Clinical presentation and outcome of pediatric patients with hemophagocytic lymphohistiocytosis in China: A retrospective multicenter study.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a heterogeneous disease with major diagnostic and therapeutic difficulties. A large-scale multicenter study of pediatric HLH is still lacking in China. PROCEDURE: The Histiocytosis Study Group of the Chinese Pediatric Society conducted this retrospective study in 2014. A total of 323 patients diagnosed with HLH between 2011 and 2013 from 12 hospitals were registered. RESULTS: The median age at diagnosis was 2.2 years (range, 0-14.6 years), with a peak age of HLH onset at 0 to 3 years (63%). Mutations in HLH-related genes were found in 27.9% (24/86) patients who underwent genetic testing. PRF1, UNC13D, STXBP2 and LYST were the predominant genes involved. Sixteen patients (66.7%) presented with only monoallelic mutations in one gene. Epstein-Barr virus (EBV) infection was the major condition related to HLH, which was documented in 74.4% (201/270) of the patients who underwent EBV detection. Of 252 evaluable patients, 64.7% (163) achieved non-active disease at the eighth week and patients treated with a protocol containing etoposide presented higher remission rates (75.6% vs. 46.8%, P < 0.001). In multivariate analysis, a younger age at diagnosis (<12 months), platelet count less than 80×109 /L, central nervous system involvement, and initial treatment using a protocol without etoposide (not HLH-94/04) were independent prognostic factors indicating resistant disease. DISCUSSION: This study first multicenter assessment of HLH in China shows some different features in Chinese children with HLH compared with those in western countries, including older age, vulnerability to EBV infection, and a high proportion of patients with single monoallelic genetic mutations.

Urinary angiotensinogen levels in relation to renal involvement of Henoch-Schonlein purpura in children.

AIM: To investigate whether urinary angiotensinogen (UAGT) levels are correlated with renal involvement of Henoch-Schonlein purpura (HSP) in children, and to explore whether UAGT has any relation to the severity of HSP. METHODS: The study sample consisted of 107 patients (50 boys and 57 girls, 6.68±2.41 years) with clinical diagnosis of HSP. A 24 h urine sample was collected before treatment. UAGT levels were measured in patients with HSP in the acute and convalescent phases by enzyme linked immunosorbent assay. RESULTS: Urinary angiotensinogen/urinary concentration of creatinine levels were significantly higher in proteinuric HSP in the acute phase and the convalescent phase (32.02±3.95 and 25.31±4.11 µg/g) compared with those with HSP without renal involvement (17.26±2.60 and 15.14±3.81 µg/g) and those with hematuric HSP (19.70±2.21 and 17.28±3.62 µg/g) (P<0.0001 and P<0.01, respectively). Using matched urine samples from the same patients, UAGT/urinary concentration of creatinine (UCr) levels of proteinuric HSP patients were significantly lower in the convalescent phase (25.31 ± 4.11 µg/g, P<0.01) than in the acute phase (32.02±3.95 µg/g). UAGT/UCr levels showed positive correlation with 24 h urine protein or serum creatinine in both hematuric HSP and proteinuric HSP groups during the acute phase (P<0.05). CONCLUSIONS: Urinary angiotensinogen levels were remarkably high in the acute phase in the patients with proteinuric HSP, suggesting increased UAGT may indicate a series of functional changes in the kidney and it may be used as a potential biomarker of severity of HSP to monitor the progression of HSP with renal involvement.

[Deferoxamine induces apoptosis of K562 cells].

OBJECTIVE: To study the molecular mechanism of apoptosis of leukemic cells (K562 cells) induced by iron chelating agent deferoxamine (DFO). METHODS: The exponentially growing K562 cells were used (1×10(6)/mL) in this study. The K562 cells were treated with different concentrations of DFO (10, 50 and 100 mmol/L), DFO+FeCl3 (10 µmol/L each) or normal saline (blank control). The cellular labile iron pool was measured with a fluorimetric assay using the metalsensitive probe calcein-AM. The viable count and cell viability were determined by typanblue assay. Cell apoptosis was determined by morphological study and flow cytometry assay. Caspase-3 activity in K562 cells was detected by colorimetry. RESULTS: After DFO treatment, the cellular labile iron pool and the viability of K562 cells were reduced and the cell apoptosis increased in a time- and dose-dependent manner compared with the blank control group. The apoptosis rate of K562 cells in the DFO+FeCl3 treatment group was not significantly different from that in the blank control group. The caspase-3 activity in K562 cells increased significantly 24 hrs after 50 and 100 µmmol DFO treatment when compared with the blank control group (P<0.01). There was a negative correlation between cellular labile iron pool and caspase-3 activity of K562 cells (r=-0.894, P<0.05). CONCLUSIONS: DFO induces apoptosis of leukemic cells possibly through decreasing cellular labile iron pool and increasing caspase-3 activity of the cells.

[Detection of the labile iron pool in leukemia cells and its significance].

To explore a rapid and easy method to detect labile iron of pool (LIP) in cells, HL-60 and K562 cells were cultured at a concentration 1 x 10(6)/ml in RPMI 1640 containing 10% heat-inactivated fetal bovine serum. The iron deprivation was induced by adding desferrioxamine (DFO) 10 - 100 micromol/L for 0 - 48 hours. The intracellular LIP was measured by probe calcein-AM. Calcein fluorescence was monitored in 1420 multilabel counter. The results indicated that when HL-60 and K562 cells were incubated with different concentrations of DFO, the calcein fluorescence intensity was higher than that of control group at 12, 24 and 48 hours (P < 0.05). Fluorescence value of representing LIP in DFO groups was lower than that in the control group. In conclusion, DFO can decrease LIP in leukemia cells. The approach used in this study may provide a simple and reliable method for detection of intracellular iron homeostasis.

[EGR-1 mRNA expression during 12-0-tetradecanoylphorbol-13-acetate-induced K562 cell differentiation].

OBJECTIVE: 12-0-tetradecanoylphorbol-13 acetate (TPA) plays an important role in precipitating cell differentiation for various tumor cells, especially leukemic cells. Changes of many genes may be involved in this process. The purpose of this study was to observe the relationship between the EGR1mRNA expression and cell differentiation during TPA-induced K562 cell differentiation. METHODS: Incubation of human K562 cells in vitro was applied to cultivate K562 cells. The cells were treated in two different ways. K562 cells of experiment group were treated with TPA and those of control group were treated without TPA. Using morphology (Wright's staining and NSE staining) and flow cytometry (FCM), the investigators observed the differentiation characteristics of K562 cells, cell-cycle and the differentiation antigen expressions of CD33 and CD14 on cell membranes. RT-PCR was carried out to assay EGR1 mRNA expression. RESULTS: After treated with TPA for 7 d, the morphology of K562 cells obviously tended to mature differentiation, like monocytes. The differentiation rate of induced K562 cells was up to 95% in experiment group and 4.5% in control group, respectively. Using SPSS software, the above result showed statistical significance (P < 0.01). Using NSE staining, K562 cells showed positive reaction. Some of them were densely stained. The positive rate was up to 86%. More than half of the positive cells could be inhibited by NaF. The inhibiting rate of NaF was up to 58.72%, showing statistical difference when compared with that of control group. FCM analysis showed that most of K562 cells stimulated by TPA underwent G1/S phase cell-cycle arrest. The composing rate of cell-cycle in TPA-treated group showed that (53.7 +/- 1.25)% of cells were at G0 + G1 phase and (44.3 +/- 1.32)% were at S phase (P < 0.05). The level of CD33 expression on cell membranes was mildly decreased from 0.997% to 0.893% (P > 0.05). However, the level of CD14 expression was significantly increased from 0.049% to 0.387% (P < 0.05). CONCLUSION: K562 cells could express EGR1mRNA during TPA-induced differentiation, which suggested that EGR1mRNA might participate in the process of K562 cells differentiating into monocyte/macrophages, and might play an important role in precipitating and maintaining cell differentiation for leukemic cells.