[Target cells of cytotoxic T cells in severe aplastic anemia in vitro]

OBJECTIVE

To clarify the specific target of severe aplastic anemia (SAA) immune attack via identifying the target cells of cytotoxic T cell attacks and the expression of apoptosis ligand on each department and each stage of bone marrow hematopoietic cells.

METHODS

A total of 15 SAA patients and 15 normal controls were recruited in the Department of Hematology, Tianjin Medical University General Hospital between March 2011 and March 2012. Factor associated suicide(Fas) protein expression of CD34(+) , CD14(+) , CD33(+) , and GlycoA(+) cells in bone marrow was detected by flow cytometry. The CD8(+) T cells of SAA patients and CD3(-) bone marrow mononuclear cells (BMMNC) of controls were sorted by immunomagnetic separation and co-cultured for 72 hours. The apoptosis rate of CD34(+) , CD14(+) , CD33(+) , and GlycoA(+) cells were measured with flow cytometry.

RESULTS

The expression of Fas protein in CD34(+) cells in SAA patients (46.59%± 27.60%) was significantly higher than that in control group (8.89%±7.28%, P<0.01). The expressions of Fas protein in CD14(+) , CD33(+) and GlycoA(+) cells in SAA group(29.29%±9.23%, 46.88%±14.30%, 15.15%±9.26%) were lower than those in control group(51.25%±38.36%, 72.06%±39.88%, 50.38%±39.88%, all P<0.05). The apoptosis rates of CD34(+) , CD33(+) and CD14(+) cells in the experimental group (CD8(+) T cells of SAA patients co-cultured with CD3(-) BMMNC of controls: 55.43%±20.50%, 38.13%±20.10%, 61.87%±21.65%)were significantly higher than those of the control group (CD8(+) T cells of controls co-cultured with CD3(-) BMMNC of controls: 35.02%±13.95%, 23.44%±10.33%, 37.04%±22.41%, all P<0.05).

CONCLUSIONS

Cytotoxic T cells in SAA patients may have a killing effect on hematopoietic stem/progenitor cells, and granulocytic and macrophagocytic cells from normal bone marrow. Moreover, Fas/Fas ligand-mediated apoptosis may play an important role in the immune pathogenesis of SAA. CD34(+) cells show markedly increased Fas protein expression, which may be the main target cells in the process of immune injury in SAA patients.

Identification of mutations in the F8 and F9 gene in families with haemophilia using targeted high-throughput sequencing

INTRODUCTION

At present, many methods are available for the genetic diagnosis of haemophilia, including indirect linkage analysis, direct sequencing. However, these methods are time-consuming, labourious, and limited in their application. Therefore, the development of new, more effective techniques is necessary.

AIM

To detect the F8 and F9 gene mutations in patients with haemophilia and their female relatives in 29 haemophilia A (HA) and 11 haemophilia B (HB) families.

METHODS

FVIII

C and FIX:C were analyzed using one-stage method, and factor VIII and factor IX inhibitors were tested using the Bethesda method. Intron 22 and one inversions were identified using long-distance polymerase chain reaction (PCR) and standard PCR. Non-inversion mutations of the F8 and F9 gene were identified by targeted high-throughput sequencing. All mutations were verified by Sanger sequencing.

RESULTS

Intron 22 inversion was detected in eight HA families and intron one inversion was detected in one HA family. Apart from the inversion mutations, 20 mutations were identified in HA families, including 17 previously reported and three novel mutations: c.5724G>A (p.Trp1908*), c.6116-1_6120delGAGTGTinsTCC (p.Lys2039Ilefs*13), and c.5220-2A>C. We found a complex rearrangement in HA: intron one inversion concomitant with exon one deletion. In HB, eight recurrent mutations were detected, including six missense mutations and two nonsense mutations.

CONCLUSION

Targeted high-throughput sequencing is an effective technique to detect the F8 and F9 gene mutations, especially for the discovery of novel mutations. The method is highly accurate, time-saving and shows great advantage in uncovering large deletion mutations and also in distinguishing the wild-type genotype and heterozygous large deletions.

[Quantities and function of NK cells in patients with positive BMMNC-Coombs test and cytopenia]

OBJECTIVE

To test NK cell quantities and function in patients with positive BMMNC-Coombs test (CBCPC) and cytopenia and to explore how NK cell participate in the progress of this disease.

METHODS

The percentage of CD3(-)CD56(+) NK cell in peripheral blood lymphocytes, the expression of activating receptor (NKG2D, NKp46, NKp44), inhibitory receptor (CD158a, CD158b), perforin and granzyme-β were detected by flow cytometry. All samples were taken from 42 patients (22 newly diagnosed and 20 in remission) and 12 healthy volunteers. The correlation between the above parameters and patients' clinical profile were evaluated.

RESULTS

①The percentage of CD3(-)CD56(+) NK cell in new diagnosed and remission CBCPC patients were significantly lower than that in healthy control [(10.04 ± 5.33)% vs (19.94 ± 7.38)%; (11.62 ± 6.80)% vs (19.94 ± 7.38)%, all P<0.01]. ② The expression of activating receptor NKG2D in new diagnosed CBCPC patients was significantly higher than that in remission group and healthy control [(74.03±18.24)% vs (45.97±29.45)%; (74.03±18.24)% vs (41.89± 15.34)% , P <0.01]. ③The expression of inhibitory receptor CD158a in new diagnosed CBCPC patients was significantly lower than that in remission group and healthy control (median: 3.72% vs 16.10%, P= 0.015; 3.72% vs 11.04%, P=0.025). ④The expression of perforin in new diagnosed and remitted CBCPC patients were significantly higher than that in healthy controls [(75.71±10.14) % vs (57.20±18.85)%, P= 0.018; (77.88±22.82)% vs (57.20±18.85)%, P=0.008]. ⑤The product of NK cell percentage and perforin expression in new diagnosed and remission CBCPC patient were significantly lower than that in healthy control [(7.68±4.54)% vs (12.13±5.19)%, P=0.011; (8.24±5.80)% vs (12.13±5.19)%, P=0.023]. The product of NK cell percentage and granzyme-β expression in the new diagnosed and remission CBCPC patient were significantly lower than that in healthy control [(7.83±5.26)% vs (14.79±8.37)%, P=0.008; (8.37 ± 6.83)% vs (14.79±8.37)%, P=0.012].

CONCLUSION

Deceased quantities and impaired total NK function might play a role in pathogenesis of CBCPC.

[Age-related differences in the clinical symptoms and triggering factors among Chinese patients with acute myocardial infarction]

OBJECTIVE

To analyze the age-related differences in the clinical symptoms and triggering factors among Chinese patients with acute myocardial infarction.

METHODS

Acute myocardial infarction Patients (n=14 854) registered in the China Acute Myocardial Infarction Registry from January 2013 to March 2014 were included in this study. Patients were divided into 4 groups: <55 years old group (3 950 patients), 55-64 years old group (4 361 patients), 65-74 years old group ( 3 759 patients), and ≥75 years old group (2 784 patients). Demographic features, medical history, clinical presentation and triggering factors were obtained via electronic data capture system.

RESULTS

(1)Persistent chest pain and sweat were the major typical symptoms 66.4%(9 863/14 854) and 63.8%(9 471/14 854)) in the whole cohort. Prevalence of persistent chest pain among four groups were 73.8%(2 915/3 950), 69.2%(3 016/4 361), 63.6%(2 394/3 759) and 55.2%(1 538/2 784), and radiating pain among four groups were 36.2%(1 428/3 950), 34.1%(1 487/4 361), 30.9%(1 160/3 759)and 25.9%(722/2 784), and sweat among four groups were 70.0%(2 765/3 950), 66.5%(2 898/4 361), 61.8%%(2 323/3 759)and 53.3%(1 485/2 784), and there were statistical significance for all above symptoms among groups (all P<0.001). (2)triggering factors before acute myocardial infarction could be found in 19.4%(2 879/14 854) of the patients. Prevalence of existed triggering factors among four groups were 23.8%(941/3 950), 21.0%(914/4 361), 16.6%(625/3 759) and 14.3%(399/2 784, P<0.001). Recent excessive unhealthy lifestyles among four groups were 20.8%(196/3 950), 11.9%(109/4 361), 10.1%(63/3 759) and 9.0%(36/2 784) among the 4 groups (P<0.001).

CONCLUSIONS

Persistent chest pain and sweat are absent in nearly half of Chinese patients in ≥75 years old group. Triggering factors prior to acute myocardial infarction could be evidenced in about twenty percent patients, and which are more often in young patients. Clinical Trail Registry: National Institutes of Health，NCT018746.

Hematogones: a sensitive prognostic factor for Chinese adult patients with acute myeloid leukemia

BACKGROUND

Hematogones (hgs) are normal B-lymphocyte precursors that increase in some hematologic diseases. Many studies indicate that hgs might be a favourable prognostic factor. We thus considered it important to determine whether hgs are also a prognostic factor for Chinese adult patients with acute myeloid leukemia (aml) and whether the hg-positive and hg-negative groups show any serologic or phenotypic differences.

METHODS

Chinese adult aml patients (n = 177) who were all initially hg-negative underwent standard chemotherapy and were thereafter divided into hg-positive and hg-negative groups according to hg levels in bone marrow during their first remission.

RESULTS

The follow-up study confirmed that survival duration (both leukemia-free and overall) was significantly greater in the hg-positive group than in the hg-negative group and was accompanied by a lower relapse rate. A retrospective study of patient characteristics at the time of first diagnosis revealed some differences between the hg-positive and the hg-negative groups, including elevations in white blood cells, lactate dehydrogenase, and β2-microglobulin in the hg-negative group. Retrospective phenotypic analysis revealed a significantly lower proportion of abnormal chromosome karyotype and CD34 expression in hg-positive patients. Finally, we evaluated whether additional intensive chemotherapy after standard chemotherapy could further increase hgs.

CONCLUSIONS

The present work verified the validity of hgs as a prognostic factor for Chinese adult patients with aml. Compared with hg-negative patients, hg-positive patients not only experienced longer survival and a lower relapse rate, but they also had some serologic and phenotypic characteristics that are all considered indicators of better outcome. Additional intensive chemotherapy could further increase the level of hgs, which might imply better clinical results.

A single fas gene mutation changes lupus onset, severity, location, and molecular abnormalities in mice

Although genetic predisposition plays a major role in the progression of systemic lupus erythematosus (SLE) and its variation in symptoms, the precise relationships between genetic changes and disease status are not well understood. Here, to demonstrate the effect of a single gene mutation on disease etiology, we examined two mouse models of SLE with the same genetic background but different Fas genes. Mice with the Fas(lpr) gene developed severe SLE with renal dysfunction and inflammatory responses in the lung and kidney. By contrast, mice with the Fas(+) gene showed disease-related abnormalities in the liver and joints. Patterns of inflammatory disease markers differed across organs between the two lines of mice. Fas(lpr) mice showed greater MMP signals in the kidney and IL-11 signals in the lung than Fas(+) mice. Fas(+) mice had higher IL-11 signal intensity in the knee region and higher CXCR4 signal intensity in the liver than Fas(lpr) mice. Our results exemplify the complexity of disease and suggest the need for individualized target-specific treatment regimens. Strengths and Limitations of this Study: Fas gene is a well characterized gene in this disease. The molecular components in human disease need more clinical data.

Novel NPHS1 splice site mutations in a Chinese child with congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS) is defined as heavy proteinuria or nephrotic syndrome occurring before 3 months of age. It is characterized by early onset and progresses to end-stage renal disease. Recently, several genes associated with CNS have been identified, including NPHS1 and NPHS2. Mutations in the NPHS1 gene have been identified in patients with CNS in Finland with relatively high frequency. Thus far, only a few case reports about CNS have described an NPHS1 mutation in China. In this study, mutational analyses of NPHS1 and NPHS2 were performed in a Chinese child with CNS. Mutations were analyzed in all exons and exon/intron boundaries of NPHS1 and NPHS2 in the patient and his parents as well as in 50 unrelated controls using polymerase chain reaction and direct sequencing techniques. No mutations were detected in NPHS2. A novel splice site mutation (IVS11+1G>A) within intron 11 and a missense mutation within exon 8 (c.928G>A) in the NPHS1 gene were detected in the child. The child's mother had normal urinalysis and a c.928G>A (D310N) heterozygous mutation, and his father had normal urinalysis and IVS11+1G>A. These were not identified in the 50 unrelated controls. The novel splice site mutation of IVS11+1G>A and a missense mutation at c.928G>A in NPHS1 were found to cause CNS in this Chinese child.

Mutational analysis of podocyte genes in children with sporadic steroid-resistant nephrotic syndrome

Recent studies have demonstrated that mutations in 4 podocyte genes, NPHS1, NPHS2, CD2AP, and WT1, are associated with the pathogenesis of steroid-resistant nephrotic syndrome (SRNS). Systematic investigation of all 4 genes for sporadic SRNS in China has not been performed. We examined 10 Chinese children with sporadic SRNS who showed no response to immunosuppressive agents and 20 SRNS controls who exhibited a response to prolonged steroid or immunosuppressive treatment and achieved complete remission. We analyzed mutations in the 4 podocyte genes, NPHS1, NPHS2, CD2AP, and WT1. Mutational analysis was performed using polymerase chain reaction and direct sequencing. Of the 10 SRNS children who showed no response to immunosuppressive agents, the compound heterozygous NPHS1 mutations 2677A>G (T893A) and *142T>C were identified in 1 patient, while a heterozygous mutation in WT1, 1180C>T (R394W), was found in another patient. Of the 20 SRNS children showing complete remission who responded to prolonged steroid therapy or immunosuppressive agents, 4 heterozygous NPHS1 mutations, 928G>A, IVS8+30C>T, IVS21+14G>A, and IVS25-23C>T, were identified in 4 patients and a heterozygous CD2AP mutation, IVS7-135G>A, was identified in 1 patient. Our results indicate the necessity of genetic examination for mutations in podocyte genes in Chinese SRNS children who show no response to immunosuppressive agents.

Distinguishing immunorelated haemocytopenia from idiopathic cytopenia of undetermined significance (ICUS): a bone marrow abnormality mediated by autoantibodies

In recent years we have observed that some patients with idiopathic cytopenia of undetermined significance (ICUS) responded well to corticosteroid and high-dose intravenous immunoglobulin treatment, indicating that some cytopenia in ICUS might be mediated by autoantibodies. In this study, we analysed 166 ICUS cases retrospectively, some of which were autoantibodies detected on haemopoietic cells in bone marrow (BM) by BM mononuclear cell (BMMNC)-Coombs test, flow cytometry (FCM), Western blot and immunofluorescence (IF). We found that 25·9% (43 of 166) of the cases had autoantibodies positive verified with BMMNC-Coombs test or FCM analysis, 72·1% (31 of 43) of whom had immunoglobulin (Ig)G autoantibody positive by Western blot. IgG could be detected in the erythroblastic islands on the BM smear of nine (32·1%, nine of 28) ICUS patients with autoantibodies by IF. Of these 43 patients, the median percentage of reticulocytes was 1·79%. More than half the patients had hyper-BM cellularity with a higher percentage of nucleated erythroid cells in the sternum. Total response rates to immunosuppressive therapy at 6, 12, 24 and > 36 months were 46·5% (20 of 43), 75% (30 of 40), 77·4% (24 of 31) and 66·7% (16 of 24), respectively. We termed this group of ICUS cases with autoantibodies as immunorelated haemocytopenia (or BMMNC-Coombs test-positive haemocytopenia).

Fas/FasL in the immune pathogenesis of severe aplastic anemia

Fas/FasL protein expression of bone marrow hematopoietic cells was investigated in severe aplastic anemia (SAA) patients. Fas expression was evaluated in CD34(+), GlycoA(+), CD33(+), and CD14(+) cells labeled with monoclonal antibodies in newly diagnosed and remission SAA patients along with normal controls. FasL expression was evaluated in CD8(+) cells in the same manner. In CD34(+) cells, Fas expression was significantly higher in the newly diagnosed SAA group (46.59 ± 27.60%) than the remission (6.12 ± 3.35%; P < 0.01) and control (8.89 ± 7.28%; P < 0.01) groups. In CD14(+), CD33(+), and GlycoA(+) cells, Fas levels were significantly lower in the newly diagnosed SAA group (29.29 ± 9.23, 46.88 ± 14.30, and 15.15 ± 9.26%, respectively) than in the remission (47.23 ± 31.56, 67.22 ± 34.68, and 43.56 ± 26.85%, respectively; P < 0.05) and normal control (51.25 ± 38.36, 72.06 ± 39.88, 50.38 ± 39.88%, respectively; P < 0.05) groups. FasL expression of CD8(+) cells was significantly higher in the newly diagnosed SAA group (89.53 ± 45.68%) than the remission (56.39 ± 27.94%; P < 0.01) and control (48.63 ± 27.38%; P <0.01) groups. No significant differences were observed between the remission and control groups. FasL expression in CD8(+) T cells was significantly higher in newly diagnosed patients, and CD34(+), CD33(+), CD14(+), and GlycoA(+) cells all showed Fas antigen expression. The Fas/FasL pathway might play an important role in excessive hematopoietic cell apoptosis in SAA bone marrow. Furthermore, CD34(+) cells are likely the main targets of SAA immune injury.

Effect of Astragalus polysaccharides on chronic atrophic gastritis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats

This study investigated the effect and mechanism of Astragalus polysaccharides (APS) on chronic atrophic gastritis (CAG) induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in rats. Histomorphological, hormone-level, and immunohistochemistry experiments were used to investigate the gastric mucosal injury. Pathological changes were readily found in CAG rats. Compared to the control rats, the CAG rats showed significantly decreased plasma levels of gastrin and somatostatin while their motilin levels increased. Moreover, PGE2 in gastric tissue increased and serum sIgA decreased significantly, while the GSH/GSSG ratio showed no change. Immunohistochemical detection showed that the expression of EGFR, COX-2, and MMP-2 was higher in the gastric tissue of CAG rats. After APS treatment, the gastric morphology of CAG rats improved. APS increased plasma gastrin and somatostatin levels significantly but had no significant effect on the motilin level. APS also decreased tissue PGE2 and increased serum sIgA in CAG rats without affecting the GSH/GSSH ratio. This study suggested that APS had a beneficial effect on CAG rats by deregulating EGFR at its downstream effectors COX-2 and MMP-2.

Effect of prolonged riluzole exposure on cultured motoneurons in a mouse model of ALS

Riluzole is the only FDA-approved drug to treat amyotrophic lateral sclerosis, but its long-term effects on motoneurons are unknown. Therefore, we treated primary mouse spinal cord cultures with 2 μM riluzole for 4-9 days and then used whole cell patch clamp to record the passive and active properties of both wild-type and SOD1(G93A) motoneurons. At this concentration, riluzole blocks >50% of the sodium component of a persistent inward current that plays a major role in determining motoneuron excitability. Prolonged riluzole treatment significantly decreased the amplitude of the persistent inward current. This effect was specific for SOD1(G93A) motoneurons, where the amplitude decreased by 55.4%. In addition, prolonged treatment hyperpolarized the resting membrane potential as well as the voltage onset and voltage maximum of the persistent inward current (∼2-3 mV in each case). These effects appeared to offset one another and resulted in no change in the firing properties. In a subset of cells, acute reapplication of 2 μM riluzole during the recording decreased repetitive firing and the persistent inward current, which is consistent with the normal effects of riluzole. The downregulation of the persistent inward current in response to prolonged riluzole administration is in contrast to the strong upregulation of this same current after descending neuromodulatory drive to the cord is lost following spinal injury. This dichotomy suggests that decreased activation of G protein-coupled pathways can induce upregulation in the persistent inward current but that direct channel block is ineffective.