Association of TAP1 and TAP2 genes with susceptibility to pulmonary tuberculosis in Koreans

Tuberculosis remains an important public health problem in Koreans. However, very few studies have reported on the genetic factors associated with TB susceptibility in Koreans. The aim of this study was to elucidate the genetic factors associated with susceptibility to pulmonary tuberculosis (PTB). We investigated the transporter associated with antigen processing –1 (TAP1) and TAP2 gene polymorphisms in 160 Korean PTB patients (categorized according to extent of lesion and TB medication history) and 210 controls. TAP2*C/E frequency was significantly increased in the PTB (p_c = 0.004, OR = 2.28). TAP2*Bky2/C/E were enriched in the retreated, far‐advanced and total PTB compared with the controls (p_c = 0.015, OR = 3.27; p_c = 0.019, OR = 2.56; p_c = 2.8 × 10^?4, OR = 2.42, respectively). In the comparison of TAP2 gene with the DRB1*08:03, which is associated with TAP2*Bky2 and PTB in Koreans, we demonstrated the hierarchy of these association factors. TAP2*C/E is independent factors as strong as DRB1*08:03, and TAP2*C/E interacts with DRB1*08:03, resulting in a striking combined association. Our results suggest that TAP2 gene has an association with PTB susceptibility, the extent of the lesion or recurrence. These associations are independent from and additive with DRB1*08:03.     

Transporter associated with antigen processing (TAP) 1 gene polymorphisms in patients with hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a lung inflammatory disease caused by the inhalation of a variety of antigens. Previous studies support the role of the major histocompatibility complex (MHC) class II genes in the susceptibility to develop HP. However, the putative role of other MHC loci has not been elucidated. Transporters associated with antigen processing (TAP) genes are located within the MHC class II region and play an important role transporting peptides across the endoplasmic reticulum membrane for MHC class I molecules assembly. The distribution of single nucleotide polymorphisms (SNPs) in TAP1 genes was analyzed in 73 hypersensitivity pneumonitis (HP) patients and 58 normal subjects. We found a significant association of the allele Gly-637 (GGC) (p=0.00004, OR=27.30, CI=3.87-548.04) and the genotypes Asp-637/Gly-637 (p=0.01, OR=16.0, CI=2.19-631.21), Pro-661/Pro-661 (p=0.006, OR=11.30, CI=2.28-75.77) with HP. A significant decrease in the frequency of the allele Pro-661 (CCA) (p=0.008, OR=0.06, CI=0-0.45), the genotype Asp-637/Asp-637 (p=0.01, OR=0.17, 95% CI=0.05-0.58) and the haplotype [Val-333 (GTC), Val-458 (GTG), Gly-637 (GGC), Pro-661 (CCA)] was detected in HP patients compared with controls (p=0.002, OR=0.07, CI=0.0-0.57). These findings suggest that TAP1 gene polymorphisms are related to HP risk, and highlight the importance of the MHC in the development of this disease.     

Analysis of IL1B, TAP1, TAP2 and IKBL polymorphisms on susceptibility to tuberculosis

Genetic determinants of human susceptibility to tuberculosis (TB) have not been completely elucidated. Interleukin-1 beta (IL-1beta) and the inhibitor of kB-like (IkBL) are important molecules that participate in the inflammatory response required for the immunological control of a broad spectrum of infectious agents. The transporter associated with antigen processing (TAP) is involved in the antigen processing via major histocompatibility complex class I molecules and in turn might regulate the T-cell response against Mycobacterium tuberculosis. To better characterize the host genetic factors determining the susceptibility to TB, we evaluated the influence of functional polymorphisms in IL1B, TAP and IKBL genes on the risk of developing pulmonary TB in a Northwestern Colombian population, an endemic area of M. tuberculosis infection. A total of 122 TB patients and 166 healthy controls (N = 166) negative for human immunodeficiency virus infection were examined for IL1B-511 and +3,953, TAP1 and TAP2 and IKBL+738 polymorphisms. Univariate analysis disclosed significant differences between patients and controls for IL1B+3,953 polymorphism. After unconditional logistic regression analysis, a strong protection conferred by IL1B+3,953 T-allele-carrying genotypes was observed. A trend between TAP2*0201 allele and disease was observed. Association between IL1B-511, TAP1 or IKBL polymorphisms and TB disease was not found. These results indicate that a functional polymorphism in the IL1B gene influences the susceptibility to TB and suggest a role for IL-1beta in the pathogenesis of mycobacterial infection.     

Association of polymorphisms of the transporter associated with antigen processing (TAP2) gene with pulmonary tuberculosis in an elderly Japanese population

The transporter associated with antigen processing 2 (TAP2) gene is involved in the immunological response to tuberculosis (TB) infection. Variations in the TAP2 gene have been associated with TB infection in small population studies in India, Columbia, and Korea. We investigated the association of TAP2 polymorphisms with TB susceptibility in an elderly Japanese population. We analyzed samples from consecutive autopsy cases (n = 1850) registered in the Japanese Geriatric SNP Research database. TB was diagnosed pathologically by TB granuloma on autopsy samples. There were 289 cases and 1529 controls. Twenty‐four single nucleotide variations (SNVs), including four missense variations in the TAP2 region, were genotyped using the Illumina Infinium Human Exome BeadChip array. Of the 24 SNVs in the TAP2 gene, rs4148871, rs4148876 (R651C), and rs2857103 showed statistically significant associations with TB susceptibility, and rs4148871 and rs2857103 also showed significant genotypic associations in a dominant allele model adjusted for age, sex, and smoking. Haplotype analysis showed that TAP2 allele *0103 conferred an increased TB risk (OR = 1.48, p = 0.0008), while the TAP2 *0201 allele was protective against TB (OR = 0.73, p = 0.0007). Our results suggest that TAP2 polymorphisms influence TB susceptibility in a Japanese population.     

IgG subclass distribution of antibody responses to protein and polysaccharide mycobacterial antigens in leprosy and tuberculosis patients

Immunoenzymatic assays were developed for the measurement of antibodies against mycobacterial lipoarabinomannan (LAM), a cell-free proteic extract (CFX) of Mycobacterium leprae, and the 38-kD protein antigen of M. tuberculosis. Sera from 108 leprosy patients, belonging to all clinical–immunological forms of the spectrum, and 81 patients with localized or disseminated tuberculosis (TB) were tested for antibodies of the four IgG subclasses. Standard calibration curves were used to allow comparisons between results of different isotypes and specificities. Mean concentrations of total IgG antibodies were higher in the overall leprosy population than in TB patients. In leprosy, levels of anti-CFX increased from tuberculoid toward lepromatous forms, with a clear switch from IgG1 to IgG2 subclass predominance. A similar IgG1 to IgG2 conversion was observed in anti-LAM antibodies, although total levels of anti-LAM were similar in patients with tuberculoid and lepromatous forms. In TB, antibodies against polysaccharide and protein antigens were both predominantly of IgG1 subclass, whatever the patient's clinical status, although lower in disseminated forms, probably due to concomitant HIV infection. A hypergammaglobulinaemia was also found in most leprosy and TB patients. In TB this was due to increased IgG1 and IgG3, especially in HIV co-infected patients. Based on the current knowledge of the influence of T cell-secreted cytokines on human immunoglobulin isotype expression, these results do not fit with a putative role of Th1 (such as found in TB and tuberculoid leprosy (TT)) and Th2 (such as found in leprosy lepromatous (LL) leprosy) environment in the isotypy of antibody responses in mycobacterial infections. Nor do variations of isotypy according to pathological conditions seem to be related to the biochemical nature of antigens, since antibodies to LAM and protein antigens had comparable evolutions of their subclass distribution. Other factors are to be investigated in order to understand better the significance and possible roles of antibodies in mycobacterial diseases.     

Pemphigus vulgaris is associated with the transporter associated with antigen processing (TAP) system

Pemphigus vulgaris (PV) is a human leukocute antigen (HLA) class II-associated autoimmune disease of the skin of unknown etiology. We recently described the association of pemphigus vulgaris with two clusters of microsatellite loci within the major histocompatibility complex region. One cluster includes the microsatellite marker TAP1CA, located in proximity to the transporter associated with antigen processing (TAP) genes. These genes are essential for class I antigen processing machinery and could be an additional set of genes involved in susceptibility to PV. The aim of this study was to investigate a possible association between TAP gene polymorphisms and PV. For this purpose we examined 37 unrelated Jewish Israeli patients with PV and compared them with 37 healthy Israeli Jewish HLA-matched controls. Significant differences were detected in TAP2 amino acid residues (p = 0.001). Two PV TAP2 risk alleles were identified (TAP2*C and TAP2*D), the frequency of which was estimated to be 37.8% in the patients and 5.3 % in the controls. This association was found to be independent of HLA-DR. It is therefore likely that TAP2 genes are involved in susceptibility to development of PV.     

BPI-ANCA in transporter associated with antigen presentation (TAP) deficiency: possible role in susceptibility to Gram-negative bacterial infections

Although HLA class I expression is diminished in patients with defects in the transporter associated with antigen presentation (TAP), recurrent Gram-negative bacterial lung infections are found from childhood onwards. As MHC class II-mediated responses are normal, other mechanisms that contribute to susceptibility to infections are presumed. The bactericidal/permeability-increasing protein (BPI) is a potent neutrophil antibiotic that neutralizes endotoxin efficiently. As antineutrophil cytoplasmic autoantibodies (ANCA) against BPI were found in the majority of cystic fibrosis patients and correlate with disease severity we examined the prevalence of BPI-ANCA and their contribution to susceptibility to bacterial infections in six TAP-deficient patients. Although only two patients showed ANCA in indirect immunofluorescence, BPI-ANCA occurred in five of six patients in ELISA. Purified IgG from BPI-ANCA-positive sera (five of six) inhibited the antimicrobial function of BPI in vitro. Epitope mapping revealed binding sites not only on the C-terminal but also on the antibiotic N-terminal portion of BPI, indicating that short linear BPI peptide fragments may be long-lived enough to become immunogens. In conclusion, BPI-ANCA are associated strongly with TAP deficiency. Inhibition of the antimicrobial BPI function by BPI-ANCA demonstrates a possible mechanism of how autoantibodies may contribute to increased susceptibility for pulmonary Gram-negative bacterial infections by diminished bacterial clearance.     

新疆妇女宫颈炎中TAP基因与HPV16的相关性

目的初步探讨TAP基因与HPV16在宫颈炎中的相关性。方法以宫颈炎(汉族84例,维族90例)为病例组,对照组为正常女性全血标本(汉族57例,维族58例)提取DNA采用PCR-扩增阻碍突变系统(PCR-ARMS)扩增TAP1和TAP2基因,同时PCR扩增HPV16特异性引物。结果 TAP1A,TAP1C在宫颈炎中单倍体型分布频率明显低于正常对照组(P0.05),TAP2D,TAP2E在宫颈炎中单倍体型分布频率明显高于正常对照组(P0.05),TAP1A,TAP1C,TAP2D,TAP2E在宫颈炎中单倍体型分布频率与HPV16无相关性。结论 TAP1A,TAP1C,TAP2D,TAP2E在宫颈炎中单倍体型分布频率与HPV16无相关性,这可能是地理分布及种族差异有关。     

An investigation of HLA-encoded genetic susceptibility to multiple sclerosis in subjects of Asian Indian and Afro-Caribbean ethnic origin

Abstract: The association of multiple sclerosis (MS) with the HLA class II loci DR and DQ was investigated in populations of Asian Indian and Afro-Caribbean ethnic origin, resident in the United Kingdom. The putative haplotype, DRB1*150l.DQA1*0102.DQB 1*0602, was weakly positively associated with MS in both races. The overall contribution to disease susceptibility of this marker was small. Over 80% of the MS patients in both racial groups did not possess this haplotype. The data suggest that other genetic and/or environmental factors may be more important in predisposing to MS in these two races. Our study also raises the possibility that genetically distinct forms of the disease may be expressed in white Caucasian and non-Caucasian populations.     

Translocation of long peptides by transporters associated with antigen processing (TAP)

The major histocompatibility complex (MHC)-encoded transporters associated with antigen processing (TAP) translocate peptides from the cytosol into the lumen of the endoplasmic reticulum (ER) where they associate with MHC class I molecules. The length of class I-binding peptides is usually 8–11 amino acids, but examples of significantly longer peptides have been described. The preferred lengths and upper and lower size limits for peptides translocated by TAP have not been determined in detail because in the currently used test systems, peptides are subject to proteolytic degradation. In the present study, three sets of individual peptides or partially randomized peptide libraries ranging between 6 and 40 residues were used that contained a radiolabeled tyrosine and a consensus sequence for ER-specific N-glycosylation at opposite ends, thus ensuring that only nondegraded peptides were monitored in the transport/glycosylation assay. For three different transporters, rat TAP1/2^a, rat TAP1/2^u and hTAP, the most efficient ATP-dependent transport was observed for peptides with 8–12 amino acids. Hexamers and longer peptides of up to 40 amino acids were also translocated, albeit less efficiently. For two of the three sets of peptides analyzed, rat TAP1/2^a showed a less stringent length selection than rat TAP1/2^u and human TAP. The superior transport of the decamer of the TNKT . Y series was not due to faster degradation or less efficient glycosylation of shorter or longer length variants. A binding assay with TAP-containing microsomes revealed a high affinity for the radiolabeled decamer (K_D = 580 nM), while other length variants were clearly inferior in their binding affinities. Thus, TAP binds and preferentially translocates peptides with a length suitable for binding to MHC class I molecules, but peptides that are considerably longer may also be substrates. About 10⁵ peptide binding sites per cell equivalent of microsomes were determined, providing an estimate for the number of TAP complexes in the ER membrane.     

Modified fine‐needle aspiration technique for diagnosis of granulomatous skin lesions with special reference to leprosy and cutaneous tuberculosis

Skin infections are commonly assessed by slit skin or scrape methods. Fine‐needle aspiration biopsy (FNAB) is highly effective especially with blanching of skin to ensure good yield and reduced bleeding. The aim of this study was to assess usefulness of cytology, especially modified FNAB technique, in diagnosis of leprosy and cutaneous tuberculosis and to identify specific cytological characteristics for diagnosis and classification. The study was conducted on 40 patients—25 cases of leprosy and 15 cases of cutaneous tuberculosis. Smears were prepared using modified FNAB technique, slit skin, and scrape methods (depending on type of lesion). Cytological diagnosis was confirmed by histopathology where the Ridley‐Jopling system was used to classify cases of leprosy. A similar attempt was made for diagnosis and classification of leprosy on cytology. Diagnoses rendered by both modalities were compared to assess the efficacy of cytological examination. Cytological diagnosis was made in 23 cases of leprosy and 12 cases of cutaneous tuberculosis. The smears showed good cellularity. A broad division into tuberculoid and lepromatous leprosy could be made fairly accurately on cytology. Maximum agreement among clinical, cytological, and histopathological diagnosis was observed in cases of tuberculoid leprosy. Smears of cutaneous tuberculosis were characterized by epithelioid cell granulomas with caseation. Overall accuracy of diagnosis was 92% in leprosy and 80% in tuberculosis. FNAB is an inexpensive and accurate procedure for diagnosis of leprosy and cutaneous tuberculosis. The modified technique yields good results. However, clinical correlation, acid‐fast staining, and culture are essential as they provide valuable supportive information. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.     

Markedly decreased expression of TAP1 and LMP2 genes in HLA class I-deficient human tumor cell lines

HLA class I antigens of the human major histocompatibility complex play an important role in immune response. These molecules present foreign antigenic peptides to cytotoxic T lymphocytes and thereby play a role in the immune surveillance of cells infected with virus or other intracellular pathogens or altered by malignant transformation. A marked deficiency or lack of expression of these antigens has been reported in a variety of human neoplasms. In the present study, we examined the expression of class I chain, β₂-microglobulin, TAP (TAP1 and TAP2) and LMP (LMP2 and LMP7) genes in a number of human tumor cell lines including small-cell lung carcinoma, hepatocellular carcinoma, colon adenocarcinoma and basophilic leukaemia. These cell lines were deficient in expression of both class I chain and β₂-microglobulin gene products. In addition, these cell lines lacked the products of MHC-encoded proteasome subunit LMP2 as well as the putative peptide transporter TAP1 genes. In contrast, TAP2 and LMP7 genes were expressed in these cell lines. Treatment of cells with γ-IFN markedly enhanced the expression of class I chain, β₂-microglobulin, TAP1 and LMP2 genes with a concomitant increase in cell-surface expression of class I molecules. The upregulation of TAP1 and LMP2 expression is associated with increased class I expression, suggesting that endogenous antigens, e.g. tumor antigens, could be presented by class I molecules following treatment of tumor cells with γ-IFN.     

Transporter (TAP)-independent processing of a multiple membrane-spanning protein,the Epstein-Barr virus latent membrane protein 2

Antigen presentation to CD8⁺ cytotoxic T lymphocytes (CTL) usually involves proteolytic cleavage of antigen in the cytosol and the delivery of epitope peptides onto major histocompatibility complex class I molecules in the endoplasmic reticulum (ER) via the heterodimeric peptide transporter TAP1/TAP2. In the few exceptional cases where TAP-independent presentation of an endogenously expressed protein has been observed, the epitope-containing domain of the protein either has naturally accessed or has been directed into the ER lumen where it is thought to become susceptible to ER proteases. Here, we describe a novel example of TAP-independent processing involving the Epstein-Barr virus (EBV) latent membrane protein LMP2, a multiple membrane-spanning protein with minimal projection into the ER. Expression of LMP2 in the TAP⁻ T2 cell line, whether from the resident EBV genome or from a recombinant vaccinia virus vector vacc-LMP2, rendered the cells sensitive to recognition by CTL clones specific for two HLA-A2.1-restricted peptide epitopes, LMP2 329–337 or 426–434. Vacc-LMP2-mediated sensitization to lysis required expression of the antigen de novo in T2 cells and was blocked by brefeldin A. In the same experiments, two other EBV-specific CTL epitopes, one derived from LMP2 but restricted through a different HLA allele (A11), the other restricted through A2.1 but derived from a different viral protein (BMLF1), did not display TAP-independent processing. The results are discussed in relation to the unusual topology of LMP2 in the membrane and the position of the epitope peptides within that structure.     

Malignant lymphoma of bronchus-associated lymphoid tissue (BALT) coexistent with pulmonary tuberculosis

A case in which malignant lymphoma occurred in association with a tuberculosis focus in a 70-year-old man is reported. Surrounding the epithelioid cell granulomas with caseous necrosis was a dense and diffuse monotonous infiltration of atypical lymphoid cells. Acid-fast bacilli were found in the granulomas and pulmonary tuberculosis was diagnosed. The infiltrating atypical lymphoid cells occasionally invaded the respiratory epithelium producing lymphoepithelial lesions. Immunohistochemically, the lymphoid cells were positive for CD20, and clonal rearrangement of the immunoglobulin heavy chain gene was demonstrated by polymerase chain reaction (PCR). We diagnosed the lesion as a pulmonary malignant lymphoma of bronchus-associated lymphoid tissue (BALT) occurring in the background of tuberculosis. This is the first reported case of pulmonary BALT lymphoma coexistent with pulmonary tuberculosis.     

ALOX5 variants associated with susceptibility to human pulmonary tuberculosis

The 5-lipoxygenase (ALOX5)-derived lipid mediators leukotrienes and lipoxins have regulatory functions in inflammation by modulating activities of immune cells and cytokine production. Recently, it was shown in ALOX5-/- mice that host control of Mycobacterium tuberculosis is regulated by 5-lipoxygenase (5-LO). ALOX5 polymorphisms were genotyped in 1916 sputum-positive patients with pulmonary tuberculosis (TB) from Ghana and in 2269 exposed, apparently healthy controls. Polymorphisms of a variable number of tandem repeats (VNTR) of the ALOX5 promoter and of the exonic non-synonymous variant g.760G>A were analysed by fragment length determination and fluorescence resonance energy transfer, respectively, and DNA sequencing. Mycobacterial lineages of >1400 isolates were differentiated biochemically and genetically. Carriers of one variant (n repeats not equal 5) and one wild-type VNTR allele (n = 5) or of the exonic allele g.760A had a higher risk of TB [P(corrected) = 0.026, odds ratio (OR) 1.19 (95% CI 1.04-1.37) and P(corrected) = 0.026, OR 1.21 (95% CI 1.04-1.41), respectively]. The association of the exonic variant was stronger in infections caused by the mycobacterial lineage M. africanum West-African 2 [P(corrected) = 0.024, OR 1.70; (95% CI 1.2-2.6)]. Determination of haplotypes revealed the strongest associaton with TB for the 'non-5/760A' haplotype compared with the 'non-5/760G' haplotype (P = 0.003, OR 1.50). Our observation of an association of ALOX5 variants with susceptibility to TB contributes evidence of the importance of 5-LO products to the regulation of immune responses to M. tuberculosis.     

Effectiveness of a home-based pulmonary rehabilitation programme in pulmonary function and health related quality of life for patients with pulmonary tuberculosis: a pilot study

Background

Patients with Pulmonary Tuberculosis (PTB) often develop impairment in pulmonary function due to anatomical changes secondary to the illness. Physiotherapy in the form of pulmonary rehabilitation has been advocated.

Objective

The aim of the study was to determine whether adherence to a six-week home-based pulmonary rehabilitation programme (PRP) improved the baseline measurements of lung function, exercise tolerance and health-related quality of life (HRQoL) in patients receiving out-patient treatment for PTB.

Method

A single blinded randomized control study design was used to assess the effects of a six-week home- based PRP in patients receiving treatment for PTB at a local clinic in Khayelitsha, Western Cape. We evaluated lung function by spirometry (MINATO AUTOSPIRO-model no. AZ-505), exercise tolerance using the 6-min-walk test (6MWT), the Borg exercise exertion scale and HRQoL using the EQ-5 D questionnaire in an intervention group (n=34) and a control group (n=33). The trend of the effects of the PRP on lung function was towards increases, but there was no statistical difference between the intervention and control groups at the end of the sixth week in the values of FVC (p=0.2; 95% CI −0.9 to 0.51) as well as FEV1 (p=0.1; 95% CI −0.07 to 0.51). Similar trend was observed for exercise tolerance, and there was no significant difference in HRQoL (p=0.789).

Conclusion

The outcome of the study provides motivation for further consideration and implementation of a pulmonary rehabilitation programme for patients with PTB.     

2006-2009年南山区学生肺结核病例情况分析

目的分析近年南山区校园结核病的发病情况,为有效预防和控制学校结核病疫情提供依据。方法将2006-2009年在深圳市南山区慢性病防治院就诊的学生肺结核初诊病例182例作为研究对象,收集病例的相关资料,采用描述性分析方法分析病例发现、分布特征和治疗转归等情况。结果 2006-2009年南山区学生肺结核病例占全区同期活动性肺结核病例的比例逐年递增,分别为0.99%、1.64%、1.88%和3.99%;因症就诊方式发现的病例分别占初诊、确诊和涂阳病例的70.9%、67.9%和90.0%,是发现学生病例的主要方式;小学、中学、大学初诊病例确诊率分别为5.56%、27.3%和35.8%,差异有统计学意义（P=0.029）。结论应采取多种措施继续加强学校肺结核预防控制工作,并将工作重点放在大学生群体。