TAP1 and TAP2 gene polymorphisms in childhood cystic echinococcosis

Association between the TAP1 gene polymorphisms and recurrent respiratory papillomatosis in patients from Western Mexico: A pilot study

Background

Recurrent respiratory papillomatosis (RRP) is a respiratory tract disease that affects children and adults and is characterized by the recurrent proliferation of multiple papillomas. The etiologic agent is the human papillomavirus, mainly genotypes 6 and 11. Furthermore, polymorphisms in TAP1 appear to influence the selection of antigenic peptides and the transport process to the rough endoplasmic reticulum, for their subsequent presentation to T lymphocytes, an essential process against viral diseases and tumor processes. Previous studies have shown that individuals with those polymorphisms are susceptible to immune, infectious, and tumor‐related diseases. The present study aimed to determine the association between the TAP1 rs1057141 (c.1177A>G) and rs1135216 (c.2090A>G) single nucleotide polymorphisms (SNPs) and RRP.

Methods

A case–control study was carried out on a group of 70 individuals (35 controls and 35 patients). RRP diagnosis, HPV genotyping, and viral load were determined through histology and PCR. SNPs rs1057141 and rs1135216 were identified through allelic discrimination, using real‐time PCR. The haplotypic analyses were performed using the Arlequin 3.5 program.

Results

HPV‐6 and HPV‐11 were the genotypes found in the samples. In the polymorphism analysis, rs1057141 showed no significant differences (p = 0.049, CI = 0.994–7.331). In contrast, a significant difference was found in rs1135216 (p = 0.039, OR = 2.4) in the allelic analysis, as well as in the dominant (p = 0.027, OR = 3.06), codominant (p = 0.033, OR = 3.06), and additive model (p = 0.043, OR = 2.505) in subjects with the G allele.

Conclusion

The G allele in rs1135216 was associated with a genetic risk of susceptibility for RRP in a population in Western Mexico.

Polyreactive antibodies as potential humoral biomarkers of host resistance to cystic echinococcosis

Polyreactive antibodies (pAb) bind to a broad range of unrelated structures, providing hosts with functional components able to rapidly recognize and protect against different pathogens. However, their roles against helminth parasites are still unexplored. Here, pAb profiles were analysed in cystic echinococcosis (CE), a zoonosis caused by the cestode Echinococcus granulosus sensu lato. Levels of anti-DNP (2,4-dinitrophenyl-hapten) antibodies were measured as a surrogate parameter of pAb in different biological settings. Firstly, levels of serum and peritoneal pAb were measured during early experimental secondary CE, using both high (Balb/c) and low (C57Bl/6) susceptible mouse strains. Serum pAb mostly differed in normal mice, being pAb levels of IgG subclasses with poor anti-parasite activities predominant in Balb/c animals. Conversely, peritoneal pAb isotypes/subclasses with efficient anti-parasite activities predominated in normal and infected C57Bl/6 mice. Secondly, sera from potentially resistant patients, susceptible individuals and healthy donors were analysed, showing higher pAb levels of the IgA and IgG-particularly IgG1-isotypes in potentially resistant individuals compared to control groups. Finally, since remarkable differences were observed in pAb profiles according to the intrinsic host susceptibility to the infection, we proposed here that pAb might be considered as potential humoral biomarkers for host resistance to CE.

Screening for microRNA-based diagnostic markers in hepatic alveolar echinococcosis

This study aims to screen differentially expressed host miRNAs that could be used as diagnostic markers for liver alveolar echinococcosis (LAE).Differentially expressed miRNAs were first screened by miRNA microarray in liver tissues from2 LAE patients and normal liver tissues from 3 LAE patients, followed by qRT-PCR validation in 15 LAE tissues and 15 normal tissues. Target genes of differentially expressed miRNAs were predicted using Targetscan, PITA and microRNAorg database, and the overlapped predicted target genes were analyzed by GO and KEGG.The hsa-miR-1237-3p, hsa-miR-33b-3p, and hsa-miR-483-3p were up-regulated whereas the hsa-miR-4306 was down-regulated in LAE tissues compared with normal controls (P < .05). The expression change of miR-483-3p was further confirmed in both liver tissues and plasma. Several predicted targets of miR-1237-3p, miR-4306, and miR-483-3p were related to DNA-dependent transcriptional regulation, developmental regulation of multicellular organisms, and biological functions such as cellular immune responses (T cell proliferation). The overlapped predicted target genes of the 4 differentially expressed miRNAs were enriched in mRNA surveillance, cancer signaling pathway, intestinal immune network, and other signal pathways.Our results indicate that miR-483-3p is a potential marker for the diagnosis of LAE, and targets of this miRNA could be the focus of further studies.

Public health risks associated with food-borne parasites

Parasites are important food‐borne pathogens. Their complex lifecycles, varied transmission routes, and prolonged periods between infection and symptoms mean that the public health burden and relative importance of different transmission routes are often difficult to assess. Furthermore, there are challenges in detection and diagnostics, and variations in reporting. A Europe‐focused ranking exercise, using multicriteria decision analysis, identified potentially food‐borne parasites of importance, and that are currently not routinely controlled in food. These are Cryptosporidium spp., Toxoplasma gondii and Echinococcus spp. Infection with these parasites in humans and animals, or their occurrence in food, is not notifiable in all Member States. This Opinion reviews current methods for detection, identification and tracing of these parasites in relevant foods, reviews literature on food‐borne pathways, examines information on their occurrence and persistence in foods, and investigates possible control measures along the food chain. The differences between these three parasites are substantial, but for all there is a paucity of well‐established, standardised, validated methods that can be applied across the range of relevant foods. Furthermore, the prolonged period between infection and clinical symptoms (from several days for Cryptosporidium to years for Echinococcus spp.) means that source attribution studies are very difficult. Nevertheless, our knowledge of the domestic animal lifecycle (involving dogs and livestock) for Echinoccocus granulosus means that this parasite is controllable. For Echinococcus multilocularis, for which the lifecycle involves wildlife (foxes and rodents), control would be expensive and complicated, but could be achieved in targeted areas with sufficient commitment and resources. Quantitative risk assessments have been described for Toxoplasma in meat. However, for T. gondii and Cryptosporidium as faecal contaminants, development of validated detection methods, including survival/infectivity assays and consensus molecular typing protocols, are required for the development of quantitative risk assessments and efficient control measures.

Immunology of Alveolar and Cystic Echinococcosis (AE and CE)

Cystic and alveolar echinococcosis are severe chronic helminthic diseases caused by the cystic growth or the intrahepatic tumour-like growth of the metacestode of Echinococcus granulosus or Echinococcus multilocularis, respectively. Both parasites have evolved sophisticated strategies to escape host immune responses, mainly by manipulating and directing this immune response towards anergy and/or tolerance. Recent research studies have revealed a number of respective immunoregulatory mechanisms related to macrophages and dendritic cell as well as T cell activities (regulatory T cells, Tregs). A better understanding of this complex parasite-host relationship, and the elucidation of specific crucial events that lead to disease, represents targets towards the development of novel treatment strategies and options.

Genetic evidence of TAP1 gene variant as a susceptibility factor in Indian leprosy patients

The heterodimeric transporter associated with antigen processing (TAP) gene loci is known to play a vital role in immune surveillance. We investigated a possible association of gene polymorphisms both in TAP1 and TAP2 in a cohort of clinically classified leprosy patients (n=222) and in ethnically matched controls (n=223). The TAP1 and TAP2 genes were genotyped for four single nucleotide polymorphisms TAP1 (rs1057141 Iso333Val and rs1135216 Asp637Gly) and TAP2 (rs2228396 Ala565Thr and rs241447 Ala665Thr) by direct sequencing and ARMS-PCR. The minor allele of TAP1 637G contributes to an increased risk to leprosy compared to controls (OR: 1.68, 95% CI 1.2-2.36, P=0.0057). An increased risk for the variant minor allele of the TAP1 637G to multibacillary (BL+LL) or paucibacillary (BT+TT) infections was also observed [multibacillary vs. controls (OR: 1.56, 95% CI 1.07-2.28, P=0.054); paucibacillary vs. controls (OR: 1.92, 95% CI 1.21-3.01, P=0.013)]. In the dominant model, the genotypes of the TAP1 rs1135216AG+GG additionally contributed to an increased risk. Overall our findings demonstrate that the TAP1 gene variant (rs1135216 Asp637Gly) influences the susceptibility to clinically classified leprosy patients in Indian population.

Immunogenetics of human echinococcosis

Susceptibility and resistance to human Echinococcus infection and disease, although poorly understood, appear to reflect a complex interaction of parasite and host immunological and genetic factors. Disease stage, progression, and prognosis following treatment appear to be strongly influenced by cytokine and antibody profiles, and more recent evidence has suggested an important role of dendritic cells (DCs) and T regulatory cells (Tregs) in immunomodulation. Microarrays have supported these findings, highlighting both known and novel pathways involved in chronic murine disease. Genetic studies to date have been few and with limited success. Advanced genomic approaches, such as genome-wide association studies (GWAS), may provide further insight to identify the relevant pathways involved, thereby facilitating a new approach for the development of new clinical therapies.