Positive Rates Of Serum Research Articles

Diagnostic value and characteristic analysis of serum nucleocapsid antigen in COVID-19 patients.

To date, several types of laboratory tests for coronavirus disease 2019 (COVID-19) diagnosis have been developed. However, the clinical importance of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen (N-Ag) remains to be fully elucidated. In this study, we sought to investigate the value of serum SARS-CoV-2 N-Ag for COVID-19 diagnosis and to analyze N-Ag characteristics in COVID-19 individuals. Serum samples collected from 215 COVID-19 patients and 65 non-COVID-19 individuals were used to quantitatively detect N-Ag via chemiluminescent immunoassay according to the manufacturer's instructions. The sensitivity and specificity of the N-Ag assay were 64.75% (95% confidence interval (95% CI) [55.94-72.66%]) and 100% (95% CI [93.05-100.00%]), respectively, according to the cut-off value recommended by the manufacturer. The receiver operating characteristic (ROC) curve showed a sensitivity of 100.00% (95% CI [94.42-100.00%]) and a specificity of 71.31% (95% CI [62.73-78.59%]). The positive rates and levels of serum SARS-CoV-2 N-Ag were not related to sex, comorbidity status or disease severity of COVID-19 (all P < 0.001). Compared with RT‒PCR, there was a lower positive rate of serum N-Ag for acute COVID-19 patients (P < 0.001). The positive rate and levels of serum SARS-CoV-2 N-Ag in acute patients were significantly higher than those in convalescent patients (all P < 0.001). In addition, the positive rate of serum SARS-CoV-2 N-Ag in acute COVID-19 patients was higher than that of serum antibodies (IgM, IgG, IgA and neutralizing antibodies (Nab)) against SARS-CoV-2 (all P < 0.001). However, the positive rate of serum SARS-CoV-2 N-Ag in convalescent COVID-19 patients was significantly lower than that of antibodies (all P < 0.001). Serum N-Ag can be used as a biomarker for early COVID-19 diagnosis based on appropriate cut-off values. In addition, our study also demonstrated the relationship between serum N-Ag and clinical characteristics.

Antibodies against thyroid-stimulating hormone receptor cause maternal-neonatal transmission of Graves' Disease.

The present study aimed to investigate whether the thyroid-stimulating hormone receptor (TSHR) autoantibodies (Ab) from mothers with Graves' disease (GD) could cause neonatal thyroid disease and the underlying mechanisms of this. An adenovirus expressing the TSHR A-subunit and a control adenovirus expressing β-galactosidase was constructed by Beijing Sino Geno Max Co., Ltd. The sequences were subsequently verified and amplified via PCR. A GD model was established in female BALB/c mice (n=90) by three intramuscular injections of a TSHR-expressing adenovirus (Ad-TSHR). Mice injected with Ad-β-galactosidase served as a sham immunization group. The immunized females were paired with unimmunized males to generate offspring. The serum levels of TSHR-Ab and thyroxine (T4) of mothers and neonates were measured after delivery. Breast milk was collected from the stomachs of neonatal mice to determine the TSHR-Ab levels. The positive rate of serum TSHR-Ab (>0.3 IU/l) in the TSHR group was 99% (89/90) and 0% in the sham group. The mother mice in the TSHR group had elevated serum T4 levels and the thyroid pathological features of Graves' hyperthyroidism.GD mice gave birth to smaller newborns with thyroid pathological changes and higher serum levels of TSHR-Ab and T4, compared to the offspring in the sham group. The TSHR-Ab levels in breast milk from the GD mice declined with time. Mice immunized with Ad-TSHR exhibited the clinicopathological features of human GD and give birth to neonates with thyroid disease at birth.

Clinical Relevance of Autoantibodies against Interleukin-2 in Patients with Systemic Lupus Erythematosus.

Background:Increased serum autoantibodies against interleukin-2 (anti-IL-2 autoantibodies) were reported in patients with systemic lupus erythematosus (SLE) and in patients receiving IL-2 therapy. This study aimed to explore the clinical relevance of serum anti-IL-2 autoantibodies and the interactions between low-dose IL-2 therapy and serum anti-IL-2 autoantibodies.Methods:Serum samples were collected from 152 SLE patients and 100 age- and gender-matched healthy controls (HCs). Among them, 75 SLE patients were followed up for 10 weeks, and all of them were treated with corticosteroids, antimalarials, and/or immunosuppressants. Forty-six out of the 75 SLE patients received low-dose IL-2 therapy additionally. Clinical and laboratory parameters were collected at baseline and week 10. Serum anti-IL-2 autoantibodies were determined by enzyme-linked immunosorbent assay.Results:Compared with HCs, median levels and positive rates of serum anti-IL-2 autoantibodies were higher in SLE patients (32.58 [23.63, 45.23] arbitrary unit [AU] vs. 37.54 [27.88, 60.74] AU, P = 0.006, and 5.0% vs. 18.4%, P = 0.002, respectively). Compared to those without the corresponding disorders, serum anti-IL-2 autoantibody was increased in patients with alopecia (49.79 [36.06, 64.95] AU vs. 35.06 [25.40, 58.46] AU, P = 0.033), but it was decreased in those with lupus nephritis (31.71 [22.60, 43.25] AU vs. 44.15 [31.43, 68.52] AU, P = 0.001). Moreover, serum anti-IL-2 autoantibody was positively correlated with serum IgA (r = 0.229, P = 0.005), total IgG (r = 0.327, P < 0.001), and total IgM (r = 0.164, P = 0.050). Treatment with exogenous IL-2 was not significantly associated with serum anti-IL-2 autoantibody. In addition, no significant difference was found in serum anti-IL-2 autoantibody between responders and nonresponders to low-dose IL-2 therapy.Conclusions:Serum anti-IL-2 autoantibody was increased and associated with disease severity in SLE. Exogenous low-dose IL-2 did not significantly induce anti-IL-2 autoantibody production.

Correlation between Helicobacter pylori infection and primary infertility

Objective To investigate whether Helicobacter pylori (H.pylori) infection correlated with primary infertility, whether H. pylori infection caused the abnormal elevation of pro-inflammatory cytokines in primary infertility women, and whether cytotoxin associated gene A (CagA) protein played a key role in it. Methods From September 2015 to August 2016, 213 patients with primary infertility (infertility group) and 97 healthy individuals (control group) were selected. According to the common etiologies, patients with primary infertility were divided into groups with single-factor infertility, multifactorial infertility and unexplained reason groups. Serum H. pylori IgG antibody and CagA antibody were examined by H. pylori antibody type test kits. The levels of interleukin (IL)-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13, IL-18, IL-1β, granulocyte-macrophage-colony stimulating factor (GM-CSF), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and IL-12p70 were tested by ProcartaPlex Immunoassays. Chi square test and independent sample t test were performed for statistical analysis and risk was assessed. Results The positive rate of serum H. pylori IgG antibody of patients with primary infertility was higher than that of healthy control group (74.0%, 37/50 vs 56.7%, 55/97), and the difference was statistically significant (odds ratio (OR)=2.173, 95% confidence interval (CI) 1.028 to 4.595, χ2=4.216, P=0.040). There was no statistically significant difference in the positive rate of CagA antibody between primary infertility group and healthy control group (71.7%, 91/127 vs 74.5%, 41/55, OR=0.863, 95%CI 0.421 to 1.772, P>0.05). The serum levels of IL-8, IL-18 and IFN-γ of H. pylori positive primary infertility patients were (35.14±12.16), (11.83±4.01) and (11.05±3.17) ng/L, respectively, which were all higher than those of H. pylori positive healthy control group ((21.44±12.35), (9.89±2.23) and (8.90±1.45) ng/L, respectively) and H. pylori negative primary infertility group ((11.45±8.63), (7.90±0.99) and (8.18±1.10) ng/L, respectively), and the differences were statistically significant (t=6.947, 3.366 and 4.811; 15.596, 8.900 and 8.068; all P<0.05). The levels of IL-8, IL-18 and IFN-γ of H. pylori positive unexplained reason primary infertility group were (39.97±11.52), (13.12±4.61) and (13.06±3.70) ng/L, respectively, which were all significantly higher than those of single-factor infertility group ((31.65±11.20), (11.12±3.46) and (10.14±2.41) ng/L, respectively) and multifactorial infertility group ((30.47±8.49), (11.13±3.79) and (10.07±2.50) ng/L, respectively); and the differences were statistically significant (t=4.217, 2.942 and 5.738; 5.138, 2.562 and 5.218; all P<0.05). In H. pylori positive primary infertility group, the levels of IL-8, IL-18 and IFN-γ of CagA positive patients were (40.42±13.80), (13.04±4.19) and (11.51±3.41) ng/L, respectively, which were all significantly higher than those of CagA negative patients ((23.49±11.57), (9.08±1.43) and (10.04±2.29) ng/L, respectively) and CagA positive individuals in healthy control group ((21.85±12.14), (10.20±2.29) and (9.31±2.38) ng/L, respectively); and the differences were statistically significant (t=6.507, 5.533 and 2.380; 7.417, 4.069 and 3.738; all P<0.05). Conclusion CagA positive H. pylori infection can increase the level of serum pro-inflammatory cytokines, which may be a risk factor of primary infertility. To patients with unexplained primary infertility, this may be the cause of infertility. Key words: Helicobacter pylori; Primary infertility; CagA; Cytokines

The value of assay of (1, 3)-β-D-glucan in bronchoalveolar lavage fluid for detection of invasive pulmonary fungal infection in critically ill patients in intensive care unit

To evaluate the value of (1, 3)-β-D-glucan (G test) in bronchoalveolar lavage fluid (BALF) in diagnosing and determining the therapeutic effects among the critically ill patients suspected with invasive pulmonary fungal infection (IPFI). Study was conducted between February 2010 and August 2011 in medical intensive care unit (MICU) of the Affiliated Hospital of Guiyang Medical College. Patients suspected of suffering from IPFI were enrolled. G tests of BALF and serum, and culture and microscopic examination of BALF were performed twice weekly.Clinical feature, mycological evidence and the results of G test were recorded. The results of IPFI were defined as "proven", "probable", "possible" and "non-IPFI". G test in BALF and serum was done with tachypleus amebocyte lysate. Positive G test was defined as cut-off index ≥20 ng/L in two consecutive measurements. Furthermore, the patients with positive G test received preemptive antifungal therapy with fluconazole or itraconazole. G tests of BALF and serum were respectively done on 7th day and 14th day of treatment. Ninety-eight patients were included. Among them, 10 patients were "proven" in whom the positive rate of BALF G test was 90.0%; 29 patients the results were considered as "probable" in whom the positive rate of BALF G test was 82.8%; in 32 patients the results were "possible" IPFI in whom the positive rate of BALF G test was 71.9%, 27 patients were "non-IPFI" in whom the positive rate of BALF G test was 7.4%. The positive rate of BALF G test was 84.6% (33/39), the positive rate of serum G test was 59.0% (23/39), the positive rate of culture of BALF was 41.0% (16/39), the positive rate of microscopic examination of BALF was 38.5% (15/39) in "proven" cases and "probable" cases. G test (cut-off ≥20 ng/L) of BALF had shown to have sensitivity, specificity, positive predictive value (PPV) of 84.6% (33/39), 92.6% (25/27), 94.3% (33/35), respectively, and negative predictive value (NPV) of 80.7% (25/31). The G test detection (cut-off ≥20 ng/L) in serum had shown to have sensitivity, specificity, PPV of 58.9% (23/39), 88.9% (24/27), 88.5%(23/26), respectively, and NPV of 60.0% (24/40), and the differences in sensitivity were statistically significant (P < 0.05). BALF G test assay tended to become positive earlier than the culture for 2-8 days with mean of (5.35 ± 2.26) days.Forty out of 56 G test positive patients were given preemptive antifungal therapy for 2 weeks, and there was a good response in 31 patients, but no response in 9 cases with 22.5% mortality. After treatment, the result of G test (ng/L) was lowered in patients with a good response in treatment group (BALF: 245.13 ± 43.84, 174.00 ± 13.01, 28.52 ± 7.38; serum: 93.26 ± 18.75, 72.15 ± 12.90, 37.37 ± 10.45, all P < 0.05). On the other hand, an elevated value suggested an unsatisfactory result in ineffective group (BALF: 267.58 ± 54.63, 309.71 ± 82.47, 486.72 ± 98.21; serum: 101.58 ± 12.75, 98.07 ± 27.45, 112.07 ± 19.21, all P < 0.05). There were significantly differences in the results of G tests on 7th day and 14th day between BALF G test and serum G test in both groups (all P < 0.05). It is suggested that BALF G test may be an useful test for early diagnosis of IPFI. Moreover, the dynamic change in G test values could be useful for assessing therapeutic response.