Comparative analysis of different enzyme immunoassays for assessment of phosphatidylserine-dependent antiprothrombin antibodies

Phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) were strongly correlated with the presence of lupus anticoagulant showing a high specificity for the diagnosis of antiphospholipid syndrome. However, the main criticism for the clinical applicability of aPS/PT testing is the lack of reproducibility of the results among laboratories. In this study, we measured IgG and IgM aPS/PT using our original in-house enzyme-linked immunosorbent assays (ELISA) and commercial ELISA kits to assess the assay performance and to evaluate the accuracy of aPS/PT results. The study included 111 plasma samples collected from patients and stored at our laboratory for aPS/PT assessment. Sixty-one samples were tested for IgG aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite? aPS/PT IgG ELISA kit (INOVA Diagnostics, Inc., USA). Fifty samples were evaluated for IgM aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite? aPS/PT IgM ELISA kit (INOVA Diagnostics). Ninety-eight percent of samples yielded concordant results for IgG aPS/PT and 82 % for IgM aPS/PT. There was an excellent agreement between the IgG aPS/PT assays (Cohen κ = 0.962) and moderate agreement between the IgM aPS/PT assays (κ = 0.597). Statistically significant correlations in the aPS/PT results were obtained from both IgG and IgM aPS/PT assays (r = 0.749, r = 0.622, p < 0.001, respectively). In conclusion, IgG and IgM detection by ELISA is accurate. The performance of aPS/PT is reliable, and concordant results can be obtained using different ELISA methods.     

AFP, AFP-L3, DCP, and GP73 as markers for monitoring treatment response and recurrence and as surrogate markers of clinicopathological variables of HCC

Background

Alpha-fetoprotein (AFP), lens culinaris agglutinin-reactive fraction of AFP (AFP-L3), des-γ-carboxy prothrombin (DCP), and Golgi protein-73 (GP73) have been used or proposed as tumor markers for hepatocellular carcinoma (HCC).

Methods

They were measured in 96 patients undergoing hepatectomy for HCC to investigate their treatment response and association with variables linked with tumor invasiveness and/or prognosis. Values at 1 month post-surgery in the 77 patients without recurrence within 6 postoperative months were adopted as those after surgery.

Results

GP73 levels did not change after hepatectomy, but levels of other markers decreased and areas under receiver operating characteristic curves (95% CI) were: 0.64 (0.56–0.72), 0.63 (0.55–0.71), 0.79 (0.73–0.86), and 0.63 (0.55–0.71) for AFP, AFP-L3, DCP, and combination of AFP and AFP-L3, respectively. Cutoff points giving specificities of 96.1% (sensitivities at these points) were: 124 ng/mL (28.1%), 10% (21.9%), and 60 mAU/mL (52.1%), for AFP, AFP-L3, and DCP, respectively. The combination of AFP and AFP-L3 provided a sensitivity of 26.0% at a specificity of 96.1%. The increased DCP value was, or tended to be, associated with a larger tumor, vascular invasion, intrahepatic metastases, and a lower grade of tumor cell differentiation. Although similar associations were found between AFP and vascular invasion as well as a lower grade of tumor cell differentiation, no such relationship was found with AFP-L3.

Conclusions

DCP is a more effective tumor marker than AFP and AFP-L3. AFP-L3 showed comparable accuracy to AFP but no benefit was found in their combination. GP73 did not play a significant role in this context. Indices of tumor invasiveness were most closely associated with DCP.     

Frequency and Significance of Antibodies to Soluble Liver Antigen/Liver Pancreas in Variant Autoimmune Hepatitis

Background: Antibodies to soluble liver antigen/liver pancreas are highly specific markers of autoimmune hepatitis. Aims: Determine the frequency and clinical significance of these antibodies in the variant syndromes. Methods: Antibodies to soluble liver antigen/liver pancreas were determined in 28 patients with variant forms, including 10 with cryptogenic chronic hepatitis and 18 with cholestatic variants. One hundred and seventy-two patients with classical autoimmune hepatitis were similarly tested. Results: Seven of the 28 patients with variant forms had the antibodies, and this frequency was not statistically different than that in classical disease (25 vs. 12%, p = 0.08). Antibodies were most common in patients with cryptogenic chronic hepatitis (40%). Seropositive patients were indistinguishable from seronegative patients with variant forms, and they responded as well to corticosteroid therapy as patients with autoimmune hepatitis. Relapse after corticosteroid withdrawal invariably occurred in the seropositive patients whether with variant or classical disease, and HLA DR3 was more common in the seropositive patients with variant forms than in normal subjects (60 vs. 15%, p = 0.03). Conclusions: Antibodies to soluble liver antigen/liver pancreas occur commonly in the variant forms of autoimmune hepatitis and identify patients that closely resemble classical disease. Seropositivity is associated with relapse after corticosteroid withdrawal and HLA DR3. The antibodies may be surrogate markers of a genetic propensity to relapse that is independent of clinical phenotype.     

Cartilage oligomeric matrix protein: A novel non-invasive marker for assessing cirrhosis and risk of hepatocellular carcinoma

AIM: To assess serum cartilage oligomeric matrix protein(COMP) as a marker of cirrhosis and risk of progression to hepatocellular carcinoma(HCC). METHODS: A COMP enzyme-linked immunosorbentassay was used to test 187 patients with chronic liver diseases at the time point of first evaluation. The selected patients included 72 with chronic hepatitis B infection, 75 with chronic hepatitis C infection, 22 with primary biliary cirrhosis, 7 with autoimmune hepatitis type 1, and 11 with alcoholic liver disease. Demographic, biochemical, histological and clinical characteristics of the patients were recorded at the first evaluation. One hundred and forty-seven patients were followed for a median [interquartile range(IQR)] duration of 96.5(102) mo. The clinical, biochemical and histological data, as well as the development of cirrhosis, HCC according to internationally accepted criteria and in case of death, a liver-related cause during the follow-up period, were recorded at the electronic database of our clinic. COMP determination was also performed in 43 healthy individuals who served as the control study group.RESULTS: COMP positivity( 15 U/L) was detected in 22%-36% among chronic liver disease groups. Strikingly, almost 83% of COMP-positive patients were cirrhotic at baseline, independently of cause of liver disease. Among the patients who developed HCC during follow-up, 73.7%(14/19) were COMP positive at baseline. COMP positivity was significantly associated with older age(P 0.001), advanced fibrosis(P = 0.001) and necroinflammatory activity(P = 0.001), higher aspartate aminotransferase(P 0.001), alanine aminotransferase(P 0.02), γ-glutamyl transpeptidase(P = 0.003), alkaline phosphatase(P = 0.001), bilirubin(P 0.05), international normalized ratio(P = 0.002) and alpha-fetoprotein levels(P 0.02), and lower albumin(P 0.001), and platelet count(P = 0.008). COMP levels [median(IQR)] were significantly higher in cirrhotics compared to non-cirrhotics [13.8(7.9) U/L vs 9.8(4.6) U/L, respectively; P 0.001]. On multivariate logistic regression analysis, COMP-positivity was independently associated only with cirrhosis(OR = 4.40, 95%CI: 1.33-14.69, P = 0.015). Kaplan-Meier analysis showed that COMP positivity was significantly associated with HCC development(P = 0.007) and higher incidence of liver-related death(P 0.001). CONCLUSION: Elevated COMP levels are strongly associated with cirrhosis and HCC progression. Serum COMP is a new promising non-invasive biomarker for HCC risk assessment in surveillance programs.