Relationships between cytokine (IL-6 and TGF-β1) gene polymorphisms and chromosomal damage in hospital workers

Cytokine gene polymorphisms have been found to be associated with a pre-disposition to a variety of diseases, including inflammatory and cancer diseases. The present study evaluated the influence of six cytokine gene polymorphisms on the level of genomic damage observed in peripheral blood lymphocytes from hospital pathologists chronically exposed to low doses of different xenobiotics. Lymphocytes from 50 pathologists and 50 control subjects were recruited and analyzed in Sister Chromatid Exchange (SCE) and Chromosomal Aberrations (CA) assays. The frequencies of six cytokine gene polymorphisms and their relationships with the cytogenetic damage levels were also evaluated. The results indicated that significant differences were found between pathologists and controls in terms of SCE frequency (p?<?0.001) and RI values (p?<?0.001), as well as in terms of CA and cells with aberrations (p?<?0.001). No associations were found between all analyzed cytokine gene polymorphisms and CA frequency in both pathologists and control groups. Vice versa, among pathologists, homozygote individuals for the IL-6 G allele showed a significantly (p?=?0.017) lower frequency of SCE with respect to heterozygote subjects. Similarly, for TGFβ₁ codon 10 locus, homozygote for T allele and heterozygote TC subjects showed a significantly (p?=?0.021) lower frequency of SCE with respect to homozygote CC individuals. Among controls, no significant differences were found in the frequency of SCE between genotypes at all loci. Based on these results, we speculate that high circulating levels of a pro-inflammatory cytokine like IL-6 and lower levels of the immunosuppressant cytokine TGFβ₁ could be associated directly with a longer duration and/or greater intensity of inflammatory processes, and indirectly with significantly higher levels of genomic damage.     

CD4 + T CELL MATTERS IN TUMOR IMMUNITY

CD4 + T cells have been shown to be able to affect tumor growth through both direct and indirect means. In addition, a requirement has been demonstrated for CD4 + T cells in the regulation and induction of T cell memory, and CD4 + suppressor T cells have been identified, stressing a role for CD4 + T cells in the induction and maintenance of antitumor immune responses. A review of the involvement of CD4 + T cells at different stages of tumor immunity is provided, and based on these data we discuss how CD4 + T cell response induction could be incorporated into tumor immunotherapy strategies. dendritic cells suppressor T cells T cell memory CD4 + T cells tumor immunology     

Acute-phase responsiveness of mannose-binding lectin in community-acquired pneumonia is highly dependent upon MBL2 genotypes

Mannose-binding lectin (MBL) is a pattern recognition receptor of the complement system and plays an important role in innate immunity. Whether or not MBL acts as an acute-phase response protein in infection has been an issue of extensive debate, because MBL responses have shown a high degree of heterogeneity. Single nucleotide polymorphisms (SNPs) in the promoter (wild-type Y versus X) and exon 1 (A versus 0) of the MBL2 gene can lead to MBL deficiency. This study investigated the influence of SNPs in the promoter and exon 1 of the MBL2 gene on the acute-phase responsiveness of MBL in 143 patients with community-acquired pneumonia. Acute-phase reactivity was observed only in MBL-sufficient genotypes (YA/YA, XA/YA, XA/XA and YA/0). In patients with wild-type exon 1 genotype A/A, positive acute-phase responses were associated with the presence of the YA haplotype and negative responses with its absence. Genotypes YA/0 and XA/XA produced equal levels of MBL in convalescence. In the acute phase, however, patients with genotype XA/XA displayed negative acute-phase responses more often than those with genotype YA/0. Correlation of MBL and C-reactive protein levels in the acute phase of pneumonia also depended upon the MBL2 genotype. In conclusion, acute-phase responsiveness of MBL was highly dependent upon the MBL2 genotype. These data suggest that heterogeneity in protein responses in the acute phase of disease should always be viewed in the light of possible influences of genetic differences in both structural and regulatory parts of the gene.     

Chronic granulomatous disease caused by mutations other than the common GT deletion in NCF1, the gene encoding the p47phox component of the phagocyte NADPH oxidase

Chronic granulomatous disease (CGD) is an inherited immunodeficiency caused by defects in any of four genes encoding components of the leukocyte nicotinamide dinucleotide phosphate, reduced (NADPH) oxidase. One of these is the autosomal neutrophil cytosolic factor 1 (NCF1) gene encoding the p47phox protein. Most (>97%) CGD patients without p47phox (A47 degrees CGD) are homozygotes for one particular mutation in NCF1, a GT deletion in exon 2. This is due to recombination events between NCF1 and its two pseudogenes (psiNCF1) that contain this GT deletion. We have previously set up a gene-scan method to establish the ratio of NCF1 genes and pseudogenes. With this method we now found, in three CGD families patients with the normal number of two intact NCF1 genes (and four psiNCF1 genes) and in six CGD families, patients with one intact NCF1 gene (and five psiNCF1 genes). All patients lacked p47phox protein expression. These results indicate that other mutations were present in their NCF1 gene than the GT deletion. To identify these mutations, we designed PCR primers to specifically amplify the cDNA or parts of the genomic DNA from NCF1 but not from the psiNCF1 genes. We found point mutations in NCF1 in eight families. In another family, we found a 2,860-bp deletion starting in intron 2 and ending in intron 5. In six families the patients were compound heterozygotes for the GT deletion and one of these other mutations; in two families the patients had a homozygous missense mutation; and in one family the patient was a compound heterozygote for a splice defect and a nonsense mutation. Family members with either the GT deletion or one of these other mutations were identified as carriers. This knowledge was used in one of the families for prenatal diagnosis.     

Association of the HLA-G 14-bp insertion/deletion polymorphism with juvenile idiopathic arthritis and rheumatoid arthritis

We tested the possible association of the 14-bp polymorphism of the HLA-G gene in the course of two inflammatory diseases, rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA). Patients and controls were genotyped for the 14-bp polymorphism by polymerase chain reaction with specific primers for the exon 8 of the human leukocyte antigen (HLA)-G gene and the amplified fragment was visualized in a 6% polyacrylamide gel. A total of 106 JIA patients, 265 RA patients, 356 healthy adults and 85 healthy children were genotyped for the 14-bp polymorphism. Female JIA patients presented a higher frequency of the -14 bp allele when compared with female healthy children (0.743 and 0.500, corrected P=0.003), which reflected in the JIA group as a whole. This increased frequency of the -14-bp allele was observed in all JIA subtypes. In RA patients, no differences in allelic and genotypic frequencies were observed between patients and controls. No correlations were observed among genotype and disease severity or clinical manifestations. Our data suggest that the HLA-G -14 bp allele is probably a risk factor for JIA, mainly in females. Considering the differences observed in relation to gender, we suggest that hormonal differences can interfere with the development of JIA. Considering the RA patients, our data agree with results from the literature and highlight the differences in the etiology of RA and JIA.     

中国汉族RhD阴性个体Rh盒子基因的测序及RHD基因的纯合性测定

目的分析中国汉族人RhD阴性个体Rh盒子基因的序列以阐明中国汉族人群RhD阴性表型形成的分子机理，并对Rh盒子基因的扩增产物进行分析以确定RHD基因的纯合性。方法74例RhD阴性个体的DNA样品首先进行多重聚合酶链反应．序列特异性引物（PCR-sequence specific primer，PCR-SSP）分析。然后对Rh盒子基因进行特异性测序分析，同时对Rh盒子基因的扩增产物采用聚合酶链反应-限制性片段长度多态性（restrict fragment length polymorphism，RFLP）方法进行RHD基因的纯合性测定。结果46例（62％）样品在多重PCR-SSP分析中显示缺失RHD基因，在PCR-RFLP分析中显示为纯合的RHD基因阴性。22例（30％）样品显示存在RHD基因，其中19例显示为杂合的RHD基因，3例显示为纯合的RHD基因。5例（7％）样品缺失RHD基因，但PCR．RFLP分析显示存在1个RHD基因，进一步的分析表明它们至少存在RHD基因第1和10外显子。1例（1％）样品显示存在RHD基因，但缺失第6外显子。对27例在多重PCR分析中显示缺失RHD基因的RhD阴性样品的杂化Rh盒子基因进行DNA测序分析，表明中国人存在与白人相一致的杂化Rh盒子基因序列。结论RHD基因缺失是引起中国汉族人PhD阴性表型形成的主要分子机理。中国人RHD基因缺失发生于与白人相一致的断点区域。     

Activation-induced cytidine deaminase: structure-function relationship as based on the study of mutants

Activation-induced cytidine deaminase (AID; gene symbol AICDA) is the key molecule required to induce immunoglobulin (Ig) class switch recombination (CSR) and somatic hypermutation (SHM) of the variable regions of Ig genes. Its deficiency causes a form of hyper-IgM (HIGM) syndrome. The study of natural AID mutants associated with HIGM as well as engineered mutants led to the characterization of the active domains of the protein. AID, through its cytidine deaminase activity, induces a targeted DNA lesion as an early step required for both CSR and SHM. Besides its cytidine deaminase activity, AID plays a further essential role in CSR, likely by recruiting CSR-specific cofactors by its C-terminus. A similar binding of SHM-specific cofactors to the N-terminal part is suggested by the functional characteristics of N(ter) AID artificial mutants. These data require confirmation in vivo. Finally, AID acts as a homo-, di-, or multimeric complex. Together, these data strongly suggest that AID, a master molecule for antibody diversification, exerts its activity on CSR not only as a cytidine deaminase enzyme but also as a docking protein, recruiting specific cofactors to a multimeric complex.