Yield of FDG PET/CT for Defining the Extent of Disease in Patients with Kaposi Sarcoma

International audienceBackground: Positron emission tomography/computed tomography with fluorodeoxyglucose (F-18) (FDG PET/CT) is increasingly used in Kaposi sarcoma (KS), but its value has not been assessed. Objectives: In this study, we aimed to evaluate the diagnostic accuracy of FDG PET/CT to define the extent of disease in KS. Methods: Consecutive patients with KS referred to our department for FDG PET/CT were included. The diagnostic accuracy of FDG PET/CT for cutaneous and extra-cutaneous KS staging was assessed on a per lesion basis compared to staging obtained from clinical examination, standard imaging, endoscopy, histological analyses, and follow-up. Results: From 2007 to 2017, 75 patients with FDG PET/CT were analyzed. The sensitivity and specificity of FDG PET/CT for the overall detection of KS lesions were 71 and 98%, respectively. Sensitivity and specificity were 100 and 85% for lymph nodes, 87 and 98% for bone, 87 and 100% for lungs, and 100 and 100% for muscle involvement, whereas sensitivity was only 17% to detect KS digestive involvement. The sensitivity of the diagnostic for KS cutaneous involvement increased from 73 to 88% when using a whole-body examination. Conclusion: FDG PET/CT showed good sensitivity and specificity for KS staging (digestive involvement excepted) and could be used for staging patients with active KS

Reintroduction of immune-checkpoint inhibitors after immune-related meningitis: a case series of melanoma patients

Immune-checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated antigen-4 and programmed cell death ligand-1) are associated with several immune-related neurological disorders. Cases of meningitis related to ICIs are poorly described in literature and probably underestimated. Several guidelines are available for the acute management of these adverse events, but the safety of resuming ICIs in these patients remains unclear. We conducted a retrospective case series of immune-related meningitis associated with ICIs that occurred between October 1 2015 and October 31 2019 in two centers: Saint-Louis and Cochin hospitals, Paris, France. Diagnosis was defined by a (1) high count of lymphocytes (>8 cells/mm3) and/or high level of proteins (>0.45 g/L) without bacteria/virus or tumor cells detection, in cerebrospinal fluid and (2) normal brain and spine imaging. Patients were followed-up for at least 6 months from the meningitis onset. Seven cases of immune-related meningitis are here reported. Median delay of meningitis occurrence after ICIs onset was 9 days. Steroid treatment was introduced in four patients at a dose of 1 mg/kg (prednisone), allowing a complete recovery within 2 weeks. The other three patients spontaneously improved within 3 weeks. Given the favorable outcome, ICIs were reintroduced in all patients. The rechallenge was well tolerated and no patients experienced meningitis recurrence. In conclusion, in our series, the clinical course was favorable and steroids were not always required. Resuming ICIs in these patients appeared safe and can thus be considered in case of isolated meningitis. However, a careful analysis of the risk/benefit ratio should be done on a case-by-case basis

TLR-2 Recognizes Propionibacterium acnes CAMP Factor 1 from Highly Inflammatory Strains

International audienceBackgroundPropionibacterium acnes (P. acnes) is an anaerobic, Gram-positive bacteria encountered in inflammatory acne lesions, particularly in the pilosebaceous follicle. P. acnes triggers a strong immune response involving keratinocytes, sebocytes and monocytes, the target cells during acne development. Lipoteicoic acid and peptidoglycan induce the inflammatory reaction, but no P. acnes surface protein interacting with Toll-like receptors has been identified. P. acnes surface proteins have been extracted by lithium stripping and shown to induce CXCL8 production by keratinocytes.Methodology and principal findingsFar-western blotting identified two surface proteins, of 24.5- and 27.5-kDa in size, specifically recognized by TLR2. These proteins were characterized, by LC-MS/MS, as CAMP factor 1 devoid of its signal peptide sequence, as shown by N-terminal sequencing. Purified CAMP factor 1 induces CXCL8 production by activating the CXCL8 gene promoter, triggering the synthesis of CXCL8 mRNA. Antibodies against TLR2 significantly decreased the CXCL8 response. For the 27 P. acnes strains used in this study, CAMP1-TLR2 binding intensity was modulated and appeared to be strong in type IB and II strains, which produced large amounts of CXCL8, whereas most of the type IA1 and IA2 strains presented little or no CAMP1-TLR2 binding and low levels of CXCL8 production. The nucleotide sequence of CAMP factor displays a major polymorphism, defining two distinct genetic groups corresponding to CAMP factor 1 with 14 amino-acid changes from strains phylotyped II with moderate and high levels of CAMP1-TLR2 binding activity, and CAMP factor 1 containing 0, 1 or 2 amino-acid changes from strains phylotyped IA1, IA2, or IB presenting no, weak or moderate CAMP1-TLR2 binding.ConclusionsOur findings indicate that CAMP factor 1 may contribute to P. acnes virulence, by amplifying the inflammation reaction through direct interaction with TLR2

TLR2 blockade inhibits <i>P</i>. <i>acnes</i> CAMP factor 1-induced CXCL8 expression.

<p>Surface protein extracts were electrophoretically separated in 10% SDS-PAGE gels (13 x 13 cm), with detection by Coomassie blue staining. Proteins of interest were excised from the gel, eluted and pooled as described in the Materials and Methods. HaCaT cells were treated for 2 h with human anti-TLR2 (dashed bar) or with goat anti-IgGa antibodies (dark gray bar) and transfected by incubation for 24 h with NF-κB transcription factor (A) and CXCL8 (-173 bp) (B) inserted into a construct upstream from the luciferase gene, after which, an internal control (the <i>Renilla</i> luciferase expression plasmid) was added to the transfection mixture. Cell were stimulated with eluted CAMP factor 1 (50 μg/ml) for 24 h at 37°C. Relative NF-κB and CXCL8 promoter activities were determined as the ratio of firefly and <i>Renilla</i> luciferase activities. Pretreated HaCaT cells were stimulated by incubation with eluted CAMP factor 1 (50 μg/ml) for 24 h at 37°C, CXCL8 mRNA levels were determined by RT-qPCR (C), and CXCL8 production was measured by ELISA (D). Control experiments were performed with cells alone (dark bar) and with stimulated cells not previously treated with CAMP factor 1 (light gray bar). Data are presented as the mean ± standard deviation of two independent experiments. Statistical significance is indicated by * <i>P</i> ≤ 0.05, ** <i>P</i> ≤ 0.01, *** <i>P</i> ≤ 0.001, **** <i>P</i> ≤ 0.0001.</p

N-terminal sequencing of the protein of interest.

<p>Surface protein extracts were electrophoretically separated in 10% SDS-PAGE gels (13 x 13 cm), with detection by Coomassie blue staining. Proteins of interest were excised from the gel, eluted and subjected to N-terminal sequencing by Edman degradation to obtain the first five amino-acid residues of each protein, as described in Materials and Methods. N-terminal sequences were compared to the <i>P</i>. <i>acnes</i> CAMP factor 1 sequence (reference stain NCTC 737, GenBank accession number AY527218.1). The peptide signal cleavage site of CAMP factor 1 is shown in bold.</p

TLR2 binding to <i>P</i>. <i>acnes</i> surface proteins.

<p><i>P</i>. <i>acnes</i> surface proteins were extracted from a 5-day culture bacterial pellet and separated by electrophoresis in a 4–12% NuPAGE LDS BisTris gel (50 μg) with detection by Coomassie blue staining (A). Separated proteins were transferred onto nitrocellulose membranes, which were incubated with recombinant TLR2 (B) and TLR4 (C) (0.1 μg/ml). TLR binding activity was detected with specific biotinylated antibodies against TLR2 and TLR4, respectively, as described in the Materials and Methods. Lane 1 contains the molecular mass markers. Lanes 2 to 7 contain proteins from strains 6919, RON, CHR, GUE, TRI, and PIE, respectively. Arrows indicate the positions of the 24.5- and 27.5-kDa bands of interest.</p

<i>P</i>. <i>acnes</i> CAMP factor 1 polymorphism.

<p>CAMP factor 1 nucleotide sequence analysis was performed on the 27 <i>P</i>. <i>acnes</i> isolates, as described in the Materials and Methods. Nucleotide (dark bold) and peptide (light gray) changes identified in <i>P</i>. <i>acnes</i> isolates relative to the reference sequence of the <i>P</i>. <i>acnes</i> NTCT 737 strain (GenBank accession number AY527218.1) are indicated by vertical bars. (A), (B and C), (D and E), (F) correspond to CAMP1 with no, 1, 2, and several mutations, respectively. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0167237#pone.0167237.t004" target="_blank">Table 4</a>.</p