Characterisation of glycoforms of ascitic fluids in benign and malignant diseases

Glycosylation of sera thyroglobulin antibody in patients with thyroid diseases

OBJECTIVE

Thyroglobulin antibody (TgAb) is an important autoantibody in thyroid diseases, which is a glycoprotein, predominantly of IgG class. Glycosylation of the IgG-Fc contributes to many effector functions exhibited by antibodies. The aim of our study was to investigate the glycosylation of sera TgAb in patients with different thyroid diseases.

DESIGN AND METHODS

Sera from 146 patients were collected and divided into four groups: Hashimoto's thyroiditis (HT, n=90), Graves' disease (GD, n=20), papillary thyroid carcinoma (PTC, n=17), and PTC with histological lymphocytic thyroiditis (PTC-T, n=19). HT patients were further divided into euthyroidism and subclinical and overt hypothyroidism groups. Lectin-ELISAs were performed to detect the relative amount of core fucose, terminal galactose, and sialic acid on each TgAb respectively.

RESULTS

Among HT, GD, and PTC groups, HT patients had significantly lower core fucose content on TgAb than the other two groups; an increasing trend of sialylation was found in PTC sera (P=0.076) compared with HT groups. PTC-T patients had significantly higher sialylated TgAb than HT and GD patients, and no significant difference was found between PTC and PTC-T. There was no significant difference in the three carbohydrate residue contents on sera TgAb among HT subgroups. In all the patients, negative correlation was found between sialic acid content and TgAb IgG levels (r=-0.736, P<0.001).

CONCLUSIONS

Our study showed that glycosylation of sera TgAb varied in different thyroid diseases and it might be involved in pathogenesis of thyroid disorders.

Fucosylated glycoproteomic approach to identify a complement component 9 associated with squamous cell lung cancer (SQLC)

Human lung cancer is a major cause of cancer mortality worldwide. Understanding the pathophysiological features and the development of novel biomarkers for diagnosis as well as treatment are major tasks. In the present study, sera from ten SQLC patients and healthy control (HEC) were collected and pooled, respectively. The pooled sera were depleted via an immunoaffinity method and further subjected to fucosylation enrichment. Enriched fucosylated glycoproteins were resolved by SDS-PAGE and subsequently analyzed by LC-ESI-MS/MS. From comparative proteomic analysis, we selected the C9 protein. C9 protein levels were validated by Western blot, protein arrays and the fucosylation levels of C9 by hybrid lectin ELISA (HLE) in the sera of 120 HEC and 118 SQLC patients. The C9 protein level was 6.4-fold higher in SQLC patients compared to HEC, as determined by Western blot analysis. The results were concurrently confirmed by a protein array that showed a C9 level significantly higher in SQLC patients, as compared to HEC, with a sensitivity of 53% and a specificity of 89%. C9 fucosylation levels were significantly higher in SQLC patients compared to HEC (p<0.05) when tested by HLE. These findings suggest that C9 and fucosylated form could serve as a useful marker for SQLC.

Value of combined detection of AFU and TCH in differential diagnosis between malignant and non-tuberculous benign ascites

The purpose of this study was to accurately evaluate the diagnostic efficacy of combined detection of ascitic fluid alpha-L-fucosidase (AFU) and cholesterol (TCH) compared with that of their individual detection. We assayed ascitic AFU activity by colorimetry and TCH level by CHOD-PAP method simultaneously in all 213 cases. Then, we assessed the value of combined detection of AFU and TCH activities with receiver operating characteristic curve (ROC curve), including diagnostic sensitivity, specificity, diagnostic accuracy, positive predict value(PV+), negative predict value(PV-) to see whether these two ascitic fluid biochemical examinations might help in differential diagnosis between malignant and non-tuberculous benign ascites. The mean values of AFU and TCH in malignant group [(164.96 ± 87.72) μmol/lh and (1.65 ± 1.00) mmol/l, respectively] were significantly higher than those in non-tuberculous benign group [(104.02 ± 62.08) μmol/lh and (0.69 ± 0.58) mmol/l, respectively] (P < 0.01). The optimal cutoff value of 101.95 μmol/lh for ascitic AFU and 1.04 mmol/l for ascitic TCH resulted in a diagnostic sensitivity of 82.3% and 70.8%, specificity of 63.2 and 83.8%, accuracy of 72.8 and 77.9%, PV+ of 65.3 and 78.2%, PV- of 83.1 and 77.8%, respectively. Combined detection of the two markers, the sensitivity, specificity, accuracy, PV+ and PV- were 86.5, 85.5, 85.9, 83.0, and 88.5%, respectively. Through comparison by Pearson Chi-square, the combined detection of AFU and TCH produced better diagnostic accuracy (85.9%) compared with the individual detection (P < 0.05). The combined detection of AFU and TCH produced better diagnostic accuracy in comparison with their individual detection, which is helpful to differential diagnosis between malignant and non-tuberculous benign ascites that may be relatively ideal markers to fit for clinical application in local hospitals.