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Lymphocyte predominant Hodgkin lymphoma, antigen-driven after all?

Poppema S

J Pathol, 2021 01;253(1):1-10.
PMID: 33044742 DOI: 10.1002/path.5567

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) was suggested as an entity separate from other types of Hodgkin lymphoma 40 years ago and recognized in the WHO classification in 2001. Based on its relatively benign course with late distant relapses, relation with lymph node hyperplasia with progressively transformed germinal centers, presence of clonal immunoglobulin gene rearrangements with somatic hypermutations and ongoing mutations, and relation with a number of inherited defects affecting the immune system, it has been suspected that NLPHL might be antigen-driven. Recent evidence has shown that cases of IgD-positive NLPHL are associated with infection by Moraxella catarrhalis, a common bacterium in the upper respiratory tract and in lymph nodes. This review summarizes the evidence for NLPHL as a B-cell lymphoma involving follicular T-lymphocytes normally found in germinal centers, its molecular features and relation to inherited immune defects, and its relation and differential diagnosis from similar entities. Finally, it discusses the evidence that in many cases a watch and wait policy might be a viable initial management strategy. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Lymphoma: an introduction into historical background, classification schemes, aetiology, geographical variation and epidemiological trend

Peh SC, Poppema S

Malays J Pathol, 2001 Dec;23(2):49-63.
PMID: 12166593
Expression of retinoblastoma protein and P16 proteins in classic Hodgkin lymphoma: relationship with expression of p53 and presence of Epstein-Barr virus in the regulation of cell growth and death

Kim LH, Peh SC, Poppema S

Hum Pathol, 2006 Jan;37(1):92-100.
PMID: 16360421

Deregulation of several genes involved in cell cycle control has been reported in classic Hodgkin lymphoma (cHL). This study aimed to investigate the expression of tumor suppressor proteins (P16(INK4A), retinoblastoma protein, and p53) in cHL in relation to the proliferation and apoptosis of Hodgkin/Reed-Sternberg (H/RS) cells, correlating with the status of Epstein-Barr virus (EBV). A total of 66 cHL cases and 10 nonneoplastic reactive lymphoid tissues were retrieved from the archives. Immunohistochemistry technique was used for the detection of protein expression. Presence of EBV infection was detected by EBV early RNA in situ hybridization. p16(INK4A) gene deletion status was assessed by fluorescence in situ hybridization technique. Expression of P16(INK4A) was observed in 49.2% of the cases, whereas positive retinoblastoma protein and p53 expressions in the H/RS cells were detected in 89.1% and 81.5% of the cases, respectively. Epstein-Barr virus positivity was detected in 53.0% of the cases. Proliferation marker, Ki-67 expression, was observed in 86.7% of the cases. There was no significant correlation between the expression of the various tumor suppressor proteins and Ki-67. Retinoblastoma protein and p53 were also not associated with the presence of EBV. An inverse relationship was observed between the expression of P16(INK4A) and the presence of EBV. There were no significant homozygous or hemizygous deletions of the p16(INK4A) gene. However, an aberrant copy number of chromosome 9 with the loss of one or more p16(INK4A) loci was detected in all cases assessable by fluorescence in situ hybridization. Loss of function of one or more tumor suppressor proteins may be involved in defective cell regulation of H/RS cells. Epstein-Barr virus may have a role in inhibiting P16(INK4A) expression, thus resulting in a perturbed p16(INK4A)-Rb cell cycle checkpoint.
TARC, a CC chemokine, is frequently expressed in classic Hodgkin's lymphoma but not in NLP Hodgkin's lymphoma, T-cell-rich B-cell lymphoma, and most cases of anaplastic large cell lymphoma

Peh SC, Kim LH, Poppema S

Am. J. Surg. Pathol., 2001 Jul;25(7):925-9.
PMID: 11420464

Thymus and activation-regulated chemokine (TARC) has been identified as a lymphocyte-directed CC chemokine that attracts activated T-helper type 2 (Th2) cells in humans. Recent studies showed that the T cells surrounding Reed-Sternberg cells in Hodgkin's lymphomas (HL) are Th2 type. Anaplastic large cell lymphomas (ALCL), T-cell-rich B-cell lymphoma (TCRBCL) can mimic HL in some instances. This study aimed to establish the pattern of TARC expression in these diseases. Immunohistochemical stain using a polyclonal goat anti-human antibody to TARC was performed on 119 cases of confirmed HL; 99 were classical type (43 mixed cellularity, 43 nodular sclerosis, 5 lymphocyte depleted, 4 lymphocyte rich, 4 unclassifiable) and 20 lymphocyte predominant HL. Additional 27 ALCL (9 T-, 18 null-cell phenotype), 16 T-cell and 8 B-cell non-Hodgkin's lymphoma (NHL) were studied. A total of 85.8% of the classical HL, one case of ALCL, and one case of large cell B-cell lymphoma with anaplastic morphology showed positive TARC expression in the tumor cells. The expression was paranuclear and/or diffuse in the cell cytoplasm. The tumor cells in all cases of lymphocyte predominant HL, TCRBCL, null ALCL, and T-NHL did not express TARC. The high frequency of TARC expression in the Reed-Sternberg cells of classical HL may explain the characteristic T-cell infiltrate in this disease. The absence in other types that may be morphologically similar indicates that staining for TARC may aid in differential diagnosis.
Dual variant of Epstein-Barr virus in Hodgkin/Reed-Sternberg cells: single-cell PCR study on latent membrane protein-1 gene

Kim LH, Peh SC, Poppema S

Int J Cancer, 2003 Nov 1;107(2):250-5.
PMID: 12949802

Isolation of single cells permits analysis of DNA or RNA from individual cells among heterogeneous populations. This technique is particularly useful in the study of classical Hodgkin's lymphoma (cHL) due to the scarcity of H/RS tumor cells among large numbers of reactive leukocytes. In a previous study, we found a high frequency of dual LMP-1 variant (concurrent presence of deleted and nondeleted variants) in cHL from whole-tissue sections. For the present study, we applied a single-cell isolation technique to determine the LMP-1 oncogene variant in EBV-associated H/RS cells. Five cases of EBV-infected cHL, containing nondeleted (n=1), deleted (n=1) and dual infection (n=3) based on whole-tissue section analysis, were selected for study. Paraffin-embedded tissue sections were stained with antibody to LMP-1 and positively stained H/RS cells isolated using a semiautomated micromanipulator. Each isolated single cell was subjected to PCR for amplification of the LMP-1 gene flanking the 30 bp deletion region and Xho1 restriction site. Cases with either nondeleted variant or the deleted variant showed similar LMP-1 variant expression in isolated single H/RS cells. However, 1 of the 3 cases with dual variants showed only the deleted variant in H/RS cells. The other 2 cases showed mixed patterns of deleted, nondeleted and dual LMP-1 variants in isolated single H/RS cells. All cases showed loss of the Xho1 restriction site, with the exception of the case with nondeleted LMP-1. Results of single-H/RS cell analysis of the Xho1 restriction site concur with those of whole-tissue section amplification. A mixed pattern of LMP-1 variants was observed in isolated H/RS cells, and it is speculated that this is due to the accumulation of mutation and deletion events.
Frequent presence of subtype A virus in Epstein-Barr virus-associated malignancies

Peh SC, Kim LH, Poppema S

Pathology, 2002 Oct;34(5):446-50.
PMID: 12408344

AIMS: Epstein-Barr virus (EBV) is associated with many human malignancies. It is implicated in a pathogenetic role in some of these tumours. Two subtypes, type A and B have been identified on the basis of DNA sequence divergence in the nuclear protein genes (EBNA) 2, 3, 4 and 6. They differ in their transforming efficiency and prevalence pattern in different geographical locations. We aimed to identify the virus subtype infection pattern in our EBV-associated diseases.
METHODS: Paraffin-embedded tissue from 38 lymphomas (17 Hodgkin's, 14 Burkitt's, four T cell and 3 B cell non-Hodgkin's lymphomas) and 14 nasopharyngeal carcinomas (NPC) were studied, with 12 reactive lymph nodes and tonsils as normal control. EBER in situ hybridisation was performed to confirm EBV association in the tumour cells. A nested polymerase chain reaction (PCR) protocol was employed using two pairs of consensus primers which flanked a 105-bp deletion in the type A virus. U2 region encoding for EBNA-2 was chosen as the target of amplification, with cell lines B95.8 and AG876 serving as positive controls for types A and B virus, respectively.
RESULTS: All cases showed presence of type A virus, consistently detected with nested PCR protocol but not with single step PCR. There was no type B virus or mix infections detected.
CONCLUSIONS: Nested PCR technique has successfully increased the sensitivity of EBV subtype detection, and type A virus is the prevalent strain associated with human diseases in Malaysia.
Fulltext The immunophenotypic patterns of follicle centre and mantle zone in Castleman's disease

Peh SC, Shaminie J, Poppema S, Kim LH

Singapore Med J, 2003 Apr;44(4):185-91.
PMID: 12952030

Castleman's disease is an uncommon disease and the histopathogenesis is poorly understood. This study aims to investigate their clinicopathological and immunophenotypic profile.
Spectrum of malignant lymphomas in Klang Hospital, a public hospital in Malaysia

Peh SC, Kim LH, Thanaletchimy N, Chai SP, Poppema S

Malays J Pathol, 2000 Jun;22(1):13-20.
PMID: 16329532

Lymphoma is a relatively common group of neoplasms diagnosed in hospital practice. This study aims to elucidate the pattern of this disease encountered in a public service hospital of the Ministry of Health, Malaysia.
Expression of Bcl-2 family members and presence of Epstein-Barr virus in the regulation of cell growth and death in classical Hodgkin's lymphoma

Kim LH, Nadarajah VS, Peh SC, Poppema S

Histopathology, 2004 Mar;44(3):257-67.
PMID: 14987230 DOI: 10.1111/j.0309-0167.2004.01829.x

AIMS: To examine the expression of the Bcl-2 family of proteins (Bcl-2, Bcl-x, Bcl-xL and Bax) in classical Hodgkin's lymphoma (cHL) and to correlate the expression of these proteins with proliferation, apoptosis and the presence of Epstein-Barr virus (EBV).

METHODS AND RESULTS: Expression of the Bcl-2 family of proteins was detected by immunohistochemistry, proliferation was determined by Ki67 labelling and apoptosis by TUNEL in-situ hybridization. EBV was detected by Epstein-Barr virus early RNA (EBER) in-situ hybridization. Expression of Bcl-2, Bcl-x, Bcl-xL and Bax was detected in the Hodgkin/Reed-Sternberg (H/RS) cells in 43.7% (27/62), 87.5% (56/64), 67.2% (41/61) and 74.6% (47/63) of the cHL cases, respectively. EBER was detected in 53% (35/66) of the cases, whereas Ki67 was observed in 86.7% (52/60) of the cases. Apoptotic H/RS cells were observed infrequently, and only 43.2% (11/26) of the cases showed an apoptotic index of > or = 10% in the H/RS cells. A statistically significant inverse relationship was observed between the expression of Bcl-2 and the presence of EBV (P = 0.003). Bcl-xL showed an inverse correlation with apoptosis in the H/RS cells (P = 0.004).

CONCLUSIONS: The higher Bcl-xL expression (67.2%) compared with Bcl-2 expression (43.5%) observed in cHL as well as the statistically significant inverse relationship between Bcl-xL and apoptosis suggests that Bcl-xL plays an important role in the survival of H/RS cells. Expression of Bax may be neutralized by other anti-apoptotic members of the family such as Bcl-2 and/or Bcl-xL.
The role of CD30, CD40 and CD95 in the regulation of proliferation and apoptosis in classical Hodgkin's lymphoma

Kim LH, Eow GI, Peh SC, Poppema S

Pathology, 2003 Oct;35(5):428-35.
PMID: 14555388

AIMS: CD30, CD40 and CD95 are members of the tumour necrosis factor receptor superfamily. Ligation to their respective ligands (CD30L, CD40L, CD95L) will generate a diverse set of signalling cascades. We aim to study the expression pattern of CD30, CD40 and CD95 in classical Hodgkin's lymphoma (cHL) and to correlate the expressions with proliferation and apoptosis in the Hodgkin/Reed-Sternberg (H/RS) cells of cHL with or without associated Epstein-Barr virus (EBV) infection.
METHODS: A total of 66 cHL cases were retrieved from the archives. Expressions of CD30, CD40, CD95 and proliferation by Ki-67 expression were detected with an immunohistochemical staining method. Apoptosis index was assessed by in situ TUNEL staining technique on 30 randomly selected cases and the presence of EBV was determined by EBER in situ hybridisation.
RESULTS: Expression of CD30, CD40 and CD95 in the H/RS cells was observed in a high proportion of the cases (100, 93.9, 90.5%, respectively). There was no significant association or correlation of the expression of these molecules with the presence of EBV. Expression of CD40 was associated with expression of the proliferation marker Ki-67 (P=0.044), whereas strong (intermediate and high) expression of CD30 showed a significant correlation with proliferation in the EBV-negative cases only (P=0.025). No correlation was observed for the expression of CD30 and CD40 with apoptosis of the H/RS cells. The childhood cases showed weaker CD95 expression in the H/RS cells than the adult cases, and the expression of CD95 was weaker than that of CD40 in the childhood group.
CONCLUSIONS: Our results showed that CD30, CD40 and CD95 are highly expressed in the H/RS cells of the majority of cases of cHL. The expression patterns seem to be independent of EBV and do not correlate with apoptosis of the H/RS cells.
Fulltext Development of multi-epitope peptide-based vaccines against SARS-CoV-2

Lim HX, Lim J, Jazayeri SD, Poppema S, Poh CL

Biomed J, 2021 03;44(1):18-30.
PMID: 33727051 DOI: 10.1016/j.bj.2020.09.005

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic involving so far more than 22 million infections and 776,157 deaths. Effective vaccines are urgently needed to prevent SARS-CoV-2 infections. No vaccines have yet been approved for licensure by regulatory agencies. Even though host immune responses to SARS-CoV-2 infections are beginning to be unravelled, effective clearance of virus will depend on both humoral and cellular immunity. Additionally, the presence of Spike (S)-glycoprotein reactive CD4+ T-cells in the majority of convalescent patients is consistent with its significant role in stimulating B and CD8+ T-cells. The search for immunodominant epitopes relies on experimental evaluation of peptides representing the epitopes from overlapping peptide libraries which can be costly and labor-intensive. Recent advancements in B- and T-cell epitope predictions by bioinformatic analysis have led to epitope identifications. Assessing which peptide epitope can induce potent neutralizing antibodies and robust T-cell responses is a prerequisite for the selection of effective epitopes to be incorporated in peptide-based vaccines. This review discusses the roles of B- and T-cells in SARS-CoV-2 infections and experimental validations for the selection of B-, CD4+ and CD8+ T-cell epitopes which could lead to the construction of a multi-epitope peptide vaccine. Peptide-based vaccines are known for their low immunogenicity which could be overcome by incorporating immunostimulatory adjuvants and nanoparticles such as Poly Lactic-co-Glycolic Acid (PLGA) or chitosan.
Fulltext Regional Diets Targeting Gut Microbial Dynamics to Support Prolonged Healthspan

Low DY, Hejndorf S, Tharmabalan RT, Poppema S, Pettersson S

Front Microbiol, 2021;12:659465.
PMID: 33995322 DOI: 10.3389/fmicb.2021.659465

In the last 150 years, we have seen a significant increase in average life expectancy, associated with a shift from infectious to non-communicable diseases. The rising incidence of these diseases, for which age is often the largest risk factor, highlights the need for contemporary societies to improve healthy ageing for their growing silver generations. As ageing is an inevitable, non-reversing and highly individualised process, we need to better understand how non-genetic factors like diet choices and commensal gut microbes can modulate the biology of ageing. In this review, we discuss how geographical and ethnic variations influence habitual dietary patterns, nutrient structure, and gut microbial profiles with potential impact on the human healthspan. Several gut microbial genera have been associated with healthy elderly populations but are highly variable across populations. It seems unlikely that a universal pro-longevity gut microbiome exists. Rather, the optimal microbiome appears to be conditional on the microbial functionality acting on regional- and ethnicity-specific trends driven by cultural food context. We also highlight dietary and microbial factors that have been observed to elicit individual and clustered biological responses. Finally, we identify next generation avenues to modify otherwise fixed host functions and the individual ageing trajectory by manipulating the malleable gut microbiome with regionally adapted, personalised food intervention regimens targeted at prolonging human healthspan.
Fulltext Immunogenicity and safety of SARS-CoV-2 vaccines in clinical trials

Lim HX, Arip M, Yahaya AAA, Jazayeri SD, Poppema S, Poh CL

Front Biosci (Landmark Ed), 2021 11 30;26(11):1286-1304.
PMID: 34856768 DOI: 10.52586/5024

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were first detected in Wuhan, China in December 2019 and resulted in a worldwide pandemic in 2020. SARS-CoV-2 infections totalled more than 180 million with 3.9 million deaths as of June 24, 2021. Tremendous research efforts have resulted in the development of at least 64 vaccine candidates that have reached Phase I to III clinical trials within 14 months. The primary efficacy endpoint for a random placebo-controlled clinical trial of a COVID-19 vaccine to be approved by US FDA should confer at least 50% protection against COVID-19. Three COVID-19 vaccines (BNT162b2, mRNA-1273 and Sputnik V) in clinical Phase III trials have now achieved >90% efficacy in preventing COVID-19. Since SARS-CoV-2 is highly contagious, vaccines are expected to achieve at least 80% herd immunity in the world's population to effectively prevent SARS-CoV-2 infections. An overview of safety, immunogenicity and efficacy of the current frontrunner vaccines are reviewed.
Fulltext The role of the university in recovering from COVID-19 and preparing for future crises-perspectives and experiences from Sunway University, Malaysia

Renganathan E, Guinto R, Mahmood J, Lacey-Hall O, Veerakumarasivam A, Poppema S

Front Public Health, 2023;11:1072823.
PMID: 37168072 DOI: 10.3389/fpubh.2023.1072823

This article is part of the Research Topic 'Health Systems Recovery in the Context of COVID-19 and Protracted Conflict'. Universities, as engines of knowledge creation and dissemination and as incubators of disciplined yet original thinking, have a key role to play in tackling the most complex challenges that societies and our planet face, from infectious diseases to the climate emergency. This commentary presents the perspectives from Sunway University, a young private university in Malaysia that made a strong commitment to the sustainable development goals (SDGs) prior to the pandemic, and its experiences in promoting research, innovation, and learning as part of COVID-19 recovery and in preparation for future crises such as the climate emergency. Some of the university's initiatives include embracing the planetary health approach, reviving essential public health functions, exploring pandemic resilience, addressing 'infodemics' and promoting science diplomacy. The example of Sunway University provides some insights on the opportunities and challenges that academic institutions face as they seek to reorient the paradigm of education, research, and service away from disciplinary siloes and towards a more integrated, preventive, accessible and translational approach.

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