Primary antibody deficiencies in Turkey: molecular and clinical aspects

Primary antibody deficiencies (PAD) are the most common subtype of primary immunodeficiencies, characterized by increased susceptibility to infections and autoimmunity, allergy, or malignancy predisposition. PAD syndromes comprise of immune system genes highlighted the key role of B cell activation, proliferation, migration, somatic hypermutation, or isotype switching have a wide spectrum from agammaglobulinemia to selective Ig deficiency. In this study, we describe the molecular and the clinical aspects of fifty-two PAD patients. The most common symptoms of our cohort were upper and lower respiratory infections, bronchiectasis, diarrhea, and recurrent fever. Almost all patients (98%) had at least one of the symptoms like autoimmunity, lymphoproliferation, allergy, or gastrointestinal disease. A custom-made next-generation sequencing (NGS) panel, which contains 24 genes, was designed to identify well-known disease-causing variants in our cohort. We identified eight variants (15.4%) among 52 PAD patients. The variants mapped to BTK (n?=?4), CD40L (n?=?1), ICOS (n?=?1), IGHM (n?=?1), and TCF3 (n?=?1) genes. Three novel variants were described in the BTK (p.G414W), ICOS (p.G60*), and IGHM (p.S19*) genes. We performed Sanger sequencing to validate pathogenic variants and check for allelic segregation in the family. Targeted NGS panel sequencing can be beneficial as a suitable diagnostic modality for diagnosing well-known monogenic PAD diseases (only 2–10% of PADs); however, screening only the coding regions of the genome may not be adequately powered to solve the pathogenesis of PAD in all cases. Deciphering the regulatory regions of the genome and better understanding the epigenetic modifications will elucidate the molecular basis of complex PADs.

     

Correction to: Primary antibody deficiencies in Turkey: molecular and clinical aspects

Immunologic Research -     

Germline mutations of aryl hydrocarbon receptor-interacting protein (<Emphasis Type="Italic">AIP</Emphasis>) gene and somatostatin receptor 1–5 and <Emphasis Type="Italic">AIP</Emphasis> immunostaining in patients with sporadic acromegaly with poor versus good response to somatostatin analogues

Objective

To determine aryl hydrocarbon interacting protein (AIP) gene variations and AIP and somatostatin receptor (SSTR) 1–5 immunostaining in patients with apparently sporadic acromegaly with poor versus good response to somatostatin analogues (SRLs).

Methods

A total of 94 patients (66 with poor and 28 with good response to SRLs) were screened for the AIP gene variations using Sanger sequencing. Immunostaining was performed in 60 tumors.

Results

Several variations, albeit some with undetermined significance, were detected, especially in poor responder patients. The prevalence of AIP mutation was 2.1% in the whole group and 1.5% in patients with poor response to SRLs. AIP, SSTR2A, and SSTR2B immunostainings were decreased in patients with poor response (p?<?0.05 for all), and other SSTRs did not differ between the groups (p?>?0.05 for all). Patients with low AIP had decreased levels of SSTR2A and SSTR3 (p?<?0.05 for all). AIP and SSTR2A immunostainings were positively correlated to the treatment response and age at diagnosis was negatively correlated (p?<?0.05 for all). In poor responder patients with high SSTR2A immunostaining, SSTR2B immunostaining and preoperative tumor size were positively and negatively correlated, respectively, to SRL response (p?<?0.05 for all).

Conclusions

Lack of response to SRLs does not necessarily increase the risk of harboring AIP mutations. The finding of decreased AIP, SSTR2A, and SSTR2B immunostaining in patients with poor response to SRLs and decreased SSTR2A and SSTR3 level in those with low AIP immunostaining suggests a possible interaction between AIP and some SSTR subtypes that might alter SRL sensitivity.

     

Plasma Adhesion and Inflammation Markers: Asymmetrical Dimethyl-L-Arginine and Secretory Phospholipase A<Subscript>2</Subscript> Concentrations before and after Laparoscopic Gastric Banding in Morbidly Obese Patients

Background The aim of this study was to examine the relationship between subclinical inflammation and weight loss by laparoscopic adjustable gastric banding (LAGB). Methods Plasma concentrations of intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), sensitive C-Reactive Protein (sCRP), asymmetrical dimethyl-L-arginine (ADMA), Secretory Phospholipase A2 (sPLA2), and metabolic markers, such as homeostatic model assessment – insulin resistance (HOMA-IR) and body mass index (BMI) were determined in morbidly obese patients (n = 18, BMI 48.6 ± 1.7 kg/m²) at baseline and 1 month after operations. Baseline levels in patients were also compared with age-matched controls (n = 20, BMI 21.3 ± 1.8 kg/m²). Plasma ICAM-1,VCAM, sCRP and ADMA, and sPLA₂ concentrations were determined by enzyme-linked immunoassay methods and colorimetric method, respectively. Results Plasma sCRP, ICAM-1, ADMA and sPLA₂ concentrations and HOMA-IR were significantly higher in morbidly obese patients than in controls (for each, P < 0.01). Plasma VCAM-1 concentration was not changed in obese patients. HOMA-IR was significantly correlated with ICAM-1, ADMA and sPLA₂ in the obese group at baseline (for each, P < 0.01). There was a significant correlation between plasma sCRP and plasma glucose,VCAM-1, ICAM-1, ADMA and sPLA₂ concentrations (for each, P < 0.01). 1 month after LAGB, mean body weight loss was 13.2 ± 6.3 kg, and plasma sCRP and ADMA concentrations and HOMA-IR and BMI were significantly decreased (for each, P < 0.01). However, these levels cannot be decreased to the levels of the controls. Conclusion Obesity and insulin resistance appear to be associated with low-grade inflammation and endothelial dysfunction. Insulin resistance and endothelial dysfunction were improved by weight loss after LAGB.     

Elevated hepatocyte growth factor expression as an autocrine c‐Met activation mechanism in acquired resistance to sorafenib in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the third leading cause of cancer‐related deaths worldwide. Limitations in HCC treatment result due to poor prognosis and resistance against traditional radiotherapy and chemotherapies. The multikinase inhibitor sorafenib is the only FDA approved drug available for advanced HCC patients, and development of second‐line treatment options for patients who cannot tolerate or develop resistance to sorafenib is an urgent medical need. In this study, we established sorafenib‐resistant cells from Huh7 and Mahlavu cell lines by long‐term sorafenib exposure. Sorafenib‐resistant HCC cells acquired spindle‐shape morphology, upregulated mesenchymal markers, and showed significant increase in both migration and invasion abilities compared to their parental counterparts. Moreover, after long‐term sorafenib treatment, HCC cells showed induction of hepatocyte growth factor (HGF) synthesis and secretion along with increased levels of c‐Met kinase and its active phosphorylated form, indicating autocrine activation of HGF/c‐Met signaling. Importantly, the combined treatment of the resistant cells with c‐Met kinase inhibitor SU11274 and HGF neutralizing antibody significantly reversed the increased invasion ability of the cells. The combined treatment also significantly augmented sorafenib‐induced apoptosis, suggesting restoration of sorafenib sensitivity. These results describe, for the first time, compensatory upregulation of HGF synthesis leading to autocrine activation of HGF/c‐Met signaling as a novel cellular strategy in the acquisition of sorafenib resistance. Therefore, we suggest that combinatorial therapeutic strategies with HGF and c‐Met inhibitors comprise promising candidates for overcoming sorafenib resistance.     

Deregulated WNT signaling in childhood T-cell acute lymphoblastic leukemia

WNT signaling has been implicated in the regulation of hematopoietic stem cells and plays an important role during T-cell development in thymus. Here we investigated WNT pathway activation in childhood T-cell acute lymphoblastic leukemia (T-ALL) patients. To evaluate the potential role of WNT signaling in T-cell leukomogenesis, we performed expression analysis of key components of WNT pathway. More than 85% of the childhood T-ALL patients showed upregulated β-catenin expression at the protein level compared with normal human thymocytes. The impact of this upregulation was reflected in high expression of known target genes (AXIN2, c-MYC, TCF1 and LEF). Especially AXIN2, the universal target gene of WNT pathway, was upregulated at both mRNA and protein levels in ∼40% of the patients. When β-CATENIN gene was silenced by small interfering RNA, the cancer cells showed higher rates of apoptosis. These results demonstrate that abnormal WNT signaling activation occurs in a significant fraction of human T-ALL cases independent of known T-ALL risk factors. We conclude that deregulated WNT signaling is a novel oncogenic event in childhood T-ALL.     

The relationship between plasma asymmetrical dimethyl-L-arginine and inflammation and adhesion molecule levels in subjects with normal, impaired, and diabetic glucose tolerance

Increasing evidence suggests that the postprandial state is a contributing factor to the development of atherosclerosis. To evaluate the effects of acute hyperglycemia on endothelial dysfunction and inflammation, plasma asymmetrical dimethyl-l-arginine (ADMA), intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1, and C-reactive protein (CRP) levels and secretory phospholipase A(2) (sPLA(2)) activities were measured in subjects with normal (n = 35), impaired (IGT) (n = 25), and diabetic (DGT) (n = 20) glucose tolerance. At baseline, plasma ADMA, sICAM-1, and CRP concentrations and plasma sPLA(2) activities were higher in both the IGT and DGT groups than in the normal glucose tolerance group (for each comparison, each P < .001). Patients with DGT have higher plasma ADMA and sICAM-1 concentrations than patients with IGT (for each, P < .001).Two hours after glucose loading, plasma ADMA and CRP concentrations and sPLA(2) activities were significantly elevated in the 3 groups when compared with baseline levels (for each comparison, P < .001). Plasma vascular cell adhesion molecule 1 and sICAM-1 concentrations were found to be elevated from baseline levels after glucose loading in the IGT and DGT groups (for each comparison, P < .001). Correlation analysis at baseline suggested that there was a significant relationship between ADMA and inflammation and soluble adhesion markers in the studied groups. In conclusion, plasma concentrations of ADMA and of inflammation and adhesion molecules were elevated in the prediabetic state. A complex interrelation could exist between ADMA and inflammation, and mechanisms involved in endothelial dysfunction are multifactorial at the prediabetic and diabetic state.     

Evaluation of PAX5 gene in the early stages of leukemic B cells in the childhood B cell acute lymphoblastic leukemia

B-lineage acute lymphoblastic leukemia (B-ALL) is a common subtype of acute leukemia in children. PAX5 plays a central role in B-cell development and differentiation. In this study, we analyzed PAX5 expression levels, transactivation domain mutations/deletions in B-ALL patients (n = 115) and healthy controls (n = 10). Relative PAX5 mRNA levels were significantly increased in B-ALL patients (p < 0.0001). PAX5 expression was also evaluated in three different B-ALL subgroups (pro B, Common B and Pre B ALL) and showed stage specific expression levels. Pro B (p = 0.04) and pre B (p = 0.04) patients showed significantly high PAX5 mRNA levels compared to stage specific controls. At least one deletion of exons 7-8 or 9 has been identified in the 41% of the patients. CD34 positivity in patients and presence of large deletions (Δ7/8/9) showed a significant correlation (p = 0.05). None of our patients showed PAX5 point mutations, but two previously identified SNPs (rs3780135 and rs35469494) were detected. Our results support that PAX5 is a critical factor in B-ALL development and aberrant PAX5 expression especially at early stages may leads to leukemic transformation.