Ixazomib-based frontline therapy followed by ixazomib maintenance in frail elderly newly diagnosed with multiple myeloma: a prospective multicenter study.

Background: Frail elderly patients with newly diagnosed multiple myeloma (NDMM) have inferior survival and less benefit from high-dose therapies. This prospective study aimed to investigate the efficacy, safety, and quality of life (QoL) of induction treatment of ixazomib/lenalidomide/dexamethasone (IRd) and ixazomib/pegylated liposomal doxorubicin/dexamethasone (IDd) followed by ixazomib/dexamethasone (Id) maintenance therapy in frail, elderly patients with NDMM. Methods: From July 2019 to December 2021, this non-randomized concurrent controlled clinical study enrolled 120 NDMM patients aged ≥65 years with frailty defined by the International Myeloma Working Group (IMWG) frailty score or Mayo geriatric scoring system. The enrolled patients received 6-8 cycles of IRd or IDd followed by Id maintenance therapy for a minimum of 2 years at the discretion of physicians based on patient's clinical characteristics (chiCTR1900024917). Findings: The median age was 71 years and 55% of the patients were males. The overall response rate (ORR) was 82% and 77%, complete response (CR) rate was 25% and 12% for IRd and IDd groups, respectively. The difference in ORR of the Idd group minus the IRd group was -5.36% (95% CI: -18.9% to 8.19%), indicating that the ORR of the IDd group was neither inferior nor non-inferior to the IRd group. After a median follow-up of 34.3 months, the median progression-free survival (PFS) was 21.6 and 13.9 months, OS was not reached and 29.2 months in IRd and IDd groups, respectively. 28 and 33 patients discontinued induction therapy, 20 and 19 discontinued maintenance therapy in IRd and IDd groups, respectively. Cumulative Grade 3 or higher hematological adverse events (AEs) occurred in 10 of the 60 patients (17%) and non-hematological AEs occurred in 15 of the 60 patients (25%) in the IRd group, while 13 of the 60 patients (22%) and 21 of the 60 patients (35%) in the IDd group. Patients were observed with clinically significant improvement in QoL when compared with that at baseline in both IRd and IDd groups by evaluation per cycle (P < 0.0001). Interpretation: The results demonstrated that compared with IRd regimen, IDd regimen showed no significant advantage, but the survival of the IDd group was shorter than that of the IRd group, indicating an all-oral outpatient triplet regimen with IRd, which has low toxicity and has improved QoL, could be the viable first-line treatment option for frail NDMM patients. Funding: The Young Elite Scientist sponsorship program by bast of Beijing Association for Science and Technology (No. BYESS2023116) and Beijing Medical Award Foundation (No. YXJL-2018-0539-0073).

[Expression of Adenovirus-mediated Human Clotting Factor IX Gene in Mouse Adipose-derived Stem Cells].

OBJECTIVE: To investigate the adenovirus-mediated expression of human clotting factor IX (hFIX) gene in mouse adipose-derived stem cells(ADSC). METHODS: The mouse ADSC were isolated and cultured in vitro, the morphology of cells was observed and its growth viability was detected by using CCK-8. Cell surface markers CD29,CD90,CD45 were identified by flow cytometry, and its diferentiation ability was identified by adipogenic and osteogenic induction. Morphological changes was observed and the growth curve should be drawn after transfecting ADSC with adenovirus containing hFIX gene. The expression of hFIX gene was detected by RT-PCR. The expression of hFIX protein in ADSC or in culture supernatant was detected by Western blot. hFIX protein in the supernatant was measured by ELISA, and the clotting factor activity of hFIX in culture supernatant was measured by one-stage method. RESULTS: The in vitro cultured mouse ADSC displayed microspherical shape and strong refractive property. Anchoring growth was lasted for 4-6 hours after planting into culture flask. After cultured for 72 hours, the cells showed long spindle-shaped fibrous and swirling arrangement. The overall growth trend of the third generation ADSC cultured in vitro was S-shaped. The formation of lipid droplets could be observed in the induced cells with Oil red O staining by inverted microscope. After alizarin red staining, the orange-red calcified bone nodes were observed in the induced cells under inverted phase contrast microscope. CD29 (99.91%) and CD90 (99.02%) highly expressed in the third generation of ADSC, but CD45 (0.94%) almost not expressed. RT-PCR showed the hFIX gene could expressed in mouse ADSC. Western blot showed that hFIX protein expressed in both ADSC and culture supernatant. FIX:Ag in cell supernatant was 21.33±3.93 ng/(106 cells.24 h) on the first day, 12.63±0.86 ng/(106 cells.24 h) on the third day and 12.63±2.36 ng/(106 cells.24 h) on the ninth day. FIX:C in culture supernatant was 8.5%. CONCLUSION: Adenovirus-carried hFIX gene can effectively transfect ADSC. ADSC modified by hFIX gene can secrete hFIX protein with coagulation activity.

[Adenovirus-mediated Expression of B-domain-Deleted Human Coagulation Factor â § in ADSC of SD Rats].

OBJECTIVE: To transinfect SD adipose tissue-derived stem cell (ADSC) in vitro with a recombinant adenoviral vector containing human B-domain-deleted FVIII (BDDhFⅧ), so as to lay the foundation for the treatment of hemophilia A by using ADSC combined with BDDhFⅧ gene. METHODS: ADSCs were isolated from the inguinal adipose tissue of SD rats and passed to third passage for identification. Third passage ADSCs were transfected in vitro with recombinant adenovirus vector Ad-BDDhFⅧ-GFP. The experiments were divided into Ad-BDDhFⅧ-GFP-transfected ADSCs group (A), Ad-GFP-transfected ADSC group (B), and untransfected ADSC group (C). CCK-8 method was used to detect the proliferation of transfected cells in three groups, and the expression level of hFⅧ antigen in cell supernatant was detected by ELISA. RT-PCR and Western blot respectively were used to detect the mRNA and protein expression of BDDhFⅧ in the three groups after transfection. RESULTS: The growth curve of third passage cells isolated and cultured showed an inverted "S" shap; the flow cytometry detection showed the positive expression of CD29, CD90, CD44, and the negative expression of CD45 in third passage cells. After the adipogenic and osteogenic induction, the cells could transformed to adipogenic and osteogenic directions. CCK-8 detection showed that the proliferation of cells in 3 groups not was influenced. ELISA showed that the expression of hFⅧAg in group A was significantly higher than that in group B and C (P＜0.05). RT-PCR showed that compared with group A, there was no target band in B and C groups, and BDDhFⅧ gene was not expressed. The results in group A were consistent with the length of amplified fragments, and BDDhFⅧ target gene was expressed. Western blot analysis showed that the expression of hFⅧ protein in group A was significantly higher than that in group B and C. (P＜0.05). CONCLUSION: Recombinant adenovirus Ad-BDDhFⅧ-GFP can effectively transfect rat ADSC in vitro, which lays an experimental foundation for gene therapy of hemophilia A.

Chinese guidelines for treatment of adult primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is a bleeding disorder commonly encountered in clinical practice. The International Working Group (IWG) on ITP has published several landmark papers on terminology, definitions, outcome criteria, bleeding assessment, diagnosis, and management of ITP. The Chinese consensus reports for diagnosis and management of adult ITP have been updated to the 4th edition. Based on current consensus positions and new emerging clinical evidence, the thrombosis and hemostasis group of the Chinese Society of Hematology issued Chinese guidelines for management of adult ITP, which aim to provide evidence-based recommendations for clinical decision making.

[A Preliminary Exploration on the Pathogenesis of Osteopenia in Patients with Hemophilia].

OBJECTIVE: To investigate the influencing factors and pathogenesis of osteopenia in the patients with hemophilia. METHODS: Twenty-three patients with hemophilia were admitted in the hospital affiliated to North China University of Science and technology from March to August 2015, including 13 severe cases, 10 mild and moderate cases. All the patients accepted the detection of serum I collagen cross-linking N terminal peptide (NTX I), osteoprotegerin (OPG), bone alkaline phosphatase (BALP), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF) and transforming growth factor-ß1 (TGF-ß1), the score scale of activity ability was recorded according to the criteria published by the U.S. Center for disease prevention and control in 2002, and 21 patients received the measurement of bone mineral density. According to the World Health Organization (WHO) definition, the clinical significance of bone mineral density (BMD) was assessed by measuring the Z level. RESULTS: Z level>-2 was recorded in 10 cases, Z≤-2 was recorded in 11 cases; the levels of body mass index (BMI) and human bone alkaline phosphatase (BALP) reflecting bone formation in 11 cases (Z≤-2) were lower than there in 10 cases (Z>-2) (P<0.05); the levels of BALP (r=0.489, P<0.05), IGF (r=0.538, P<0.05) and BMI (r=0.572, P<0.01) positively correlated significantly with BMD (P<0.05); the levels of bFGF (r=0.570, P<0.01) and OPG (r=0.505, P<0.05) positively correlated with NTX I, indicating bone destruction (P<0.05); the score of activity ability of severe patients was significantly lower than that of mild and moderate cases (P<0.05), BMD levels of these 2 groups were not statistically different (P>0.05). CONCLUSION: The BMD level does not correlate with the clinial grouping of hemophilia, the low body mass index may be a risk factor for bone lose; the mechanism of hemophilia patient's bone lose may be related with the decrease of osteogenic activity, the IGF can prevent bone lose in hemophilia, the bFGF and OPG can promote bone metabolism of the patients with hemophilia.

Na+-induced Ca2+ influx through reverse mode of Na+-Ca2+ exchanger in mouse ventricular cardiomyocyte.

BACKGROUND: Dobutamine is commonly used for clinical management of heart failure and its pharmacological effects have long been investigated as inotropics via ß-receptor activation. However, there is no electrophysiological evidence if dobutamine contributes inotropic action due at least partially to the reverse mode of Na+-Ca2+ exchanger (NCX) activation. METHODS: Action potential (AP), voltage-gated Na+ (INa), Ca2+ (ICa), and K+ (Ito and IK1) currents were observed using whole-cell patch technique before and after dobutamine in ventricular cardiomyocytes isolated from adult mouse hearts. Another sets of observation were also performed with Kb-r7943 or in the solution without [Ca2+]o. RESULTS: Dobutamine (0.1-1.0 µM) significantly enhanced the AP depolarization with prolongation of AP duration (APD) in a concentration-dependent fashion. The density of INa was also increased concentration-dependently without alternation of voltage-dependent steady-status of activation and inactivation, reactivation as well. Whereas, the activities for ICa, Ito, and IK1 were not changed by dobutamine. Intriguingly, the dobutamine-mediated changes in AP repolarization were abolished by 3 µM Kb-r7943 pretreatment or by simply removing [Ca2+]o without affecting accelerated depolarization. Additionally, the ratio of APD50/APD90 was not significantly altered in the presence of dobutamine, implying that effective refractory period was remain unchanged. CONCLUSIONS: This novel finding provides evidence that dobutamine upregulates of voltage-gated Na+ channel function and Na+ influx-induced activation of the reverse mode of NCX, suggesting that dobutamine may not only accelerate ventricular contraction via fast depolarization but also cause Ca2+ influx, which contributes its positive inotropic effect synergistically with ß-receptor activation without increasing the arrhythmogenetic risk.

KCa1.1 is potential marker for distinguishing Ah-type baroreceptor neurons in NTS and contributes to sex-specific presynaptic neurotransmission in baroreflex afferent pathway.

Sexual-dimorphic neurocontrol of circulation has been described in baroreflex due largely to the function of myelinated Ah-type baroreceptor neurons (BRNs, 1st-order) in nodose. However, it remains unclear if sex- and afferent-specific neurotransmission could also be observed in the central synapses within nucleus of solitary track (NTS, 2nd-order). According to the principle of no mixed neurotransmission among afferents and differentiation of Ah- and A-types to iberiotoxin (IbTX) observed in nodose, the 2nd-order Ah-type BRNs are highly expected. To test this hypothesis, the excitatory post-synaptic currents (EPSCs) were recorded in identified 2nd-order BRNs before and after IbTX using brain slice and whole-cell patch. These results showed that, in male rats, the dynamics of EPSCs in capsaicin-sensitive C-types were dramatically altered by IbTX, but not in capsaicin-insensitive A-types. Interestingly, near 50% capsaicin-insensitive neurons in females showed similar effects to C-types, suggesting the existence of Ah-types in NTS, which may be the likely reason why the females had lower blood pressure and higher sensitivity to aortic depressor nerve stimulation via KCa1.1-mediated presynaptic glutamate release from Ah-type afferent terminals.

[Changes of CD34(+) and CD71(+)CD45(-) cell levels in bone marrow of MDS and AA patients].

This study was aimed to investigate the changes of CD34(+) and CD71(+)CD45(-) cell levels in MDS and AA patients. A total of 25 cases MDS and 43 cases of AA (18 cases SAA and 25 cases of NSAA) from January 2010 to October 2013 in the Department of Hematology, affiliated hospital of Hebei United University were enrolled in this study. The complete blood count, bone marrow smears, bone marrow biopsy, karyotype analysis and bone marrow blood cell immune genotyping (mainly the proportion of CD34(+) cells, CD71(+)CD45(-) cells in nucleated cells) were carried out for all patients; the changes of CD34(+) and CD71(+)CD45(-) cell levels in patients with MDS and AA (SAA NSAA) were compared; the differences of white blood cell count, platelet count and hemoglobin concentration in patients with count of CD71(+)CD45(-) ≥ 15% or <15% were analyzed. The results showed that the count of CD34(+) in MDS group was higher than that in AA (NSAA and SAA) group (P < 0.05). The count of CD71(+)CD45(-) cells in MDS group was higher than that in SAA (P < 0.05), there was no significant difference between NSAA group and MDS group. In MDS group with CD71(+)CD45(-) ≥ 15%, the platelet count was significantly higher than that in NSAA group (P < 0.05); and there was no statistical difference for leukocyte, platelet count and hemoglobin level between MDS and NSAA group with CD71(+)CD45(-) <15% (P > 0.05). It is concluded that the count of CD34(+) cells in MDS patients is significantly higher than that in AA and SAA patients. The count of CD71(+)CD45(-) cells in MDS group is significantly higher than that of SAA group. The platelet count in MDS patients with CD71(+)CD45(-) cells ≥ 15% is significantly higher than that of the NSAA group.

Gender differences in histamine-induced depolarization and inward currents in vagal ganglion neurons in rats.

Evidence has shown gender differences regarding the critical roles of histamine in the prevalence of asthma, anaphylaxis, and angina pectoris. Histamine depolarizes unmyelinated C-type neurons without any effects on myelinated A-type vagal ganglion neurons (VGNs) in male rats. However, little is known if VGNs from females react to histamine in a similar manner. Membrane depolarization and inward currents were tested in VGNs isolated from adult rats using a whole-cell patch technique. Results from males were consistent with the literature. Surprisingly, histamine-induced depolarization and inward currents were observed in both unmyelinated C-type and myelinated A- and Ah-type VGNs from female rats. In Ah-type neurons, responses to 1.0 µM histamine were stronger in intact females than in males and significantly reduced in ovariectomized (OVX) females. In C-type neurons, histamine-induced events were significantly smaller (pA/pF) in intact females compared with males and this histamine-induced activity was dramatically increased by OVX. Female A-types responded to histamine, which was further increased following ovariectomy. Histamine at 300 nM depolarized Ah-types in females, but not Ah-types in OVX females. In contrast, the sensitivity of A- and C-types to histamine was upregulated by OVX. These data demonstrate gender differences in VGN chemosensitivity to histamine for the first time. Myelinated Ah-types showed the highest sensitivity to histamine across female populations, which was changed by OVX. These novel findings improve the understanding of gender differences in the prevalence of asthma, anaphylaxis, and pain. Changes in sensitivity to histamine by OVX may explain alterations in the prevalence of certain pathophysiological conditions when women reach a postmenopausal age.

Subtype identification in acutely dissociated rat nodose ganglion neurons based on morphologic parameters.

Nodose ganglia are composed of A-, Ah- and C-type neurons. Despite their important roles in regulating visceral afferent function, including cardiovascular, pulmonary, and gastrointestinal homeostasis, information about subtype-specific expression, molecular identity, and function of individual ion transporting proteins is scarce. Although experiments utilizing the sliced ganglion preparation have provided valuable insights into the electrophysiological properties of nodose ganglion neuron subtypes, detailed characterization of their electrical phenotypes will require measurements in isolated cells. One major unresolved problem, however, is the difficulty to unambiguously identify the subtype of isolated nodose ganglion neurons without current-clamp recording, because the magnitude of conduction velocity in the corresponding afferent fiber, a reliable marker to discriminate subtypes in situ, can no longer be determined. Here, we present data supporting the notion that application of an algorithm regarding to microscopic structural characteristics, such as neuron shape evaluated by the ratio between shortest and longest axis, neuron surface characteristics, like membrane roughness, and axon attachment, enables specific and sensitive subtype identification of acutely dissociated rat nodose ganglion neurons, by which the accuracy of identification is further validated by electrophysiological markers and overall positive predictive rates is 89.26% (90.04%, 76.47%, and 98.21% for A-, Ah, and C-type, respectively). This approach should aid in gaining insight into the molecular correlates underlying phenotypic heterogeneity of nodose ganglia. Additionally, several critical points that help for neuron identification and afferent conduction calibration are also discussed.

Remodeling of hyperpolarization-activated current, Ih, in Ah-type visceral ganglion neurons following ovariectomy in adult rats.

Hyperpolarization-activated currents (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A- and Ah-type visceral ganglion neurons (VGN). Whether alterations in Ih underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of Ih remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage 'sag' as well as 'rebound' action potentials immediately following hyperpolarizing current injections, which both were suppressed by the Ih blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of Ih during the preceding spike trains. Ovariectomy reduced whole-cell Ih density, caused a hyperpolarizing shift of the voltage-dependence of Ih activation, and slowed Ih activation. OVX-induced Ih remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored Ih density and accelerated Ih activation in Ah-type cells. In conclusion, Ih plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats.

Tumor-initiating cells and tumor vascularization.

Tumor-initiating cells (TICs) with stem-like cell properties initiate and sustain progressive growth, resulting in a heterogeneous tumor mass. The survival and growth of tumors rely on the development of a vasculature to provide nutrients and oxygen. Crosstalk between TICs and vascularization may be one of the central players in the initiation, long-term maintenance, and progression of tumors. This review surveys current evidence concerning the crosstalk that occurs in tumor/stromal interactions, including genetic change, vascular niche, hypoxia, and dormancy of tumors. A better understanding of this crosstalk might help provide the basis for developing more effective therapeutic drug targets.

[Effects of STI571 combined with As2O3 on proliferation, apoptosis and caspase 3, Bcl-xL expression of K562 cells].

This study was aimed to explore the effects of STI571 alone or with As2O3 on proliferation, apoptosis and caspase 3, bcl-xL mRNA expression of K562 cells, and the molecular mechanism of As2O3 enhancing the anti-leukemia effect of STI571 so as to provide the scientific basis for clinical treatment of chronic myeloid leukemia. The effect of drugs on proliferation of K562 cells was assayed by MTT method, the apoptosis rate of K562 cells was detected by flow cytometry with Annexin V/PI double staining, the caspase 3, bcl-xL mRNA expressions of K562 cells were determined by real time quantitative PCR. The results showed that STI571 alone or with As2O3 both could inhibit the proliferation of K562 cells. OD value in test groups reduced along with prolonging of action times, the OD values between different time points were significantly different (p < 0.05), furthermore the OD values at 72 hours in test groups were lowest, while as compared with control group, OD values at same time points in test groups all gradually decreased, among which decrease of OD value in test 5 group was most significant. The flow cytometric detection indicated that along with time prolonging, the apoptotic rate in control group not obviously changed, but the apoptotic rate in test groups gradually increased, the difference between time points was significant (p < 0.05), moreover apoptotic rate increased most obviously at 72 hours, while as compared with control group, apoptotic rate at same time points in test groups was gradually enhanced (p < 0.05), among which the apoptotic rate in test 5 group was highest. The real time qPCR assay revealed that as compared with control group, the bcl-xL mRNA expression in test groups reduced with decrease of 2-ΔΔCT value, furthermore the decrease of expression level in test 3 group was higher than that in test 2 group (p < 0.05), while the caspase 3 mRNA expression in test groups was enhanced with increase of 2-ΔΔCT value, moreover the increase of expression level in test 3 group was higher than that in test 2 group (p < 0.05). It is concluded that the STI571 can inhibit the proliferation of K562 cells, accelerate the apoptosis of K562 cells. The STI571 combined with As2O3 can enhance these two effects, increase the expression of caspase-3 mRNA and decrease the expression of bcl-xL mRNA. Therefore, the effect of STI571 combined with As2O3 on expression of caspase 3 and bcl-xL mRNA may be one of molecular mechanisms underlying their synergic antileukemia efficacy.

Identification of seven novel mutations in the factor VIII gene in 18 unrelated Chinese patients with hemophilia A.

BACKGROUND: Hemophilia A (HA) is an X-linked inherited bleeding disorder caused by decreased activity of factor VIII (FVIII) due to heterogenous mutations in the FVIII coding gene (F8). The type of mutation plays an important role in the FVIII inhibitor formation. To date, several studies on the spectra of F8 defects have been performed in Western populations, but similar studies in Asian races are scarce. Here, we reported the distribution of the F8 gene mutations in 18 unrelated Chinese patients with HA. METHODS: Intron 22 and intron 1 inversions in the F8 gene were screened in 158 unrelated patients with HA using a long-distance PCR and multiplex PCR method. Direct sequencing of the coding region of the F8 gene was used to identify the mutations responsible for HA in 18 unrelated Chinese HA patients who were negative for intron 22 and intron 1 inversions; sequences were compared with the HAMSTeRS database. A clotting method was used to assay the FVIII activity level and the Bethesda assay was used to detect the FVIII inhibitor. RESULTS: A total of 18 different HA F8 mutations were identified, seven of which were described for the first time. These novel mutations included five small deletions, one point mutation and one small insertion. One novel mutation (4382-3 AC deletion) was associated with inhibitor development. CONCLUSION: These data extend our insight into the mechanisms by which novel amino acid mutations may lead to HA and how the HA patient genotypes influence the risk of FVIII inhibitor.

[Frequency of factor VIII inhibitor in the patients with hemophilia A and environmental risk factors for inhibitor development].

OBJECTIVE: To screen for factor VIII inhibitor in patients with hemophilia A (HA) and explore the environmental risk factors for inhibitor development. METHODS: Totally 265 patients with HA were enrolled, including 107 consecutive inpatients and outpatients in Peking Union Medical College Hospital from April 2003 to April 2007 and 158 patients newly recruited from other hospitals. FVIII: C activity was measured by one-stage coagulation assay. FVIII inhibitor was determined using Bethesda method. RESULTS: In 265 HA patients, FVIII inhibitor was detected in 22 patients (8.3%). Nine of them (86.4%) were low responders (inhibitor titers < or = 5 000 BU/L), 3 (13.6%) were high responders (the titers > 5 000 BU/L). The frequency of FVIII inhibitor was 50% in the patients aged over 50 years, which was significantly higher than those in other age groups (P = 0. 000). Among 158 newly recruited patients with full clinical data, the frequency of FVIII inhibitor was 12.8% in patients who had received infusion of FVIII products for more than 12 doses on average each year, while it was 5.8% in whom the infusion doses were less than 12 (P = 0.156). The frequency of FVIII inhibitor was 28.5% in patients with a history of continuous infusion of FVIII products whereas it was only 1.6% in patients without such history (P = 0.000). In patients who exposed to multiple-branded or single-branded FVIII products, the frequencies of FVIII inhibitor were 9.3% and 3.9%, respectively (P = 0.229). CONCLUSION: The development of factor VIII inhibitor in patients with hemophilia A may be related to the age and the history of continuous infusion of FVIII products.

[Detection of factor VIII intron 1 inversion in severe haemophilia A].

OBJECTIVE: Screening the intron 1 inversion of factor VIII (FVIII) in the population of severe haemophilia A(HA) in China and performing carrier detection and prenatal diagnosis. METHODS: Using LD-PCR to detect intron 22 inversions and multiple-PCR within two tubes to intron 1 inversions in severe HA patients. Carrier detection and prenatal diagnosis were performed in affected families. Linkage analysis and DNA sequencing were used to verify these tests. RESULTS: One hundred and eighteen patients were seven diagnosed as intron 22 inversions and 7 were intron 1 inversions out of 247 severe HA patients. The prevalence of the intron 1 inversion in Chinese severe haemophilia A patients was 2.8% (7/247). Six women from family A and 2 from family B were diagnosed as carriers. One fetus from family A was affected fetus. CONCLUSION: Intron 1 inversion could be detected directly by multiple-PCR within two tubes. This method made the strategy more perfective in carrier and prenatal diagnosis of haemophilia A.