Progressive multifocal leukoencephalopathy--progress made and lessons relearned

Evaluation of regional cerebral glucose metabolism in patients with malignant lymphoma of the body using statistical image analysis

Objectives

The aim of this study was to clarify the characteristics of regional cerebral glucose metabolic abnormalities in patients with malignant lymphoma of the body using statistical image analyses. Post-therapeutic changes in cerebral glucose metabolism were also evaluated.

Methods

The subjects consisted of 30 patients, including 16 patients with diffuse large B-cell lymphoma and 14 patients with other types of lymphoma. Patients with primary cerebral lymphoma were excluded from this study. All patients underwent CT and whole-body FDG-PET scans, including 4-min brain scans using a dedicated PET/CT scanner during both the pre- and post-treatment periods. The whole-body scans started 60 min after the administration of 185 MBq of FDG, after which the brain data were extracted from whole-body data. The degree of regional cerebral glucose metabolism was evaluated on a voxel-by-voxel basis using statistical parametric mapping (SPM). The total tumor glycolytic volume of the body was measured using a separate workstation. The normal control subjects were 12 persons who underwent medical check with FDG-PET/CT and had no lesions suggesting malignant tumor.

Results

The level of regional cerebral glucose metabolism decreased in association with an increase in the total glycolytic volume in the bilateral frontal and parietal cortices. After chemotherapy, the statistical image analysis demonstrated an interval recovery of the cerebral glucose metabolism of the bilateral parietal and occipital cortices in the good responders, whereas there were no significant differences observed in regional cerebral glucose metabolism between the pre- and post-treatment images in the poor responders. Comparison between normal control subjects and patients with pre-treatment lymphoma also showed that the regional cerebral glucose metabolism decreased in the parieto-occipital cortices in patients with lymphoma compared to normal control subjects.

Conclusions

We demonstrated that patients with malignant lymphoma of the body exhibited abnormal regional cerebral glucose metabolism, which improves after chemotherapy. Although the mechanism underlying the reduction of cerebral glucose metabolism remains unclear, our findings indicate the functional alternation and/or subclinical damage of the brain in patients with malignant lymphoma.

Sorption of tetracycline and chlortetracycline on K- and Ca-saturated soil clays, humic substances, and clay-humic complexes

Tetracycline (TC) and chlortetracycline (CTC) are used extensively for growth promotion and therapeutic purposes in livestock production. The sorption of TC and CTC on clays, humic substances (HS), and clay-humic complexes (clay-HC) derived from two agricultural soils was quantified using dilute CaCl2 (Ca) and KCI (K) as background solutions. In all systems, the soil components sorbed > 96% of added tetracyclines. Strongest sorption was observed for clays, followed by HS, and then clay-HC. Greater sorption by the Ca systems than the K systems and decreased sorption with increasing pH suggests that cation bridging and cation exchange contribute to sorption. X-ray diffraction analysis showed that TC and CTC were sorbed in the interlayers of smectites and that the presence of HS reduced interlayer sorption of tetracyclines by smectites in clay-HC. The results indicate that tetracyclines are dominantly sorbed on soil clays and that HS in clay-HC either mask sorption sites on clay surfaces or inhibit interlayer diffusion of tetracyclines.

[Progressive multifocal leukoencephalopathy secondary to JC virus infection after liver transplantation and treatment of recurrent hepatitis C]

Progressive multifocal leucoencephalopathy due to JC virus is a rare complication of liver transplantation. Only four cases have already been described in the literature. This disease is difficult to differentiate from leucoencephalopathy associated with immunosuppressive drugs such as cyclosporin or tacrolimus. Positive diagnosis of progressive multifocal leucoencephalopathy no longer requires cerebral biopsy. It must be confirmed by positive JC virus RNA amplification in the cerebrospinal fluid. We report a case of progressive multifocal leucoencephalopathy occurring 18 months after liver transplantation for hepatitis C-related cirrhosis.

Long-term remission in progressive multifocal leukoencephalopathy caused by idiopathic CD4+ T lymphocytopenia: a case report

Progressive multifocal leukoencephalopathy is caused by JC virus, an opportunistic infection of the central nervous system. Antiretroviral treatment for progressive multifocal leukoencephalopathy in human immunodeficiency virus-infected patients is beneficial, but few data exist for patients who are not infected with human immunodeficiency virus. Idiopathic CD4+ T lymphocytopenia excludes human immunodeficiency virus infection. We describe a patient with progressive multifocal leukoencephalopathy with underlying idiopathic CD4+ T lymphocytopenia in whom functional recovery occurred without antiviral therapy.

Changes in the natural history of progressive multifocal leukoencephalopathy in HIV-negative lymphoproliferative disorders: impact of novel therapies

The aims of this study were to evaluate the clinical characteristics of HIV-negative patients affected by lymphoproliferative disorders (LPD) who developed progressive multifocal leukoencephalopathy (PML), to delineate the risk factors, and to analyze whether the new antineoplastic therapies are changing the natural history of this infectious disease. We retrospectively analyzed 46 cases with confirmed LPD-associated PML published from 1958 to 2004. Patients were stratified according to two different time periods: group A included patients diagnosed before 1989, and group B included patients diagnosed since 1990, after introduction of purine analogues. Group A patients (n = 22) had received alkylating agents and/or radiotherapy, and the majority (63.6%) had advanced Hodgkin disease. At univariate analysis, uncontrolled Hodgkin disease was the only risk factor for PML. In group B patients (n = 24), the most frequent treatments received were purine analogues (58.3%) and high-dose therapy with hematopoietic stem cell transplantation (33.3%; HDT/HSCT). B-cell chronic lymphocytic leukemia (45.8%) and aggressive non-Hodgkin lymphoma (24.9%) were the most frequent underlying LPDs. Patients treated with purine analogues were more likely to have active LPD, lower CD4 cell counts, and to be older and male than were HSCT recipients. The median interval from purine analogues or HDT/HSCT to PML was 11 months. In HDT/HSCT recipients, this interval was delayed for 10 months when peri-transplantation rituximab was used. Univariate analysis identified age >55 years, male sex, and CD4 cell counts <or=0.2 x 10(9)/L as risk factors for PML in patients treated with purine analogues. Mortality rates were 95.4% (group A patients), 90% (purine analogues), and 62.5% (HDT/HSCT recipients). At univariate analysis, the only factor that significantly correlated with recovery from infection was female sex. Our findings indicate (1) the possible reduction in reported cases associated with Hodgkin disease and the increasing number of published cases associated with the new antineoplastic therapies (purine analogues and HDT/HSCT); (2) among patients treated with purine analogues, PML is more common in male patients with CD4 cell counts <or=0.2 x 10(9)/L; (3) the use of rituximab after HDT/HSCT seems to delay the onset of PML; and (4) the prognosis is slightly better in transplant recipients.

Progressive multifocal leukoencephalopathy in transplant recipients

Progressive multifocal leukoencephalopathy (PML) is a demyelinating infection caused by the JC virus. It is an emerging disease in transplant recipients; however, it remains poorly defined. Twenty-four cases of PML reported in the literature in transplant recipients were reviewed. Of the 24 cases, nine occurred in renal, six in bone marrow, four in liver, three in heart and two in lung transplant recipients. Median time to onset was 17 months; 71% occurred within 24 months of transplantation. PML tended to occur later in the kidney recipients (P=0.04). Seventy-five percent had subacute presentation; hemiparesis (50%), apathy (46%) and confusion (38%) were the most frequently presented features. Treatment included reduction of immunosuppression and chemotherapy, mainly cidofovir. Death occurred within 2.5 months of the onset of symptoms in 17 patients (71%). PML is a unique entity that should be considered in any transplant recipient with neurological symptoms. The outcome is usually fatal, although regression has been reported.

Bulky nonproteinogenic amino acids permit the design of very small and effective cationic antibacterial peptides

The rate of multidrug-resistant infections is rapidly rising. Cationic antibacterial peptides are active against resistant pathogens and have low propensity for resistance development, but because of their unfavorable medicinal properties, cationic antibacterial peptides have been a limited clinical success. We have found that introduction of nongenetically coded amino acids and other lipophilic modifications opens the opportunity for development of extremely short and highly active antibacterial peptides with improved medicinal properties.

Nervous system infections in patients with cancer

The diagnostic approach to the patient with cancer with suspected CNS infection depends on an analysis of the patient's immune defect, the time course of development of manifestations of infection, and the type of clinical syndrome with supportive evidence for a specific diagnosis coming from laboratory and neuroradiographic data. Most patients with CNS infections can be grouped into those with signs of meningitis or meningoencephalitis and those with focal mass lesions. A smaller group presents with stroke-like onset. Except for the group with strokes, those with focal deficits usually present in a more indolent fashion, whereas those with meningitis and encephalitis present more acutely [63]. Patients with B-lymphocyte dysfunction are susceptible to encapsulated bacterial pathogens. Patients with T-lymphocyte impairment develop CNS infections that are caused by intracellular pathogens, particularly viruses (HSV, JC, CMV, HHV-6), Nocardia, Aspergillus, and Toxoplasma. Many noninfectious entities, such as drug treatment complications, radiation effects, recurrent tumor, and paraneoplastic syndromes, can mimic CNS infections. Although cryptococcosis, bacterial meningitis, and some viral infections are easily diagnosed from Gram's stain, culture, or PCR, patients with mass lesions may require tissue biopsy to confirm diagnosis. Patients with cancer differ from normal hosts in the distribution of pathogens, and there is a wider range of differential diagnostic issues, both infectious and noninfectious, for the relatively few clinical syndromes that present as potential CNS infections.

Progressive multifocal leukoencephalopathy and idiopathic CD4+lymphocytopenia: a case report and review of reported cases

Progressive multifocal leukoencephalopathy (PML) is a well recognized demyelinating neurological disorder caused by JC virus. Idiopathic CD4(+) lymphocytopenia (ICL) is a syndrome first described by the Centers for Disease Control and Prevention as a CD4(+) count <300 cells/mm(3) or a CD4(+) count that is <20% of the total T cell count on 2 occasions, with no evidence of human immunodeficiency virus (HIV) infection on testing, and absence of any defined immunodeficiency or therapy that depresses the levels of CD4(+) T cells. To the best of our knowledge, this is the third reported case of PML and ICL, and also the first reported case of the use of cidofovir to treat PML in a patient not infected with human immunodeficiency virus.

Comparison of cytosine arabinoside delivery to rat brain by intravenous, intrathecal, intraventricular and intraparenchymal routes of administration

We evaluated the delivery of 14C-cytosine arabinoside (AraC) to rat brain by: 1) intravenous (IV) bolus, by 2) intrathecal (IT) and 3) intraventricular (IVT) infusion, and by 4) convection-enhanced delivery (CED) into the caudate nucleus. Plasma and brain AraC metabolites were measured with HPLC, and distribution and concentration of 14C-AraC in brain sections were measured by quantitative autoradiography. After IV administration, the alpha and beta plasma half-lives were 1.9 and 46.5 min, respectively. The blood-to-brain transfer constant of AraC was 2.5+/-1.4 microliter g(-1) min(-1), compatible with high water solubility. After IT and IVT administration, tissue levels were high at the brain and ventricular surfaces, but declined exponentially into brain. After CED, maximum brain levels were up to 10,000 times higher than the IV group, and the distribution pattern was one of high 14C-AraC concentration in the convective component, with exponentially declining concentrations outside this region. The rate loss constant from brain was 0.002+/-0.0004 min(-1), suggesting that AraC was accumulating in brain cells. AraC was metabolized into uracil arabinoside within the brain. 14C-AraC was infused into 1 dog and distributed widely in the ipsilateral hemisphere. These studies suggest that delivery of AraC to brain parenchyma by the IV, IT or IVT routes will be subtherapeutic. Delivery by CED can achieve, and maintain, therapeutic levels of AraC in the brain, and should be further evaluated as a potential method of drug delivery.

Quantification of human polyomavirus JC in brain tissue and cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy by competitive PCR

Activation of human polyomavirus JC (JCV) infection is the cause of the central nervous system (CNS) disease progressive multifocal leukoencephalopathy (PML). Previous studies with uncontrolled quantification systems suggested that the virus load in the CNS correlates with the state of disease and might reflect therapeutic effects. Therefore the aim of this study was the development of a competitive system with standard PCR techniques that allowed rapid detection of JCV subtypes, simultaneous differentiation of the two human polyomaviruses JCV and BKV and absolute quantification of the virus burden in initial diagnosis and progressive disease states. Subtype- and species-specificity of the PCR was achieved with the development of a degenerative PCR primer pair that detected JCV DNA in a range regularly found in PML samples, but did not amplify BKV DNA. The accuracy of the system was evaluated by quantification of known amounts of cloned JCV DNA with a competitive JCV-specific template that exhibited a comparable amplification rate to that of the native product. The calibration study demonstrated a linear correlation over a wide range of DNA concentrations on the background of buffer or JCV-negative diagnostic samples. The reliability of the system for PML diagnosis was analysed by calibration and determination of the virus burden in tissue and cerebrospinal fluid (CSF) of 11 PML patients confirming the accuracy in both types of samples under diagnostic conditions. Comparison of the JCV DNA concentration in tissue and CSF by a tightly controlled quantification technique revealed for the first time differences in a range of about four orders of magnitude and a variable virus load in CSF samples taken at comparable states of disease. This pointed to an individual course of virus shedding and demonstrates that a controlled competitive PCR system of high accuracy is essential for reliable quantification of virus DNA either in initial diagnosis, in progressive disease or for the evaluation of therapeutic effects.

Progressive multifocal leukoencephalopathy: simultaneous detection of JCV DNA and anti-JCV antibodies in the cerebrospinal fluid

We report on a case of biopsy-proven progressive multifocal leukoencephalopathy (PML) in a patient without obvious immunodeficiency. Analysis of the cerebrospinal fluid revealed the simultaneous presence of JC virus DNA and of locally produced, anti-JC virus antibodies. The intrathecal humoral immune response increased throughout the course of the disease, whereas the detection of the JC genome became ultimately negative in spite of the continuous extension of the lesions with fatal outcome.

Absence of thallium-201 brain uptake in progressive multifocal leukoencephalopathy in AIDS patients

OBJECTIVE

To evaluate the presence of thallium-201 brain uptake determined by thallium-201 brain SPECT (Tl-201 SPECT) in patients with progressive multifocal leukoencephalopathy (PML) and AIDS.

MATERIAL AND METHODS

Six AIDS patients with stereotactic biopsy diagnosis of PML were prospectively evaluated with Tl-201 SPECT, Magnetic Resonance Imaging (MRI), and proton magnetic resonance spectroscopy (1H-MRS). Tl-201 SPECT results were compared with 2 patients with AIDS and biopsy proven primary CNS lymphoma.

RESULTS

In all patients with PML, Tl-201 SPECT studies showed lack of uptake while MRI demonstrated subcortical white matter focal brain lesions and 1H-MRS disclosed metabolic abnormalities. Intense thallium uptake (uptake ratios of 3.2 and 5.6) was demonstrated in the 2 patients with primary CNS lymphoma.

CONCLUSIONS

The present study shows that PML lesions are not detectable on Tl-201 SPECT while MRI and 1H-MRS demonstrate abnormalities, and intense thallium-201 uptake may be detected in primary CNS lymphoma. These results suggest that Tl-201 SPECT is a method which, combined with other non-invasive techniques such as MRI and 1H-MRS, may help in the diagnostic approach of PML and to differentiate PML from other high proliferative brain lesions characterized by positive thallium uptake.