Toll- like receptor 2 polymorphism and IL-6 profile in relation to disease progression in chronic HBV infection: a case control study in Egyptian patients

Chronic hepatitis B (CHB) has a wide range of outcomes depending on host immune responses mainly Toll-like receptors (TLRs) signaling and released cytokines. Toll-like receptor 2 (TLR2) single nucleotide polymorphisms (SNPs) and interleukin 6 (IL-6) may influence the course of CHB. We aimed to elucidate the relation between TLR-2 polymorphism, IL-6 profile, and CHB progression. We analyzed TLR-2 polymorphism (SNP; rs3804099) in 185 CHB patients and 60 controls using TaqMan allelic discrimination assay. Serum IL-6 levels were assessed by ELISA. IL-6 levels were considerably higher in active CHB and cirrhotic patients compared with inactive carriers and controls (P < 0.001). IL-6 showed positive correlation with ALT and advanced fibrosis in active CHB patients (r = 0.31, P = 0.02). A significant positive correlation was noticed between IL-6 and HBV DNA PCR in all CHB groups. TT genotype of rs3804099/TLR-2 was significantly more prevalent in inactive carriers compared to active hepatitis patients (P = 0.04, OR = 0.39 and 95% CI: 0.16–0.95). Both heterozygous CT and mutant TT genotypes were significantly more frequent among inactive carriers compared to cirrhotic patients (P = 0.01, OR = 0.33, 95% CI: 0.13–0.81 and P = 0.009, OR = 0.32, 95% CI: 0.13–0.77). TT genotype was significantly related to lower IL-6 levels in active hepatitis and cirrhotic groups (P = 0.005 and P = 0.001, respectively) showing that TLR mutations would be associated with milder hepatitis activity and lower possibility for disease progression. There may be a positive association between TLR2 rs3804099 polymorphism and hepatitis B activity. IL-6 is a good indicator of CHB disease progression.

     

Heterozygous carriers of succinyl-CoA:3-oxoacid CoA transferase deficiency can develop severe ketoacidosis

Succinyl-CoA:3-oxoacid CoA transferase (SCOT, gene symbol OXCT1) deficiency is an autosomal recessive disorder in ketone body utilization that results in severe recurrent ketoacidotic episodes in infancy, including neonatal periods. More than 30 patients with this disorder have been reported and to our knowledge, their heterozygous parents and siblings have had no apparent ketoacidotic episodes. Over 5 years (2008–2012), we investigated several patients that presented with severe ketoacidosis and identified a heterozygous OXCT1 mutation in four of these cases (Case1 p.R281C, Case2 p.T435N, Case3 p.W213*, Case4 c.493delG). To confirm their heterozygous state, we performed a multiplex ligation-dependent probe amplification analysis on the OXCT1 gene which excluded the presence of large deletions or insertions in another allele. A sequencing analysis of subcloned full-length SCOT cDNA showed that wild-type cDNA clones were present at reasonable rates to mutant cDNA clones. Over the following 2 years (2013–2014), we analyzed OXCT1 mutations in six more patients presenting with severe ketoacidosis (blood pH ≦7.25 and total ketone body ≧10 mmol/L) with non-specific urinary organic acid profiles. Of these, a heterozygous OXCT1 mutation was found in two cases (Case5 p.G391D, Case6 p.R281C). Moreover, transient expression analysis revealed R281C and T435N mutants to be temperature-sensitive. This characteristic may be important because most patients developed ketoacidosis during infections. Our data indicate that heterozygous carriers of OXCT1 mutations can develop severe ketoacidotic episodes in conjunction with ketogenic stresses.     

Mutation update on ACAT1 variants associated with mitochondrial acetoacetyl‐CoA thiolase (T2) deficiency

Mitochondrial acetoacetyl‐CoA thiolase (T2, encoded by the ACAT1 gene) deficiency is an inherited disorder of ketone body and isoleucine metabolism. It typically manifests with episodic ketoacidosis. The presence of isoleucine‐derived metabolites is the key marker for biochemical diagnosis. To date, 105 ACAT1 variants have been reported in 149 T2‐deficient patients. The 56 disease‐associated missense ACAT1 variants have been mapped onto the crystal structure of T2. Almost all these missense variants concern residues that are completely or partially buried in the T2 structure. Such variants are expected to cause T2 deficiency by having lower in vivo T2 activity because of lower folding efficiency and/or stability. Expression and activity data of 30 disease‐associated missense ACAT1 variants have been measured by expressing them in human SV40‐transformed fibroblasts. Only two variants (p.Cys126Ser and p.Tyr219His) appear to have equal stability as wild‐type. For these variants, which are inactive, the side chains point into the active site. In patients with T2 deficiency, the genotype does not correlate with the clinical phenotype but exerts a considerable effect on the biochemical phenotype. This could be related to variable remaining residual T2 activity in vivo and has important clinical implications concerning disease management and newborn screening.     

Frequency of toll-like receptor 4 variants and association with treatment response in children with primary immune thrombocytopenia

Objectives : To investigate the frequency of toll-like receptor 4 (TLR4) variants c.896A>G (p.Asp299Gly) and c.1196C>T (p.Thr399Ile) among Egyptian children with primary immune thrombocytopenia (pITP), and their association with disease course and response to treatment. Methods : A case–control study that included 80 children with pITP and 50 age- and sex-matched healthy controls. TLR4 c.896A>G and c.1196C>T variants were genotyped using polymerase chain reaction–restriction fragment length polymorphism. Patients were classified according to their response to treatment after 3 months as responders and nonresponders. Results : Compared with controls, children with pITP had significantly higher minor allele frequencies of TLR4 p.Asp299Gly (16.25% vs. 6%, odds ratio [OR] 3.04, 95% confidence interval [CI]: 1.16–9.36, p = .014) and p.Thr399Ile (20% vs. 4%, OR 6, 95% CI: 2.02–24.01, p < .001). The presence of p.Asp299Gly variant was significantly associated with chronic ITP (OR 7.78, 95% CI: 2.04–35.69, p < .001) and non-response to therapy with steroid (OR 11.67, 95% CI: 1.32–104.08, p = .012), but not thrombopoietin-receptor agonist (OR 1.67, 95% CI: 0.35–8.19, p = .464). Likewise, having p.Thr399Ile variant was significantly associated with chronic ITP (OR 5.14, 95% CI: 1.6–17.4, p = .002) and non-response to therapy with steroid (OR 6.1, 95% CI: 1.01–49.06, p = .046) but not thrombopoietin-receptor agonist (OR 1.57, 95% CI: 0.33–7.58, p = .515). Conclusion : The presence of TLR4 p.Asp299Gly or p.Thr399Ile variant may be associated with ITP predisposition, chronicity, and non-response to upfront steroid therapy. These findings enhance our understanding of the complex pathophysiology of pITP with potentially important clinical implications.