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Notes: HLA-class III region genes may be associated with susceptibility to insulin-dependent diabetes mellitus (IDDM). In this study an Ncol polymorphism of the tumour necrosis factor beta (TNF-β) gene, which is positioned next lo the tumour necrosis factor alpha (TNF-α) gene in the HLA class 111 region, was detected by restriction fragment length polymorphism (RFLP). This polymorphism has previously been reported lo be located in the TNF-α gene. Caucasian HLA-DR3.4 heterozygous IDDM patients (n=-26) and DR-matched healthy controls (n=19). as well as randomly selected IDDM patients (n = 27) and controls (n = 25) were studied. In addition four multiplex families (49 individuals) and eight HLA-non-identical sibpairs concordant for IDDM were analysed.The TNF-β gene RFLP analysis showed fragments of 5.5 kb and 10.5 kb, which behaved as alleles. In all groups there was a haplotype assignment of the TNF-β 5.5-kb allele to BS, DR3 haplotypes, and of the TNF-β 10.5-kb allele to B15.DR4-positive haplotypes. The allelic and genotypic frequencies differed between DR3.4 IDDM patients and DR3,4 controls, and the DR3.4 control group differed significantly from the randomly selected control group (P 〈 0.0079), In HLA-DR3,4-atid DQw8-positive persons, the DR3 haplotypes carried the 10.5-kb allele ihrcL- times more frequently in IDDM patients than in controls, suggesting that the 10.5-kb allele when present on DR3 haplotyes may contribute lo susceplibility to IDDM in DR3.4 heterozygous individuals, A contributory role of the Hl.5-kballele in genetic IDDM susceptibility was supported by the sibpair analysis, in which all were TNF-/1 identical. Five were 10,5 kb homozygous. and the remaining three pairs were 5.5.10,5 kb heterozygous.Twenty-five healthy and eight newly diagnosed IDDM patients were randomly selected to study the Escherichia coli lipopolysaccharides (LPS)-purified protein derivate (tuberculin) (PPD)-, and phytohaemagglutinin (PHA)-stimulated monocyte (Mo) secretions of interleukin 1 bela (IL-1/J)and TNb-α in relation lo the Ncol TNF-/f gene polymorphism. The LPS- and PHA stimulated Mo IL-l/f and TNF-a: secretions were significantly lower for the TNF-β 5.5.10,5 kb heterozygous individuals than for TNF-β 10.5 kb homozygous individuals. Furthermore, the Mo IL-1β and TNF-a secretions of IDDM patients were significantly higher than the Mo secretions of TNF-β genolype-matched healthy controls.This study suggests an association between the 10.5 kb TNF-β allele and IDDM, and demonstrates an association between monokine responses and TNF-β genotypes. These observations may have implications for understanding the pathogenesis of HLA-associated autoimmune diseases including IDDM.

Notes: Interleukin 1β(IL-1β) and tumour necrosis factor alpha (TNF-α) may be pathogenetically important in insulin-dependent diabetes mellitus (IDDM), which is associated with genes of the HLA region. Since a regulatory role of HLA region genes on monokine production may exist, we looked for an association between the monokine and prostaglandin E2 (PGE2) responses of monocytes (Mo) from 20 healthy males (18–50 years) with HLA-DR types relevant for IDDM susceptibility and resistance (DR 1,2, DR 1,3, DR 1,4, DR 3,4). Monokine assays were established and evaluated and the secretions of IL-1β, TNF-α, and PGE2 measured in Mo cultures (2 h, 6 h, 20 h) prepared by endotoxin-free techniques and stimulated by low-dose E. coli lipopolysaccharides (LPS). There were no significant associations between Mo responses and HLA-DR phenotype. Likewise, Mo from DR2 (n=5) and DR4 (n= 5) homozygous healthy males demonstrated no significant differences in monokine and PGE2 responses of Mo.In the HLA class III region a diallelic TNF-β gene Ncol polymorphism consisting of alleles of 5.5 kb and 10.5 kb was recently described and associated with susceptibility to autoimmune diseases including IDDM. We report that IL-1β and TNF-α responses of Mo from TNF-β 10.5 kb homozygous healthy individuals were significantly higher than for TNF-β 5.5/10.5 kb heterozygotes.IL-1β and TNF-α responses of Mo from males (18–35 years) with newly diagnosed (n= 10) and long-standing IDDM (n= 10) and from age- and HLA-DR-matched healthy males (n= 10) were studied. LPS, gamma interferon (IFN), and TNF-α-stimulated Mo cultures were investigated. No significant differences were found between Mo responses of IDDM patients and controls. IFN (1000 U/ml) in the presence of LPS significantly potentiated LPS-stimulated Mo TNF-α secretion and reduced the levels of IL-β immunoreactivity in Mo lysates. IFN and TNF-α did not have any effects on LPS-stimulated Mo secretion of IL-1 β immunoreactivity.We conclude that Mo IL-1β and TNF-α production is normal in patients with recent-onset and long-standing IDDM. The interindividual differences in monokine responses may be accounted for by the diallelic human TNF-β gene polymorphism rather than by HLA class II genes. This observation may be important for understanding the association of certain H LA haplotypes with autoimmune phenomena and disease.

Notes: The effects of dietary supplementation with ω-3-polyunsaturated fatty acids (ω-3-PUFA) on the proliferative response of PBMC and on the secretion of monokines and arachidonic acid metabolites from PBMC and monocytes (Mo) from healthy subjects and patients with recent-onset insulin-dependent diabetes mellitus (IDDM) were examined. Three groups of eight to nine healthy individuals were randomized to either 2.0 g/day or 4.0 g/day of ω-3-PUFA devoid of vitamins A and D, or an isocaloric amount of placebo. Furthermore, eight patients with recent-onset IDDM received 4.0 g/day of ω-3-PUFA. IL-lβ production and TNF-α secretion was determined before and after 7 weeks of treatment, and 10 weeks after withdrawal of treatment. Significant increases in platelet and PBMC membrane eicosapentaenoic acid was found in ω-3-PUFA-treated individuals. ω-3-PUFA treatment significantly reduced the content of IL-Ib in lysates of PBMC, but did not affect PBMC or Mo secretion of IL-1β, TNF-α or prostaglandin E2 (PGE2) or PBMC leukotriene B4 (LTB4) secretion in healthy subjects or in IDDM patients. A significant inhibition of the PHA-stimulated. but not the spontaneous or PPD-stimulated, proliferative response of PBMC was observed in healthy and diabetic subjects treated with (o-3-PUFA. No correlation was found between PHA-stimulated PBMC proliferation and PBMC secretion of TNF-α and IL-1β. There were no significant differences in the spontaneous or the PPD-or PHA-stimulated proliferative responses of PBMC between diabetic and healthy individuals at entry. We conclude that although dietary supplementation with 4.0 g/day of ω-3-PUFA inhibits the proliferation of PBMC and reduces IL-I immunoreactivity in PBMC and Mo, it does not alter monokine, PGE2 or LTB4, secretion in healthy or IDDM subjects.

Notes: The genes located between class II and class I HLA genes including polymorphic tumour necrosis factor (TNF) genes may contribute to the disease susceptibility in IDDM. Restriction fragment polymorphisms of the TNF-β gene have been found to be fixed in the major IDDM susceptibility haplotypes, the B62,DR4 haplotype being associated with the 10.5-kb fragment and the B8,DR3 haplotype with a 5.5-kb fragment. We studied this TNF polymorphism in a sample of diabetic families. In all IDDM-associated haplotypes (n= 129) the 5.5-kb allele was more frequent than in haplotypes found only in healthy family members (n=112) (58.1% versus 40.2%, P〈0.01). Among IDDM haplotypes the B62,DR4 haplotype was characterized by the 10.5-kb TNF fragment, whereas two other common Finnish IDDM-associated DR4 haplotypes-A24,B39,DR4 and A2,B56,DR4-had the 5.5-kb TNF fragment. Both IDDM-associated and non-associated DR3 positive haplotypes were linked to the 5.5-kb fragment. The distribution of various combinations of TNF alleles in IDDM probands (n= 63) did not differ from that expected according to the Hardy-Weinberg distribution. Our results indicate that the 10.5-kb allele of TNF-β gene as such is not a risk factor contributing to DR4/DQ8-associated susceptibility. Alternatively, there may be heterogeneity in pathogenetic effector mechanisms.

Notes: In the present study we characterized the frequencies of two polymorphisms within the MHC-linked heat shock protein (HSP) 70 genes in patients with insulin-dependent diabetes mellitus (IDDM) (n= 114) and healthy control individuals (n = 110). Significant differences in genotype and allelic frequencies were observed for both polymorphisms between randomly selected patients and controls. However, for the HSP70-2 polymorphisms this was solely due to linkage disequilibrium with DR3. The rare HSP70-Hom 2-allele was significantly more frequent in controls than in patients. It showed strong association with certain tumour necrosis factor (TNF) (class III) and HLA-B and -A (class I) alleles independent of HLA-DQ and -DR alleles. By typing 257 individuals from 55 IDDM multiple-case families two extended MHC-haplotypes, including class II-, TNF- and class I-markers, carrying the rare HSP70-Hom allele were defined. One was only transmitted to diabetic offspring, whereas the other was only transmitted to unaffected offspring. The functional implication of the polymorphism in the heat shock-inducible HSP70-2 gene was analysed by studying HSP70-2 mRNA expression after heat shock in peripheral blood mononuclear cells from individuals with different HSP70-2 genotypes. Preliminary data showed that individuals homozygous for the PstI 8.5-kb allele consistently had slightly lower expression than heterozygous and 9·0-kb homozygous individuals.

Notes: CD4 is a candidate gene in autoimmune diseases, including Type 1 diabetes mellitus (T1DM), because the CD4 receptor is crucial for appropriate antigen responses of CD4+ T cells. We previously found linkage between a CD4-1188(TTTTC)5−14 promoter polymorphism and T1DM. In the present study, we screened the human CD4 promoter for mutations and identified three frequent single nucleotide polymorphisms (SNPs): CD4-181C/G, CD4-521C/G and CD4-1050T/C. The SNPs are in strong linkage disequilibrium (LD) and association with the CD4-1188(TTTTC)5−14 alleles, and we observed nine CD4 promoter haplotypes, of which four are frequent. We genotyped the SNPs in 253 Danish T1DM families (1129 individuals) and found evidence for linkage and association of a CD4 (A4-1188T-1050G-521C-181) haplotype to T1DM. In reporter studies, we show that (1) the T1DM-associated CD4 haplotype encodes high constitutive promoter activity and (2) the CD4-181G variant encodes higher stimulated promoter activity than the CD4-181C variant. This difference is in part neutralized in the frequently occurring CD4 promoter haplotypes by the more upstream genetic variants. Thus, we report functional impact of a novel CD4-181C/G SNP on stimulated CD4 promoter activity and the identification of a novel CD4 haplotype with high constitutive promoter activity that is linked and associated with T1DM.

Notes: [Auszug] The IDDM2 locus encoding susceptibility to type 1 diabetes was mapped previously to a 4.1–kb region spanning the insulin gene and a minisatellite or variable number of tandem repeats (VNTR) locus on human chromosome 11p15.5. By ‘cross–match’ haplotype analysis and linkage ...

Notes: [Auszug] The role of human chromosome 2 in type 1 diabetes was evaluated by analysing linkage and linkage disequilibrium at 21 microsatellite marker loci, using 348 affected sibpair families and 107 simplex families. The microsatellite D2S152 was linked to, and associated with, disease in families from ...

Notes: Summary Due to a short observation period previous studies may have underestimated prevalence and recurrence risk of IDDM in relatives of IDDM patients. To obtain a more exact life-time risk estimate we identified 310 probands, representative of Danish IDDM patients, characterized by current age more than 50 years, age at onset 40 years or less and diabetes duration of more than 30 years. Family data were obtained from 291 probands. Mean “observation” times (age) (± SD) for siblings (n =553) and offspring (n =359) were 59.4±16.1 years and 33.8±8.8 years, respectively. Of the probands 73 (25.1 %) had at least one first-degree relative with IDDM. Seventeen percent had at least one affected sibling. An increase from 10.4 % to 22.4 % of having first-degree relatives with IDDM among probands with age at onset below 20 years was observed during the period from proband at age 21 years up to 1 September 1992. Among affected siblings 48 % of the second cases were affected more than 10 years after the first affected sibling. Using the life-table method cumulative recurrence risks from time of birth were calculated for siblings up to age 30 years of 6.4 % and up to age 60 years of 9.6 %. For offspring the risk up to age 34 years was 6.3 %. In addition, we present a life-table method evaluating the cumulative recurrence risk from time of onset in the proband, as this is the most relevant when giving genetic counselling. In conclusion, the long-term risks of IDDM in siblings and offspring are high compared to that shown in previous reports. [Diabetologia (1994) 37: 321–327]