Association of serum amyloid A and prognosis in people with diabetes and COVID-19: A retrospective cohort study.

AIMS/INTRODUCTION: Serum amyloid A (SAA) is an acute phase reactive protein that plays a vital role in the early diagnosis, risk prediction, efficacy observation and prognosis evaluation of infectious diseases. This study aimed to assess the association between SAA levels and the prognosis of patients with coronavirus disease 2019 (COVID-19) and diabetes. MATERIALS AND METHODS: We carried out this retrospective cohort study from March 2022 to May 2022. The population was stratified by tertiles of SAA levels: low (<8.5 mg/L), medium (8.5-36 mg/L) and high (>36 mg/L). The primary outcome was whether the patient developed severe COVID-19, and secondary outcomes included the need for invasive mechanical ventilation and length of hospital stay. Logistic regression analyses were carried out to identify risk factors affecting the prognosis of patients with COVID-19 and diabetes. RESULTS: We analyzed 910 diabetes patients with COVID-19. The median age of the patients was 69 years, and 52.3% were men. As SAA levels increased, the proportion of severe COVID-19 (6.3% vs 7.3% vs 22.8%, P < 0.001) and the proportion of invasive mechanical ventilation also increased among the three groups. Patients with high SAA levels had a longer length of hospital stay compared with patients with medium SAA and low SAA levels. Univariate logistic regression analysis showed that SAA >36 mg/L further increased the odds ratio to 4.423 (P < 0.001) for the development of severe COVID-19 compared with low SAA. Multivariate logistic regression analysis, adjusted for age and sex, confirmed that SAA >36 mg/L remained an independent risk factor for the development of severe COVID-19 (adjusted odds ratio 3.038, P < 0.001). CONCLUSIONS: SAA levels are strongly associated with poor prognosis in patients with COVID-19 and diabetes.

Serum alpha 1-acid glycoprotein and interleukin-8 elevations in felines with localized and metastatic tumors.

OBJECTIVE: This study aimed to investigate the expression of acute phase proteins and plasma cytokines in cats with various tumor types and varying metastatic statuses. ANIMALS: 5 clinically healthy cats and 22 cats with neoplastic disease that underwent CT imaging before treatment were enrolled. Patients were grouped based on their tumor types and metastatic status. METHODS: Blood samples were collected from all cats for general blood analyses before they underwent CT imaging. The remaining plasma sample was frozen for subsequent alpha 1-acid glycoprotein (AGP), serum amyloid A (SAA), and feline cytokine panel measurements. These results were compared with those of healthy cats as well as between metastatic status and tumor types. RESULTS: Only 4 cats (18%) exhibited elevated SAA levels, whereas 16 (73%) showed elevated AGP levels. AGP was significantly increased in cats with tumors (P = .016), while SAA was not. Only IL-8 showed a significant difference (P = .002) between cats with primary tumors and those with radiologically suspected tumor metastasis. CLINICAL RELEVANCE: While AGP is a more prominent biomarker than SAA in cats with tumors, a significant elevation of AGP and SAA levels in association with metastasis and specific tumor types could not be identified. Alternatively, further investigation is warranted to evaluate the potential significance of IL-8 in tumor progression and metastasis.

Clinical diagnostic value of IL-14, 1L-16 and SAA in periodontitis.

OBJECTIVES: Periodontitis is a chronic infectious disease, which leads to inflammatory destruction of periodontal supporting tissues. Interleukin 14 (IL-14), Interleukin 16 (IL-16) and serum amyloid A (SAA) have been demonstrated to be abnormally expressed in inflammatory diseases. Therefore, this study was performed to analyzed the expression and potential clinical values of IL-14, 1L-16 and SAA in periodontitis. MATERIALS AND METHODS: A total of 100 periodontitis patients and 100 healthy volunteers were recruited and the saliva and serum samples were collected. Then the C-reactive protein (CRP), procalcitonin (PCT), IL-14, 1L-16 and SAA levels in the saliva and serum of periodontitis patients were measured by Elisa kits. Besides, the significance of CRP, PCT, IL-14, 1L-16 and SAA in periodontitis patients were analyzed by receiver operating characteristic (ROC) analysis. RESULTS: The results showed that CRP, PCT, IL-14, 1L-16 and SAA levels were significantly increased in the the saliva and serum of the periodontitis patients. Additionally, the area under the curve (AUC) of saliva CRP, PCT, IL-14, 1L-16 and SAA for the diagnosis of periodontitis were 0.9035, 0.9435, 0.9508, 0.9500 and 0.9467, respectively. The AUC of serum CRP, PCT, IL-14, 1L-16 and SAA for the diagnosis of periodontitis were 0.9035, 0.9435, 0.9508, 0.9500 and 0.9467, respectively. What's more, the diagnostic value of IL-14, 1L-16 and SAA were enhanced when combining with CRP and PCT. CONCLUSION AND CLINICAL RELEVANCE: This study demonstrated that IL-14, IL-16 and SAA expressions were upregulated in periodontitis patients and exhibited a significant significance for periodontitis diagnosis.

Effect of Bariatric Surgery on Serum Amyloid A Protein: a Systematic Review and Meta-analysis.

BACKGROUND: Obesity is a chronic inflammatory condition and this meta-analysis evaluated the impact of bariatric surgery on SAA. METHODS: Studies included all types of bariatric surgery where SAA was measured before and after the surgical procedure. RESULTS: Meta-analysis of 11 clinical studies (n = 394 individuals) confirmed a significant reduction in SAA following bariatric surgery (SMD: - 0.971, 95% CI: - 2.721, 0.779, p < 0.001). Meta-regression did not show any association between the changes in BMI and the absolute difference in SAA levels. No relationship between the changes in SAA and the length of follow-up was found. CONCLUSION: Bariatric surgery significantly improved SAA. The decrease in SAA was not related to time after surgery or changes in BMI. Bariatric surgery may thus have an independent effect on SAA.

Association between Serum Amyloid A Levels and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.

BACKGRUOUND: To date, consistent data have not been reported on the association between serum amyloid A (SAA) levels and type 2 diabetes mellitus (T2DM). The purpose of this study was to systematically summarize their relationship. METHODS: Databases including PubMed, Cochrane Library, Embase, Web of Science, and MEDLINE were searched until August 2021. Cross-sectional and case-control studies were included. RESULTS: Twenty-one studies with 1,780 cases and 2,070 controls were identified. SAA levels were significantly higher in T2DM patients than in healthy groups (standardized mean difference [SMD], 0.68; 95% confidence interval [CI], 0.39 to 0.98). A subgroup analysis showed that the mean age of participants and the continent that participants were from were related to differences in SAA levels between cases and controls. Furthermore, in T2DM patients, SAA levels were positively associated with body mass index (r=0.34; 95% CI, 0.03 to 0.66), triglycerides (r=0.12; 95% CI, 0.01 to 0.24), fasting plasma glucose (r=0.26; 95% CI, 0.07 to 0.45), hemoglobin A1c (r=0.24; 95% CI, 0.16 to 0.33), homeostasis model assessment for insulin resistance (r=0.22; 95% CI, 0.10 to 0.34), C-reactive protein (r=0.77; 95% CI, 0.62 to 0.91), and interleukin-6 (r=0.42; 95% CI, 0.31 to 0.54), but negatively linked with highdensity lipoprotein cholesterol (r=-0.23; 95% CI, -0.44 to -0.03). CONCLUSION: The meta-analysis suggests that high SAA levels may be associated with the presence of T2DM, as well as lipid metabolism homeostasis and the inflammatory response.

Acute Phase Protein Response in Native and Imported Horses After Routine Combination Vaccination Protocol.

Fibrinogen and serum amyloid A (SAA) are commonly measured equine acute phase proteins. Limited data exist on SAA and fibrinogen responses to combination vaccination protocols in horses. A prospective cohort study evaluating SAA, fibrinogen, and rectal temperature following a standard combination vaccination. Blood for measurement of SAA and serum fibrinogen and rectal temperatures were obtained before (0 hour) and after vaccination (24, 48, 72, 96, 168 hours). After vaccination, SAA and fibrinogen increased in all horses. Imports had elevated SAA from 24-168 hours, whereas native horses returned to baseline by 168 hours. Compared to native horses, SAA was significantly higher in imports (coefficient 24-168 hours 358, 95%CI: 46-671 mg/L; P = .03). Fibrinogen increased significantly from 24 to 168 hours postvaccination, but groups did not differ (coefficient -16; 95%CI: -69 to 37 mg/dL; P = .5). Absolute rectal temperatures were significantly higher in imports throughout, including 0 hour (median 37.8; IQR 37.7-38.0 vs. 37.3; 37.1-37.3; P = .002). At 24 hours postvaccination when temperatures significantly increased above baseline in both groups, there was a small but significant difference in the percent change relative to baseline (coefficient 1.9; 95%CI 0.8%-2.9%; P = .002). A standard combination vaccination protocol elicited an acute phase response in all horses. Compared to native previously vaccinated horses, imports had a stronger SAA response. The observed response is worthy of consideration when examining recently vaccinated imported horses.

Effect of plasma transfusion on serum amyloid A concentration in healthy neonatal foals and foals with failure of transfer of passive immunity.

BACKGROUND: Anecdotal evidence suggests plasma transfusions increase serum amyloid A (SAA) concentrations in healthy neonatal foals making this marker of inflammation inappropriate for therapeutic decision making in such animals. HYPOTHESIS/OBJECTIVES: Administration of hyperimmune fresh frozen plasma (FFP) increases SAA concentration in healthy foals and in foals with failure of transfer of passive immunity (FTPI). ANIMALS: Eighty-six healthy foals. METHODS: Prospective cohort study. Foals <24 hours of age receiving plasma transfusion for treatment of FTPI (serum immunoglobulin G [IgG] concentrations <8 g/L; n = 17) or as a preventative measure for Rhodococcus equi infection (IgG >8 g/L; n = 33) were enrolled. A healthy nontransfused group of foals (IgG >8 g/L; n = 21) also was included. Serum amyloid A concentration was determined before (t0h) and after (t24h) administration of FFP. Changes in blood SAA concentration were assessed using linear regression models. RESULTS: No statistical differences were found in SAA concentration at t0h or t24h among the 3 groups (P > .05, for all comparisons). The variation in SAA concentration before (t0h) and after (t24h) plasma transfusion showed that administration of FFP was not associated with the changes in SAA concentration (P > .05). An association between SAA concentration at t0h and at 24 hours (P < .05) was identified, where foals with higher SAA concentration at t0h also had higher SAA concentration at t24h. CONCLUSIONS AND CLINICAL IMPORTANCE: Administration of FFP to newborn foals was not associated with changes in SAA concentration.

Serum Amyloid A in Stable Patients with Chronic Obstructive Pulmonary Disease Does Not Reflect the Clinical Course of the Disease.

Serum amyloid A (SAA) is a good systemic marker of the exacerbations of chronic obstructive pulmonary disease (COPD), but the significance of SAA in stable patients with COPD has not been widely investigated. We aimed to evaluate the SAA level in peripheral blood from stable patients with COPD and to search for correlations between SAA and other inflammatory markers and clinical characteristics of the disease. Serum SAA, IL-6, IL-8, TNF-alpha, basic blood investigations, pulmonary function testing and a 6-min walk test were performed. The correlations between SAA and other inflammatory markers, functional performance and the number of disease exacerbations were evaluated. A total of 100 consecutive patients with COPD were analyzed. No correlations between SAA and inflammatory markers as well as pulmonary function were found. Hierarchical clustering identified two clusters incorporating SAA: one comprised SAA, PaO2 and FEV1 and the second was formed of SAA and nine other disease markers. The SAA level was higher in patients with blood eosinophils < 2% when compared to those with blood eosinophils ≥ 2% (41.8 (19.5-69.7) ng/mL vs. 18.9 (1.0-54.5) ng/mL, respectively, p = 0.04). We conclude that, in combination with other important disease features, SAA may be useful for patient evaluation in stable COPD.

Detection and Typing of Renal Amyloidosis by Fluorescence Spectroscopy Using the Environmentally Sensitive Fluorophore K114.

PURPOSE: To demonstrate that spectral analysis using the K114 fluorophore can detect and differentiate AL and AA renal amyloidosis. PROCEDURES: Kidney biopsies from patients with AL amyloidosis, AA amyloidosis, and normal samples with no evident pathology were stained with Congo Red and K114. The specimens were imaged on a spectral confocal microscope. RESULTS: Congo Red displayed homogeneous spectra across the three tissue types while K114 chromatically distinguished between normal tissue, AL amyloid, and AA amyloid. Additionally, Congo Red displayed an increased risk of false positive staining compared to K114. Spectral phasors computed from K114-stained tissue sections quantitatively differentiated the three tissue types. K114-stained amyloid deposits displayed a significantly greater increase in brightness after 50 images acquired in rapid succession compared to normal tissue. Quantitative analysis of intensity changes in the background of diseased tissue also differentiated AL and AA amyloid samples, suggesting widespread amyloid deposition. Both amyloid and the backgrounds of diseased samples red-shifted while normal tissue blue-shifted in response to repeated imaging, supporting this theory. CONCLUSIONS: K114 staining of renal biopsies is a promising technique to detect and differentiate types of renal amyloidosis. Due to the advantages this method has over traditional Congo Red staining, the techniques presented here warrant further development for potential use in clinical settings.

Markers of inflammation in free-living African elephants (Loxodonta africana): Reference intervals and diagnostic performance of acute phase reactants.

INTRODUCTION: Acute phase reactants (APRs) have not been investigated in free-living African elephants (Loxodonta africana), and there is little information about negative APRs albumin and serum iron in elephants. OBJECTIVES: We aimed to generate reference intervals (RIs) for APRs for free-living African elephants, and to determine the diagnostic performance of APRs in apparently healthy elephants and elephants with inflammatory lesions. METHODS: Stored serum samples from 49 apparently healthy and 16 injured free-living elephants were used. The following APRs and methods were included: albumin, bromocresol green; haptoglobin, colorimetric assay; serum amyloid A (SAA), multispecies immunoturbidometric assay, and serum iron with ferrozine method. Reference intervals were generated using the nonparametric method. Indices of diagnostic accuracy were determined by receiver-operator characteristic (ROC) curve analysis. RESULTS: Reference intervals were: albumin 41-55 g/L, haptoglobin 0.16-3.51 g/L, SAA < 10 mg/L, and serum iron 8.60-16.99 µmol/L. Serum iron and albumin concentrations were lower and haptoglobin and SAA concentrations were higher in the injured group. Serum iron had the best ability to predict health or inflammation, followed by haptoglobin, SAA, and albumin, with the area under the ROC curve ranging from 0.88-0.93. CONCLUSIONS: SAA concentrations were lower in healthy African vs Asian elephants, and species-specific RIs should be used. Serum iron was determined to be a diagnostically useful negative APR which should be added to APR panels for elephants.

WISER Survivor Trial: Combined Effect of Exercise and Weight Loss Interventions on Inflammation in Breast Cancer Survivors.

PURPOSE: Physical inactivity and obesity increase risk for breast cancer recurrence and cardiovascular death; inflammation is hypothesized to mediate these associations. METHODS: In a four-arm randomized controlled trial, 318 breast cancer survivors with overweight or obesity were randomized to exercise alone, weight loss alone, exercise plus weight loss, or control for 12 months. Inflammation outcomes included C-reactive protein (CRP), serum amyloid A (SAA), intracellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). RESULTS: Compared with control, exercise alone increased ICAM-1 (9.3%; 95% confidence interval [CI] = 1.6-16.9) and VCAM-1 (8.6%; 95% CI = 2.6-14.5) but did not change CRP or SAA. Compared with control, weight loss alone reduced CRP (-35.2%; 95% CI = -49.9 to -20.7), and SAA (-25.6%; 95% CI = -39.8 to -11.9) but did not change ICAM-1 or VCAM-1. Compared with control, exercise plus weight loss reduced CRP (-44.1%; 95% CI = -57.1 to -31.1) and SAA (-26.6%; 95% CI = -40.5 to -12.6) but did not change ICAM-1 or VCAM-1. Among 194 participants with elevated CRP at baseline (e.g., >3 mg·L -1 ), compared with control, weight loss alone (0.17; 95% CI = 0.04-0.30) and exercise plus weight loss (0.31; 95% CI = 0.16-0.46) increased the probability of achieving normal CRP at month 12. In analyses that consolidated randomized groups, body weight and adiposity reductions, but not change in fitness level, correlated with decreased CRP, SAA, and ICAM-1 levels. CONCLUSIONS: In breast cancer survivors with overweight or obesity, weight loss or exercise plus weight loss reduced measures of inflammation that are associated with breast cancer recurrence and cardiovascular death.

Values of combined C-reactive protein, procalcitonin and serum amyloid A in differential diagnosis of bacterial and non-bacterial community acquired pneumonia in children.

This research aimed to explore the clinical value of C-reactive protein (CRP), procalcitonin (PCT), and serum amyloid A (SAA) in early diagnosis of bacterial pneumonia. CRP, PCT, and SAA levels of children with bacterial pneumonia, children with non-bacterial pneumonia, and healthy children were compared. The sensitivity and specificity of CRP, PCT, and SAA in the diagnosis of bacterial pneumonia in children were compared. CRP, PCT, and SAA levels were significantly lower in healthy children when compared with children with Community acquired pneumonia (CAP). ROC analyses showed that CRP, PCT, and SAA all had good accuracy in distinguishing bacterial pneumonia from non-bacterial pneumonia. The combination of CRP, PCT, and SAA further enhanced the accuracy in distinguishing bacterial pneumonia from non-bacterial pneumonia. In conclusion, the expression levels of CRP, PCT, and SAA could indicate the status of bacterial pneumonia. The combined test of CRP, PCT, and SAA had the highest diagnostic accuracy.

Evaluation of serum concentration of acute-phase proteins (haptoglobin and serum amyloid A) in the affected Arabian foals with rhodococcosis.

BACKGROUND: Early detection of Rhodococcus equi pneumonia in foals is essential for horse health and for veterinarians. OBJECTIVES: This study aimed to demonstrate the usefulness of assessing the serum concentration of acute-phase proteins (APPs) in the early diagnosis of pneumonia. METHODS: The study evaluated APPs in 19 Arabian foals with R. equi pneumonia and compared them with 18 normal Arabian foals in equestrian clubs in Tabriz, Iran. Affected foals were identified through history, clinical findings and bacterial culture of tracheal washing. Biochemical methods and polymerase chain reaction tests were performed by examining the 16S rRNA and vapA genes to confirm the diagnosis of bacterial isolates. Blood samples were taken from all sick and healthy horses, and their serum was isolated. APPs in the serum were measured in all the samples. RESULTS: Rhodococcosis increased the serum concentration of haptoglobin (Hp) and serum amyloid A (SAA) (p < 0.001). The relationship between SAA and Hp was meaningful in the infected group (r = 0.933) but not in the healthy group. In cases where there are clinical findings of R. equi pneumonia, the concentration of SAA and Hp can help the effectiveness of treatment. - CONCLUSIONS: Serum concentration analysis of APPs can be helpful in early diagnosis and successfully treating foals with R. equi pneumonia.

Comparison of the ELISA method with the nephelometric method for determination of serum amyloid A in patients with COVID 19.

This study aimed to examine the agreement of the serum amyloid A (SAA) values determined using the ELISA test and the nephelometric automated method. This study included 80 serum samples obtained from patients with COVID-19. Samples were determined using ELISA and the nephelometric method. Wilcoxon signed ranks test showed a statistically significant difference in the calculated median values (Z = -2.432, p = 0.015). The correlation between methods was statistically significant (r = 0.603, p < 0.0001). Bland Altman analysis showed a bias of 56.6 mg/L and a relative bias of 7.4% between the methods. The results of this study indicate that further studies are needed that will examine the compliance between the ELISA and the nephelometric method for determining SAA, and the results must be carefully interpreted based on the method used.

Use of serum amyloid A in equine medicine and surgery.

Serum amyloid A (SAA) has become an indispensable part of the management of equine patients in general practice and specialized hospital settings. Although several proteins possess acute phase properties in horses, the usefulness of SAA exceeds that of other acute phase proteins. This is due to the highly desirable kinetics of the equine SAA response. SAA concentrations exhibit a rapid and pronounced increase in response to inflammation and a rapid decline after the resolution of inflammation. This facilitates the detection of inflammatory disease and real-time monitoring of inflammatory activity. SAA may be used in all stages of patient management: (1) before diagnosis (to rule in/rule out inflammatory disease), (2) at the time of diagnosis (to assess the severity of inflammation and assist in prognostication), and (3) after diagnosis (to monitor changes in inflammatory activity in response to therapy, with relapse of disease, or with infectious/inflammatory complications). By assessing other acute phase reactants in addition to SAA, clinicians can succinctly stage inflammation. White blood cell counts and serum iron concentration change within hours of an inflammatory insult, SAA within a day, and fibrinogen within 2-3 days; the interrelationship of these markers thus indicates the duration and activity of the inflammatory condition. Much research on the equine SAA response and clinical use has been conducted in the last decade. This is the prerequisite for the evidence-based use of this analyte. However, still today, most published studies involve a fairly low number of horses. To obtain solid evidence for use of SAA, future studies should be designed with larger sample sizes.

[Association study of serum LncRNA MALAT1 and SAA with type 2 diabetic kidney disease].

To investigate the correlation of serum long noncoding RNA-metastasis associated lung adenocarcinoma transcript 1(LncRNA MALAT1) and serum amyloid A(SAA) with diabetic kidney disease. Retrospective research was used, and 40 patients with type 2 diabetes and 80 patients with type 2 diabetic kidney disease patients who were treated in Tianjin Medical University Chu Hsien-I Memorial Hospital from August 2021 to February 2022 were selected, and 40 healthy subjects were selected during the same period. Reverse transcription-polymerase chain reaction(RT-PCR) was used to detect serum LncRNA MALAT1. SAA were detected with enzyme linked immunosorbent assay (ELISA). Automatic biochemistry analyzer was used to detect serum creatinine (CREA) and low-density lipoprotein cholesterol(LDL-C),automatic blood glucose analyzer to detect serum fasting plasma glucose (FPG), automatic glycated hemoglobin analyzer to detect hemoglobin A1C (HbA1c), and automatic immunoassay analyzer to detect urinary albumin to creatinine ratio(UACR). Differences between groups were compared by t test and analysis of variance. Pearson analysis was used to analyze the correlation between MALAT1, SAA and other indicators. Receiver operating characteristic curve(ROC) was used to evaluate the auxiliary diagnostic value of MALAT1 and SAA for diabetic kidney disease. The results showed that MALAT1 and SAA in the diabetic kidney disease with mass albuminuria group were higher than those in the type 2 diabetes mellitus group (q=8.57, P<0.01; q=11.09, P<0.01) and the diabetic kidney disease with microalbuminuria group (q=3.96, P<0.05; q=7.85, P<0.01). MALAT1 had a high correlation with UACR, CREA, SAA, HbA1c and FPG (r value was 0.706, 0.643, 0.578, 0.553, and 0.524, all P<0.01), and SAA had a high correlation with UACR, HbA1c and FPG (r value was 0.664, 0.617, and 0.595, all P<0.01). ROC curve analysis of the diagnostic value of LncRNA MALAT1 and protein SAA for diabetic kidney disease showed that the areas under curve (AUC) were 0.741 and 0.744, respectively. The combined diagnostic value of the two was the greatest (AUC=0.801). In summary, MALAT1 and SAA were elevated in the serum of patients with type 2 diabetes. Their concentrations in the serum of group with diabetic kidney disease were higher than that in the type 2 diabetes group, and the serum concentrations of MALAT1 and SAA in group with mass albuminuria are higher than the group with microalbuminuria. MALAT1 and SAA were both closely related to UACR and HbA1c, and there is a correlation between them. Both of them may have ancillary diagnostic value for diabetic kidney disease.

The relation between C-reactive protein and serum amyloid A in patients with autoinflammatory diseases.

BACKGROUND: Autoinflammatory diseases are rare disorders of the innate immune system characterized by fever and other signs of inflammation. A feared complication of autoinflammatory diseases is the development of AA amyloidosis. AA amyloidosis is caused by extracellular deposition of soluble serum amyloid A (SAA) proteins as insoluble amyloid fibrils leading to organ damage. Prolonged high levels of SAA are a prerequisite to develop AA amyloidosis. Since measurement of SAA is relatively expensive and sometimes unavailable, C-reactive protein (CRP) is often used as a surrogacy marker to test for inflammation. OBJECTIVE: The aim of this research is to evaluate the possible relation between CRP and SAA. METHODS: A retrospective cohort of patients with autoinflammatory diseases (n = 99) where SAA and CRP blood testing was performed in the period between 2015 and 2021 in the University Medical Centre in Groningen was used to investigate the correlation between CRP and SAA. RESULTS: CRP and SAA have a high correlation (rho = 0.755, p < 0.001). A CRP value below 0.45 mg/L results in 100% sensitivity for SAA below 4 mg/L. CRP below 5 mg/L is a good predictor of SAA below 4 mg/L with 85.4% sensitivity and 83.6% specificity. Only prednisone and erythrocyte sedimentation rate (ESR) significantly influence the relation between CRP and log10SAA. CONCLUSION: There was a significant correlation between CRP and SAA in our retrospective cohort. CRP levels below 5 mg/L proved to be highly predictive of SAA levels below 4 mg/L. This may not be true for patients on steroids.

Serum amyloid A (SAA) and Interleukin-6 (IL-6) as the potential biomarkers for gastric cancer.

To explore serum amyloid A (SAA) and interleukin-6 (IL-6) as potential diagnostic biomarkers for gastric cancer (GCa) and the application value of the combined diagnosis of SAA, IL6, and Cancer embryonic antigen. Serum samples were collected before the initial surgery from 159 patients comprising samples from 122 patients with GCa and 37 patients with benign gastric disease. All patients were hospitalized at Beijing Aerospace General Hospital in China between 2018 and 2020. The IL-6 and SAA levels were assessed using standard laboratory protocols. The levels of SAA and IL-6 were significantly higher in patients with GCa than in controls. Compared with the healthy group, the concentration of SAA and IL-6 in FIGO III-IV group were significantly higher and the difference were statistically significant. In addition, significant differences were observed between the FIGO III-IV group and FIGO I-II groups. The Receiver operating characteristic (ROC) curve for the combined detection of SAA, IL-6, and Cancer embryonic antigen showed an area under the curve (AUC) of 0.948, sensitivity of 91.0%, and specificity of 89.2%. Spearman's correlation analysis indicated obvious correlations among the levels of serum SAA, IL-6, advanced FIGO stage, lymphatic invasion, and distant metastasis. AA and IL-6 may serve as useful biomarkers for poor prognosis of GCa. Clinical diagnosis combined with SAA and IL-6 may help assess therapeutic outcomes.

Validation of an automated immunoturbidimetric assay for feline serum amyloid A.

BACKGROUND: Serum Amyloid A (SAA) is a major acute phase protein in cats, increasing rapidly in response to various inflammatory diseases. An automated latex-enhanced immunoturbidimetric assay for human SAA (LZ-SAA, Eiken), previously validated for use in cats, has had further major modification (VET-SAA, Eiken) for specific use in veterinary diagnostic laboratories but has yet to be validated in cats. RESULTS: Intra-assay and inter-assay CVs for the VET-SAA assay ranged from 1.88-3.57% and 3.98-6.74%, respectively. Linearity under dilution was acceptable with no prozone effect observed. Limit of detection was 1.65 mg/L and limit of quantification was 6 mg/L. Haemoglobin and triglyceride showed no adverse interference, but bilirubin produced positive bias in samples with low SAA. Comparison with the LZ-SAA assay showed significant correlation with proportional bias increasing as SAA concentration increased, likely related to differing calibration standards. SAA was significantly higher in patients with inflammatory disease compared with non-inflammatory disease, and in patients with moderate to highly elevated α1-AGP compared with patients with normal α1-AGP. Improvement of the assay range may be required to fully evaluate differences between disease groups at low SAA levels. Based on ROC curve analysis, at a cut-off point of 20.1 mg/L the VET-SAA assay discriminated between inflammatory and non-inflammatory disease with sensitivity of 0.93 and specificity of 0.99. CONCLUSIONS: The automated VET-SAA assay is a robust, precise, and accurate method for measurement of feline SAA which can clearly identify patients with inflammatory disease. It should be a valuable biomarker for use in feline medicine.