Clinical Utility of 18F-FDG PET/CT in the Work-up of Children with Uveitis.

PURPOSE: To evaluate 18F-fluorodeoxyglucose Positron Emission Tomography/ultra low dose Computed Tomography (18F-FDG PET/ ULD CT) in the work-up of pediatric uveitis. METHODS: Retrospective study of 12 children followed for uveitis who underwent whole body 18F-FDG PET/ULD CT between 2011 and 2019. RESULTS: The average age of the patients was 11 years. A total of 100% of patients presented with bilateral uveitis, 50% had panuveitis and 92% had various choroidal involvement. Relevant information for diagnosis was provided in four patients. 5/12 had an abnormal 18F-FDG uptake. Of these, three patients had pathognomonic images of active granulomatous diseases. Three patients underwent PET CT-guided biopsies of which two were positive for sarcoidosis. CONCLUSION: 18F-FDG PET/CT provided important information for final diagnosis in approximately 30% (4/12) of pediatric patients with bilateral uveitis. Whole body FDG PET/ULD CT can contribute to the final diagnosis thanks to pathognomonic image of active granulomatous disease and/or by indicating metabolically active site of biopsy that would not be visualized in thorax CT.

Diagnosis of Cytomegalovirus Anterior Uveitis in Two European Referral Centers.

PURPOSE: To evaluate diagnostic methods and clinical signs of CMV anterior uveitis (AU), a rarely described entity in Europe. METHODS: We included patients with clinical characteristics of CMV AU and positive PCR and/or Goldmann-Witmer coefficient (GWc) for CMV. RESULTS: We report 21 patients with unilateral uveitis (100%) and signs of Posner-Schlossman syndrome (PSS) (n = 20, 95.2%), Fuchs uveitis syndrome (FUS) (n = 1, 4.7%), and endotheliitis (n = 4, 19,04%). PCR was positive in 15/21 (71.4%) and GWc in 8/9 patients (88.9%) in aqueous for CMV. GWc was the only positive test in 6/9 patients (66,6%). When PCR alone was performed (without GWc) in the first tap, repeated aqueous taps were needed, twice in five cases and thrice in one case. CONCLUSION: Combining PCR and GWc were very helpful to confirm the clinical diagnosis of CMV AU. In case of very high clinical suspicion and negative results, repeated tap seems to be recommended.

P2Y2R deficiency attenuates experimental autoimmune uveitis development.

We aimed to study the role of the nucleotide receptor P2Y2R in the development of experimental autoimmune uveitis (EAU). EAU was induced in P2Y2+/+ and P2Y2-/- mice by immunization with IRBP peptide or by adoptive transfer of in vitro restimulated semi-purified IRBP-specific enriched T lymphocytes from spleens and lymph nodes isolated from native C57Bl/6 or P2Y2+/+ and P2Y2-/- immunized mice. Clinical and histological scores were used to grade disease severity. Splenocytes and lymph node cell phenotypes were analyzed using flow cytometry. Semi-purified lymphocytes and MACS-purified CD4+ T lymphocytes from P2Y2+/+ and P2Y2-/- immunized mice were tested for proliferation and cytokine secretion. Our data show that clinical and histological scores were significantly decreased in IRBP-immunized P2Y2-/- mice as in P2Y2-/- mice adoptively transfered with enriched T lymphocytes from C57Bl/6 IRBP-immunized mice. In parallel, naïve C57Bl/6 mice adoptively transferred with T lymphocytes from P2Y2-/- IRBP-immunized mice also showed significantly less disease. No differences in term of spleen and lymph node cell recruitment or phenotype appeared between P2Y2-/- and P2Y2+/+ immunized mice. However, once restimulated in vitro with IRBP, P2Y2-/- T cells proliferate less and secrete less cytokines than the P2Y2+/+ one. We further found that antigen-presenting cells of P2Y2-/- immunized mice were responsible for this proliferation defect. Together our data show that P2Y2-/- mice are less susceptible to mount an autoimmune response against IRBP. Those results are in accordance with the danger model, which makes a link between autoreactive lymphocyte activation, cell migration and the release of danger signals such as extracellular nucleotides.

[Post-streptococcal uveitis]. / Uvéites post-streptococciques.

PURPOSE: The role of streptococcal infections in the development of uveitis remains uncertain. Here we describe a series of patients with suspected poststreptococcal uveitis. OBSERVATION: Four retrospective cases were collected (two males and two females). All patients had a sore throat or an episode of pyrexia 2 to 10 weeks before the onset of uveitis and elevated antistreptolysin-O titer (ASOT); no other cause of uveitis was found. Uveitis was bilateral in all the cases and recurrent in only one. In two patients, inflammation was limited to the anterior segment. One patient had intermediate uveitis. One patient had posterior uveitis with multiple white-dot lesions as well as macular and optic disc swelling. The two cases with anterior uveitis were treated only topically and the two others received a short course of systemic steroids. No systemic antibiotics were given. CONCLUSIONS: These cases suggest that uveitis could be a manifestation of poststreptococcal syndrome and have a good prognosis.

Extracellular nucleotides and interleukin-8 production by ARPE cells: potential role of danger signals in blood-retinal barrier activation.

PURPOSE: RPE cell activation is an important feature of autoimmune uveitis. This investigation focused on whether extracellular nucleotides could contribute to this activation, and the effects of ATPgammaS, UTP, and UDP on the production of IL-8 by RPE cells was studied in relation to their expression of functional P2Y receptors. METHODS: ARPE-19 cells were cultured with ATPgammaS, UTP, UDP, and TNF. IL-8 gene transcription and protein production were measured by semiquantitative RT-PCR and ELISA. Western blot analysis and RT-PCR were used to investigate ERK 1/2 activation and P2Y expression. Changes in intracellular calcium and cAMP concentration were analyzed by spectrofluorometry and radioimmunoassay. RESULTS: Stimulation of ARPE-19 cells with ATPgammaS, UTP, and UDP induced IL-8 gene transcription and protein secretion. TNFalpha induction of IL-8 secretion was also increased by ATPgammaS, UTP, and UDP. Nucleotide induction of IL-8 production was blocked by PD98059, and all nucleotides stimulated ERK 1/2 phosphorylation. P2Y(2) and P2Y(6) mRNAs were detected in ARPE-19 cells. All tested nucleotides induced a pulse of intracellular calcium. CONCLUSIONS: ATPgammaS, UTP, and UDP stimulate both basal and TNFalpha-induced IL-8 secretion in RPE cells through an ERK 1/2-dependent pathway. The results suggest that those effects are mediated by P2Y(2) and P2Y(6) receptors.