Analysis of complement and plasma cells in the brain of patients with anti-NMDAR encephalitis.

OBJECTIVES: Most patients with anti-NMDA receptor (NMDAR) encephalitis have intrathecal synthesis of antibodies, which cause a decrease of cell surface and synaptic NMDAR. Antibodies are immunoglobulin G (IgG)1 and IgG3 subtypes and can potentially activate complement. We examined whether complement immunoreactivity and antibody-secreting cells (plasma cells/plasmablasts) are present in the brain of these patients. METHODS: Cultured rat hippocampal neurons were used in an immunocytochemical assay to test whether patients' antibodies can fix complement. Using the same reagents (antibodies to C9neo, C(5b-9), C3), complement immunoreactivity was determined in the brain of 5 patients, the teratoma of 21 patients, and appropriate control tissues. A set of markers for B (CD20), T (CD3, CD4, CD8) and antibody-secreting cells (plasma cells/plasmablasts, CD138) were used to examine the brain inflammatory infiltrates. RESULTS: Patients' antibodies were able to bind complement in vitro, but deposits of complement were not detected in patients' brain. Parallel experiments with teratomas showed that in contrast to the brain, the neural tissue of the tumors contained complement. Analysis of the inflammatory infiltrates in brain samples from autopsy or biopsy performed 3-4 weeks after symptom presentation demonstrated numerous antibody-secreting cells (CD138+) in perivascular, interstitial, and Virchow-Robin spaces, and B and T cells predominantly located in perivascular regions. CONCLUSIONS: Complement-mediated mechanisms do not appear to play a substantial pathogenic role in anti-NMDAR encephalitis. In contrast, there are copious infiltrates of antibody-secreting cells (plasma cells/plasmablasts) in the CNS of these patients. The demonstration of these cells provides an explanation for the intrathecal synthesis of antibodies and has implications for treatment.

A topical azithromycin preparation for the treatment of acne vulgaris and rosacea.

BACKGROUND: Erythromycin is a common therapy for acne and rosacea. A newer macrolide, azithromycin, offers superior tissue distribution and cellular concentration and is an effective oral anti-acne agent. Topical formulations such as erythromycin have been a major clinical therapy for acne. To date, no topical solution of azithromycin is available for the treatment of acne. OBJECTIVE: To prepare a stable topical 2% azithromycin formulation that could be used in an acne clinical trial to determine the efficacy of topical azithromycin in treating subjects with acne vulgaris and acne rosacea. METHODS: The study was divided into two phases. In phase I, azithromycin was prepared over a range of ethanol/water concentrations to determine solubility. The stability of a 2% azithromycin in 60% ethanol/water preparation was assessed by high-pressure liquid chromatography. The temperature, light, and pH dependence of the stability was also assessed. In phase II, a single center, randomized, double-blind, treatment-controlled study compared once-nightly application of topical 2% azithromycin versus 2% erythromycin. A total of 20 subjects with moderate inflammatory acne and 20 with rosacea were examined clinically at 0, 2, 4, 8, and 12 weeks for a 12-week period. Efficacy was evaluated with the Physician's Visual Analog Scale evaluation (PVAS), the papulopustule count, and acne severity rating (in subjects with acne). RESULTS: In phase I, azithromycin was soluble in 60% ethanol/water. A 2% azithromycin in 60% ethanol/water solution maintained stability at room temperature for up to 26 weeks but at 37 degrees C there was some decay (16%) at 26 weeks. The stability was greatest at pH 6.8 and was unaffected by ambient light exposure. In phase II, the number of inflammatory lesions decreased in both acne and rosacea subjects treated with 2% erythromycin (7.56, p=0.03 and 4.4, p=0.01, respectively). Azithromycin was not as effective for the treatment of rosacea. Both azithromycin (p=0.01) and erythromycin (p=0.03) treatment significantly reduced the inflammatory lesion count in acne vulgaris. No significant adverse events were identified in the acne group. In patients with rosacea, transient irritation occurred in five patients. CONCLUSIONS: A 2% azithromycin in 60% ethanol/water solution can be prepared and is stable for at least 6 months at room temperature. The methodology and power of the study were adequate to identify improvement in acne vulgaris and rosacea. Though it appears the formulation of topical azithromycin was at least comparable with topical erythromycin, larger studies would be needed to determine whether topical azithromycin has any significant advantage over topical erythromycin.

Expression of microtubule-associated protein 2 in benign and malignant melanocytes: implications for differentiation and progression of cutaneous melanoma.

Cutaneous melanocytic neoplasms are known to acquire variable characteristics of neural crest differentiation. Melanocytic nevus cells in the dermis and desmoplastic melanomas often display characteristics of nerve sheath differentiation. The extent and nature of neuronal differentiation characteristics displayed by primary and metastatic melanoma cells are not well understood. Here, we describe induction of a juvenile isoform of microtubule-associated protein 2 (MAP-2c) in cultured metastatic melanoma cells by the differentiation inducer hexamethylene bisacetamide. Up-regulation of this MAP-2 isoform, a marker for immature neurons, is accompanied by extended dendritic morphology and down-regulation of tyrosinase-related protein 1 (TYRP1/gp75), a melanocyte differentiation marker. In a panel of cell lines that represent melanoma tumor progression, MAP-2c mRNA and the corresponding approximately 70-kd protein could be detected predominantly in primary melanomas. Immunohistochemical analysis of 61 benign and malignant melanocytic lesions showed abundant expression of MAP-2 protein in melanocytic nevi and in the in situ and invasive components of primary melanoma, but only focal heterogeneous expression in a few metastatic melanomas. In contrast, MAP-2-positive dermal nevus cells and the invasive cells of primary melanomas were TYRP1-negative. This reciprocal staining pattern in vivo is similar to the in vitro observation that induction of the neuronal marker MAP-2 in metastatic melanoma cells is accompanied by selective extinction of the melanocytic marker TYRP1. Our data show that neoplastic melanocytes, particularly at early stages, retain the plasticity to express the neuron-specific marker MAP-2. These observations are consistent with the premise that both benign and malignant melanocytes in the dermis can express markers of neuronal differentiation.

Epidermal stratification reduces the effects of UVB (but not UVA) on keratinocyte cytokine production and cytotoxicity.

Ultraviolet (UV) radiation induces cytokine release from cultured keratinocytes as well as from epidermis in vivo. The purpose of this study was to determine whether differentiation of cultured keratinocytes into stratified epithelium decreases the effects of UVA and UVB radiation on cytokine release. Interleukin-1 (IL-1) alpha, IL-1 beta and tumor necrosis factor (TNF)-alpha release from human keratinocytes and reconstituted human epidermis was measured after exposure to UVA or UVB radiation. Release of IL-1 alpha, IL-1 beta, and TNF-alpha was induced by both UVA and UVB radiation from both keratinocytes and reconstituted epidermis. Release of these cytokines was correlated with cytotoxicity. Keratinocyte cultures were far more sensitive to UVB radiation than reconstituted epidermis, in terms of both cytotoxicity and cytokine release. In contrast, epidermal stratification/differentiation had much less effect on the sensitivity to UVA radiation. We conclude that epidermal stratification and the formation of a stratum corneum provide protection against UVB radiation but have limited barrier effect against UVA radiation.