Relationship between serum adenosine deaminase levels and liver histology in autoimmune hepatitis

AIM To evaluate the relationship between serum adenosine deaminase(ADA) levels and histological features in patients with autoimmune hepatitis(AIH).METHODS A total of 80 subjects(52 AIH cases and 28 healthy controls) were included in the study. Patients were diagnosed according to the simplified criteria suggested by the International Autoimmune Hepatitis Group. All of the cases had been diagnosed with AIH between 2010-2015 at Hacettepe University, Department of Gastroenterology. Serum blood samples were collected and stored at-80 ℃ until the biochemical estimation of ADA activity. The diagnosis of patients was confirmed by liver biopsy. Serum ADA > 20 U/L was considered to be high level.RESULTS Mean serum ADA levels were significantly higher in AIH patients than those in healthy controls(25.4 ± 9.6 U/L vs 12.8 ± 2.2 U/L, P < 0.001). Serum ADA levels > 20 U/L were found in 63.5% AIH patients and in 0% healthy controls(P < 0.001). Mean serum ADA levels were significantly increased in each stage of histological activity: 15.2 ± 3.5 U/L for patients with mild interface hepatitis, 23.1 ± 10.0 U/L for patients with moderate interface hepatitis and 30.9 ± 7.0 U/L for patients with severe interface hepatitis(P < 0.001). Correlation analysis showed that there was a positive association between serum ADA levels and histological activity(r = 0.71, P < 0.001). Receiver operating characteristic analysis suggested that 24.5 U/L was the optimum cut-off point of ADA level for severe interface hepatitis(sensitivity 88%, specificity 85.2%, area under thecurve: 0.88).CONCLUSION Because of the positive correlation with inflammatory activity, serum ADA level may be a potential biomarker for predicting or monitoring histological activity in patients with AIH.

Role of ascites adenosine deaminase in differentiating between tuberculous peritonitis and peritoneal carcinomatosis

AIM： To investigate the usefulness of tumor markers and adenosine deaminase in differentiating between tuberculous peritonitis （TBP） and peritoneal carcinoma- tosis （PC）. METHODS： A retrospective analysis of data was per- formed on consecutive patients who underwent perito- neoscopic and abdominal computed tomography （CT） evaluations. Among 75 patients at the Seoul National University Hospital from January 2000 to June 2010 who underwent both tests, 27 patients （36.0%） and 25 patients （33.3%） were diagnosed with TBP and PC, re- spectively. Diagnosis was confirmed by peritoneoscopic biopsy. RESULTS： Serum c-reactive protein （7.88：1：6.62 mg/ dL vs 3.12 ＋ 2.69 mg/dL, P = 0.01）, ascites adenos- ine deaminase （66.76：1：32.09 IU/L vs 13.89 ：l： 8.95 IU/L, P 〈 0.01）, ascites lymphocyte proportion （67.77 ：1： 23.41% vs 48.36 ＋ 18.78%, P 〈 0.01）, and serum- ascites albumin gradient （0.72 ＋ 0.49 g/dL vs 1.05 ＋ 0.50 g/dL, P = 0.03） were significantly different be- tween the two groups. Among tumor markers, serum and ascites carcinoembryonic antigen, serum carbohy- drate antigen 19-9 showed significant difference be- tween two groups. Abdominal CT examinations showed that smooth involvement of the parietal peritoneum was more common in the TBP group （77.8% vs 40.7%） whereas nodular involvement was more common in the PC group （14.8% vs 40.7%, P = 0.04）. From receiver operating characteristic （ROC） curves ascites adeno- sines deaminase （ADA） showed better discriminative capability than tumor markers. An ADA cut-off level of 21 IU/L was found to yield the best results of differ- ential diagnosis; sensitivity, specificity, positive predic- tive value, and negative predictive value were 92.0%, 85.0%, 88.5% and 89.5%, respectively. CONCLUSION： Besides clinical and radiologic findings, ascitic fluid ADA measurement is helpful in the differen- tial diagnosis of TBP and PC.

Adenosine deaminase 2 regulates the activation of the toll-like receptor 9 in response to nucleic acids

Human cells contain two types of adenosine deaminases(ADA)each with unique properties:ADA1,which is present in all cells where it modulates intracellular functions and extracellular signaling,and ADA2,which is secreted by immune cells.The exact intracellular functions of ADA2 remain undetermined and less defined than those of ADA1.ADA2 has distinct characteristics,such as low adenosine affinity,heparin-binding ability,and putative lysosomal entry.Here,we confirm that ADA2 is a lysosomal protein that binds toll-like receptor 9(TLR9)agonists,specifically CpG oligodeoxynucleotides(CpG ODNs).We show that interferon-alpha(IFN-α)is secreted in response to TLR9 activation by CpG ODNs and natural DNA and markedly increases when ADA2 expression is downregulated in plasmacytoid dendritic cells(pDCs).Additionally,the pretreatment of pDCs with RNA further stimulates IFN-αsecretion by pDCs after activation with CpG ODNs.Our findings indicate that ADA2 regulates TLR9 responses to DNA in activated pDCs.In conclusion,decreasing ADA2 expression or blocking it with specific oligonucleotides can enhance IFN-αsecretion from pDCs,improving immune responses against intracellular infections and cancer.

Delayed-onset adenosine deaminase deficiency with a novel synonymous mutation and a case series from China

Background Adenosine deaminase(ADA)is a key enzyme in the purine salvage pathway.Genetic defects of the ADA gene can cause a subtype of severe combined immunodeficiency.To date,few Chinese cases have been reported.Methods We retrospectively reviewed the medical records of patients diagnosed with ADA deficiency in Beijing Children's Hospital and summarized the previously published ADA deficiency cases from China in the literature.Results Nine patients were identified with two novel mutations(W272X and Q202=).Early-onset infection,thymic abnor-malities and failure to thrive were the most common manifestations of Chinese ADA-deficient patients.The ADA genotype has a major effect on the clinical phenotype.Notably,a novel synonymous mutation(c.606G>A,p.Q202=)was identified in a delayed-onset patient,which affected pre-mRNA splicing leading to a frameshift and premature truncation of the protein.Furthermore,the patient showed γδT cells expansion with an increased effect or phenotype,which may be associated with the delayed onset of disease.In addition,we reported cerebral aneurysm and intracranial artery stenosis for the first time in ADA deficiency.Five patients died with a median age of four months,while two patients received stem cell transplantation and are alive.Conclusions This study described the first case series of Chinese ADA-deficient patients.Early-onset infection,thymic abnormalities and failure to thrive were the most common manifestations in our patients.We identified a synonymous muta-tion that affected pre-mRNA splicing in the ADA gene,which had never been reported in ADA deficiency.Furthermore,we reported cerebral aneurysm in a delayed-onset patient for the first time.Further study is warranted to investigate the underlying mechanisms.

Combined detections of interleukin 27, interferon-γ, and adenosine deaminase in pleural effusion for diagnosis of tuberculous pleurisy

Background Previous studies reported interleukin-27 （IL-27）, interferon-y （IFN-γ）, or adenosine deaminase （ADA） alone plays a helpful role in diagnosing tuberculous pleural effusion （TPE）. The present study aims at comparing the diagnostic accuracy of pleural IL-27, IFN-γ, and ADA, and investigate the diagnostic accuracy of the combination of IL-27, IFN-γ, or/ and ADA for differentiating TPE from pleural effusions with the other etiologies. Methods The concentrations of IL-27, IFN-γ and ADA were simultaneously determined in pleural fluids and sera from 40 patients with TPE; 26 with malignant pleural effusion, seven with infectious pleural effusion, and eight with transudative pleural effusion by enzyme linked immunosorbent assay and colorimetric method. The corresponding biochemical indexs were also simultaneously determined. Results The concentrations of pleural IL-27 and IFN-γ in the tuberculous group were significantly higher than those in the malignant, infectious, and transudative groups. The concentrations of ADA in TPE were significantly higher than those in MPE or transudative effusions, while much lower than those in infectious effusions. Among these three biomarkers, IL- 27 was the most effective for TPE diagnosis, with the cut off value of 900.8 ng/L. IL-27 had a high sensitivity of 95% and specificity of 97.6% for differential diagnosis of TPE from non-TPEs. Combinations of IL-27, IFN-γ and ADA measurements further increased the sensitivity or specificity up to 100%. Conclusions Compared to non-TPEs, IL-27, IFN-γ and ADA all simultaneously increased in TPE; and among these three rapid detection methods, IL-27 appeared to be the best for distinguishing tuberculous from non-TPEs, especially from MPE. Combinations of the three markers （IL-27, IFN-γ and ADA） yielded the highest sensitivity and specificity. These findings suggest that the applications of a new biomarker, IL-27, alone or with IFN-γ and ADA, may contribute to more efficient diagnosis strategies in the management of tuberculous pleurisy.

Combined Determination of CEA, Tch and ADA for Differential Diagnosis of Ascites

Objective: To study the value of combined determination of carcinoembryonic antigen (CEA), total cholesterol (Tch) and adenosine deaminase (ADA) in the differential diagnosis of ascites due to different causes. Methods: Sixty-eight cases with ascites were divided into 3 groups based on their etiology, namely malignant ascites, tubercular ascites and non-tubercular benign ascites. CEA, Tch, and ADA were measured and analyzed in different ascites. Results: CEA was significantly higher in malignant ascites than in benign ascites, the sensitivity and specificity for malignant ascites being 50% and 100% respectively. Tch is higher or equal to 1.54 mmol/L in tubercular ascites and lower or equal to 1.18 mmol/L in non-tubercular benign ascites, and Tch level in malignant ascites was frequently between that in tubercular acites and non-tubercular benign ascites. Ascitic fluid ADA activity was higher than 30 U/L in 80% of tubercular ascites, while none of non-tubercular benign ascites reached to such level. Conclusion: CEA, Tch and ADA are valuable for the diagnosis and differential diagnosis of ascitic etiology and combine measurements of these indices can increase the diagnostic efficiency.

Effect of genetic factors on the association between coronary artery disease and PTPN22 polymorphism

PTPN22 has been previously found associated with coronary artery disease(CAD). In the present note we have studied the effect of p53 codon 72,acid phosphatse locus 1(ACP1) and adenosine deaminase(ADA) genetic polymorphism on the strength of association between PTPN22 and CAD. We have studied 133 non diabetic subjects with CAD,122 non diabetic cardiovascular patients without CAD and 269 healthy blood donors. Informed written consent was obtained from all subjects and the study was approved by the Ethical Committee. A high significant association between PTPN22 and CAD is observed in carriers of *A allele of ACP1 with a higher proportion of *T allele carriers in non diabetic subjects with CAD as compared to controls and to non diabetic subjects with cardiovascular diseasewithout CAD. A similar pattern is observed in carriers of *Pro allele of p53 codon 72 with a higher proportion of *T allele carriers in non diabetic subjects with CAD as compared to other groups. A highly significant association between PTPN22 and CAD is observed in carriers of ADA2 *2 allele with higher proportion of *T allele carriers in non diabetic subjects with CAD as compared to other group. There is a high significant correlation between the number of factors that contributes to increase the strength of association between PTPN22 *T and CAD and the proportion of *T carriers in CAD. ACP1,p53 codon 72 and ADA are involved in immune reaction and give an important additive contribution to the strength of association between PTPN22 and CAD. This study stresses the importance of the simultaneous analysis of multiple genes functionally related to a specific disease: the approach may give important hints to understand multifactorial disorders.

Honey prevents hepatic damage induced by obstruction of the common bile duct

AIM:To examine the possible effects of honey supplementation on hepatic damage due to obstruction of the common bile duct in an experimental rat model. METHODS:The study was performed with 30 male rats divided into three groups:a sham group,an obstructive jaundice group,and an obstructive jaundice plus honey group. At the end of the study period,the animals were sacrificed,and levels of nitric oxide(NO) ,and NO synthase(NOS) activities were measured in liver tissues,and levels of adenosine deaminase(ADA) and alanine transaminase(ALT) activities were measured in serum. RESULTS:Blood ALT and ADA activities were significantly elevated in the jaundice group as compared to those of the sham group. In the obstructive jaundice plus honey group,blood ALT and ADA activities were significantly decreased as compared to those of the jaundice group. In erythrocytes and liver tissues,NO levels were found to be significantly higher in the obstructive jaundice plus honey group compared to those of the sham group. Additionally,NO levels were found to be significantly higher in liver tissues from the animals in the obstructive jaundice plus honey group than those of the jaundice group.CONCLUSION:Honey was found to be beneficial in the prevention of hepatic damage due to obstruction of the common bile duct.

Cysteine Not Required for Catalytic Activity of Adenosine Deaminase

Homology comparison of human, murine and E coli adenosine deaminases revealed a single conserved cysteine residue. On the basis of many previous reports indicating that there is an essential Cys residue involved in enzymatic activity, this conserved Cys was proposed to be the essential one involved in the catalytic activity of the enzyme. Using site directed mutagenesis and steady state kinetics, the role of the single conserved Cys residue was tested. However, results presented here indicate that this conserved Cys is not required for enzyme activity, strongly suggesting that cysteine should not be required for the enzymatic activity of adenosine deaminase. The preponderance of previously reported data indicating the “essentiality” of the Cys residue for enzymatic activity are discussed .

Gene therapy and genome editing for primary immunodeficiency diseases

In past two decades the gene therapy using genetic modified autologous hematopoietic stem cells(HSCs)transduced with the viral vector has become a promising alternative option for treating primary immunodeficiency diseases(PIDs).Despite of some pitfalls at early stage clinical trials,the field of gene therapy has advanced significantly in the last decade with improvements in viral vector safety,preparatory regime for manufacturing high quality virus,automated CD34 cell purification.Hence,the overall outcome from the clinical trials for the different PIDs has been very encouraging.In addition to the viral vector based gene therapy,the recent fast moving forward developments in genome editing using engineered nucleases in HSCs has provided a new promising platform for the treatment of PIDs.This review provides an overall outcome and progress in gene therapy clinical trials for SCID-X,ADA-SCID,WAS,X-CGD,and the recent developments in genome editing technology applied in HSCs for developing potential therapy,particular in the key studies for PIDs.

Genetics of severe combined immunodeficiency

Severe Combined Immunodeficiency(SCID)is an inherited group of rare,lifethreatening disorders due to the defect in T cell development and function.Clinical manifestations are characterised by recurrent and severe bacterial,viral,and fungal opportunistic infections that start from early infancy period.Haematopoietic stem cell transplantation(HSCT)is the treatment of choice.The pattern of inheritance of SCID may be X-linked or autosomal recessive.Though the diagnosis of SCID is usually established by flow cytometry-based tests,genetic diagnosis is often needed for genetic counselling,prognostication,and modification of pre-transplant chemotherapeutic agents.This review aims to highlight the genetic aspects of SCID.

Insight into the deamination mechanism of 6-cyclopropylamino guanosine analogs for anti-HIV drug design

Deamination is a crucial step in the transformation of 6-cyclopropylamino guanosine prodrug to its active form. A convenient method using capillary electrophoresis （CE） without sample labeling was developed to analyze the deamination of a series of D-/L-6-cyclopropylamino guanosine analogs by mouse liver homogenate, mouse liver microsome, and adenosine deaminase （ADA）. A two-step process involving a 6-amino guanosine intermediate formed by oxidative N-dealkylation was demonstrated in the metabolism of 6-cyclopropylamino guanosine to 6-hydroxy guanosine. The results indicated that the transformation rates of different prodrugs to the active form varied greatly, which were closely correlated with the configuration of nucleosides and the structure of glycosyl groups. Most importantly, D-form analogs were metabolized much faster than their L-counterparts, thus clearly pointed out that compared to guanine, modification of glycosyl part might be a better choice for the development of L-Kuanosine analogs for the treatment of HIV,