HLA DRB1, DQB1 and insulin promoter VNTR polymorphisms: interactions and the association with adult-onset diabetes mellitus in Czech patients.

Both the human leucocyte antigen (HLA) DRB1 and the HLA DQB1 gene loci play a role in the development and progression of autoimmune diabetes mellitus (T1DM). Similarly, the insulin promoter variable number tandem repeats (INS-VNTR) polymorphism is also involved in the pathogenesis of diabetes mellitus (DM). We studied the association between each of these polymorphisms and DM diagnosed in patients older than age 35 years. Furthermore, we analysed possible interactions between HLA DRB1/DQB1 and INS-VNTR polymorphisms. Based on C-peptide and GADA levels we were able to distinguish three types of diabetes: T1DM, latent autoimmune diabetes in adults (LADA) and T2DM. INS-VNTR was genotyped indirectly by typing INS-23HphI A/T polymorphism. The genotype and allele frequencies of INS-23HphI did not differ between each of the diabetic groups and group of healthy subjects. We did, however, observe an association between the INS-23HphI alleles, genotypes and C-peptide secretion in all diabetic patients: A allele frequency was 86.2% in the C-peptide-negative group vs. 65.4% in the C-peptide-positive group (P(corr.) < 0.005); AA genotype was found to be 72.4% in the C-peptide-negative group vs. 42.6% in the C-peptide-positive groups (P(corr.) < 0.01). The HLA genotyping revealed a significantly higher frequency of HLA DRB1*03 allele in both T1DM and LADA groups when compared to healthy subjects: T1DM (25.7%) vs. control group (10.15%), odds ratio (OR) = 3.06, P < 0.05; LADA (27.6%) vs. control (10.15%), OR = 3.37, P < 0.01. The simultaneous presence of both HLA DRB1*04 and INS-23HphI AA genotype was detected in 37.5% of the T1DM group compared to only 9.2% of the healthy individuals group (OR = 5.9, P(corr.) < 0.007). We summarize that in the Central Bohemian population of the Czech Republic, the INS-23HphI A allele appears to be associated with a decrease in pancreatic beta cell secretory activity. HLA genotyping points to at least a partial difference in mechanism, which leads to T1DM and LADA development as well as a more diverse genetic predisposition in juvenile- and adult-onset diabetes. The simultaneous effect of HLA and INS-VNTR alleles/genotypes predispose individuals to an increased risk of diabetes development.

KCNJ11 E23K polymorphism and diabetes mellitus with adult onset in Czech patients.

In this work, we studied the association of the E23K polymorphism of the Kir6.2 ATP-sensitive potassium channels in 212 Czech patients with diabetes mellitus who were diagnosed after the age of 35. Patients were classified into T1DM, LADA and T2DM groups based on C-peptide and GADA levels. Carriers of the predisposing Kir6.2 E23K K allele showed no increased risk of either type of diabetes mellitus development. On the other hand, we found a correlation between E23K SNP of the KCNJ11 gene and C-peptide levels, which may be considered a measure of pancreatic beta-cell activity, although this correlation was not statistically significant. In conclusion, we failed to confirm the Kir6.2 E23K as a genetic marker for T1DM, LADA and T2DM in the Central Bohemian population of the Czech Republic.

PCR in lyme neuroborreliosis: a prospective study.

OBJECTIVES: DNA proof is the only widely available direct diagnostic tool in Lyme borreliosis. Sensitive PCR detecting of spirochetal DNA was prepared and a prospective study in neuroborreliosis was performed. MATERIALS AND METHODS: 57 hospitalised patients with active neuroborreliosis and proved CSF antibodies synthesis were examined. Nested-PCR (utilizing three targets) was used for the detection of specific DNA in plasma, CSF and urine. RESULTS: Before treatment 36 positive patients (63.1%) were found in all tested specimens in parallel, 28 patients (49.1%) were positive in urine, 20 in CSF (35.0%) and 16 in plasma 28.0%). Later only urine was tested and the following results were obtained: 17 positive patients (30.0%) immediately after treatment, 8 (14.0%) after 3 months and one patient persisted positivity after 6 months. CONCLUSIONS: The highest sensitivity of PCR was achieved in the acute period of neuroborreliosis - 63.1% in three body fluids comparing with CSF antibody synthesis.

Apoptosis as an early event in the development of multiple organ failure?

We have recently developed a simple method of plasma free DNA detection, which enables us to distinguish between apoptotic and genomic (necrotic) DNA. After applying this method to the critically ill, we revealed apoptotic DNA on the day of admission to be higher than later when multiple-organ failure developed. Moreover, apoptotic DNA contributed to total plasma DNA much more than DNA from necrotic cells and its increase predicted future development of multiple-organ failure and death.

HLA in Czech adult patients with autoimmune diabetes mellitus: comparison with Czech children with type 1 diabetes and patients with type 2 diabetes.

Type 1 diabetes results from an autoimmune insulitis, associated with HLA class II alleles. The evidence about HLA allele association is not clear in patients diagnosed after 35 years of age. In this study we have analyzed HLA alleles of DQB1 and DRB1 genes by sequence specific primer (SSP)-PCR technique in adult patients with disease onset after 35 years of age. Two hundred and eighty-one patients were divided into three groups according to the insulin therapy, the level of C peptide (CP), and GAD antibodies (anti-GAD). Group 1 (type 1 diabetes in adults) was characterized by CP less than 200 pmol/L and anti-GAD more or less than 50 ng/mL (n = 80). All of them had insulin therapy within 6 months after diagnosis. Group 2 latent autoimmune diabetes mellitus in adults (LADA) was defined by a minimum 6-month-long phase after diagnosis without insulin therapy, and was characterized by CP more than 200 pmol/L and anti-GAD more than 50 ng/mL (n = 70). Group 3 (type 2 diabetes) was characterized by CP more than 200 pmol/L and anti-GAD less than 50 ng/mL (n = 131). None ever had insulin therapy. In group 1, there was increased frequency of DRB1*04 (45.0% vs. controls 14.1%, OR = 5.0, P < 0.0005) and DQB1*0302 alleles (43.3% vs. controls 11.1%, OR = 6.1, P < 0.00005). There was increased frequency of DRB1*03 and DQB1*0201, and decreased frequency of DQB1*0602 (3.3% vs. controls 20.2%), but it was not significant. In group 2, there was a significantly increased frequency of DRB1*03 only (50.0% vs. controls 21.2%, OR = 3.7, P < 0.05). Compared with children with type 1 diabetes and adults with type 2 diabetes (group 3), we conclude that the presence of predisposing DQB1 alleles in adults with type 1 diabetes decreases with the age, probably due to environmental factors. Only the DRB1*03, but not the DQB1 gene, becomes the main predisposing allele in LADA patients. These findings suggest that the presence of HLA-DQB1*0302 identifies patients at high risk of requiring insulin treatment. Type 1 diabetes mellitus (DM) in children or adults may have partly different immunogenetic etiopathogenesis than LADA.

Prostate-specific antigen: current status.

PSA is the most important of all tumor markers because it has significant applications in all aspects of the management of men with prostatic disease. Certainly, the most important utilization of PSA is for early detection of this most ubiquitous of all human neoplasms. In this article the authors describe the molecular forms of PSA and their characteristics, the factors influencing values of serum concentration of PSA, the problems of screening, and particularly the possibility to use PSA for detection of prostate carcinoma. A big problem in prostate carcinoma detection is the low specificity of PSA at the concentrations between 4-10 ng/ml, the so-called diagnostic gray zone, where the incidence of prostate carcinoma is only 25%. The authors evaluate the methods which make it possible to increase the sensitivity and/or specificity of PSA detection, such as PSA density, PSA density of the transition zone, PSA velocity, PSA doubling time, age-specific PSA, free PSA and, prospectively, the use of the RT-PCR technique.

[Hemochromatosis. Determination of the C282Y mutation frequency in the population of the Czech Republic and sensitivity of hemochromatosis detection using Guthrie cards]. / Stanovení frekvence C282Y mutace pro populaci Ceské republiky a Hemochromatosis. Stanovení frekvence C282Y mutace pro populaci Ceské republiky a citlivá detekce hemochromatózy z Guthrie karet.

BACKGROUND: Hereditary haemochromatosis (HH) is a multi-organ disease characterized by increased deposition of iron in some tissues. When discovered early the disease is curable. The Caucasian population is burdened with a high incidence of carriers and homozygotes. The recent discovery of the gene for haemochromatosis (HFE) and of the major mutation C282Y makes direct diagnosis possible. METHODS AND RESULTS: Exploiting a newly-designed polymerase chain reaction system, we determined the frequency of the C282Y mutation of the HFE gene in the Czech population by analysis of 278 chromosomes from anonymous clients of an in vitro fertilization centre (128 male and 150 female karyotypes respectively). There were 14 heterozygotes of the C282Y mutation (6 males and 8 females) and no asymptomatic homozygotes. All 12 patients with classically diagnosed haemochromatosis were homozygous for the C282Y mutation. Twelve Guthrie cards ten years old were tested as a source of the PCR signal for C282Y with a positive result in all cases (100% efficiency). CONCLUSIONS: Our data suggest that the approximate frequency of heterozygotes (carriers) of hereditary haemochromatosis in the Czech population is 1:10 which is comparable with data from the Central European region. The frequency of the major mutation among patients with HH was 100% (12/12), however, the difference with data from neighbouring countries (Austria, Germany) cannot be considered significant due to the small number of patients tested. We also showed the possibility of a retro-diagnosis of the presence/absence of C282Y mutation from Guthrie cards.

[Detection of HCV RNA in anti-HCV positive patients with chronic hepatic porphyria]. / Prkaz HCV RNA u anti-HCV pozitivních nemocných chronickou jaterní porfyrií (PCT).

BACKGROUND: In 1994 the authors published first results of anti-HCV antibodies in the group of 92 porphyria cutanea tarda patients, tested with ELISA second generation enzymatic method. Positivity, found in 21.7 per cent of them, was significantly higher when compared with the results of healthy blood-donors. Anti-HCV reactivity thus ascertained can be, however, non-specific in some cases and need not necessarily indicate existence of an active replication of hepatitis C-virus. The authors have therefore subsequently tried to verify the above results by the more sensitive polymerase chain reaction (PCR), enabling the proof of viral RNA and thus an assessment of the replication-activity of HCV. This study completes their previous findings for the evidence of viraemia in anti-HCV reactive PCT-patients. METHODS AND RESULTS: 21 of 92 PCT-patients were reactive when examined with the second generation ELISA method (Sanofi, Pasteur). HCV RNA was examined in 20 subjects from the above group (one patient died in the meantime) by means of PCR. Positive HCV RNA was found in 17 patients, i.e. in 85 percent of them. Percutaneous liver biopsy without visual control was performed in 17 anti-HCV reactive and HCV RNA positive patients and in 46 anti-HCV negative porphyrics. The biopsy-findings were significantly worse in the HCV RNA-positive group. Also the average activity of ALT and AST was significantly higher in the patients with positive HCV RNA when compared with anti HCV-negative subjects. CONCLUSIONS: High frequency of HCV-infection (21.7 percent) was found in our group of 92 PCT-patients. Viraemia was present in the vast majority (85 per cent) of them, for they had also positive HCV RNA besides anti-HCV reactivity. These patients had also higher ALT- and AST-activity and more severe histological liver-changes. HCV-infection is the main virological cause of their liver lesion, beside ethylism. Hepatocellular carcinoma is rather exceptional in our porphyria patients in spite of their frequent HCV-infection.

Anti-DNA and anti-platelet specificities of SLE-derived autoantibodies: evidence for CDR2H mutations and CDR3H motifs.

Although polyreactivity appears to be a characteristic feature of natural autoantibodies, polyreactive anti-DNA autoantibodies can be derived both from patients with autoimmune disease and from normal individuals. It is unclear whether these autoantibodies differ depending on their origin, but previous studies from our laboratory have suggested that polyreactive systemic lupus erythematosus (SLE)-derived platelet-binding anti-DNA autoantibodies have more restricted antigen reactivity and greater functional activity than normal-derived polyreactive autoantibodies. The objective of the present study was to characterize the VH and VL region sequences of 10 human hybridoma anti-DNA autoantibodies derived from peripheral blood lymphocytes of different origins [SLE, rheumatoid arthritis (RA), or normal] to determine whether there are structural differences between these autoantibodies. We show that although some unmutated germline structures (VH and VL) are represented, these are not restricted to anti-DNA autoantibodies from normal individuals and that two normal-derived anti-DNA antibodies showed quite extensively mutated VH genes. However, these mutations, unlike those found in the CDR2H of several of the SLE-derived antibodies, did not appear to be antigen-selected. Three different amino acid motifs, putatively involved in antigen binding specificity, were observed in the CDR3H segments of some of the autoantibodies. One was the previously described YYGSG motif, which was found in a normal-derived anti-DNA autoantibody, while two new potential motifs were observed only in SLE-derived platelet-binding anti-DNA autoantibodies. These data suggest that antigenic and functional differences between SLE-derived and normal-derived platelet-binding anti-DNA autoantibodies may be due to antigen-selected mutations in the CDR2H and specific amino acid motifs in the CDR3H.

Control of autoantibody affinity by selection against amino acid replacements in the complementarity-determining regions.

Rheumatoid factor (RF) autoantibodies can be produced in healthy individuals after infections or immunizations and thus escape normal tolerization mechanisms. It has not been clear whether such autoantibodies can undergo somatic hypermutation and affinity maturation similar to antibodies to exogenous antigens. We have investigated how these autoantibodies are regulated in normal individuals by analyzing the sequences of monoclonal IgM RFs obtained as hybridomas from donors after immunization. The variable regions undergo extensive hypermutation, but in contrast to antibodies against exogenous antigens, there is a strong selection against mutations that result in replacement of amino acids in the hypervariable, or complementarity-determining, regions. Furthermore, we found no increase in affinity of these RFs with the accumulation of mutations. This suggests that high-affinity variants are tolerized during the hypermutation process and there is a peripheral mechanism operating on certain autoreactive B cells that, while not deleting or anergizing all autoreactive cells, prevents the generation of high-affinity autoantibodies. Comparison of RFs by using the VH1 DP-10 heavy chain variable region segment from both normal individuals and rheumatoid arthritis (RA) patients suggests that RF from RA patients may not be subject to such a controlling mechanism.

Molecular characterization of the GM 4672 human lymphoblastoid cell line and analysis of its use as a fusion partner in the generation of human-human hybridoma autoantibodies.

The GM 4672 lymphoblastoid cell line has been used in cell hybridization experiments with peripheral blood lymphocytes (PBLs) in order to generate human-human hybridomas that secrete immunoglobulins directed against a number of different autoantigens. The GM 4672 cells were fused with PBLs isolated from patients with rheumatoid arthritis or systemic lupus erythematosus, or from normal individuals, and the resulting hybridomas were screened for reactivity to platelets, erythrocytes, DNA, cardiolipin, human IgG-Fc, phosphatidylethanolamine, and for lupus anticoagulant activity. This report analyzes the results from 149 fusion experiments completed over a period of nine years. Fifty to sixty-six percent of the fusion experiments resulted in immunoglobulin-secreting clones, with an average of 15 clones/fusion. The hybridoma antibodies were predominantly of the IgM heavy chain isotype, and 67% expressed kappa light chains. Although most hybridoma antibodies (78%) recognized a single autoantigen, 22% recognized more than one autoantigen and were considered polyreactive. In addition, the light and heavy chain variable regions of the antibody secreted by the GM 4672 cell line were amplified by the polymerase chain reaction technique and sequenced. The GM 4672 light chain was encoded by a VkI gene and used a Jk4 minigene. The GM 4672 heavy chain was derived for the rearrangement of a gene from the VH4 subgroup and used a JH4 minigene. The 8 amino acid long diversity region was generated by the fusion of the DK1 and DLR2 genes. The hybridomas generated in fusion experiments, when examined, did not appear to secrete antibodies using the immunoglobulin variable regions derived from the GM 4672 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The molecular basis of brown, an old mouse mutation, and of an induced revertant to wild type.

The murine b locus encodes the tyrosinase related protein, TRP-1, a putative membrane-bound, copper-containing enzyme having about 40% amino acid identity with tyrosinase. The protein is essential for production of black rather than brown hair pigment. We show that skin of mutant brown mice contains the same amount of TRP-1 mRNA as wild type. On sequencing the coding region of the mutant mRNA we find four nucleotide differences from the wild-type (Black) sequence. Two of these differences result in different amino acid residues encoded by the brown allele. By sequencing the TRP-1 gene from a mouse in which a reversion from brown to Black has been induced by ethylnitrosourea we are able to show that only one of these amino acid changes, which substitutes a tyrosine for a conserved cysteine, is the cause of the brown phenotype. This mutation is adjacent to another cysteine at which, in the analogous position in tyrosinase a mutation results in the albino phenotype. The sequence of the revertant is the first report of DNA sequence of an ethylnitrosourea-induced genetic change in mouse.

Clinical and molecular problems of polycystic kidney disease.

Using nephrological, genealogical and molecular genetic methods, the authors examined 85 members of 19 families with autosomal dominant polycystic kidney disease. With the aid of probe 3'HVR, alpha-globin and restriction endonuclease Pvu II, the families were found 95% informative. The rate of diagnostic reliability was also 95%. The authors verified the homogeneity of the disease in the Czech population and the applicability of the probe and endonuclease for molecular gene diagnostics in the population.

[Clinical and molecular problems in polycystic kidneys]. / Klinická a molekulární problematika polycystických ledvin.

The authors examined, using nephrological, genealogical and molecular genetic methods, 85 subjects from 19 families with autosomal dominant heredity of polycystic kidney disease. Using the probe 3HVR alpha-globin and restriction endonuclease Pvu II, the authors assessed 95% informative families in the given group and the reliability of the diagnosis was also 95%. The authors tested the homogeneity of the disease in the Czech population and the applicability of the mentioned probe and endonuclease for molecular genetic testing of our population.

The possible mutagenic effect of the occupation of TV announcer.

In a group of TV announcers, a significant increase in the number of classical aberrations was detected in peripheral blood: 7.5 +/- 3.477% in comparison with 3 control groups (A - 7 healthy women matched for sex, age and place of residence, B - 9 members of TV technical staff, C - 9 actors and actresses) with a mean aberration level of 2.96 +/- 1.136. SCE numbers were not increased in the TV announcers compared to controls. An increased frequency of reproduction failure has also been noticed in TV announcers (females). A decrease in the level of aberrant cells was noticed when the announcer had been on holiday, although this was not statistically significant. The possible mutagens in the working environment of TV announcers are discussed; there is a suspicion that azodyes, present in cosmetics or other chemicals, may be the mutagenic factor.