HHV-8/KSHV is not associated with AIDS-related primary central nervous system lymphoma

Diagnostic value of EBV-DNA in CSF for PCNSL in AIDS patients with focal brain lesions: A meta-analysis of diagnostic test

BACKGROUND

Epstein-Barr virus (EBV) infection plays a crucial role in the progression of acquired immunodeficiency syndrome related primary central nervous system lymphoma (AR-PCNSL). This study aimed at evaluating the diagnostic value of cerebrospinal spinal fluid (CSF) EBV-deoxyribonucleic acid (DNA) for PCNSL in patients with infection of human immunodeficiency (HIV) virus through a meta-analysis of diagnostic test.

METHODS

A systematic search in PubMed, Embase, Web of Science, Wanfang, Chinese Biomedical Database and Chinese National Knowledge Infrastructure was conducted before May 10, 2022. Heterogeneity among the studies was assessed using Q test and I2 statistics. Publication bias was assessed using the Deek's funnel plot asymmetry test. Statistical analyses were performed using Stata 16.0 software. The pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratios (DOR) and 95% confidence intervals (CI) were caculated to evaluate the diagnostic value. A symmetric receiver operating characteristic (SROC) curve and the area under the SROC curve (AUC) were constructed to evaluate the test-performance.

RESULTS

Twelve studies were included in the final analyses, with a total of 141 patients with AR-PCNSL and 590 controls. The pooled diagnostic values were sensitivity of 0.83 (95% CI: 0.73-0.90), specificity of 0.95 (95%CI: 0.89-0.98), PLR of 17.8 (95%CI: 6.8-46.1), NLR of 0.17 (95%CI: 0.10-0.30), DOR of 102 (95%CI: 28-379), and AUC of 0.94 (95%CI: 0.91-0.96).

CONCLUSION

In summary the overall diagnostic value of CSF EBV-DNA is very high and it can be a reliable diagnostic biomarker for AR-PCNSL.

Characteristic chromosomal imbalances in primary central nervous system lymphomas of the diffuse large B-cell type

We performed a genome wide screening for genomic alterations on a series of 19 sporadic primary central nervous system lymphomas (PCNSL) of the diffuse large B-cell type by comparative genomic hybridization (CGH). The tumors were additionally analyzed for amplification and rearrangement of the BCL2 gene at 18q21 as well as for mutation of the recently cloned BCL10 gene at 1p22. Eighteen tumors showed genomic imbalances on CGH analysis. On average, 2.1 losses and 4.7 gains were detected per tumor. The chromosome arm most frequently affected by losses of genomic material was 6q (47%) with a commonly deleted region mapping to 6q21-q22. The most frequent gains involved chromosome arms 12q (63%), 18q and 22q (37% each), as well as 1q, 9q, 11q, 12p, 16p and 17q (26% each). High-level amplifications were mapped to 9p23-p24 (1 tumor) and to 18q21-q23 (2 tumors). However, PCR-based analysis, Southern blot analysis and high-resolution matrix-CGH of the BCL2 gene revealed neither evidence for amplification nor for genetic rearrangement. Mutational analysis of BCL10 in 16 PCNSL identified four distinct sequence polymorphisms but no mutation. Taken together, our data do not support a role of BCL2 rearrangement/amplification and BCL10 mutation in PCNSL but indicate a number of novel chromosomal regions that likely carry yet unknown tumor suppressor genes or proto-oncogenes involved in the pathogenesis of these tumors.

Changing pattern of primary cerebral lymphoma in the highly active antiretroviral therapy era

Before the introduction of highly active antiretroviral therapy (HAART), human immunodeficiency virus (HIV)-related primary central nervous system lymphoma (PCNSL) represented one of the most prevalent causes of focal brain lesions in HIV-infected people. The prognosis of PCNSL was very poor, with median survival time not exceeding 2 months. Brain biopsy was the method of choice for the definitive diagnosis, but it was and remains an invasive procedure with morbidity and mortality as well as considerable costs in terms of patients' management and quality of life. The strict association between AIDS-PCNSL and Epstein-Barr virus led to the suggestion that EBV DNA in cerebrospinal spinal fluid (CSF) might serve as a diagnostic marker, reducing the time required for diagnosis and allowing a minimally invasive approach. The clinical usefulness of this methodology has been largely demonstrated through clinical practice. After the introduction of HAART in clinical practice, a survival benefit has been observed for most persons with acquired immunodeficiency syndrome (AIDS)-associated opportunistic infections and cancers. In particular, for patients with non-Hodgkin lymphoma, a higher likelihood of response to chemotherapy as well as a longer survival has been found as a consequence of the use of combined antiretroviral therapy. Although larger studies did not show significant changes in survival of HIV-infected patients with PCNSL in the era of HAART, small case series and anecdotal reports showed the benefit of HAART in the treatment of PCNSL. Nevertheless, these patients' survival still remains very poor and it could be hypothesized that, other than specific cancer prognostic determinants and severe immunodeficiency, viral pathogenesis as well as EBV-specific immunologic dysfunction may be responsible.

Kaposi's sarcoma-associated herpesvirus: clinical, diagnostic, and epidemiological aspects

Kaposi's sarcoma-associated herpesvirus (KSHI) is one of the few viruses proven to be associated with tumorigenesis in humans. Its causal association with all clinical and epidemiological variants of Kaposi's sarcoma (KS) is well established. KSHV is also involved in the pathogenesis of primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD). Possible associations of KSHV with other clinical settings have been extensively examined. The findings from several of these studies are contradictory and are yet to be resolved. Concentrated effort over the last decade, since the initial discovery of KSHV, led to the development of several experimental systems that resulted in a better comprehension of the biological characteristics of KSHV and set the stage for the understanding of mechainisms by which diseases are induced by the virus. The development of molecular, histological, and serological tools for KSHV diagnosis allowed researchers to track the transmission and to study the epidemiology of KSHV. These assays have been applied, in particular in ambiguous cases, in order to confirm clinically and pathologically based diagnoses. Here, we review the advances in the clinical, experimental, diagnostic, and epidemiological research of KSHV.

Molecular methods for diagnosis of viral encephalitis

Hundreds of viruses cause central nervous system (CNS) disease, including meningoencephalitis and postinfectious encephalomyelitis, in humans. The cerebrospinal fluid (CSF) is abnormal in >90% of cases; however, routine CSF studies only rarely lead to identification of a specific etiologic agent. Diagnosis of viral infections of the CNS has been revolutionized by the advent of new molecular diagnostic technologies to amplify viral nucleic acid from CSF, including PCR, nucleic acid sequence-based amplification, and branched-DNA assay. PCR is ideally suited for identifying fastidious organisms that may be difficult or impossible to culture and has been widely applied for detection of both DNA and RNA viruses in CSF. The technique can be performed rapidly and inexpensively and has become an integral component of diagnostic medical practice in the United States and other developed countries. In addition to its use for identification of etiologic agents of CNS disease in the clinical setting, PCR has also been used to quantitate viral load and monitor duration and adequacy of antiviral drug therapy. PCR has also been applied in the research setting to help discriminate active versus postinfectious immune-mediate disease, identify determinants of drug resistance, and investigate the etiology of neurologic disease of uncertain cause. This review discusses general principles of PCR and reverse transcription-PCR, including qualitative, quantitative, and multiplex techniques, with comment on issues of sensitivity, specificity, and positive and negative predictive values. The application of molecular diagnostic methods for diagnosis of specific infectious entities is reviewed in detail, including viruses for which PCR is of proven efficacy and is widely available, viruses for which PCR is less widely available or for which PCR has unproven sensitivity and specificity, and nonviral entities which can mimic viral CNS disease.

Primary Central Nervous System Lymphoma

Standard therapy does not exist for the treatment of primary central nervous system lymphoma. This is because of low patient numbers, slow accrual to clinical trials, and the absence of phase III randomized clinical trials. Neuro-oncologists agree that whole brain irradiation alone is no longer the best treatment option; treatment should include high-dose methotrexate chemotherapy, and treatment strategies must combine efficacy without untoward toxicity. However, beyond this, there is no widespread consensus. Significant neurocognitive toxicity has been associated with combined chemotherapy-radiation regimens, especially in elderly patients. This has prompted many to defer radiation therapy in all patients except those that refuse chemotherapy, those that have a partial response to chemotherapy, or those that have disease progression through chemotherapy. There is supporting evidence for this approach; however, confirmatory data from multicenter clinical trials and 5-year survival rates are unavailable. This underscores the importance of ongoing clinical trials.

Molecular pathology of primary intraocular lymphoma

PURPOSE

To evaluate immunoglobulin heavy chain (IgH) gene rearrangements, cytokines and chemokines, and infectious agents in primary intraocular B-cell lymphoma (PIOL) cells, in order to better diagnose and understand PIOL.

METHODS

We studied ocular specimens from 57 patients with PIOL at the National Eye Institute from 1991 to 2001. Specimens were analyzed for IgH gene rearrangements using microdissection and polymerase chain reaction (PCR). We measured vitreal interleukin (IL)-10 and IL-6 levels by enzyme-linked immunosorbent assay. IL-10 mRNA was studied in PIOL cells using microdissection and reverse transcribed (RT)-PCR. Chemokine and chemokine receptor expression was examined by using immunohistochemistry. Infectious DNA of human herpetic virus-8 (HHV-8), Epstein-Bar virus (EBV), and Toxoplasma gondii was detected by using microdissection and PCR and was confirmed with Southern blot hybridization.

RESULTS

IgH rearrangement(s) were demonstrated in all 50 tested cases. Cytokine levels were measured in the vitreous of 39 patients. Thirty-one had measurable cytokine levels: 24 of 31 had elevation of IL-10 relative to that of IL-6, and, in contrast, only 7 of 31 had elevation of IL-6 relative to IL-10. IL-10 mRNA was abundant in lymphoma cells of 6 examined cases. Lymphoma cells expressed chemokine receptors of CXCR4 and CXCR5 in three tested cases. HHV-8 DNA was found in 6 of 32 cases (18.8%), EBV DNA in 2 of 21 (9.5%), and T gondii DNA in 2 of 16 (12.5%).

CONCLUSIONS

Molecular analyses detecting IgH rearrangements and vitreal levels of IL-10 and IL-6 are useful adjuncts for PIOL diagnosis. A role for specific infectious agents is hypothesized in the pathogenesis of some cases of PIOL. B-cell chemokine is likely involved in attracting PIOL cells into the eye.

Diagnostic advances and new trends for the treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare non-Hodgkin's lymphoma arising in the brain. Recent increase in its incidence has been noted both in immunocompetent individuals and patients with immunodeficiency. This review will focus on the epidemiology, pathogenesis, diagnosis and treatment of this aggressive extranodal lymphoma in immunocompetent patients. Stereotactic biopsy is usually required for diagnosis, while molecular biology and/or cytofluorimetric analysis may confirm the presence of clonal proliferation in the cerebrospinal fluid (CSF). Methotrexate-based chemotherapy plus whole-brain radiotherapy are the standard treatment for PCNSL and achieve a high rate of complete remissions (CR), but long-term neurotoxicity may heavily compromise the patient's quality of life. The metabolic rate of controversial gadolinium-enhancing lesions on magnetic resonance (MR) scans may be assessed with positron emission tomography (PET), which discriminates radiation necrosis from true recurrence. Withholding radiotherapy in patients achieving CR after first-line chemotherapy is a new and interesting treatment option, while the role of high-dose chemotherapy with stem cell rescue is still uncertain.

Polymerase chain reaction as a diagnostic adjunct in herpesvirus infections of the nervous system

Polymerase chain reaction (PCR) is a powerful technique that allows detection of minute quantities of DNA or RNA in cerebrospinal fluid (CSF), vesicle and endoneurial fluids, blood, fresh-frozen, and even formalin-fixed tissues. Various infectious agents can be detected with high specificity and sensitivity, including bacteria, parasites, rickettsia and viruses. PCR analysis of CSF has revolutionized the diagnosis of nervous system viral infections, particularly those caused by human herpesviruses (HHV), and has now replaced brain biopsy as the gold standard for diagnosis of herpes simplex virus (HSV) encephalitis. PCR analysis of both CSF and nervous system tissues has also broadened our understanding of the spectrum of disease caused by HSV-1 and -2, cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV), and HHV-6. Nonetheless, positive tissue PCR results must be interpreted cautiously, especially in cases that lack corroborating clinical and neuropathologic evidence of infection. Moreover, positive PCR results from tissues do not distinguish latent from productive (lytic) viral infections. In several neurological diseases, negative PCR results have provided strong evidence against a role for herpesviruses as the causative agents. This review focuses on the use of PCR tests to diagnose HSV and VZV infections of the nervous system.

Immunohistochemical assessment of human herpesvirus 8 infection in primary central nervous system large B cell lymphomas

BACKGROUND/AIMS

Primary central nervous system large B cell lymphomas (PCNSLs) are frequently associated with Epstein-Barr virus (EBV) in patients with AIDS and less frequently in those without AIDS. Human herpesvirus 8 (HHV-8) has been detected in these tumours by the polymerase chain reaction (PCR) at low copy number, suggesting its presence in a cell compartment other than the malignant one. The aim of this study was to use immunohistochemistry to assess HHV-8 infection in a series of PCNSLs from patients with and without AIDS.

METHODS

The antibody LN53, which reacts with the latent nuclear antigen 1 (LNA1) of HHV-8, was used on tissue sections from 35 patients (17 with and 18 without AIDS) with PCNSL. In addition, DNA was available for PCR (open reading frame 26 (ORF 26), ORF 72, ORF 75) in three patients (two without AIDS, one with AIDS).

RESULTS

None of the 35 cases contained either DNA sequences or LNA1 positive cells.

CONCLUSIONS

These results confirm the lack of HHV-8 infection in tumour cells of PCNSL. In addition, HHV-8 infected bystander cells do not express LNA1 latent protein in this setting.

Primary effusion lymphoma: a liquid phase lymphoma of fluid-filled body cavities

Primary effusion lymphoma (PEL) is a B-cell neoplasm characterized by infection of the tumor clone by human herpesvirus type-8/Kaposi's sarcoma-associated herpesvirus (HHV-8/KSHV) and by liquid growth in fluid-filled body spaces. During its entire clinical course, the lymphoma tends to remain localized to the serous body cavities with no formation of solid tumor masses. The epidemiology of PEL points to a close link with underlying immunodeficiency of the host, as most cases develop in individuals severely immunocompromised because of preexisting acquired immunodeficiency syndrome. The histogenesis and pathogenesis of PEL have been clarified to a sizeable extent by intensive investigations performed since the disease recognition in 1995. PEL is composed of postgerminal center B cells, which bridge immunoblastic and anaplastic features and typically display a non-B, non-T phenotype consistent with late stages of B-cell differentiation. HHV-8/KSHV is thought to play a major role in PEL pathogenesis via expression of several viral latent genes, which have the potential to affect B-cell growth. Other factors involved in PEL pathogenesis include deregulation of cytokine and growth factor autocrine loops, molecular alterations of the tumor DNA, cell cycle abnormalities, stimulation and selection by antigen, and infection by Epstein-Barr virus, which occurs in 70% of PEL cases. In the years since the disease discovery, the distinctiveness of the biological and clinicopathological features of PEL has prompted its recognition as an independent lymphoma category by the World Health Organization classification system of hematologic neoplasms.

Primary CNS lymphoma: clinical presentation, pathological classification, molecular pathogenesis and treatment

Primary CNS lymphomas (PCNSL) represent malignant non-Hodgkin's B cell lymphomas, which are confined to the central nervous system. They show a dramatic increase in frequency in the immunocompromised as well as in the immunocompetent population. Recent studies have identified germinal center B cells as the cellular origin of PCNSL; however, the details of their molecular pathogenesis still remain to be elucidated. Treatment recommendations are not clearly established. Radiotherapy (RT) is efficient in terms of tumor response, but not curative. Median survival after RT alone is about 1 year. According to the results of uncontrolled studies the combination of RT and chemotherapy based on high-dose methotrexate (HD-MTX) is most efficient in terms of survival rates. However, long-term neurotoxicity overshadows treatment efficacy, especially in patients over 60 years of age. The authors favor the systematic evaluation of chemotherapy alone with protocols including HD MTX, because unicenter results are promising in terms of both survival as well as quality of life in long term survivors.

The role of cytokines in the pathogenesis and management of AIDS-related lymphomas

AIDS-related non-Hodgkin lymphomas (AIDS-NHL) consistently derive from B-cells and are characterized by extreme clinical aggressiveness. At histological level, AIDS-NHL are classified as AIDS-related Burkitt's lymphoma (AIDS-BL), AIDS-related diffuse large cell lymphoma (AIDS-DLCL) and AIDS-related primary effusion lymphoma (AIDS-PEL). The role of cytokines in the pathogenesis and management of AIDS-NHL has been studied to a certain extent. Production of large quantities of human IL-10 occurs frequently in AIDS-BL and correlates with latent EBV infection of the tumor clone. Lesser amounts of the cytokine are released in EBV negative cases. The pathogenetic role of IL-10 in AIDS-BL is suggested by the observation that IL-10 antisense oligonucleotides inhibit proliferation of the lymphoma. A significant fraction of AIDS-BL cell lines produce TNFbeta. Among AIDS-NHL, the release of TNFbeta appears to be specific for AIDS-BL. The pathogenetic relevance of TNFbeta in lymphomagenesis is suggested by the observation that some BL cell lines use TNFbeta as an autocrine growth factor. Some cases of AIDS-BL, particularly those carrying EBV infection, also secrete IL-6, IL-7 and IL-12. With respect to AIDS-DLCL, many cases express the IL-6R, rendering these cells responsive to the paracrine stimulation by the IL-6 produced by nearby T-cells, macrophages and endothelial cells which are frequently abundant in these tumor samples. The tumor clone itself, however, generally fails to release IL-6. AIDS-PEL is characterized by secretion of large amounts of IL-6 and IL-10. Some PEL cases also release oncostatin M. Apart from human IL-6, PEL also express viral IL-6, which is encoded by the HHV-8 genome. The biological relevance of both IL-6 and IL-10 in PEL proliferation and growth has been recently clarified in vitro and in vivo. Overall, these data suggest that activation of different cytokine loops clusters with different clinico-pathologic categories of AIDS-NHL and may represent the potential target of novel therapeutic strategies.

Kaposi's sarcoma-associated herpesvirus-positive primary effusion lymphoma arising in the subarachnoid space

Primary effusion lymphoma (PEL) is a rare and distinctive type of B-cell non-Hodgkin's lymphoma (NHL) that occurs primarily, although not exclusively, in patients with AIDS. It usually develops as a lymphomatous effusion in the absence of a tumor mass, characteristically contains the Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8), usually also contains the Epstein-Barr virus (EBV), displays a characteristic cytomorphology bridging immunoblastic and anaplastic large cell lymphoma, often expresses an indeterminate immunophenotype, and a B-cell genotype. Thus far, PEL has been limited almost entirely to the pleural, peritoneal, and pericardial cavities. We describe a NHL occurring in a gay man with AIDS that is typical of PEL in that it arose in a body cavity or space without an associated tumor mass, displays the cytomorphology typical of PEL, is a clonal B-cell neoplasm, and contains KSHV as well as EBV. This case is singularly distinctive in that it is the first case of PEL reported to arise in the subarachnoid space. This unique case further supports the strong association between KSHV and malignant lymphoma arising in body cavities and growing as an effusion.

Classification, pathogenesis and molecular pathology of primary CNS lymphomas

Classification, pathogenesis and molecular pathology of primary central nervous system lymphomas (PCNSL) pose major clinico-pathologic problems. Application of histopathologic classification schemes developed for nodal lymphomas, i.e. the Kiel Classification and the Working Formulation, is not reliable and clinically not relevant for PCNSL. The more recent REAL Classification will simplify subtyping of PCNSL, but reliability and clinical significance remain to be determined. There are virtually no experimental data on whether PCNSL develop outside of the brain, or whether they arise from polyclonal lymphoproliferations within the brain. Mutations of oncogenes and tumor suppressor genes have been analyzed in only a few tumors, and their type and frequency is essentially unknown. In conclusion, compared with both neuroectodermal brain tumors and nodal lymphomas, and given the increasing incidence and clinical impact of PCNSL, there is a remarkable lack of histopathologic consensus as well as a surprising shortage of pathogenetic and molecular genetic information.