Clinical outcomes of natalizumab-associated progressive multifocal leukoencephalopathy

OBJECTIVE

Natalizumab, a therapy for multiple sclerosis (MS), has been associated with progressive multifocal leukoencephalopathy (PML), a rare opportunistic infection of the CNS associated with the JC virus. We assessed clinical outcomes and identified variables associated with survival in 35 patients with natalizumab-associated PML.

METHODS

Physicians provided Karnofsky scores and narrative descriptions of clinical status. Data were supplemented by the natalizumab global safety database.

RESULTS

At the time of analysis, 25 patients (71%) had survived. Survivors were younger (median 40 vs 54 years) and had lower pre-PML Expanded Disability Status Scale scores (median 3.5 vs 5.5) and a shorter time from symptom onset to diagnosis (mean 44 vs 63 days) compared with individuals with fatal cases. Of patients with nonfatal cases, 86% had unilobar or multilobar disease on brain MRI at diagnosis, whereas 70% of those with fatal cases had widespread disease. Gender, MS duration, natalizumab exposure, prior immunosuppressant use, and CSF JC viral load at diagnosis were comparable. Most patients were treated with rapid removal of natalizumab from the circulation. The majority of patients developed immune reconstitution inflammatory syndrome and were treated with corticosteroids. Among survivors with at least 6 months follow-up, disability levels were evenly distributed among mild, moderate, and severe, based on physician-reported Karnofsky scores.

CONCLUSIONS

Natalizumab-associated PML has improved survival compared with PML in other populations. Disability in survivors ranged from mild to severe. A shorter time from symptom onset to diagnosis and localized disease on MRI at diagnosis were associated with improved survival. These data suggest that earlier diagnosis through enhanced clinical vigilance and aggressive management may improve outcomes.

Integrative analysis of gene expression patterns predicts specific modulations of defined cell functions by estrogen and tamoxifen in MCF7 breast cancer cells

To explore the mechanisms whereby estrogen and antiestrogen (tamoxifen (TAM)) can regulate breast cancer cell growth, we investigated gene expression changes in MCF7 cells treated with 17beta-estradiol (E2) and/or with 4-OH-TAM. The patterns of differential expression were determined by the ValiGen Gene IDentification (VGID) process, a subtractive hybridization approach combined with microarray validation screening. Their possible biologic consequences were evaluated by integrative data analysis. Over 1000 cDNA inserts were isolated and subsequently cloned, sequenced and analyzed against nucleotide and protein databases (NT/NR/EST) with BLAST software. We revealed that E2 induced differential expression of 279 known and 28 unknown sequences, whereas TAM affected the expression of 286 known and 14 unknown sequences. Integrative data analysis singled out a set of 32 differentially expressed genes apparently involved in broad cellular mechanisms. The presence of E2 modulated the expression patterns of 23 genes involved in anchors and junction remodeling; extracellular matrix (ECM) degradation; cell cycle progression, including G1/S check point and S-phase regulation; and synthesis of genotoxic metabolites. In tumor cells, these four mechanisms are associated with the acquisition of a motile and invasive phenotype. TAM partly reversed the E2-induced differential expression patterns and consequently restored most of the biologic functions deregulated by E2, except the mechanisms associated with cell cycle progression. Furthermore, we found that TAM affects the expression of nine additional genes associated with cytoskeletal remodeling, DNA repair, active estrogen receptor formation and growth factor synthesis, and mitogenic pathways. These modulatory effects of E2 and TAM upon the gene expression patterns identified here could explain some of the mechanisms associated with the acquisition of a more aggressive phenotype by breast cancer cells, such as E2-independent growth and TAM resistance.

Characterization and cloning of a major high molecular weight house dust mite allergen (Der f 15) for dogs

Although house dust mites (HDM(s)) are important elicitors of canine allergy, the low molecular weight molecules defined as major allergens for humans do not appear to be major allergens for dogs. Western blotting of Dermatophagoides farinae (D. farinae) extracts with sera from sensitized dogs showed that the majority of animals had IgE antibodies specific for two proteins of apparent molecular weights of 98 and 109kDa (98/109kDa). The N-terminal sequences of these two proteins were identical, suggesting they were very closely related, and sequencing of internal peptides showed the protein(s) to have homology with insect chitinases. A purified preparation of 98/109kDa proteins elicited positive intradermal skin tests (IDST(s)) in a group of well-characterized atopic dogs sensitized to D. farinae, but not in normal dogs. A rabbit polyclonal antiserum raised against the purified proteins was used to immunoscreen a D. farinae cDNA library. The mature coding region of the isolated chitinase cDNA predicts a protein of 63.2kDa; sequence analysis and glycan detection blotting suggest that the molecule is extensively O-glycosylated. Monoclonal antibodies made against the purified native protein were used to localize the chitinase in sections of whole D. farinae mites. The protein displayed an intracellular distribution in the proventriculus and intestine of the mite, suggesting that it has a digestive, rather than a moulting-related, function. The high prevalence of IgE antibodies to this antigen in canine atopic dermatitis makes it a major HDM allergen for dogs, and the protein has been formally designated Der f 15.

Glucuronic acid- and branched sugar-containing glycolipid antigens of Mycobacterium avium

The pentasaccharide hapten of the dominant glycopeptidolipid antigen of serovariant 19 of the Mycobacterium avium complex is noteworthy because of the uniqueness of its distal glycobiose, the presumed antigen determinant, which contains a 3,4-di-O-methyl glucuronic acid and a novel branched sugar. The detailed structure of the entire pentasaccharide has been established by high field 1H and 13C NMR, fast atom bombardment/mass spectrometry, and various specific degradations as 3,4-di-O-Me-beta-D-GlcAp-(1----3)-2,4-di-O-Me-3-C-Me-3,6-dideox yhexosyl-(1----3)-alpha-L-Rhap-(1----3)-alpha-L-Rhap-( 1----2)-6-dT al; the extreme acid lability of the novel penultimate sugar presented special structural challenges. Thus, the task of defining the variable epitopes of M. avium serovariants in order to charter the epidemiology of opportunistic mycobacterial diseases continues to reveal an unexpected order of sugar diversity and complexity.

Fetal rhabdomyoma of the parotid gland in an infant: histological, immunohistochemical, and ultrastructural features

A case of fetal rhabdomyoma of the parotid gland in a 3-year-old infant is presented. The histological, ultrastructural, and immunohistochemical findings in this very uncommon benign tumor are described together with a review of the literature.

An attempt to separate xiphopagus twins sharing a common heart, liver, and duodenum

An attempt was made to separate 7-wk-old conjoined twins. It proved unsuccessful because of extensive cardiac malformations in the shared heart. Details of operation and postmortem findings are described.

Familial occurrence of persistent Mullerian structures in otherwise normal males

Eight cases of males with persistent Müllerian structures are reported in four pairs of unrelated siblings. A genetically inherited failure to produce or to respond to the Müllerian-inhibiting substance elaborated by the fetal testis is postulated.