[Clinical application value of peripheral blood metagenomic next-generation sequencing test for patients with hematological diseases accompanied by fever].

Objective: To investigate the clinical application value of peripheral blood metagenomic next-generation sequencing (mNGS) test for patients with hematological diseases accompanied by fever. Methods: The blood mNGS results and clinical data of inpatients with hematological diseases accompanied by fever treated in the Hematology Department of Tianjin Medical University General Hospital in March 2020 to June 2021were retrospectively analyzed. A total of 90 patients with 98 cases of specimens were included. The pathogen distribution characteristics and mNGS test performance were analyzed. Results: The positive rate of peripheral blood mNGS was significantly higher than that of traditional examination (68.37% vs 37.76%, P<0.001) and blood culture (68.37% vs 9.18%, P<0.001) . Viral, bacterial, and fungal infections accounted for 38.81%, 14.93%, and 2.99% in patients with single-pathogen infections, respectively. Polymicrobial infections accounted for 43.28%, in which viral and bacterial coinfections were the most common type (25.37%) . There were 55 virus-positive cases (82.09%) , 30 bacteria-positive cases (44.78%) , and 14 fungus-positive cases (20.90%) . The clinical approval rate of peripheral blood mNGS was 64.63% (63/98) . The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of peripheral blood mNGS were 75.68%, 36.07%, 41.79%, and 70.97%, respectively, and the overall consistency rate with traditional examination was 51.02%. Of the 22 pulmonary infection cases with no detectable pathogens by conventional tests, the pathogens were identified by peripheral blood mNGS in 14 cases, 10 of which were clinically approved. Conclusion: The positive rate of peripheral blood mNGS was significantly higher than that of blood culture and traditional laboratory examination. Peripheral blood mNGS had a high clinical recognition rate, sensitivity, and NPV in the detection of pathogens in patients with hematological diseases accompanied by fever.

[Significance of anti-EPO receptor antibody in immune-related pancytopenia].

Objective: To confirm the presence of erythropoietin receptor (EPOR) antibody in patients with immune-related pancytopenia (IRP) and to evaluate the significance of EPOR in IRP. Methods: A total of 59 newly-diagnosed IRP patients, 62 patients with IRP in remission, 14 patients with aplastic anemia (AA), 15 patients with myelodysplastic syndromes (MDS) and 33 healthy controls were enrolled in this study from January 2013 to June 2015 in Tianjin Medical University General Hospital. The anti-EPOR antibody was detected by enzyme-linked immunosorbent assay(ELISA). The expression of EPOR mRNA was detected by quantitative real-time PCR (qRT-PCR). The correlation between the data and the clinical indicators of patients was analyzed. Results: The levels of anti-EPOR antibodies were higher in the newly-diagnosed IRP patients than in the remission IRP group, AA group, MDS group and controls(0.84±0.39 vs 0.46±0.25, 0.49±0.25, 0.50±0.25, 0.53±0.14, all P<0.05). The expression of EPOR- mRNA was up-regulated in the newly-diagnosed IRP group than in the remission IRP group and the controls. The positive rate of EPOR antibody was significantly elevated in the patients with low hemoglobin level (<100 g/L), positive GlycoA antibody, or low complement C3 (all P<0.05). Anti-EPOR antibody was significantly decreased in the IRP patients responding to immunosuppressive therapy. Conclusions: Anti-EPOR autoantibody is present in patients with IRP. Detection of anti-EPOR antibody has important clinical value in the diagnosis, differential diagnosis and treatment effect evaluation of IRP.

[Studies on bioconversion conditions and stereoselectivity of Arthrobacter K1108 hydantoinase].

The bioconversion conditions of hydantoinase of Arthrobacter K1108 were studied. It was shown that the optimum temperature of the enzyme is 55 degrees C, and the optimum pH is 7.0. The enzyme can be activated by Co2+ and Fe2+, while inhibited by Ca2+. The optimal substrate of the hydantoinase is 5-benzylhydantoin, while 5-phenylhydantoin and 5-indolylmethylhydantoin cannot effectively digested, showing a high specificity on the substrates. An investigation on the hydantoinase stereoselectivity mechanism showed that the N-carbamoylamino acid hydrolase is stereoselective but the hydantoin hydrolase is not.