Melting temperature mapping method in children: Rapid identification of pathogenic microbes

INTRODUCTION

The melting temperature (Tm) mapping method (TM) identifies bacterial species by intrinsic patterns of Tm values in the 16S ribosomal RNA gene (16S rDNA) extracted directly from whole blood. We examined potential clinical application of TM in children with bloodstream infection (BSI).

METHODS

This was a prospective observational study at a children's hospital in Japan from 2018 to 2021. In patients with diagnosed or suspected BSI, we investigated the match rates of pathogenic bacteria identified by TM and blood culture (BC), the inspection time to identification of TM, and the amount of bacterial DNA in blood samples.

RESULTS

The median age of 81 patients (93 samples) was 3.6 years. Of 23 samples identified by TM, 11 samples matched the bacterial species with BC (positive-match rate, 48 %). Of 64 TM-negative samples, 62 samples were negative for BC (negative-match rate, 97 %). Six samples, including one containing two pathogenic bacterial species, were not suitable for TM identification. In total, the matched samples were 73 of 93 samples (match rate, 78 %). There were seven samples identified by TM in BC-negative samples from blood collected after antibiotic therapy. Interestingly, the bacteria were matched with BC before antibiotic administration. These TM samples contained as many 16S rDNA copies as the BC-positive samples. The median inspection time to identification using TM was 4.7 h.

CONCLUSIONS

In children with BSI, TM had high negative-match rates with BC, the potential to identify the pathogenic bacteria even in patients on antibiotic therapy, and more rapid identification compared to BC.

REGISTERING CLINICAL TRIALS

UMIN000041359https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000047220.

Bacillus Calmette-Guérin (BCG) Infections at High Frequency in Both AR-CGD and X-CGD Patients Following BCG Vaccination

BACKGROUND

Patients with chronic granulomatous disease (CGD) develop severe infections, including Bacillus Calmette-Guérin (BCG). Although the autosomal recessive CGD (AR-CGD) patients should hypothetically develop relatively fewer infections compared to the X-linked CGD (X-CGD) patients due to more residual reactive oxygen intermediates, the impacts of BCG vaccination on AR-CGD and X-CGD patients are unclear. Herein, we demonstrated the clinical features of BCG infections, treatments, and genetic factors in CGD patients after BCG vaccination under the Japanese immunization program.

METHODS

We collected data retrospectively from 43 patients with CGD and assessed their history of initial infection, age at diagnosis of CGD, BCG vaccination history, clinical course, treatment for BCG infections, and genetic mutations associated with CGD.

RESULTS

Fourteen CGD patients avoided BCG vaccination because of other preceding infections and family history. Of 29 patients with CGD who received BCG vaccination, 20 patients developed BCG infections. Although the age at onset of initial infection in X-CGD patients was significantly younger than that in AR-CGD patients (P < .01), the onset and frequency of BCG infections were similar in X-CGD and AR-CGD patients. In X-CGD patients, BCG infections equally developed in the patients carrying missense, insertion, deletion, nonsense, and splice mutations of CYBB. All CGD patients with BCG infections were successfully treated with anti-tuberculous drugs.

CONCLUSIONS

Although X-CGD patients develop severe infections at a younger age than AR-CGD patients, our data suggested that BCG infections develop at high frequency in both AR-CGD and X-CGD patients, regardless of genotype and mutant forms.

Modulation of human Valpha24(+)Vbeta11(+) NKT cells by age, malignancy and conventional anticancer therapies

Immunotherapy strategies aimed at increasing human Vα24⁺Vβ11⁺ natural killer T (NKT) cell numbers are currently a major focus. To provide further information towards the goal of NKT cell-based immunotherapy, we assessed the effects of age, cancer status and prior anticancer treatment on NKT cell numbers and their expansion capacity following α-galactosylceramide (α-GalCer) stimulation. The percentage and absolute number of peripheral blood NKT cells was assessed in 40 healthy donors and 109 solid cancer patients (colorectal (n=33), breast (n=10), melanoma (n=17), lung (n=8), renal cell carcinoma (n=10), other cancers (n=31)). Responsiveness to α-GalCer stimulation was also assessed in 28 of the cancer patients and 37 of the healthy donors. Natural killer T cell numbers were significantly reduced in melanoma and breast cancer patients. While NKT numbers decreased with age in healthy donors, NKT cells were decreased in these cancer subgroups despite age and sex adjustments. Prior radiation treatment was shown to contribute to the observed reduction in melanoma patients. Although cancer patient NKT cells were significantly less responsive to α-GalCer stimulation, they remained capable of substantial expansion. Natural killer T cells are therefore modulated by age, malignancy and prior anticancer treatment; however, cancer patient NKT cells remain capable of responding to α-GalCer-based immenotherapies.

Effects of leukapheresis protocol, cell processing and cryopreservation on the generation of monocyte-derived DC for immune therapy

BACKGROUND

Many clinical trials of DC-based immunotherapy involve administration of monocyte-derived DCs (Mo-DC) on multiple occasion. We aimed to determine tbe optimal cell processing procedures and timing (leukapheresis, RBC depletion and cryopreservation) for generation of Mo-DC for clinical purposes.

METHODS

Leukapheresis was undertaken using a COBE Spectra. Two instrument settings were compared - the standard semi-automated software (Version 4.7) (n = 10) and the fully automated software (Version 6.0) (N = 40). Density gradient centrifugation using Ficoll, Percoll, a combination of these methods or neither for RBC depletion were compared. Outcomes (including cell yield and purity) were compared for cryopreserved unmanipulated monocytes and cryopreserved Mo-DC.

RESULTS

Software Version 6.0 provided significantly better enrichment for monocytes (P < 0.05) but 25% fewer total monocytes. Final Mo-DC purity was not influenced by leukapheresis or RBC depletion method, but was critically dependent on monocyte adherence. Version 6.0 produced significantly lower RBC and platelet contamination (P < 0.0005) but in vitro RBC depletion could not routinely be omitted. Only 5-6% of monocytes harvested resulted in Mo-DC (95% lost in cell processing or failing to differentiate).

DISCUSSION

Cell losses remained significant despite attempts to minimise processing steps during Mo-DC generation. Reduction in RBC and platelets achieved with software version 6.0 was insufficient to offset the disadvantage of the lower monocyte yield. Substantial savings in materials and other costs can be achieved if Mo-DC for multiple treatments are generated from cryopreserved monocytes rather than from fresh monocytes.

Human peripheral blood Valpha24+ Vbeta11+ NKT cells expand following administration of alpha-galactosylceramide-pulsed dendritic cells

BACKGROUND AND OBJECTIVES

We have undertaken the first clinical trial involving the administration of alpha-GalactosylCeramine (alpha-GalCer)-pulsed dendritic cells (DCs) to human subjects, to determine safety, optimal dose, optimal administration route and immunological effects.

MATERIALS AND METHODS

Subjects (n = 4) with metastatic malignancy received two infusions of alpha-GalCer-pulsed DCs intravenously, and two infusions intradermally. The percentages of Valpha24 Vbeta11 NKT cells in peripheral blood (PB) were determined by three-colour flow cytometry and the PB NKT cell numbers were calculated using the total number of PB lymphocytes/ml determined by automated full-blood counts.

RESULTS

No serious treatment related adverse events were observed during the study period. Administration of alpha-GalCer-pulsed DCs in vivo can significantly (P < 0.03) increase PB Valpha24+ Vbeta11+ NKT cell numbers above pretreatment baseline levels after the transient fall in the NKT numbers within 48 h.

CONCLUSIONS

Administration of alpha-GalCer-pulsed DCs is well tolerated, modulates PB Valpha24+ Vbeta11+ NKT cells and may have a role in the therapy of malignancies sensitive to activities of Valpha24+ Vbeta11+ NKT cells, or for autoimmune diseases.

Transcriptional suppression of the estrogen receptor by truncated estrogen receptor-alpha

The estrogen receptor (ER) is composed of six major functional domains - the A/B domain as the activation function 1 domain, domain C as the DNA-binding domain, domain D as a hinge domain, and domain E/F as the ligand-dependent transcriptional domains. A novel protein (designated as SRB-RGS) that interacted with domains C and D of ER alpha (ER alpha C/D) repressed the transcriptional activity of ER alpha. In this study, we have examined whether ER alpha C/D releases transcriptional suppression of ER alpha by intrinsic SRB-RGS. The expression vector of ER alpha C/D was transfected to the human cancer cell, KPL-1, which expressed the intrinsic ER. Unexpectedly, transcriptional suppression of ER by ER alpha C/D was observed. COS-7 cells, which have no intrinsic ER, showed a similar suppression of ER alpha by co-transfection of ER alpha and ER alpha C/D. The DNA-binding and the estrogen-binding activities of ER alpha decreased on co-transfection of ER alpha C/D, suggesting a decrease in the receptor protein itself. It is likely that the degradation of ER by co-transfection caused the transcriptional suppression of the ER.

Identification of a component that induces flowering of Lemna among the reaction products of alpha-ketol linolenic acid (FIF) and norepinephrine

A stress-induced fatty acid [FIF; 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid] incubated with (-)-norepinephrine (NE) strongly induces flower formation in Lemna paucicostata [Yokoyama et al. (2000), Plant Cell Physiol. 41: 110). The increase of flower-inducing activity was well correlated with the decrease in FIF in the incubation mixture, and the reaction proceeded rapidly at higher pH. We detected small amounts of many active components in the mixture after incubation by HPLC analysis. In this study, two major components, named FN1 and FN2, of the reaction mixture were isolated, and their absolute stereostructures were determined. FN1 showed a strong flower-inducing activity and was identified as a tricyclic alpha-ketol fatty acid, 9(R)-11-[(2'R,8'R,10'S,11'S)-2',8'-dihydroxy-7'-oxo-11'-[(Z)-2-pentenyl]-9'-oxa-4'-azatricyclo[6.3.1.0(1.5)]dodec- 5'en-10'-yl]-9-hydroxy-10-oxoundecanoic acid [corrected]. FN2, the C-9 epimer of FN1, showed no flower-inducing activity. The absolute stereostructure of FIF was also determined by a modification of Mosher's method. The 9-hydroxyl group was found to be predominantly 9R, with an enantiomeric excess of 40% (70% 9R and 30% 9S). FN1 was derived from 9R-type FIF and FN2 from 9S-type FIF. Various catecholamines and related substances were investigated for the ability to develop flower-inducing activity upon incubation with FIF. The essential structures were catechol and ethylamine groups (dopamine).

Polymorphisms in the coding region of mtDNA and effects on clinical outcome of unrelated bone marrow transplantation

The entire protein-coding region was divided into 45 fragments, separately amplified and analyzed for polymorphism by the PCR-SSCP (single-strand conformation polymorphism) method. The effect of polymorphism mismatching on the clinical outcome of unrelated bone marrow transplantation was studied to clarify whether products from mtDNA become minor antigens. Variability in PCR-SSCP pattern combinations of the 45 fragments suggests that each individual has a different polymorphism combination in the protein-coding region if all the coding regions were compared at the nucleotide sequence level. Nonsynonymous polymorphisms were found at relatively high frequency in MTATP8 and MTND3. Both the polymorphisms with and without substitution matched the peptide-binding motifs of HLA-A*0201. The effects of the polymorphism matching were retrospectively analyzed in 340 recipients transplanted with HLA-A, -B, -DRB1 allele-matched bone marrow from unrelated donors. There were no effects of polymorphism matching on the incidence of acute GVHD and cumulative disease-free survival. These results suggest that polymorphisms which generate peptides, with and without substitutions, that bind the same HLA molecule hardly influence GVHD because the difference between the HLA-peptide complexes is minute.

Profiling of genes expressed in human monocytes and monocyte-derived dendritic cells using cDNA expression array

Using a human cDNA expression array, we obtained expression profiles of 588 genes in CD14+ monocytes and monocyte-derived dendritic cells (DCs). Overall, 22 genes were upregulated, and nine genes were downregulated in DCs of both samples from two different individuals. Many of the genes that were upregulated in DCs encode proteins that are related to differentiation, cell structure, migration, termination of cell cycle as well as proliferation, e.g. tumour necrosis factor-alpha (TNF-alpha), tumour necrosis factor receptor II (TNFRII), thymosin beta-10, epithelial discoidin domain receptor 1, replication factor C, putative transcription factor DB1, alpha catenin, transforming growth factor-beta 1, prohibitin, p53-regulating protein and neu differentiation factor. Among the downregulated genes in DCs were genes that encode proteins of cell cycle regulation: mitotic growth and transcription activator, platelet-derived growth factor receptor-beta subunit, interleukin 2 receptor (IL-2R)-gamma subunit, IL-7R-alpha subunit, leucocyte interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR). Semi-quantitative reverse transcription-polymerase chain reaction method confirmed the upregulated expression levels in DCs for TNFRII, TNF-alpha, alpha catenin and downregulation of IFN-gamma, GM-CSFR on four different donor samples of DCs and monocytes. Moreover, our data show the presence of a 'switch-on' step for the TNF-alpha and TNFRII gene expression in immature DCs for further differentiation into mature DCs.

[Standardization of hemopoietic colony assay reagents]

Several Japanese Red Cross blood centers have begun cooperating with hospitals in peripheral blood stem cell transplantation research. However, most have not yet standardized their techniques or reagents for that purpose yet. Consequently, wide variations are often observed in data from different blood centers, especially for hemopoietic colony assays. We compared our colony assay reagent set with those in three commercial colony assay kits. The best results were obtained with the kit from a manufacturer referred to here as company A. Although our reagent set obtained lower colony values, the CFU-GM, BFU-E, and total colony values correlated well with those obtained using company A's kit (r = 0.74, 0.80, and 0.97, respectively). Company A's kit gave reproducible results even with the use of different lots, and includes reagents that can be stored for up to two years at -20 degrees C. These features highlighted its advantages as a standard reagent set.

Adenine phosphoribosyltransferase deficiency identified by urinary sediment analysis: cellular and molecular confirmation

Adenine phosphoribosyltransferase deficiency is an autosomal recessive purine enzyme defect that causes urolithiasis and, in severe cases, renal failure. Most homozygotes with this disorder were identified by analyses of excreted or surgically removed urinary stones, but some were identified only because they were family members of symptomatic individuals. We report here the detection of adenine phosphoribosyltransferase deficiency in two cases by routine analysis of urinary sediments. 2,8-Dihydroxyadenine-like spherical crystals were observed in the urinary sediment, and a diagnosis of homozygous adenine phosphoribosyltransferase deficiency was confirmed by cellular and molecular methods. A molecular diagnostic system using the polymerase-chain reaction and single-strand conformational polymorphism analysis proved to be a rapid and sensitive method to identify the APRT*J allele, a common mutant allele among the Japanese people. These methods will facilitate identification of symptomatic and asymptomatic individuals with homozygous adenine phosphoribosyltransferase deficiency.