Progressive multifocal leukoencephalopathy in patients with chronic kidney disease

Progressive multifocal leukoencephalopathy (PML) is an opportunistic central nervous system infection caused by the human polyomavirus 2, leading to demyelination from oligodendrocyte death and rapid neurologic decline. Most commonly, PML affects patients in immunocompromised states. However, rare reports of PML in an immunocompetent host exist. Here, we report two cases of PML in older individuals with chronic kidney disease (CKD). CKD can ultimately lead to immune system dysfunction and place patients in a relatively immunosuppressed state. Testing for JC virus should remain a consideration for rapid, unexplained neurologic decline even without known immunocompromised status in the appropriate clinical setting.

"Peppering the pons": CLIPPERS or myelin oligodendrocyte glycoprotein associated disease?

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a distinct pathologic entity of unknown etiology. Here, we describe the clinical and radiologic presentation of myelin oligodendrocyte glycoprotein associated disease (MOG-AD) with features mimicking CLIPPERS. Three patients met the 2017 CLIPPERS diagnostic criteria, while one patient had a single lesion in the pons that mimicked CLIPPERS lesions. All had an excellent response to steroids, but the three who met the CLIPPERS criteria had a relapsing course. When CLIPPERS is observed, it is crucial to test for mimickers. The ever-expanding spectrum of MOG-AD calls for further research into the immunopathogenesis of its several phenotypes.

Large-scale analysis of DNA methylation in chronic lymphocytic leukemia

AIMS

B-cell chronic lymphocytic leukemia (CLL) is a heterogeneous malignancy that clinically ranges from indolent to rapidly progressive. CLL, like other cancers, can be affected by epigenetic alterations.

MATERIALS & METHODS

A microarray discovery-based study was initiated to determine DNA methylation in CLL cases with a range of CD38 expression (1–92%).

RESULTS

Many loci were either methylated or unmethylated across all CD38 levels, but differential methylation was also observed for some genes. Genomic sequencing of DLEU7 confirmed extensive cytosine methylation preferentially in patient samples with low CD38 expression, whereas NRP2, SFRP2 and ADAM12 were more commonly methylated in those with high CD38 expression.

CONCLUSION

This study demonstrates that CLL is affected by CpG island methylation in some genes that segregate with CD38 expression levels, while most others show similar methylation patterns across all levels. The CpG island methylation in certain functional gene groups and pathway-associated genes that are known to be deregulated in CLL provides additional insights into the CLL methylome and epigenetic contribution to cellular dysfunction. It will now be useful to investigate the effectiveness of epigenetic therapeutic reversal of these alterations to develop effective treatments for the disease.

Epigenetic regulation of WNT signaling in chronic lymphocytic leukemia

Certain WNT and WNT network target genes are expressed at higher or lower levels in chronic lymphocytic leukemia compared with normal B-cells. This includes upregulation of nuclear complex genes, as well as genes for cytoplasmic proteins and WNT ligands and their cognate receptors. In addition, epigenetic silencing of several negative regulators of the WNT pathway have been identified. The balance between epigenetic downregulation of negative effector genes and increased expression of positive effector genes demonstrate that the epigenetic downregulation of WNT antagonists is one mechanism, perhaps the main mechanism, that is permissive to active WNT signaling in chronic lymphocytic leukemia. Moreover, constitutive activation of the WNT network and target genes is likely to impact on additional interacting signaling pathways. Based on published studies, we propose a model of WNT signaling that involves mainly permissive expression, and sometimes overexpression, of positive effectors and downregulation of negative regulators in the network. In this model, DNA methylation, histone modifications and altered expression of microRNA molecules interact to allow continuous WNT signaling.

Differential DNA methylation patterns of small B-cell lymphoma subclasses with different clinical behavior

Non-Hodgkin's lymphoma (NHL) is a group of malignancies of the immune system with variable clinical behaviors and diverse molecular features. Despite the progress made in classification of NHLs based on classical methods, molecular classifications are a work in progress. Toward this goal, we used an array-based technique called differential methylation hybridization (DMH) to study small B-cell lymphoma (SBCL) subtypes. A total of 43 genomic DMH experiments were performed. From these results, several statistical methods were used to generate a set of differentially methylated genes for further validation. Methylation of LHX2, POU3F3, HOXC10, NRP2, PRKCE, RAMP, MLLT2, NKX6.1, LRP1B and ARF4 was validated in cell lines and patient samples and demonstrated subtype-related preferential methylation patterns. For LHX2 and LRP1B, bisulfite sequencing, real-time reverse transcriptase-polymerase chain reaction and induction of gene expression following treatment with the demethylating agent, 5'-aza-2'-deoxycytidine, were confirmed. This new epigenetic information is helping to define molecular portraits of distinct subtypes of SBCL that are not recognized by current classification systems and provides valuable potential insights into the biology of these tumors.