Clinical diagnosis and treatment of hereditary thrombocytopenia and purpura: a report of five cases and literature review / 中华血液学杂志

Objective: To report the clinical manifestations and laboratory features of five patients with congenital thrombotic thrombocytopenic purpura (cTTP) and explore its standardized clinical diagnosis and treatment along with a review of literature. Methods: Clinical data of patients, such as age of onset, disease manifestation, personal history, family history, and misdiagnosed disease, were collected. Treatment outcomes, therapeutic effects of plasma infusion, and organ function evaluation were observed. The relationship among the clinical manifestations, treatment outcomes, and ADAMTS13 gene mutation of patients with cTTP was analyzed. Additionally, detection of ADAMTS13 activity and analysis of ADAMTS13 gene mutation were explored. Results: The age of onset of cTTP was either in childhood or adulthood except in one case, which was at the age of 1. The primary manifestations were obvious thrombocytopenia, anemia, and different degrees of nervous system involvement. Most of the patients were initially suspected of having immune thrombocytopenia. Acute cTTP was induced by pregnancy and infection in two and one case, respectively. ADAMTS13 gene mutation was detected in all cases, and there was an inherent relationship between the mutation site, clinical manifestations, and degree of organ injury. Therapeutic or prophylactic plasma transfusion was effective for treating cTTP. Conclusions: The clinical manifestations of cTTP vary among individuals, resulting in frequent misdiagnosis that delays treatment. ADAMTS13 activity detection in plasma and ADAMTS13 gene mutation analysis are important bases to diagnose cTTP. Prophylactic plasma transfusion is vital to prevent the onset of the disease.

Preparation and Application of Monoclonal Antibody Against Human von Willebrand Factor Propeptide / 中国实验血液学杂志

OBJECTIVE@#To develop monoclonal antibodies that can specifically recognize human von Willebrand factor (VWF) propeptide (VWFpp) in plasma, and establish a rapid and reliable method for the detection of VWFpp antigen in plasma by using the double-antibody sandwich ELISA with the obtained anti-VWFpp monoclonal antibody.@*METHODS@#The recombinant human VWFpp (D1 and D2 regions) protein expressed in eukaryotic cells was used as immunogen to immunize BALB/c mice with routine method, so as to obtain clones of fusion cells. After screening and identification, hybridoma cell lines secreting monoclonal antibodies against VWFpp were selected, and then double-antibody sandwich ELISA assay was used to construct VWFpp antigen detection kit for the determination of VWFpp in human plasma. The levels of VWFpp antigen in plasma of 12 leukemia patients who underwent bone marrow transplantation were dynamically detected.@*RESULTS@#Two hybridoma cell lines that can be subcultured continuously and secrete monoclonal antibodies against VWFpp were obtained and named SZ175 and SZ176 respectively. Identified by ELISA and Western blot, the antibodies could both specifically recognize VWFpp but couldn't recognize mature VWF (without propeptide). Based on the principle of double-antibody sandwich ELISA, monoclonal antibodies SZ175 and SZ176 were successfully made into a kit for detecting VWFpp antigen. The plasma VWFpp levels of leukemia patients before and after bone marrow transplantation were dynamically detected. The results showed that the plasma VWFpp levels of the patients after transplantation were significantly higher than those before transplantation.@*CONCLUSION@#Two monoclonal antibodies against VWFpp were successfully prepared, and a double-antibody sandwich ELISA detection kit for VWFpp antigen was constructed, which provides a powerful tool for further study on the biological function of VWFpp, the clinical diagnosis and classification of von Willebrand disease (VWD), and the prognostic monitoring of endothelial injury-related diseases.

Recent Advances in SARS-CoV-2-Induced Immune Thrombocytopenia --Review / 中国实验血液学杂志

SARS-CoV-2-induced immune thrombocytopenia (SARS-CoV-2-induced ITP) is an autoimmune disease secondary to virus infections. Its diagnosis is often based on exclusion of other possible causes of thrombocytopenia in COVID-19 patients. Common laboratory examinations include coagulation function, thrombopoietin and drug-dependent antibodies. Since both bleeding and thrombosis risks are seen in SARS-CoV-2-induced ITP patients, individual remedy is essential for the treatment of this disease. Because thrombopoietin receptor agonist(TPO-RA) has the side effect of accelerating thrombosis and may aggravate the pulmonary embolism symptoms of patients, it should be used for refractory SARS-CoV-2-induced ITP patients only. This review briefly summarizes the recent research progress in the pathogenesis, diagnosis and treatment of SARS-CoV-2-induced ITP.

Clinical Significance of Pretransplant Serum Ferritin Level in Patients with Prolonged Thrombocytopenia after Allogeneic Hematopoietic Stem Cell Transplantation / 中国实验血液学杂志

OBJECTIVE@#To investigate the correlation between pretransplant serum ferritin (SF) level and prolonged or prolonged isolated thrombocytopenia (PT) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).@*METHODS@#The clinical data of 35 patients with PT after allo-HSCT were retrospectively analyzed, and 35 patients were matched according to age and sex as a controls from 424 allo-HSCT patients with normal platelet count. The serum ferritin level before the transplantation was analyzed. The potential risk factors were analyzed by chi-square test and Fisher's exact test as well as univariate and multivariate logistic regression. The survival curve was estimated by the Kaplan-Meier model to explore its clinical significance. In addition, ROC curve was used to verify the predictive power of SF.@*RESULTS@#Compared with control group, the SF level in the PT group before transplantation significantly increased (P=0.001). Multivariate analysis results showed that SF level before transplantation was a risk factor for prolonged thrombocytopenia after HSCT, and patients with SF≥1000 ng / ml showed a higher risk of death (P=0.014). ROC curve showed that SF level could be used as a predictor of prolonged thrombocytopenia after allo-HSCT.@*CONCLUSION@#The SF level before allo-HSCT relates with occurrence and prognosis of PT in patients after allo-HSCT. Detection of SF level can provide guidance for the intervention of prolonged thrombocytopenia after HSCT.

Reaserch Advances in the Treatment of Primary Immune Thrombocytopenia--Review / 中国实验血液学杂志

Primary immune thrombocytopenia (ITP) is a blood system disease mediated by autoimmune mechanism. Currently, the goal of treatment for primary ITP is to keep patients' peripheral platelet count at a safe level to prevent severe bleeding. Recently, avatrombopag and fostamatinib have been approved by the FDA for the treatment of primary ITP in adults, while new drugs such as rozanolixizumab, efgartigimod, PRTX-100, decitabine and atorvastatin have shown efficacy in early clinical trials. This review summarizes the current accepted therapies for the clinical treatment of primary ITP in adults, and briefly discuss the progress of new therapies.

Establishment and Clinical Application of Flow Cytometric Immunobead Array in Detecting Plasma von Willebrand Factor Antigen / 中国实验血液学杂志

OBJECTIVE@#To establish a novel flow cytometric immunobead array (FCIA) for detecting plasma von Willebrand factor antigen (vWF:Ag), and to analyze the clinical value of FCIA in predicting the prognosis of patients with ischemic stroke (IS).@*METHODS@#Anti-human vWF monoclonal antibody SZ29 IgG was coated on microspheres overnight, the diluted plasma was added after blocking, then incubated with FITC-conjugated sheep-anti-human vWF IgG polyclonal antibody, and finally detected by flow cytometry. The plasma vWF in 21 case of von Willebrand disease (vWD) and 105 controls (CTL) were detected by FCIA and ELISA, so as to carry out methodological assessment. Plasma vWF:Ag of 61 IS patients was detected by FCIA and the data of prognosis followed-up for 2-year were collected.@*RESULTS@#The linear fitting of FCIA was good (R2=0.99) without significant difference between FCIA and ELISA. The Bland-Altman bias was 1.12% with 95% limits of agreement that spanned from -45.06% to 47.30%, and the slope of the linear regression was 0.97 (r=0.86, P＜0.01). Importantly, the FCIA method was faster than ELISA, and superior to the ELISA in the detection of low levels of vWF:Ag. The levels of vWF:Ag, vWF:GPIbR and vWF:CB in IS patients were significantly higher than those in healthy controls (Z=8.36, 8.71, 6.22, respectively, P＜0.01).@*CONCLUSION@#The FCIA for detecting plasma vWF:Ag is not only an effective supplement to ELISA, but also the efficiency is faster and more sensitive, thus improves the diagnosis of type 3 vWD. Elevated levels of vWF: Ag in IS patients indicate the poor recovery of daily activities and prognosis.

Efficacy of Haploidentical Hematopoietic Stem Cell Transplantation in Treatment of Intermediate Risk Acute Myeloid Leukemia with Negative for FLT3-ITD, NPM1 or Biallelic CEBPA Mutation / 中国实验血液学杂志

OBJECTIVE@#To compare the efficacy of haploidentical hematopoietic stem cell transplantation (hi-HSCT) HLA-matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) and post-remission chemotherapy (PR-CT) in treatment of intermediate risk acute myeloid leukemia with negative for FLT3-ITD, NPM1 or biallelic CEBPA mutation.@*METHODS@#The clinical data of patients with intermediate risk NPM1/non-CEBPA/FLT3-ITD AML from October 2009 to May 2016 were retrospectively analyzed.@*RESULTS@#The overall survival rate of the patients treated with PR-CT, MSD-HSCT or hi-HSCT was 63.7%, 71.7%, 75.5%, respectively (P＜0.05); the disease-free survival (DFS) rate was 52.8%, 67.1%, 71.3% respectively (P＜0.001); the cumulative incidence of relapse was 24.7%, 16.9%, 14.4% respectively (P＜0.05); the non-relapse mortality was 26.2%, 17.3%, 14.4% reapectively (P＞0.05). The analysis of transplantation, related adverse events showed that II-IV grade of aGVHD in the MSD-HSCT group and hi-HSCT group was 48.9% and 45.6% respectively (P＞0.05); the extensive cGVHD event was 21.6% and 8.8% (P＜0.05) respectively.@*CONCLUSION@#The efficiency of hi-HSCT and MSD-HSCT is superior to that of PR-CT for treatment of patients with intermediate risk NPM1/non-CEBPA/FLT3-ITD AML after CR1, there is no statistically significant difference in the efficiency of consolidatorg treatment and the transplantation-related mortality between hi-HSCT and MSD-HSCT.

Effect of Protein Kinase A Activation on Aggregation Function of Platelets / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of protein kinase A (PKA) activation on aggregation funetion of platelets in vitro.@*METHODS@#The peripheral blood of healthy adults were collected, and the washed platelets were gained from collected peripheral blood. The washed platelets were treated with PKA activator Forskolin, then the platelet aggregation was induced by using Ristocetin, Thrombin, Collagen and ADP respectively, the platelet aggregation level was detected by the platelet aggregator.@*RESULTS@#Compared with the controls, 5 μmol/L forskolin significantly inhibited ADP and collagen-induced platelet aggregation (P＜0.001), and showed mild inhibiting effect on Thrombin-induced platelet aggregation (P＜0.05). 2.5-10 μmol/L forskolin significantly inhibited ADP and Collagen -induced platelet aggregation (P＜0.001); but not showed significantly inhibitory effects on Ristocetin-induced platelet aggregation (P＞0.05).@*CONCLUSION@#PKA activation inhibits agonists-induced platelet aggregation.

Effect of Recombinant Protein in the Spacer Domain on ADAMTS13 Activity / 中国实验血液学杂志

OBJECTIVE@#To obtain the recombinant protein of spacer domain in von Willebrand factor cleaving protease (ADAMTS13), and further study its biological function in ADAMTS13.@*METHODS@#The prokaryotic expression vector was constructed by using the template of plasmid with full-length ADAMTS13, and then transfected into E coli., following the induction of IPTG with the low temperature (30 ℃). The recombinant protein was purified with Ni-NTA agarose column by gradient imidazole. The purity and immune activity of purified products were identified with SDS-PAGE and Western blot respectively. By Adding the recombinant protein to the plasma of immune-mediated thrombotic thrombocytopenic purpura (iTTP) patients, the activity of ADAMTS13 was tested.@*RESULTS@#The prokaryotic expression vector was successfully constructed and the protein of spacer domain with the high purity was obtained. Western blot showed that the recombinant fragment could both react with monoclonal antibody against 6×His and polyclonal sheep IgG against ADAMTS13 (Gln34-Trp688). The protein formed a main lane at the position of 15 kDa with SDS-PAGE. It was demonstrated that the recombinant protein could efficiently elevate the ADAMTS13 activity in plasma of iTTP patients to reach normal level by functional experiment.@*CONCLUSION@#The recombinant protein has high purity and immune activity, which provides the experimental basis for further research on mechanism of iTTP involved in spacer domain.

Clinical observation of desmopressin in the treatment of 15 patients with DDAVP / 中华血液学杂志

Objective: To assess the significance of DDAVP use in the diagnosis and treatment of VWD. Methods: An analysis of 15 VWD cases who referred to Hematology Division of First affiliated Hospital of Soochow University and treated with DDAVP from March 2016 to August 2018 was conducted. Efficacy and treatment response of DDAVP were monitored by observations of changes in factor Ⅷ procoagulant (FⅧ∶C) and von Willebrand Factor (VWF) related indicators before and 2 h after DDAVP injection. Results: Of 15 cases with VWD, 7 males and 8 females with a median age of 23 (6-46) years, 7 of 9 type I VWD patients achieved complete response (CR) , 1 type 2A VWD case CR, 5 type 3 VWD ones no response (NR) . The VWF multimer analysis in 5 patients combined with other plasma VWF values were in accordance with the known diagnosis. Conclusions: DDAVP was effective in most type 1 patients, and ineffective in some type 2 and almost all type 3 cases. It was helpful for diagnosis and subsequent treatment planning.