Our aim was to compare different immobilized erythropoietin (EPO) preparations for their ability to detect anti-EPO IgG antibodies in blood sera of EPO-treated patients with ELISA technique. 294 serum samples of the patients treated with erythropoietin were analyzed. 127 serum samples of patients who did not receive recombinant human EPO (rhEPO) were studied for comparative analysis. ELISA assay was performed, and different rhEPO drugs were immobilized on the anti-EPO monoclonal antibody-coated plates. Horseradish peroxidase-conjugated mouse monoclonal antibodies to human IgG, IgG1, and IgG4 was used for detection. The following drugs were studied: recombinant human erythropoietin rhEPO-beta (Shandong Kexing Bioproducts), European standard of erythropoietin BRP 3, commercial drugs Aranesp (Amgen Europe B.V.), Mircera (F. Hoffmann-La Roche Ltd.), Eprex (Johnson & Johnson LLC), Eralfon (Pharmaceutical Company Sotex). The sensitivity of the method was expressed as a positivity index (IP). IP calculated as the ratio of OD from tested sera to OD at the cut-off levels. The latter was assumed as a mean OD±SD for serum samples from EPO-naive patients. The results were evaluated as positive with IP > 1.1, and negative at IP < 0.9. Results in the range of 0.9 ≤ IP < 1.1 were considered as unidentified. Among the 294 samples, 32 specimens were evaluated as positive or unidentified for total IgG anti-EPO antibodies. The unidentified samples were detected in 1.0-1.7% of all cases. IgG1 subclass antibodies were found in 50-56.3% of patients and IgG4 subclass antibodies, in 43.850% of the patients. Mann—Whitney test showed a significant difference between the test samples compared to control group for all the ELISA modifications (p = 0.001). The Kruskal—Wallis test did not show significant differences between the IP results obtained with any of five immobilized EPO drugs (p = 0.05). The correlation quotient of IP was in the range of 0.99-0.96 for total IgG and > 0.98 for two subclasses of antibodies. Linear regression coefficients were close to one, thus indicating absence of significant differences in the sensitivity of the compared methods. This study indicate the opportunity of using the similar test systems to determine anti-EPO antibodies in the patients treated with various rhEPO drugs. Therefore, it is possible to develop a universal commercial test system to this purpose.

Background. Secondary hyperparathyroidism (sHPT) is one of the serious complications in chronic kidney disease and is associated with progressive bone disease and vascular calcification.The objective of the study was to determine the impact of Mimpara (Cinacalcet HCl) on mineral disorder, bone turnover and bone mineral density (BMD) versus parathyroidectomy (PTx) in haemodialysis patients’ refractory to alfacalcidol. Materials and methods. 62 haemodialysis patients with sHPT were enrolled in this 6=months prospective study. All of them had surgical indications for PTx. Surgical indications was established according to clinical or biological assessment. 40 patients underwent Mimpara treatment. Dose of Mimpara was titrated every 4 weeks. Sequential doses included 30–180 (mean 59.1 ± 34.2) mg/day. 22 patients underwent PTx. The surgical technique was depended on quantity of hyperplastic parathyroid glands.Results. In 6 months mean iPTH, Ca, Са×Р, CTx and OC levels significantly decreased by 55.7%, 13.8%,34.3%, 21.4 and 1.4% in the Mimpara group vs. 90.7%, 14%, 55.5%, 58.7% and 26.9% in the PTx group. Median serum iPTH level decreased by 30% after initiation of Mimpara in 94.3% patients, from them by 50%in 74.3%. Achieved the KDOQI treatment targets for PTH in 28.6% patients.In 6 months after PTx median serum iPTH level was 100 pg/ml in 50% patients, achieved the KDOQI treatment targets in 27.3%, 300 pg/ml in 18.2%. Median serum 25(ОН)D after PTx significantly increase by 127.3% vs 6.72% in the Mimpara group. In 6 months active restoration of BMD was found in the PTx patients, and patients treated with Cinacalcet showed stabilization of BMD.Mimpara therapy led to a reduction in glandular volume during the course of the study: in both glands with a baseline volume 500 mm3 and with a baseline volume ≥500 mm3. Conclusions. PTx and Cinacalcet therapy improves phosphorus=calcium homeostasis, bone turnover, but bone resorption and formation markers decreased better in the PTx group compared to Cinacalcet group. The effectiveness and safety of Mimpara for secondary hyperparathyroidism were evaluated in dialysis patients’ refractory to alfacalcidol, which reduced the need for parathyroidectomy in patient without severe osteodystrophy.