Interleukin 12B gene polymorphism and apparent resistance to hepatitis C virus infection.

Cellular immunity with interferon gamma production could have a role in protection from hepatitis C virus (HCV). Interleukin (IL)-12 is a key cytokine in promoting such anti-viral T helper 1 (Th1) responses. We hypothesized that a genetic background able to promote cellular responses may be associated with apparent protection from infection and have investigated the distribution of the functional 1188A/C polymorphism of IL-12B in HCV exposed but uninfected cases. The frequency of the high IL-12-producing C allele was determined by restriction enzyme genotyping in 76 exposed-uninfected individuals and 105 healthy controls. Overall, the C allele was found in 27.6% of exposed-uninfected cases compared with 16.7% of healthy controls [chi(2) = 6.3, P = 0.02, odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.1-3.2]. CC genotype was found in 10.5% of exposed-uninfected cases compared with 0.9% controls (chi(2) = 9.3, P = 0.01, OR = 12, 95% CI = 1.5-100). Individuals at high risk of HCV infection yet who remain uninfected may be resistant in some way to infection. In our cohort of exposed-uninfected cases a genetic background of enhanced IL-12 production was associated with apparent resistance to HCV infection. This lends support to a central role for cellular immune responses in protecting from infection.

Relation of mesangial IgA glomerulonephritis to polymorphism of immunoglobulin heavy chain switch region.

We have investigated the switch regions of Ig heavy chain genes of patients with IgA glomerulonephritis (IgA-GN) using restriction fragment length polymorphism (RFLP) analysis. Genomic DNA from patients and controls was digested with the restriction endonuclease Sst I and transferred to nylon membranes using the Southern blot procedure and hybridized with a probe homologous to the switch region of the Ig C mu gene (S mu) which detects RFLPs in both S mu and the switch region of the Ig C alpha 1 gene (S alpha 1). A significant decrease in the frequency of the 2.6;2.1 kb heterozygous S mu phenotype was found in patients with IgA-GN (P = 0.003). With respect to the S alpha 1 region, there was a significant increase in the frequency of the 7.4 kb S alpha 1 phenotype (P = 0.002). In addition, a significant increase in the frequency of the 7.4 kb S alpha 1 allele was found (P = 0.0002). These results suggest that gene(s) within the Ig heavy chain loci may be important in the pathogenesis of IgA-GN.

Missense mutations in the insulin promoter factor-1 gene predispose to type 2 diabetes.

The transcription factor insulin promoter factor-1 (IPF-1) plays a central role in both the development of the pancreas and the regulation of insulin gene expression in the mature pancreatic beta cell. A dominant-negative frameshift mutation in the IPF-l gene was identified in a single family and shown to cause pancreatic agenesis when homozygous and maturity-onset diabetes of the young (MODY) when heterozygous. We studied the role of IPF-1 in Caucasian diabetic and nondiabetic subjects from the United Kingdom. Three novel IPF-1 missense mutations (C18R, D76N, and R197H) were identified in patients with type 2 diabetes. Functional analyses of these mutations demonstrated decreased binding activity to the human insulin gene promoter and reduced activation of the insulin gene in response to hyperglycemia in the human beta-cell line Nes2y. These mutations are present in 1% of the population and predisposed the subject to type 2 diabetes with a relative risk of 3.0. They were not highly penetrant MODY mutations, as there were nondiabetic mutation carriers 25-53 years of age. We conclude that mutations in the IPF-1 gene may predispose to type 2 diabetes and are a rare cause of MODY and pancreatic agenesis, with the phenotype depending upon the severity of the mutation.

Functional differences between the susceptibility Z-2/C-106 and protective Z+2/T-106 promoter region polymorphisms of the aldose reductase gene may account for the association with diabetic microvascular complications.

Studies have shown that polymorphisms located at positions -106 and approximately -2100 base pairs (5'ALR2) in the regulatory region of the aldose reductase gene are associated with susceptibility to microvascular complications in patients with diabetes. The aim was to investigate the functional roles of these susceptibility alleles using an in vitro gene reporter assay. Susceptibility, neutral and protective 5'ALR2/-106 alleles were transfected into HepG2 cells and exposed to excess D-glucose (D-glucose at final concentrations 14 or 28 mmol/l). Transcriptional activities were determined using a dual luciferase reporter gene assay. The "susceptibility alleles" Z-2 with C-106 had the highest transcriptional activity when compared with the "protective" combination of Z+2 with C-106 alleles (58.7+/-9.9 vs. 10.1+/-0.7; P<0.0001). Those constructs with either the Z or Z-2 in combination with the C-106 allele had significantly higher transcriptional activities when compared to those with the T-106 allele (Z/C-106, 37.4+/-5.4 vs. Z/T-106 7.7+/-1.6, P<0.003; Z-2/C-106, 58.7+/-9.9 vs. Z-2/T-106 10.9+/-0.6, P<0.0001). These results demonstrate that the Z-2/C-106 haplotype is associated with elevated transcriptional activity of the aldose reductase gene. This in turn may explain the role of these polymorphisms in the susceptibility to diabetic microvascular complications.

Polymorphism in the 5'-end of the aldose reductase gene is strongly associated with the development of diabetic nephropathy in type I diabetes.

Recent studies suggest that the gene encoding aldose reductase (ALR2), the enzyme that converts glucose to sorbitol, may confer susceptibility to microvascular disease. DNA from 275 British Caucasian patients with type I diabetes and 102 normal healthy control patients were typed for a (CA)n dinucleotide repeat polymorphic marker in the 5'-region of the ALR2 gene using polymorase chain reaction (PCR). A highly significant decrease in the frequency of the Z+2 allele was found in patients with nephropathy (nephropathy group) compared with those with no complications after a 20-year duration of diabetes (uncomplicated group) (12.7 vs. 38.2%, respectively, chi2 = 18.6, P < 0.00001); this was accompanied by an increase in the Z-2 allele in the nephropathy group (32.0 vs. 12.7% in the uncomplicated group). The nephropathy group also had a significant decrease in the Z/Z+2 genotype compared with the uncomplicated patients (10.7 vs. 44.7%, chi2 = 16.0, P < 0.0001) and an increased frequency of the Z/Z-2 genotype. There was no significant association with diabetic retinopathy. These results demonstrate that the ALR2 gene may play a role in susceptibility to diabetic nephropathy; individuals with the Z+2 allele are more than seven times less likely to develop diabetic renal disease than those without this marker. This marker may prove valuable in screening for patients with diabetic nephropathy at diagnosis of diabetes.

A novel polymorphism in the 5' flanking region of the glucose transporter (GLUT1) gene is strongly associated with diabetic nephropathy in patients with Type 1 diabetes mellitus.

Glucose transporter 1 (GLUT1) activity has been implicated in renal hypertrophy and extracellular matrix formation in mesangial cells. Recent studies have suggested that polymorphisms in the GLUT1 gene are associated with susceptibility to diabetic nephropathy (DN) in patients with diabetes mellitus. In this study, a novel polymorphism (A-2841T) in the 5' flanking region of GLUT1 was examined in 288 patients with Type 1 diabetes mellitus (T1DM) and 101 normal controls. The polymorphisms were amplified and the fragment digested with the enzyme HpyCH4V. There was a highly significant increase in the frequency of the TT-2841 genotype in patients with nephropathy (n=131) compared with those with either no microvascular complications after a 20-year duration of diabetes (uncomplicated; n=72; 54.5% vs. 2.7%, chi=79.4, P<.000001). There was no difference between the uncomplicated group and those who only had retinopathy (n=50; 2.7% vs. 4.0%, respectively). The frequency in recently diagnosed patients was 17.1% and only 2.0% in normal controls. In contrast, the AA genotype was found in 13.6% of the nephropaths, 76.3% of uncomplicated, 48.0% of retinopaths, and 65% of normal controls. These results confirm previous reports of an association between the GLUT1 gene and susceptibility to DN but not retinopathy. The localisation of this polymorphism suggests that it may be involved in the expression of the gene.

Pediatric autoimmune liver diseases: the molecular basis of humoral and cellular immunity.

Pediatric autoimmune liver disease is mainly represented by two similar liver disorders: autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (ASC), both characterized by hypergammalobulinemia, interface hepatitis and the presence of a wide range of circulating autoantibodies. Although similar features are seen in AIH and inflammatory bowel disease, histological biliary changes are more common in ASC. In addition to their role as diagnostic markers, autoantibodies, such as anti-extractable nuclear antigen (ENA) antibodies and liver kidney microsomal antibody type 1 (LKM1) may be involved directly in inducing aggressive liver diseases. Although the cellular immune response in pediatric autoimmune liver disease has been less intensively investigated than humoral immunity, the importance of antigen specific T cells has been explored. Both alphabeta and gammadelta T cells derived from either peripheral blood and liver biopsies have highly heterogeneous TCR gene usage and cytolytic activity has been demonstrated. There have been attempts to seek triggers of liver autoimmunity and several sequences shared in common between autoantigens and hepatotropic viruses, namely hepatitis B, C and cytomegalovirus have been identified. The presence of cross-reactivity between homologous sequences, especially between HCV and cytochromes, supports the possibility that molecular mimicry plays a role in the induction of autoantibodies and autoreactive cytotoxic T cells.

Polymorphism of the T cell receptor beta-chain in Graves' disease.

We investigated the T cell antigen receptor constant (TCR beta) beta-chain genes of patients with Graves' disease using restriction fragment length polymorphism analysis. Genomic DNA from patients and normal subjects was digested with the restriction endonuclease Bg1 II, transferred to nylon membranes using the Southern blot technique, and hybridized with a TCR beta probe. A significant increase in the frequency of the 10.0; 9.2-kilobase heterozygous phenotype was found in GD (68.6%) vs. 42.1% in normal subjects (P = 0.003). Using the complex phenotype TCR homozygote (hetero) DR3 as a reference (odds ratio = 1.00), we found that the risk for Graves' disease was restricted to TCR beta heterozygote/DR3+ individuals (odds ratio = 8.31; chi 2 = 11.82; P = 0.0009); in the absence of TCR beta heterozygosity, DR3 was not significantly associated with the disease. These results suggest that TCR beta chain genes also are associated with susceptibility to GD and that the association is most pronounced in (or restricted to) those individuals who are HLA DR3 positive.

A CA repeat polymorphism of the IFN-gamma gene is associated with susceptibility to type 1 diabetes.

Recent studies have shown that loci outside the HLA region are involved in determining susceptibility to type 1 diabetes. Polymorphisms in the coding and noncoding regions of the genes encoding cytokines may be involved in modulating the immune response to self and nonself antigens. There is increasing evidence that an imbalance and disruption of the Thl and Th2 T cell subsets play a key role in the development of experimental and clinical type 1 diabetes. The aim of this study was to investigate the frequency of a CA dinucleotide repeat polymorphism in the interferon-gamma (IFN-gamma) gene (IFNG) and a C(-590)T polymorphism of the interleukin-4 (IL-4) gene in 236 Caucasoid patients with type 1 diabetes. There was a highly significant increase in the 3/3 IFNG genotype in the patients compared with normal healthy controls (34.3% vs. 13.5%, p<0.0001) as well as a significant increase in allele 3 of the IFNG locus in the patients compared with controls (51.9% vs. 31.7%, p<0.00001). In contrast, no significant differences were found in the frequency of the C(-590)T IL-4 polymorphism between patients and controls. These results suggest that polymorphisms of the IFNG gene may modify the function of this proinflammatory mediator and the response to pancreatic islet beta cells.

A polymorphism in the promoter region of the gene for interleukin-6 is associated with susceptibility to type 1 diabetes mellitus.

Type 1 diabetes mellitus is an autoimmune disease characterized by the destruction of the insulin-producing islet beta cells. It is likely that several genetic and environmental factors contribute to this process. There is increasing evidence showing that polymorphisms in cytokine genes may play an important role in modifying the immune response. Interleukin-6 (IL-6) is a cytokine that has been implicated in a number of immune-mediated diseases. Further, there is a polymorphism at position -174 (G(-174)C) of the promoter region of the IL-6 gene that may alter the expression of the gene. In this study, the G(-174)C polymorphism was investigated in 257 Caucasoid patients with type 1 diabetes, 53 two-parent-proband trios, and 120 normal, healthy controls. DNA was amplified using amplimers that flank the G(-174)C site, and the products were digested with the restriction endonuclease NlaIII to detect the G or the C allele. The homozygous G,G(-174) genotype was increased in the patients compared with the normal controls (50.6% vs. 33.3%, p < 0.002), with a decrease in the C,C genotype in the patients compared with the controls (12.5% vs. 24.2%, respectively, p < 0.004). In the 53 trios studied, the G allele was transmitted in 29 of 53 informative meioses. There was no association with age at onset of diabetes or the presence of diabetic complications. In conclusion, these results suggest that the IL-6 gene may contribute to the genetic susceptibility to type 1 diabetes.

Polymorphisms of the aldose reductase gene and susceptibility to diabetic microvascular complications.

Diabetes is a major cause of mortality and morbidity due to the long term microvascular complications of this disease. There is now convincing evidence to show that genetic factors together with elevated blood glucose play an important role in the susceptibility to diabetic nephropathy as well as retinopathy. The polyol pathway is thought to play an important role in the pathogenesis of diabetic microvascular complications. Aldose reductase is the first and rate-limiting enzyme of the polyol pathway. Polymorphisms in the promoter region as well as elsewhere in the gene have been associated with susceptibility to nephropathy, retinopathy as well as diabetic neuropathy. These associations have been replicated in patients with either type 1 or type 2 diabetes mellitus as well as across ethnic groups. These polymorphisms in the promoter region are also associated with expression of the gene. Although clinical trials using inhibitors of aldose reductase to treat diabetic microvascular complications have largely been unsuccessful, the identification of the susceptibility genes may help in the design of future drug regimens.

A study of cytokine protein secretion, frequencies of cytokine expressing cells and IFN-G gene polymorphisms in normal individuals.

BACKGROUND: Cytokines are major regulators of immune responses, and there is evidence that they play a role in allograft rejection. Before embarking on a detailed study of pretransplant cytokine profiles in renal allograft recipients, we wished to investigate variations in cytokine protein secretion, numbers of cytokine expressing T cells, and cytokine gene polymorphisms in normal volunteers. METHODS: Twenty normal healthy volunteers were studied. Cytokine protein secretion [interleukin- (IL) 2, IL-4, IL-10, and interferon- (IFN) y] and numbers of cytokine expressing CD3+ T cells (IL-2, IL-4, IL-10, and IFN-gamma) were quantified by means of enzyme-linked immunosorbent assay and two-color flow cytometry respectively. IFN-gamma gene polymorphisms were determined by polymerase chain reaction and autoradio graphy. RESULTS: Large interindividual variations in both the quantity of IL-2, IL-4, IL-10, and IFN-gamma cytokine protein secreted and numbers of IL-2 and IFN-gamma expressing T cells were demonstrated. However, numbers of IL-4 and IL-10 expressing cells were found to be below detectable limits by flow cytometry. In the case of IFN-gamma, a bi-modal distribution was seen for the quantity of protein secreted. In addition, correlations were observed between IL-2 protein and frequency of IL-2 expressing T cells. However, no relationship was found between IFN-gamma protein levels, numbers of IFN-gamma expressing cells and IFN-gamma gene polymorphisms. CONCLUSIONS: We have demonstrated large differences in both numbers of T helper 1 cytokine expressing cells and the quantity of T helper 1 and T helper 2 cytokine protein secreted between normal individuals. Although the amount of IL-2 protein secreted appeared to be determined by the frequency of IL-2 expressing cells, this was not the case for IFN-gamma.

Immunoglobulin (Gm) allotype frequencies in idiopathic membranous nephropathy and minimal change nephropathy.

40 Caucasoid patients with idiopathic membranous nephropathy (IMN) and 49 Caucasoid patients with minimal change nephropathy (MCN) were immunoglobulin allotyped for the Gm markers G1m (1, 2, 3) and G3m (5, 11, 21). Compared with normal controls the IMN group had a significantly decreased incidence of the G1m (3); G3m (5, 11) phenotype (P = less than 0.005). This decrease was accompanied by concommitant increase in both the G1m (1, 3); G3m (5, 11, 21) and the G1m (1, 2, 3); G3m (5, 11, 21) phenotypes. The result was most pronounced in IMN patients with deteriorating renal function. In contrast no significant differences were observed between the Gm phenotype frequencies of the MCN patients and controls.

Polymorphisms of the aldose reductase gene and susceptibility to retinopathy in type 1 diabetes mellitus.

PURPOSE: Aldose reductase (ALR2) is the first and rate-limiting enzyme of the polyol pathway and is involved in the pathogenesis of diabetic retinopathy. Polymorphisms of the ALR2 gene are associated with susceptibility to diabetic retinopathy in Chinese and Japanese patients with type 2 diabetes. There are no reports investigating these polymorphisms in white patients with type 1 diabetes from either Western Europe or North America. A CA dinucleotide repeat polymorphism (5'ALR2; located at -2100 bp) as well as a novel C(106)T polymorphism was investigated in 229 white patients with type 1 diabetes, with or without retinopathy. METHODS: The DNA was typed for these polymorphisms using conventional polymerase chain reaction techniques. RESULTS: There was a highly significant increase in the frequency of the Z-2 5'ALR2 allele and Z-2/X (where X is not Z+2) genotype in patients with diabetic retinopathy (n = 159) compared with those without who had diabetes of 20 years' duration (uncomplicated, n = 70; chi(2) = 17.0, P < 0.0001). There was a similar decrease in the Z+2/Y genotype (where Y is not Z-2; chi(2) = 30.1, P < 0.000,001) in the patients with retinopathy compared with the uncomplicated diabetes group. The C/Z-2 C(-106)T/5' ALR2 haplotype was found in 33.3% of the patients with retinopathy and 8.7% of the patients with uncomplicated diabetes. CONCLUSIONS: These results confirm previous studies in other populations and in type 2 diabetes showing that polymorphisms in the promoter region of the ALR2 gene are associated with susceptibility to diabetic retinopathy.

Immunoglobulin C mu gene restriction fragment length polymorphisms associated with chronic renal failure.

The DNA's of 41 patients with various forms of renal disease and of 52 controls were investigated for restriction fragment length polymorphisms (RFLP), using a probe recognising the immunoglobulin Cmu heavy chain gene. With the restriction endonuclease Sst 1, 50 of the controls and 12 of the patients had the expected single 4.3 kilobase (kb) fragment. The remaining 29 patients and 2 controls displayed two patterns of banding, 8 patients and 1 control had a 6.8 kb band in addition to the 4.3 kb, and 21 patients and 1 control had a single band of 5.1 kb. In addition, a significant association between high creatinine levels (greater than 150 mumol/l) and abnormal bands was found (21/25 patients with high levels had abnormal bands compared with only 5/16 patients with normal levels). These results are evidence for an association between the human immunoglobulin heavy chain region and renal disease and they apparently confirm an association already reported at the protein level. However, the new RFLP bands, although reproducible and restricted to renal patients, occur in an area where few polymorphisms would be expected. Further, the association with high creatinine suggests some subtle interaction between the creatinine pathway and this area of the human chromosome.

The HLA-E locus is associated with age at onset and susceptibility to type 1 diabetes mellitus.

Previous studies have suggested that the human leukocyte antigen (HLA) class I region may be involved in determining the age at onset and clinical severity of type 1 diabetes. We have investigated the frequency of polymorphisms of the nonclassical HLA class I gene, HLA-E, in 199 British Caucasian patients with type 1 diabetes and 82 healthy controls. A highly significant increase in the frequency of the HLA-E 0101 genotype was found in the patients compared to controls (chi(2) = 15.3, p < 0.00009). The frequency of the HLA-E 0101 genotype was increased in those patients diagnosed after 10 years of age, while the frequency of the 0101, 0103 genotype was significantly increased in those subjects diagnosed before 10 years of age (chi(2) = 26.0 p < 0.000003 and chi(2) = 13.0 p < 0.0003, respectively). No obvious interaction between the HLA-E locus and the class II DQB1*0201, 0302, and 0501 susceptibility alleles was found. This is the first report of an association between the HLA-E locus and susceptibility to an autoimmune disease.

Association of immunoglobulin Gm allotypes with antiglomerular basement membrane antibodies and their titer.

We studied the immunoglobulin Gm allotypes in 41 patients with glomerular nephritis caused by autoantibodies to glomerular basement membrane (GBM). Gm phenotypes of all 41 patients were attributable to combinations of the 3 Gm haplotypes commonly found in Caucasoid populations; identified by the allotypes Gm 1,21 (ag), Gm 1,2,21 (axg), and Gm 3,5,11 (fb). The incidence of the putative haplotype Gm 1,2,21 (axg) was greatly increased in the patients being present in 22 of 41 (56%) of patients compared to 28 of 167 controls. (Pcor = 1.5 X 10(-5]. The increase in Gm 1,2,21 (axg) was attributable entirely to presumed heterozygotes with the phenotype Gm 1,2,21;3,5,11 (axg;fb), with concomitant decreases in the frequencies of patients with the phenotypes Gm 1,21 (ax) and with Gm 3,5,11 (fb). Heterozygotes at Gm loci had higher titers of anti-GBM antibodies irrespective of the presence of Gm 1,2,21 (axg). Thus genes within or closely linked to the Gm complex in addition to HLA linked genes influence susceptibility to or clinical expression of anti-GBM disease.

A susceptibility region for myasthenia gravis extending into the HLA-class I sector telomeric to HLA-C.

We have analyzed a series of HLA region markers in 207 UK Caucasoids with early-onset myasthenia gravis (EOMG, onset before age 40), where there is a strong female bias. The well known associations with HLA-DR3 and -B8 have now proved to be significantly stronger in the 165 females than in the 42 males. In patients (of either sex) lacking -DR3, there was also a significant increase in HLA-DR2. Although the muscle weakness in EOMG is clearly mediated by autoantibodies, the associations are consistently stronger with HLA-B8 (in class I) than with HLADR3 (in class II), as confirmed here. We therefore typed 87-137 cases for polymorphisms at four loci in the intervening class III region, and also at three in the adjacent stretch of class I. At each locus, one allele tended to co-occur with HLA-B8 and showed strong and highly significant associations in the patients. There appeared to be a region of maximal susceptibility extending from HSP70 (in class III) past HLA-B and HLA-C at least 600 kb telomerically into the class I region, which is now being mapped in detail. Any candidate genes here that act shortly after puberty may allow more precise localization of susceptibility.

Increased frequency of IgG heavy chain marker Glm(2) and of HLA-B8 in Lambert-Eaton myasthenic syndrome with and without associated lung carcinoma.

In view of the evidence for an autoimmune pathogenesis of the Lambert-Eaton myasthenic syndrome, we have sought associations with IgG heavy chain allotypes (Gm) and HLA antigens in 30 patients, of whom 20 had evidence of lung carcinoma (histologically proven small ("oat") cell type in 17). A highly significant overall increase in frequency of Glm(2) (chi 2 = 10.95; p less than 0.001; n = 30) and of HLA-B8 (chi 2 = 19.07; p less than 0.001; n = 23) was observed. These two factors apparently occurred independently of each other. The Glm(2) frequency in 36 non-myasthenic small cell carcinoma cases was the same as in a control panel (n = 167). We conclude that Glm(2) and HLA-B8 both associate with increased susceptibility to the Lambert-Eaton myasthenic syndrome, and suggest that Glm(2) may be in linkage disequilibrium with a limited number of VH genes coding for antibodies to restricted antigenic determinants at the nerve terminals, which may be shared by the carcinoma cells.

Analysis of the peripheral T-cell receptor V beta repertoire in newly diagnosed patients with type I diabetes.

Type I diabetes is an autoimmune disease characterised by a marked activation of peripheral T cells around the time of clinical diagnosis. Studies of T-cell antigen receptor V beta (TCRBV) gene usage in type I diabetes have been conflicting. Using a semi-quantitative polymerase chain reaction technique and flow cytometry we have investigated the TCRBV gene usage of 13 newly diagnosed patients with type I diabetes and 11 normal healthy controls. No preferential TCRBV gene usage was found between patients and controls even after matching for HLA-DR3 and/or -DR4. In addition, no significant differences in TCRBV gene usage were found between sequential samples taken over a period of up to 7 months following diagnosis. These results suggest that the TCR repertoire of these patients is heterogeneous and it is unlikely that a single 'pathogenic' T-cell clone is dominant at the clinical onset of the disease.