Blastic plasmacytoid dendritic cell neoplasm presenting as leukemia without cutaneous lesion.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy, recognized as a distinct entity in the WHO 2008 classification of hematolymphoid neoplasm. Described for the first time in 1994 as CD4+ cutaneous lymphoma with high expression of CD56, BPDCN has been known previously with various names such as blastic natural killer (NK) leukemia/lymphoma, agranular CD4+ CD56+ hematodermic neoplasm, and agranular CD4+ NK cell leukemia. This disease usually presents with cutaneous involvement as the first manifestation, with subsequent or simultaneous spread to bone marrow and peripheral blood. Leukemia as the first presenting symptom without any cutaneous involvement is a rare finding and can masquerade as acute undifferentiated leukemia. We present here such a case of a 59-year-old male who presented as leukemia without any cutaneous lesion but subsequently developed a scalp nodule.

Status of inflammatory biomarkers in the population that survived the Bhopal gas tragedy: a study after two decades.

Bhopal gas tragedy is considered as one of the world's worst industrial disaster. Approximately, 3,000-6,000 people died and 200,000 injured due to the leak of 40 tons of methyl isocyanate (MIC) gas from a pesticide plant. We aimed to decipher any persistent and subtle immunotoxic effects of MIC in the survivors of the tragedy. The study was divided into 3 groups i.e. group I (n=40); Age and gender matched non-exposed healthy controls recruited from places within the geographical region of Bhopal but from unaffected zones, group II (n=40); Age and gender matched non-exposed healthy controls recruited from places well outside geographical region of Bhopal and group III (n=40); Age and gender matched MIC exposed subjects from affected zones inside geographical region of Bhopal and the status of inflammatory biomarkers (IL-8, IL-1beta, IL-6, TNF, IL-10, IL-12p70 cytokines and C-reactive protein) were analysed. The results displayed a significant increase in the levels of all circulating inflammatory biomarkers in the MIC exposed group in comparison to non-exposed cohorts. A toxin induced genetic and/or epigenetic alteration seems to be the likely underlying cause. However, further studies are essential for both mechanistic understanding and clinical implications of these patterns.

Comparative evaluation of hepatitis B surface antigen-loaded elastic liposomes and ethosomes for human dendritic cell uptake and immune response.

The aim of the present study was to evaluate two vesicular carrier systems, ethosomes and elastic liposomes loaded with hepatitis B surface antigen, for in vitro qualitative and quantitative uptake by human dendritic cells (DCs) and ability to stimulate T lymphocytes. Quantitative uptake of antigen-loaded carriers was documented by flow cytometry, and internalization of the systems by the DCs was studied using spectral bioimaging. Ability of antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes and levels of TH1/TH2 cytokines were also examined using flow cytometry. Both vesicular carrier systems as antigen delivery modules and DCs as antigen-presenting cells were able to generate a protective immune response. However, ethosomes were found to have higher internalizing ability and immunogenicity in comparison with elastic liposomes. These properties of ethosomes coupled with their skin-navigating potential, make it an attractive vehicle for development of a transcutaneous vaccine against hepatitis B in preference to elastic liposomes. FROM THE CLINICAL EDITOR: Two carrier systems for more potent vaccine administration - ethosomes and elastic liposomes loaded with hepatitis B surface antigen - are compared. Ethosomes demonstrated higher internalizing ability and immunogenicity. Due to their known skin-navigating potential, ethosomes may represent an attractive vehicle for development of a transcutaneous vaccine against hepatitis B.

Systemic and mucosal immune response induced by transcutaneous immunization using Hepatitis B surface antigen-loaded modified liposomes.

We have evaluated the efficiency of novel modified liposomes (ethosomes) for transcutaneous immunization (TCI) against Hepatitis B. Antigen-loaded ethosomes were prepared and characterized for shape, lamellarity, fluidity, size distribution, and entrapment efficiency. Spectral bio-imaging and flow cytometric studies showed efficient uptake of Hepatitis B surface antigen (HBsAg)-loaded ethosomes by murine dendritic cells (DCs) in vitro, reaching a peak by 180 min. Transcutaneous delivery potential of the antigen-loaded system using human cadaver skin demonstrated a much higher skin permeation of the antigen in comparison to conventional liposomes and soluble antigen preparation. Topically applied HBsAg-loaded ethosomes in experimental mice showed a robust systemic and mucosal humoral immune response compared to intramuscularly administered alum-adsorbed HBsAg suspension, topically applied plain HBsAg solution and hydroethanolic (25%) HBsAg solution. The ability of the antigen-pulsed DCs to stimulate autologous peripheral blood lymphocytes was demonstrated by BrdU assay and a predominantly TH1 type of immune response was observed by multiplex cytometric bead array analysis. HBsAg-loaded ethosomes are able to generate a protective immune response and their ability to traverse and target the immunological milieu of the skin may find a potential application in the development of a transcutaneous vaccine against Hepatitis B virus (HBV).

Evaluation of uptake and generation of immune response by murine dendritic cells pulsed with hepatitis B surface antigen-loaded elastic liposomes.

Hepatitis B surface antigen (HBsAg)-loaded elastic liposomes were studied for qualitative and quantitative uptake in vitro by murine dendritic cells (DCs) generated from bone marrow mononuclear cells. Internalization of the vesicles by the DCs was documented using fluorescence microscopy. Kinetics of uptake of antigen-loaded elastic vesicles by the DCs studied through flow cytometry showed a peak uptake at 6h. The ability of the antigen pulsed DCs to stimulate autologous peripheral blood lymphocytes was demonstrated by BrdU assay. Further evaluation by multiplex cytometric bead array analysis demonstrated a predominantly TH1 type of immune response. Our results suggest that HBsAg-loaded elastic vesicles as antigen delivery module and DCs as antigen presenting cells are able to generate a protective immune response. The property of elastic liposomes to traverse and target the immunological milieu of the skin makes it an attractive vehicle for development of a transcutaneous vaccine against hepatitis B virus.

Resistance of bcr-abl-positive acute lymphoblastic leukemia to daunorubicin is not mediated by mdr1 gene expression.

In vitro resistance to anthracyclines is thought to be a poor prognosis in achieving long-term remission in patients with acute lymphoblastic leukemia (ALL). Expression of a multidrug resistance gene (mdr1) that codes for 170 Kd transmembrane glycoprotein is responsible for conferring resistance to malignant cells to anthracyclines. The t(9:22) translocation, resulting in bcr-abl fusion gene, is commonly found in B-lineage ALL and is known to be a poor prognostic factor for long-term remission. To investigate whether resistance to anthracyclines contributes to poor prognosis in bcr-abl-positive ALL, we studied daunorubicin sensitivity by an in vitro colorimetric methyl tetrazolium (MTT) assay in B-lineage ALL patients who were bcr-abl-positive and compared them with the B-lineage, age-matched bcr-abl-negative group. We also looked for and compared the presence of mdr1 gene expression in these two groups of patients by RT-PCR. Of the 46 patients included in the study, 16 (34.7%) were positive for the bcr-abl fusion gene. mdr1 gene expression was seen in 14 of these 46 patients (30.4%). However, the expression of the mdr1 gene was relatively lower in the bcr-abl-positive group (3 out of 16, 18.7%) compared to the bcr-abl-negative group (11 out of 30, 36.6%). The median LD(50) of daunorubicin (concentration lethal to 50% of the leukemic blasts) differed significantly between bcr-abl-positive and -negative patients (P = 0.018). This in vitro study suggests that bcr-abl-positive ALL is relatively resistant to daunorubicin, but this resistance is not mediated through mdr1 gene expression.

Drug sensitivity assay for leukaemic cells by flow cytometry.

BACKGROUND & OBJECTIVES: Drug sensitivity assays are useful in oncology practice for evaluating the sensitivity of malignant cells to anti-cancer drugs. The usefulness of such assays for the prediction of clinical response to therapy has also been demonstrated. The existing methods used for this purpose are time consuming and labour intensive. Here we report a simplified flow cytometry based assay for evaluating the in vitro drug sensitivity of leukaemic cells. METHODS: The chemo-sensitivity of three human leukaemic cell lines (a lymphoblastoid cell line, Jurkat; an erythroleukaemic cell line, K 562 and a myelomonocytic cell line HL-60) was investigated by flow cytometry. Flow cytometry was used to determine LD50 (50% inhibitory concentration) for prednisolone on Jurkat and daunorubicin on HL 60 and K 562 cell lines respectively. Per cent cell death could directly be assessed on a flow cytometer by measuring the fluorescence after staining with propidium iodide (PI). For comparison MTT assay was also performed using prednisolone on Jurkat and daunorubicin on HL-60. RESULTS: Cytotoxic effect of drugs was found to be dose dependent. Mean LD50 of prednisolone for Jurkat cells by flow cytometry was 0.805 +/- 0.058 mg/ml and by MTT assay 0.866 +/- 0.115 mg/ml. Mean LD50 of daunorubicin for HL-60 was 1.96 +/- 0.05 micrograms/ml by flow cytometry and 1.90 +/- 0.282 micrograms/ml by MTT assay. The mean LD50 of daunorubicin to K 562 was 0.49 +/- 0.049 mg/ml by the flow cytometry method. The inter-assay variation for the LD50 by flow cytometry based assay was found to be 6, 14 and 10 per cent for Jurkat, HL-60 and K 562 respectively. INTERPRETATION & CONCLUSION: We report a flow cytometry based drug-sensitivity assay for leukaemic cells, which uses a single dye staining and is rapid, technically simple and reproducible. The results compare well with the more commonly used MTT assay, which is labour intensive and time consuming. The limitation of our method is that it can only be used for studying cells in suspension and is therefore not suitable for adherent cell lines.

In vitro resistance of leukaemic blasts to prednisolone in bcr-abl positive childhood acute lymphoblastic leukaemia.

BACKGROUND & OBJECTIVES: Although the outcome of children with acute lymphoblastic leukaemia (ALL) has improved dramatically over the last decade, some children still fare poorly and relapses are seen. The sensitivity of leukaemic cells to corticosteroids has emerged as an important prognostic factor in ALL. The t(9,22) translocation, resulting in the bcr-abl fusion gene, is a non-random translocation found in B-lineage acute lymphoblastic leukaemia. It is also known to be an independent poor prognostic factor for long-term disease free survival. We studied the association between the presence of bcr-abl fusion gene and in vitro prednisolone resistance in children with B-lineage acute lymphoblastic leukaemia at diagnosis. METHODS: A total of 23 children (aged 1-16 yr, median age: 12 yr) with B-lineage acute lymphoblastic leukaemia at diagnosis were included in the study. The presence of bcr-abl fusion gene was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and the in-vitro resistance to prednisolone was measured by short term colorimetric methyl thiazol tetrazolium (MTT) assay. RESULTS: A median LD50 (lethal dose for 50% cells) for prednisolone in bcr-abl positive children (n=7) was 1.6 mg/ml (range: 0.25-5.0 mg/ml) and that of bcr-abl negative children (n=16) was 0.35 mg/ml (range 0.62-1.0 mg/ml). The median LD50 for prednisolone differed significantly between the bcr-abl positive and negative groups of children with acute lymphoblastic leukaemia (P<0.005). INTERPRETATION & CONCLUSION: This is probably the first report to show that leukaemic blasts of bcr-abl positive children with ALL are about four-fold resistant to prednisolone as compared to blasts from bcr-abl negative children. This suggests that one of the reasons for the poor prognosis of bcr-abl positive ALL could be a lower steroid sensitivity.