-
[show abstract]
[hide abstract]
ABSTRACT: Molecules involved in antigen processing (LMP) and peptide transport (TAP) are coded by polymorphic genes. This polymorphism may influence the peptide antigen selection process and play a role in the pathogenesis of human brucellosis. We studied the polymorphism of the antigen processing and transport genes (LMP and TAP) in 61 patients with human brucellosis and 102 controls from southern Spain. We found no differences in the frequencies of the LMP and TAP genotypes between the patients and the controls. Study of the patients with and without focal or complicated forms showed a significant increase in the TAP2A/TAP2F genotype in those with focal forms compared with those without focal forms (16% vs 0%, p = 0.02), though this difference lost its significance after correction for the number of comparisons. This study suggests that larger studies will be needed to confirm or rule out the possible association of the TAP2A/TAP2F genotype or other possible associations with focal forms of brucellosis.
Human immunology 07/2010; 71(7):708-11. · 2.55 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Diagnosis of brucellosis can be difficult in certain scenarios where conventional microbiological techniques have important limitations. The aim of this study was to develop a LightCycler Quantitative PCR assay in serum samples to discriminate between active and past brucellosis. In total, 110 serum samples from 46 brucellosis patients and 64 controls, including persons who had recently been treated for brucellosis, asymptomatic persons exposed to brucellosis, and patients with febrile syndromes involving a differential diagnosis with brucellosis, were studied. Brucella spp.-specific sequences of the PCR primers and probe were selected from the gene encoding an immunogenic membrane protein of 31 kDa (BCSP31). The analytical sensitivity was 1 x 10(1) fg of Brucella DNA. The mean threshold cycles for brucellosis patients and controls were 31.8 +/- 1.7 and 35.4 +/- 1.1, respectively (p <0.001). The best cut-off for bacterial DNA load was 5 x 10(3) copies/mL. At this cut-off, the area under the receiver operating characteristic curves was 0.963 (95% CI 0.920-1.005), with a sensitivity of 93.5% and a specificity of 98.4%. Under the assay conditions, the LightCycler Quantitative PCR in serum samples seems to be highly reproducible, rapid, sensitive and specific. It is therefore a useful method for both the initial diagnosis and the differentiation between past and active brucellosis.
Clinical Microbiology and Infection 12/2008; 14(12):1128-34. · 4.54 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We investigated the polymorphism of the transmembrane region of the MICA gene (major histocompatibility complex class I chain-related gene A) in relation to susceptibility to human brucellosis. We typed 114 patients with brucellosis and 121 healthy controls for MICA transmembrane polymorphism with polymerase chain reaction methods combined with fluorescent technology. We found a significant decrease in the frequency of the MICA-A4 allele in the patients with brucellosis compared with the controls (4.4% vs 10.3%, Pc = 0.03). The frequency of the MICA-A5 allele was increased in the group of patients with focal complications (15% vs 38%, Pc = 0.004). Our data suggest the MICA-A4 allele shows a tendency to be protective against infection by Brucella melitensis. Furthermore, the MICA-A5 allele appears to confer susceptibility to focal forms in patients with brucellosis.
Tissue Antigens 05/2007; 69(4):358-60. · 2.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The induction of immune tolerance in transplant recipients has been sought for many years but only a fundamental understanding of the immunological mechanisms underlying graft rejection will allow manipulation of the anti-graft immune response. In general, acute rejection is better understood and treated than chronic rejection, as they occur through partially different mechanisms. It is now generally accepted that recognition of same-species, non-self antigens (allorecognition) occurs through at least two different mechanisms, the direct and indirect pathways. In the direct pathway, donor MHC molecules on the surface of donor antigen-presenting cells (APCs) are recognised directly by the recipient's T cells. This mechanism is so immediate that it seems to be primarily involved in acute graft rejection. Since APCs of donor origin are depleted with time a second mechanism, the indirect pathway, takes over to cause chronic rejection, in which foreign MHC molecules are internalised, partially digested and presented as peptides to recipient T cells. Nonetheless, a number of studies are only fully understood when a third proposed allorecognition mechanism is taken into account. This is the semi-indirect pathway, as discussed in this short report.
Transplant Immunology 01/2007; 17(1):3-6. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We genotyped 83 patients with brucellosis and 101 controls to determine the influence of polymorphisms of the interferon gamma (IFNG) and interleukin 10 (IL10) genes on protection against, or susceptibility to, human brucellosis and its complications. The results showed a significant increase in the IFNG +874A/A genotype in patients compared with controls (34% vs. 19%) (P = 0.023, odds ratio = 2.17, 95% confidence interval 1.05-4.51). No significant differences were detected in the frequency distribution of the IL10 genotypes between patients and controls. Similarly, no significant differences were observed in the genotype frequencies of either of the two cytokines between complicated and non-complicated forms of brucellosis. Persons who are homozygous for the IFNG +874A allele may have a higher risk of contracting brucellosis.
European Journal of Immunogenetics 01/2004; 30(6):433-5.
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to investigate the possible influence of the tumor necrosis factor alpha (TNFA) gene promoter polymorphisms and HLA class II genes on the susceptibility to or development of human brucellosis. TNFA genotypes (at positions -308 and -238) were determined in 59 patients with brucellosis and 160 healthy controls by polymerase chain reaction-restriction fragment length polymorphism. There were no significant differences between the patients and the controls for the TNFA-238 genotypes. However, when the overall TNFA-308 genotype distribution of the brucella patients was compared with that of the control subjects, a significant skewing was observed (P = 0.02). The TNFA-308.1/2 genotype was present at significantly higher frequency in the total patient as a whole compared with control subjects (30% versus 15%; P = 0.01, odds ratio (OR) 2.49, 95% confidence interval (CI) 1.16-5.33). No statistically significant differences in the distribution of HLA-DRB1 or DQB1 alleles were observed between brucella patients and control subjects. Stratification to correct for interdependence of TNFA-308.2 and HLA-DR3 alleles confirmed that, in spite of their strong linkage disequilibrium, the association of TNFA-308.2 with brucellosis was independent of HLA-DR3.
Clinical & Experimental Immunology 10/2000; 121(3):480-3. · 3.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The induction of immune tolerance in transplant recipients has been sought for many years but only a fundamental understanding of the immunological mechanisms underlying graft rejection will allow manipulation of the anti-graft immune response. In general, acute rejection is better understood and treated than chronic rejection, as they occur through partially different mechanisms.It is now generally accepted that recognition of same-species, non-self antigens (allorecognition) occurs through at least two different mechanisms, the direct and indirect pathways.In the direct pathway, donor MHC molecules on the surface of donor antigen-presenting cells (APCs) are recognised directly by the recipient's T cells. This mechanism is so immediate that it seems to be primarily involved in acute graft rejection. Since APCs of donor origin are depleted with time a second mechanism, the indirect pathway, takes over to cause chronic rejection, in which foreign MHC molecules are internalised, partially digested and presented as peptides to recipient T cells. Nonetheless, a number of studies are only fully understood when a third proposed allorecognition mechanism is taken into account. This is the semi-indirect pathway, as discussed in this short report.
Transplant Immunology.
