1.Observation of dendritic cell morphology under light, phase-contrast or confocal laser scanning microscopy.
Tan, Yuen-Fen ; Leong, Chooi-Fun ; Cheong, Soon-Keng
The Malaysian Journal of Pathology 2010;32(2):97-102
Dendritic cells (DCs) are professional antigen presenting cells of the immune system. They can be generated in vitro from peripheral blood monocytes supplemented with GM-CSF, IL-4 and TNF alpha. During induction, DCs will increase in size and acquire multiple cytoplasmic projections when compared to their precursor cells such as monocytes or haematopoietic stem cells which are usually round or spherical. Morphology of DCs can be visualized by conventional light microscopy after staining or phase-contrast inverted microscopy or confocal laser scanning microscopy. In this report, we described the morphological appearances of DCs captured using the above-mentioned techniques. We found that confocal laser scanning microscopy yielded DCs images with greater details but the operating cost for such a technique is high. On the other hand, the images obtained through light microscopy after appropriate staining or phase contrast microscopy were acceptable for identification purpose. Besides, these equipments are readily available in most laboratories and the cost of operation is affordable. Nevertheless, morphological identification is just one of the methods to characterise DCs. Other methods such as phenotypic expression markers and mixed leukocyte reactions are additional tools used in the characterisation of DCs.
Dendritic Cells/*cytology
;
Microscopy, Confocal
;
Microscopy, Phase-Contrast
2.Gamma irradiation and red cell haemolysis: a study at the Universiti Kebangsaan Malaysia Medical Centre
Rabeya Yousuf ; Mohd Herman Mobin ; Chooi Fun Leong
The Malaysian Journal of Pathology 2015;37(2):91-94
Gamma-irradiation of blood components is regarded a safe procedure used for prevention of transfusionassociated
graft-versus-host disease. However, reports showed that irradiation can cause erythrocyte
haemolysis and damage to the RBC membrane. In Universiti Kebangsaan Malaysia Medical Centre
(UKMMC), a number of suspected transfusion reactions (TR) featured unusual isolated episodes
of red-coloured-urine or haemoglobinuria among paediatric patients without clinical features of
acute haemolytic TR. Haemolysis of irradiated red cells was suspected as a cause. This study was
conducted to evaluate haemolytic changes of RBC components following irradiation. A prospective,
pre- and post- irradiation comparative study was conducted on 36 paired RBC-components in the
blood-bank, UKMMC in the year 2013. Samples were tested for plasma-Hb, percent-haemolysis,
plasma-potassium (K+) and lactate dehydrogenase (LDH) level. Post-irradiation mean plasma-Hb
and percent-haemolysis were significantly higher than pre-irradiation values at 0.09±0.06g/dl VS
0.10±0.06g/dl and 0.19±0.13% VS 0.22±0.13% respectively, while plasma-K+ and LDH values
did not show significant difference. However, the mean percent-haemolysis level was still within
recommended acceptable levels for clinical use, supporting that irradiated RBC units were safe and
of acceptable quality for transfusion. There was no conclusive reason for isolated haemoglobinuria
following transfusion of irradiated red-cell products. Further research is suggested to investigate
the other possible causes.
3.Cellular mechanisms of emerging applications of mesenchymal stem cells
Pooi-Ling Mok ; Chooi-Fun Leong ; Soon-Keng Cheong
The Malaysian Journal of Pathology 2013;35(1):17-32
Mesenchymal stem cells (MSC) are multipotent, self-renewing cells that can be found mainly in the
bone marrow, and other post-natal organs and tissues. The ease of isolation and expansion, together
with the immunomodulatory properties and their capability to migrate to sites of infl ammation and
tumours make them a suitable candidate for therapeutic use in the clinical settings. We review here
the cellular mechanisms underlying the emerging applications of MSC in various fi elds.
4.Extensive myelofibrosis responsive to treatment for acute erythroblastic leukaemia.
S-Abdul-Wahid Fadilah ; Raja-Sabudin Raja-Zahratul-Azma ; Chooi-Fun Leong
The Malaysian journal of pathology 2006;28(1):55-8
Intense myelofibrosis is rarely associated with de novo acute myeloid leukaemia (AML) except in acute megakaryoblastic leukaemia (AML-M7) where there is diffuse marrow fibrosis as a consequence of proliferation of neoplastic myeloid cells. AML associated with significant myelofibrosis developing both de novo or secondary to primary (idiopathic) myelofibrosis is characterised by a fulminant course and extremely poor prognosis, primarily due to treatment-resistant disease. The prognostic value of degree of marrow fibrosis in de novo AML has been poorly investigated. We describe a case of extensive myelofibrosis associated with acute erythroblastic leukaemia (AML-M6) that responded to induction therapy of the leukaemia.
Myelofibrosis
;
Acute
;
Leukemia, Myelocytic, Acute
;
therapeutic aspects
;
prognostic
5.Experimental production of clinical-grade dendritic cell vaccine for acute myeloid leukemia.
Yuen-Fen Tan ; Geok-Choo Sim ; Aziz Habsah ; Chooi-Fun Leong ; Soon-Keng Cheong
The Malaysian journal of pathology 2008;30(2):73-9
Dendritic cells (DC) are professional antigen presenting cells of the immune system. Through the use of DC vaccines (DC after exposure to tumour antigens), cryopreserved in single-use aliquots, an attractive and novel immunotherapeutic strategy is available as an option for treatment. In this paper we describe an in vitro attempt to scale-up production of clinical-grade DC vaccines from leukemic cells. Blast cells of two relapsed AML patients were harvested for DC generation in serum-free culture medium containing clinical-grade cytokines GM-CSF, IL-4 and TNF-alpha. Cells from patient 1 were cultured in a bag and those from patient 2 were cultured in a flask. The numbers of seeding cells were 2.24 x 10(8) and 0.8 x 10(8), respectively. DC yields were 10 x 10(6) and 29.8 x 10(6) cells, giving a conversion rate of 4.7% and 37%, respectively. These DC vaccines were then cryopreserved in approximately one million cells per vial with 20% fresh frozen group AB plasma and 10% DMSO. At 12 months and 21 months post cryopreservation, these DC vaccines were thawed, and their sterility, viability, phenotype and functionality were studied. DC vaccines remained sterile up to 21 months of storage. Viability of the cryopreserved DC in the culture bag and flask was found to be 50% and 70% at 12 months post cryopreservation respectively; and 48% and 67% at 21 months post cryopreservation respectively. These DC vaccines exhibited mature DC surface phenotypic markers of CD83, CD86 and HLA-DR, and negative for haemopoietic markers. Mixed lymphocyte reaction (MLR) study showed functional DC vaccines. These experiments demonstrated that it is possible to produce clinical-grade DC vaccines in vitro from blast cells of leukemic patients, which could be cryopreserved up to 21 months for use if repeated vaccinations are required in the course of therapy.
Vaccines
;
month
;
Grade
;
Clinical
;
Lower case ecks
6.Molecular responses during chemotherapy in acute myeloid leukemias in predicting poor-response to standard chemotherapy.
Maha, Abdullah ; Cheong, Soon-Keng ; Leong, Chooi-Fun ; Seow, Heng-Fong
The Malaysian Journal of Pathology 2009;31(2):81-91
Signal transduction pathways are constitutively expressed in leukaemic cells resulting in aberrant survival of the cells. It is postulated that in cells of chemo-sensitive patients, chemotherapy induces apoptotic signals leading to cell death while survival signals are maintained in cells of chemo-resistant patients. There is very little information currently, on the expression of these mediators in patients immediately after chemotherapy initiation. We examined the expression pattern of proinflammatory cytokines, signaling molecules of the PI3K and MAPK pathways molecules and death receptor, DR5 on paired samples at diagnosis and during chemotherapy in acute myeloid leukaemia patients treated with cytosine arabinoside and daunorubicin. The results were correlated with remission status one month after chemotherapy. We found that in chemo-sensitive patients, chemotherapy significantly increased the percentage of cases expressing TNF-alpha (p = 0.025, n = 9) and IL-6 (p = 0.002, n = 11) compared to chemo-resistant cases. We also observed an increased percentage of chemo-sensitive cases expressing DR5 and phosphorylated p38, and Jnk. Thus, expression of TNF-alpha, IL-6, DR5, phospho-p38 and phospho-Jnk may regulate cell death in chemo-sensitive cases. In contrast, a significantly higher percentage of chemo-resistant cases expressed phospho-Bad (p = 0.027, n = 9). IL-beta and IL-18 were also found to be higher in chemo-resistant cases at diagnosis and during chemotherapy. Thus, expression of various cellular molecules in leukaemic blasts during chemotherapy may be useful in predicting treatment outcome. These cellular molecules may also be potential targets for alternative therapy.
7.Transfected human mesenchymal stem cells do not lose their surface markers and differentiation properties.
Yap, Fei-Ling ; Cheong, Soon-Keng ; Ammu, Radhakrishnan ; Leong, Chooi-Fun
The Malaysian Journal of Pathology 2009;31(2):113-20
In this study, we evaluated the biological properties of human mesenchymal stem cells transfected (hMSC) with a plasmid vector expressing human cytokine interleukin-12 (IL-12). Surface markers were analysed by immunophenotyping using flow cytometry. Differentiation capability was evaluated towards adipogenesis and osteogenesis. We demonstrated that successfully transfected hMSC retained their surface immunophenotypes and differentiation potential into adipocytes and osteocytes. These results indicate that hMSC may be a suitable vehicle for gene transduction.
Antigens, Surface/metabolism
;
Biological Markers/metabolism
;
Bone Marrow Cells/cytology
;
Bone Marrow Cells/metabolism
;
Cell Differentiation/physiology
;
Cells, Cultured
;
Flow Cytometry
;
Immunophenotyping
;
Interleukin-12/genetics
;
Interleukin-12/metabolism
;
Mesenchymal Stem Cells/*cytology
;
Mesenchymal Stem Cells/metabolism
;
Transfection
8.Comparison of Abtectcell III and Diamed red cell antibody screening kit for detection of clinically significant red cells alloantibody
Sharifah Mai Sarah Syed Azim ; Nor Asiah Muhamad ; Leong Chooi Fun ; Noor Hamidah Hussin
The Malaysian Journal of Pathology 2015;37(2):109-114
Antibody screening is important for the antenatal screening and pre-transfusion tests. This study
aimed to compare the MUT/Mur kodecytesAbtectcell III (CSL Abtectcell III) red cell antibody
screening kit with DiaMed ID-Dia Cell I-II-III Asia that was then used in our laboratory. In this
study, 125 samples were randomly chosen, with 67 samples of known antibody specificities and
58 samples identified as negative for antibody, as the negative control. Concordant negative results
were obtained in 57 out of 58 antibody negative samples. Concordant antibody positive results
with both reagents were seen in 49 out of 67 samples. There were 18 discrepant results of antibody
screening with CSL Abtetcell III (16/18 for vMNS antibodies). The sensitivity and specificity for
CSL Abtectcell III were 73.0% and 98.3% respectively. In conclusion, the CSL Abtectcell III reagent
would be an acceptable alternative for screening of red cell alloantibodies. It was able to detect all
the clinically significant alloantibodies.
9.Double Philadelphia chromosome-positive B acute lymphoblastic leukaemia in an elderly patient
Tang Yee-Loong ; Raja Zahratul Azma Raja Sabudin ; Leong Chooi-Fun ; Clarence Ko Ching-Huat
The Malaysian Journal of Pathology 2015;37(3):275-279
A rare case of double Philadelphia chromosome-positive B Acute lymphoblastic Leukaemia (B-ALL)
is reported here. A 60-year-old lady presented with one month history of fever, submandibular
lymphadenopathy, loss of appetite and weight loss. Physical examination revealed multiple palpable
cervical lymph nodes. Blood film showed leucocytosis with 72% blasts. Bone marrow assessment
confirmed a diagnosis of B-ALL with presence of double Philadelphia (Ph) chromosomes. As she was
very ill, she was initially treated with an attenuated regimen of induction chemotherapy consisting
of rituximab, cyclophosphamide, vincristine and prednisolone (R-CVP) along with intrathecal
chemotherapy comprising methotrexate, cytarabine and hydrocortisone. Bone marrow examination
post-induction chemotherapy showed >5% blasts. She was subsequently re-induced with rituximab,
cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) along with intrathecal
chemotherapy, following which she went into complete remission. Consolidation chemotherapy
consisting of methotrexate, methylprednisolone, cytarabine, intrathecal chemotherapy and imatinib
was subsequently administered followed by maintenance chemotherapy consisting of vincristine,
prednisolone and imatinib (IDEAMOP). She developed spontaneous bruises and relapsed four
months into her maintenance chemotherapy with 90% blasts in the bone marrow which was treated
with fludarabine, cytarabine and granulocyte colony stimulating factor (FLAG). Unfortunately she
developed neutropenic sepsis which was complicated by invasive lung aspergillosis. Bone marrow
examination post-FLAG showed 80% blasts. Despite aggressive antifungal therapy, her lung infection
worsened and she finally succumbed to her illness 13 months after the initial diagnosis. We highlight
a rare case of elderly B-ALL with double Ph chromosomes which carries a poor prognosis despite
aggressive treatment for the disease and its complications.
10.Dismal outcome of therapy-related myeloid neoplasm associated with complex aberrant karyotypes and monosomal karyotype: a case report
Tang Yee-Loong’ Chia Wai-Kit ; Yap Ernie Cornelius Sze-Wai ; Julia Mohd Idris ; Leong Chooi-Fun ; Salwati Shuib ; Wong Chieh-Lee
The Malaysian Journal of Pathology 2016;38(3):315-319
Introduction: Individuals who are exposed to cytotoxic agents are at risk of developing therapyrelated
myeloid neoplasms (t-MN). Cytogenetic findings of a neoplasm play an important role in
stratifying patients into different risk groups and thus predict the response to treatment and overall
survival. Case report: A 59-year-old man was diagnosed with acute promyelocytic leukaemia.
Following this, he underwent all-trans retinoic acid (ATRA) based chemotherapy and achieved
remission. Four years later, the disease relapsed and he was given idarubicin, mitoxantrone and
ATRA followed by maintenance chemotherapy (ATRA, mercaptopurine and methotrexate). He
achieved a second remission for the next 11 years. During a follow-up later, his full blood picture
showed leucocytosis, anaemia and leucoerythroblastic picture. Bone marrow examination showed
hypercellular marrow with trilineage dysplasia, 3% blasts but no abnormal promyelocyte. Fluorescence
in-situ hybridisation (FISH) study of the PML/RARA gene was negative. Karyotyping result
revealed complex abnormalities and monosomal karyotype (MK). A diagnosis of therapy-related
myelodysplastic syndrome/myeloproliferative neoplasm with unfavourable karyotypes and MK was
made. The disease progressed rapidly and transformed into therapy-related acute myeloid leukaemia
in less than four months, complicated with severe pneumonia. Despite aggressive treatment with
antibiotics and chemotherapy, the patient succumbed to the illness two weeks after the diagnosis.
Discussion and Conclusion: Diagnosis of t-MN should be suspected in patients with a history of
receiving cytotoxic agents. Karyotyping analysis is crucial for risk stratification as MK in addition
to complex aberrant karyotypes predicts unfavourable outcome. Further studies are required to
address the optimal management for patients with t-MN.