Tumor necrosis factor-alpha -863C/A polymorphism is associated with Guillain-Barré syndrome in Bangladesh

Association of mannose-binding lectin 2 gene polymorphisms with Guillain-Barré syndrome

Complement activation plays a critical role in the pathogenesis of Guillain-Barré syndrome (GBS), a debilitating immune-mediated neuropathy. Mannose-binding lectin (MBL) is a complement activation factor of lectin pathway which as genetic host factor may influence the susceptibility or severity of GBS. We investigated the frequency of MBL2 promoter (- 550H/L and - 221X/Y) and functional region (exon 1 A/O) polymorphisms and their association with disease susceptibility, clinical features and serum MBL among GBS patients (n = 300) and healthy controls (n = 300) in Bangladesh. The median patient age was 30 years (IQR: 18-42; males, 68%). MBL2 polymorphisms were not significantly associated with GBS susceptibility compared to healthy controls. HL heterozygosity in GBS patients was significantly associated with mild functional disability at enrolment (P = 0.0145, OR, 95% CI 2.1, 1.17-3.82). The HY, YA, HA and HYA heterozygous haplotypes were more common among mildly affected (P = 0.0067, P = 0.0086, P = 0.0075, P = 0.0032, respectively) than severely affected patients with GBS. Reduced serum MBL was significantly associated with the LL, OO and no HYA variants and GBS disease severity. No significant association was observed between MBL2 polymorphisms and electrophysiological variants, recent Campylobacter jejuni infection or anti-ganglioside (GM1) antibody responses in GBS. In conclusion, MBL2 gene polymorphisms are related to reduced serum MBL and associated with the severity of GBS.

Meta-analysis for association of TNFA-308(G > A) SNP with vitiligo susceptibility

Vitiligo is an autoimmune progressive skin depigmenting disease. Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine and plays a crucial role in vitiligo development. Since there are conflicting results and consensus is lacking for the association of the TNFA gene -308 G > A polymorphism with vitiligo susceptibility; we performed a meta-analysis of all the available studies to investigate the association of TNFA -308 G > A polymorphism with vitiligo risk. 11 studies involving 2199 vitiligo patients and 3083 controls were included in the meta-analysis. The meta-analysis revealed an increased vitiligo risk with "AA", "GA" and "AA" + "GA" genotypes and 'A' allele in the overall (p = 0.006, p = 0.003, p = 0.001 & p = 0.003) and Egyptian populations (p = 0.001, p < 0.00001, p < 0.00001 & p = 0.002). Moreover, we found association for "GA" and "AA" + "GA" genotypes in Asian population (p = 0.0009 & p = 0.005) and for 'A' allele in Asian and middle eastern populations (p = 0.04 & p = 0.0002). Interestingly the disease activity based analysis revealed significant association for "GA", "AA" + "GA" genotypes and 'A' allele with active vitiligo patients in the North American population (p = 0.02). Moreover, we found significant association for "GA", "AA" + "GA" genotypes and 'A' allele with localized vitiligo in overall (p = 0.02, p = 0.02 & p = 0.04) and Asian (p = 0.004, p = 0.003 & p = 0.01) populations. Overall, our meta-analysis suggests the involvement of susceptible 'A' allele with: i) vitiligo susceptibility in overall population and specifically with Asian, Middle Eastern and Egyptian populations; ii) vitiligo disease activity in North American population and iii) localized vitiligo in overall population and specifically in Asian population.

Genetic polymorphisms in Guillain-Barré Syndrome: A field synopsis and systematic meta-analysis

OBJECTIVE

Guillain-Barré Syndrome (GBS) is considered to be a complex immune-mediated neuropathy. In the past few years, numerous studies were performed to detect the association between genetic polymorphisms and GBS risk. However, the findings of these studies were controversial. Thus, we conducted this field synopsis and systematic meta-analysis for further evaluating the possible associations between all available genetic polymorphisms and GBS susceptibility.

METHODS

Relevant studies focusing on the association between all genetic polymorphisms and GBS risk were obtained by a comprehensive literature search. The pooled odds ratios (ORs) as well as 95% confidence intervals (CIs) were used for assessing the strength of association. Subgroup analyses stratified by ethnicity and GBS subtype were further performed. Moreover, sensitive analysis and publication bias were conducted for evaluating the reliability of the results.

RESULTS

Among the initial identified 333 articles, 41 articles reporting on 220 genetic polymorphisms were extracted for conducting this systematic review. Then, we performed 95 primary and 94 subgroup meta-analyses for 59 variants with at least three independent studies available. The results showed significant association between four variants (FcγR IIA rs1801274, TNF-α rs1800629, HLA DRB1*0401 and HLA DRB1*1301) and GBS susceptibility. In the subgroup analysis, three (TNF-α rs1800629, TNF-α rs1800630 and TLR4 rs4986790) and two (FcγR IIA rs1801274, HLA DRB1*14) variants showed association with increased GBS risk in Asian and Caucasian population, respectively. Also, TNF-α rs1800629 was significant associated with AMAN subtypes of GBS. Furthermore, sensitivity analysis, funnel plots and Egger's test displayed robust results, except for FcγR IIA rs1801274. Additionally, for 161 variants with less than three studies, 17 genetic variants have been found to be significantly related with GBS risk in our systematic review.

INTERPRETATION

In our study, we assessed the association between all available genetic polymorphisms and GBS susceptibility. We hope our findings would be helpful for identifying novel genetic biomarkers and potential therapeutic targets for GBS.

Axonal variants of Guillain-Barré syndrome: an update

Axonal variants of Guillain-Barré syndrome (GBS) mainly include acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, and pharyngeal-cervical-brachial weakness. Molecular mimicry of human gangliosides by a pathogen's lipooligosaccharides is a well-established mechanism for Campylobacter jejuni-associated GBS. New triggers of the axonal variants of GBS (axonal GBS), such as Zika virus, hepatitis viruses, intravenous administration of ganglioside, vaccination, and surgery, are being identified. However, the pathogenetic mechanisms of axonal GBS related to antecedent bacterial or viral infections other than Campylobacter jejuni remain unknown. Currently, autoantibody classification and serial electrophysiology are cardinal approaches to differentiate axonal GBS from the prototype of GBS, acute inflammatory demyelinating polyneuropathy. Newly developed technologies, including metabolite analysis, peripheral nerve ultrasound, and feature selection via artificial intelligence are facilitating more accurate diagnosis of axonal GBS. Nevertheless, some key issues, such as genetic susceptibilities, remain unanswered and moreover, current therapies bear limitations. Although several therapies have shown considerable benefits to experimental animals, randomized controlled trials are still needed to validate their efficacy.

Toll-like receptor-4 299Gly allele is associated with Guillain-Barré syndrome in Bangladesh

Objective

TLR4 plays an important role in the pathogenesis of Guillain‐Barré syndrome (GBS). The relationships between TLR4 polymorphisms and susceptibility to GBS are poorly understood. We investigated the frequency and assessed the association of two single nucleotide polymorphisms (SNPs) in the extracellular domain of TLR4 (Asp299Gly and Thr399Ile) with disease susceptibility and the clinical features of GBS in a Bangladeshi cohort.

Methods

A total of 290 subjects were included in this study: 141 patients with GBS and 149 unrelated healthy controls. The TLR4 polymorphisms Asp299Gly and Thr399Ile were genotyped using polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) assay.

Results

The minor 299Gly allele was significantly associated with GBS susceptibility (P = 0.0137, OR = 1.97, 95% CI = 1.17–3.31), and was present at a significantly higher frequency in patients with the acute motor axonal neuropathy (AMAN) subtype of GBS (P = 0.0120, OR = 2.37, 95% CI = 1.26–4.47) than acute inflammatory demyelinating polyneuropathy (AIDP) subtype (P = 0.961, OR = 1.15, 95% CI = 0.38–3.48); when compared to healthy controls. The genotype frequency of the Asp299Gly polymorphism was not significantly different between patients with GBS and healthy controls. The Asp299‐Thr399 haplotype was associated with a significantly lower risk of developing GBS (P = 0.0451, OR = 0.63, 95% CI = 0.40–0.99). No association was observed between the Thr399Ile polymorphism and GBS disease susceptibility.

Interpretation

The TLR4 minor 299Gly allele was associated with increased susceptibility to GBS and the axonal GBS subtype in the Bangladeshi population. However, no associations were observed between the genotypes of the Asp299Gly and Thr399Ile SNPs and antecedent C. jejuni infection or disease severity in Bangladeshi patients with GBS.

Lack of association between single-nucleotide polymorphisms of pro- and anti-inflammatory cytokines and HTLV-1-associated myelopathy / tropical spastic paraparesis development in patients from Rio de Janeiro, Brazil

Background

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a progressive neurological and inflammatory disease, associated with HTLV-1 infection. HAM/TSP neurological disease is a consequence of an inflammatory reaction, and adaptive immune responses, through the secretion of anti-inflammatory and pro-inflammatory cytokines, play an important role in the outcome of infection and disease progression. Studies addressing the association between cytokines functional single nucleotide polymorphisms and HAM/TSP development are scarce.

Methods

The genetic polymorphisms of cytokine genes were evaluated in HAM/TSP patients (n = 68) and in asymptomatic HTLV-1 positive carriers (n = 83) from Rio de Janeiro, Brazil, in a case-control study. HTLV-1 infected patients were genotyped for SNPs in five cytokine genes: TNFA-308G/A, IL6-174G/C, IFNG + 874 T/A, TGFB at the codons + 10 T/C and + 25G/C, IL10-592C/A and -819C/T, and -1082A/G and proviral load (PVL) was quantified. Associations between genotypes, haplotypes, clinical outcome and pro viral load were evaluated.

Results

Lack of association between the cytokine polymorphisms and disease outcome was observed. The genotypes TNFA-308GG, IL6-174GG/GC, IL10-592AA and -819CC and TGFb1 high producers phenotypes were correlated with higher PVL in HAM/TSP patients versus asymptomatic carriers.

Conclusions

We did not observe association between cytokine polymorphisms and risk for HAM/TSP development in Brazilian HTLV-1 infected individuals, regardless of differences in PVL between HAM/TSP versus asymptomatic carriers in specific cytokine polymorphisms.

Guillain-Barré syndrome, transverse myelitis and infectious diseases

Guillain-Barré syndrome (GBS) and transverse myelitis (TM) both represent immunologically mediated polyneuropathies of major clinical importance. Both are thought to have a genetic predisposition, but as of yet no specific genetic risk loci have been clearly defined. Both are considered autoimmune, but again the etiologies remain enigmatic. Both may be induced via molecular mimicry, particularly from infectious agents and vaccines, but clearly host factor and co-founding host responses will modulate disease susceptibility and natural history. GBS is an acute inflammatory immune-mediated polyradiculoneuropathy characterized by tingling, progressive weakness, autonomic dysfunction, and pain. Immune injury specifically takes place at the myelin sheath and related Schwann-cell components in acute inflammatory demyelinating polyneuropathy, whereas in acute motor axonal neuropathy membranes on the nerve axon (the axolemma) are the primary target for immune-related injury. Outbreaks of GBS have been reported, most frequently related to Campylobacter jejuni infection, however, other agents such as Zika Virus have been strongly associated. Patients with GBS related to infections frequently produce antibodies against human peripheral nerve gangliosides. In contrast, TM is an inflammatory disorder characterized by acute or subacute motor, sensory, and autonomic spinal cord dysfunction. There is interruption of ascending and descending neuroanatomical pathways on the transverse plane of the spinal cord similar to GBS. It has been suggested to be triggered by infectious agents and molecular mimicry. In this review, we will focus on the putative role of infectious agents as triggering factors of GBS and TM.

Associations between tumor necrosis factor-α gene polymorphisms and the risk of Guillain-Barré syndrome and its subtypes: A systematic review and meta-analysis

This meta-analysis aimed to assess the relationship between tumor necrosis factor-α (TNF-α) polymorphisms and Guillain-Barré syndrome (GBS) or its subtypes of acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), and acute motor-sensory axonal neuropathy (AMSAN). A total of six studies with 1013 cases and 1029 controls were included. Our pooled data indicated that TNF-α 308G/A polymorphism was significantly associated with GBS, AMAN, and AMSAN but not with AIDP; TNF-α 857C/T polymorphism was significantly associated with AMAN but not with GBS or AIDP. Besides, no association was found between TNF-α 238G/A and 863C/A polymorphisms and GBS or its subtypes.