201 (91% celiac patients vs. 12% controls; p = 0.000002). There was no additional susceptibility associated with alleles at the DPB locus. This study confirms the hypothesis that susceptibility is associated with a particular combination of DQ alleles and the ethnic variation in DR frequencies is secondary to linkage disequilibrium with these DQ alleles.