Association between the Interleukin-1 Receptor Antagonist (IL1RN) Variable Number of Tandem Repeats (VNTR) Polymorphism and Lymphoma

Introduction: Lymphoma is a common hematopoietic cancer. Immunosuppression is one of the main risk factors for the development of lymphoma. The interleukin (IL)-1 receptor antagonist IL1RN, which binds to the IL-1 receptor, moderates a variety of immune responses related to IL-1. We aimed to assess the impact of IL1RN variable number of tandem repeats (VNTR) polymorphism on lymphoma risk in an Iranian population sample. Materials and Methods: DNA was extracted from peripheral blood of 120 subjects with non-Hodgkin Lymphoma (NHL), 50 subjects with Hodgkin's lymphoma (HL), and 186 unrelated healthy individuals. IL1RN VNTR polymorphism was detected using polymerase chain reaction. Results: Our findings revealed that the IL1RN VNTR polymorphism was associated with protection against NHL (P≤0.001, OR: 0.30, 95% CI: 0.18-0.53). The IL1RN 2 allele significantly decreased the risk of NHL (p = 0.023, OR = 0.66, 95%CI = 0.46-0.93). In addition, we found that IL1RN 1/2 was associated with a lower risk of HL (p ≤0.001, OR = 0.24, 95%CI = 0.12-0.50). Conclusion: Our results suggest that the presence of IL1RN VNTR polymorphism is associated with a decreased risk of lymphoma in an Iranian subpopulation in southeast Iran.

Genotyping of Mycobacterium tuberculosis spreading in Hanoi, Vietnam using conventional and whole genome sequencing methods

Hanoi is the capital of Vietnam, one of the 30 countries with a high tuberculosis (TB) burden. Fundamental data on the molecular epidemiology of the disease is required for future TB management. To identify lineages and genotypes of Mycobacterium tuberculosis (Mtb), conventional genotyping data from clinical isolates of the Hanoi area was compared with whole genome sequencing (WGS) analysis from 332 of 470 samples. It was obtained from lineage-specific single nucleotide variants (SNVs), large sequence polymorphisms, spoligotyping, and variable number of tandem repeats (VNTR) analysis using mycobacterial interspersed repetitive unit (MIRU) and Japan anti-tuberculosis association (JATA) locus sets. This information was directly compared with results obtained from WGS. Mini-satellite repeat unit variants were identified using BLAST search against concatenated short read sequences, the RepUnitTyping tool. WGS analysis revealed that the Mtb strains tested are diverse and classified into lineage (L) 1, 2 and 4 (24.7, 57.2 and 18.1% respectively). The majority of the L2 strains were further divided into ancient and modern Beijing genotypes, and most of the L1 group were EAI4_VNM strains. Although conventional PCR-based genotyping results were mostly consistent with information obtained through WGS analysis, in-depth analysis identified aberrant deletions and spacers that may cause discordance. JATA-VNTR sets, including hypervariable loci, separated large Beijing genotypic clusters generated by MIRU15 into smaller groups. The distribution of repeat unit variants observed within 33 VNTR loci showed clear variation depending on the three lineages. WGS-based pairwise-SNV differences within VNTR-defined genotypic clusters were greater in L1 than in L2 and L4 (P = .001). Direct comparisons between results of PCR-based genotyping and in silico analysis of WGS data would bridge a gap between classical and modern technologies during this transition period, and provide further information on Mtb genotypes in specific geographical areas.

Variable number of tandem repeats of 9 Plasmodium vivax genes among Southeast Asian isolates

The variable number of tandem repeats (VNTRs) provides valuable information about both the functional and evolutionary aspects of genetic diversity. Comparative analysis of 3 Plasmodium falciparum genomes has shown that more than 9% of its open reading frames (ORFs) harbor VNTRs. Although microsatellites and VNTR genes of P. vivax were reported, the VNTR polymorphism of genes has not been examined widely. In this study, 230 P. vivax genes were analyzed for VNTRs by SERV, and 33 kinds of TR deletions or insertions from 29 P. vivax genes (12.6%) were found. Of these, 9 VNTR fragments from 8 P. vivax genes were used for PCR amplification and sequence analysis to examine the genetic diversity among 134 isolates from four Southeast Asian countries (China, Republic of Korea, Thailand, and Myanmar) with different malaria endemicity. We confirmed the existence of extensive polymorphism of VNTR fragments in field isolates. This detection provides several suitable markers for analysis of the molecular epidemiology of P. vivax field isolates.