Development of a Chemiluminescence Assay for Total N-Terminal Propeptide of Type I Collagen and Its Evaluation in Lung Transplantation

Serum P1NP, one of the important biomarkers for bone turnover, is commonly used for the prediction of bone fracture and the prognosis of osteoporosis after therapy. We developed a P1NP chemiluminescence assay and evaluated changes in bone metabolism markers in lung transplant patients. The screened 2 P1NP antibodies with constructed antigens and α-1 chain antigens expressed by the Corynebacterium glutamate expression system were applied into assay development. The assay performance was evaluated to examine the reliability. A normal Q-Q plot was used to establish male reference interval. Changes of bone metabolism markers before and after lung transplantation in 19 patients were evaluated. The linear factor R of P1NP reagent was greater than 0.99. The limit of detection was 3.32 ng/ml. The precision of the three batches of P1NP reagents was lower than 8%. Method comparison with Roche P1NP reagent showed that the correlation coefficient R2 was 0.91. In the monitoring of bone mass in a short time, bone metabolism markers can better indicate the change of bone mass, while the traditional bone mineral density detection is lagging behind the bone metabolism markers. P1NP and β-CrossLap to bone mass change in patients after lung transplantation, and P1NP and β-CrossLap are very good clinical markers for bone mass monitoring.

A Simple and Rapid Light-Initiated Chemiluminescence Assay for Quantitation of Artemisia-Specific Immunoglobulin E

<b><i>Background:</i></b> Light-initiated chemiluminescence assay (LICA) is a homogeneous assay that has been successfully used for the quantitation of food allergen-specific immunoglobulin E (sIgE), but not inhaled allergen-sIgE. Simultaneously, current assays used to detect allergen-sIgE are serum consuming and/or time consuming. Hence, we established a method for the quantitation of <i>Artemisia</i>-sIgE based on LICA and verified its performance according to the clinical guideline documents, laying a foundation for the quantitation of inhaled and food allergen-sIgE in parallel on LICA. <b><i>Methods:</i></b> The assay was established after optimizing the first incubation time and the dilutions of <i>Artemisia</i>-coated chemibeads, biotinylated goat anti-human IgE, and serum. In order to quantitate <i>Artemisia</i>-sIgE, the calibration curve was established with a high positive serum of known concentration. The assay performance was confirmed per the clinical guideline documents. In addition, the correlation between the results of LICA and capture enzyme-linked immunosorbent assay was evaluated. <b><i>Results:</i></b> The developed LICA’s coefficients of variation of repeatability and intermediate precision were 3.20%, 2.14%, and 3.85% and 4.30%, 4.00%, and 4.40%, respectively. The limit of detection was 0.10 kU_A/L, and the limit of quantitation was 0.11 kU_A/L. The range of linearity was from 0.27 kU_A/L to 97.53 kU_A/L (<i>r</i> = 0.9968). The correlation coefficient (<i>r</i>) for the correlation analysis between results of LICA and capture ELISA was 0.9087. This assay was successfully applied in 64 human serum samples, showing good sensitivity (82.20%) and specificity (100%). <b><i>Conclusion:</i></b> An <i>Artemisia</i>-sIgE quantitation assay based on LICA was successfully established. Its performance satisfied the clinical requirements and could be widely used in clinical laboratories.