CD4/CD8 ratio in aqueous humor in Uveitis

Signature of Circulating Biomarkers in Recurrent Non-Infectious Anterior Uveitis. Immunomodulatory Effects of DHA-Triglyceride. A Pilot Study

The purpose of this study was to identify circulating biomarkers of recurrent non-infectious anterior uveitis (NIAU), and to address the anti-inflammatory effects of triglyceride containing docosahexaenoic acid (DHA-TG). A prospective multicenter study was conducted in 72 participants distributed into: patients diagnosed with recurrent NIAU in the quiescence stage (uveitis group (UG); n = 36) and healthy controls (control group (CG); n = 36). Each group was randomly assigned to the oral supplementation of one pill/day (+) containing DHA-TG (n = 18) or no-pill condition (−) (n = 17) for three consecutive months. Data from demographics, risk factors, comorbidities, eye complications and therapy were recorded. Blood was collected and processed to determine pro-inflammatory biomarkers by bead-base multiplex assay. Statistical processing with multivariate statistical analysis was performed. The mean age was 50, 12 (10, 31) years. The distribution by gender was 45% males and 55% females. The mean number of uveitis episodes was 5 (2). Higher plasma expression of interleukin (IL)-6 was detected in the UG versus the CG (p = 5 × 10⁻⁵). Likewise, significantly higher plasma levels were seen for IL-1β, IL-2, INFγ (p = 10⁻⁴), and TNFα (p = 2 × 10⁻⁴) in the UG versus the CG. Significantly lower values of the above molecules were found in the +DHA-TG than in the -DHA-TG subgroups, after 3 months of follow-up, TNFα (p = 10⁻⁷) and IL-6 (p = 3 × 10⁻⁶) being those that most significantly changed. Signatures of circulating inflammatory mediators were obtained in the quiescent stage of recurrent NIAU patients. This 3-month follow-up strongly reinforces that a regular oral administration of DHA-TG reduces the inflammatory load and may potentially supply a prophylaxis-adjunctive mediator for patients at risk of uveitis vision loss.

CD4- and CD8-expressing cells in the chambers of normal, cataract and uveitic eyes: A comparative study in dogs

The main aims of this study were to determine whether CD4⁺ and CD8⁺ cells are present in the normal chambers of the eye in dogs and to verify the hypothesis that uncomplicated cataract may be associated with the local recruitment of CD4⁺ and CD8⁺ cells. The presence of CD4⁺ and CD8⁺ cells was detected in aqueous humor (AH) of normal and cataract eyes. The study did not reveal differences in the percentage and absolute number of CD4⁺ cells between normal and cataract eyes. However, the values of these parameters in AH from cataract eyes were approximately 2- and 3-fold higher than in normal eyes, respectively. The mean percentage and absolute count of CD8⁺ cells increased approximately by 2.7- and 6-fold, respectively, in AH samples from cataract eyes compared to normal ones. The absolute count of CD4⁺ and CD8⁺ cells in AH of uveitic eyes was approximately 5- and 3-fold higher than in cataract eyes. The results indicate that CD4⁺ and CD8⁺ cells occur constitutively in the normal chambers of the eye in dogs. However, it should be pointed out that both of these cell populations appeared in trace amounts. The development of uncomplicated cataract in dogs may not be immunologically neutral in terms of the local immune response, but it may be associated with the recruitment of CD8⁺ cells into the eye chambers. This event does not seem to be of an inflammatory nature because it appears on a scale a few times smaller than in the course of uveitis.

Intraocular leucocyte subpopulations analysis by multiparametric flow cytometry in human uveitis

PURPOSE

The aim of this study was to describe the cellular infiltrate in aqueous and vitreous samples of patients with uveitis analysed by multiparametric flow cytometry.

METHODS

This is a retrospective analysis of aqueous and vitreous samples analysed by flow cytometry for diagnostic purposes, in cases of masquerade syndromes and infectious and non-infectious uveitis. Data collected included demographics, anatomical classification of uveitis, phenotypic diagnosis, anterior chamber cells grading, vitreous haze and time of follow-up since presentation to sample obtained.

RESULTS

Thirty-one samples (17 aqueous and 14 vitreous fluids) from 31 patients, 18 men, were analysed. The mean age at the time of sample collection was 60.23±17.03 years. The most frequent anatomical classification was panuveitis (14 of 31). T cells accounted for the main cellular component in the majority of the samples (10 of 13 aqueous samples; 7 of 14 in vitreous samples). CD4:CD8 ratios ranged from 0.21 to 16.3 in the case of aqueous samples and from 0.5 to 9.7 in the case of vitreous samples.

DISCUSSION

Flow cytometry analysis of aqueous and vitreous samples from patients with uveitis could provide insight into the pathogenesis of human uveitis and help develop accurate animal models which better mimic human disease.

Activation of the Notch signaling pathway disturbs the CD4+/CD8+, Th17/Treg balance in rats with experimental autoimmune uveitis

OBJECTIVE AND DESIGN

The present study aimed to investigate the relationship between the disturbed balance of CD4⁺/CD8⁺, Th17/Treg and the activation of the Notch signaling pathway in experimental autoimmune uveitis (EAU).

METHODS

An EAU rat model was induced in Lewis rats, and pathology analysis was performed by hematoxylin and eosin (H&E) staining. CD4⁺, CD8⁺, Th17, and Treg levels in spleen, lymph nodes and eye tissues were determined by flow cytometry. Meanwhile, the expression of Notch1, DLL4, IL-10, and IL-17 was determined by quantitative polymerase chain reaction (Q-PCR) and enzyme-linked immunosorbent assay (ELISA). In addition, the inhibitory effect of N-(N-(3,5-difluorophenacetyl-L-alanyl))-S-phenylglycine t-butyl ester (DAPT) on Th17 differentiation by Notch signaling in vitro was further investigated using T lymphocytes from EAU rats on day 12 post-immunization by flow cytometry.

RESULTS

The pathological results showed that inflammatory cell infiltration occurred in ocular tissues in EAU rats. The CD4⁺/CD8⁺ and Th17/Treg ratios in EAU rats were apparently higher than those in normal control individuals. Q-PCR and ELISA analyses indicated the expression of Notch1, DLL4, IL-10, and IL-17 in EAU rats gradually increased on day 6 after immunization, peaked on day 12, and then gradually decreased. The dynamic trends in Notch1 and DLL4 expression in EAU rats were identical to those of CD4⁺/CD8⁺ and Th17/Treg levels. DAPT can significantly inhibit the activation of Notch signaling, decrease Th17 cell differentiation, and attenuate the level of the Th17 cell lineage, contributing to the balance of the Th17/Treg ratio.

CONCLUSION

The activation of the Notch signaling pathway can regulate Th17 and Treg cell differentiation, disrupt the CD4⁺/CD8⁺ and Th17/Treg balance, and aggravate the severity of EAU; inactivation of the Notch signaling pathway contributes to the CD4⁺/CD8⁺ and Th17/Treg balance in EAU rats. Our findings highlighted that the dynamic change in the CD4⁺/CD8⁺ and Th17/Treg ratio was consistent with the expression trend of Notch signaling in EAU rats, suggesting that Notch signaling may be a potentially important therapeutic target in clinical practice.

Laboratory investigations in uveitis: current practice and future directions

Diagnosis and management of uveitis always remains a challenge to the treating ophthalmologists. Rapid diagnosis and timely initiation of appropriate, effective treatment in uveitis are the critical determinants that lead to good visual outcome and reduce the risk of ocular morbidity. In the last decade, significant progress has been made in molecular diagnostic modalities and in development of newer diagnostic tools, which included serological tests and imaging techniques. However, a tailored approach to laboratory investigations based on meticulous history and comprehensive ocular evaluation has been propounded as the gold standard for successful management of an uveitic entity. In this article, we review the laboratory diagnostic tests in uveitis as well as recent technological advances in laboratory science, which may be the future direction for diagnosis of uveitis.

Increased Aqueous Humor CD4+/CD8+ Lymphocyte Ratio in Sarcoid Uveitis

Purpose: To determine aqueous humor CD4+/CD8+ T-lymphocyte ratio changes in sarcoid and non-sarcoid uveitis with anterior chamber involvement. Methods: The case-control study includes 61 patients with either anterior uveitis, intermediate uveitis with anterior spill, or panuveitis. A total of 21 of them were categorized as sarcoid uveitis and 40 as non-sarcoid uveitis according to diagnostic criteria. CD4+/CD8+ ratio in the aqueous humor was determined using flow cytometry. Results: Significantly higher CD4+/CD8+ ratio in the aqueous humor was observed in patients with sarcoid uveitis (6.3 ± 1.4; mean ± SEM) compared to non-sarcoid uveitis (1.6 ± 0.1; mean ± SEM). Whole blood CD4+/CD8+ ratio was not elevated in subjects with sarcoid and non-sarcoid uveitis. Aqueous humor CD4+/CD8+ ratio >3.5 was observed to be associated with sarcoid uveitis (OR 38, 95% CI 7.0-205.2). Conclusion: Increased aqueous humor CD4+/CD8+ ratio in sarcoid uveitis. Immunophenotyping of localized lymphocytosis in aqueous humor could be utilized as an additional confirmatory marker for ocular sarcoidosis.

CD25+CD127+Foxp3- Cells Represent a Major Subpopulation of CD8+ T Cells in the Eye Chambers of Normal Mice

The aim of this study has been to determine whether eye chambers constitute part of the normal migratory pathway of naive CD4⁺ and CD8⁺ T cells in mouse and if natural CD4⁺CD25⁺Foxp3⁺ and CD8⁺CD25⁺Foxp3⁺ regulatory T cells are present within these eye compartments. To this aim, the cells obtained from aqueous humor (AH) of normal mice were phenotyped in terms of the expression CD4, CD8, CD25, CD127 and transcription factor Foxp3. The mean percentage of CD8⁺ T cells in the total AH lymphocyte population was as high as 28.69%; the mean percentage of CD8^high and CD8^low cells in this population was 34.09% and 65.91%, respectively. The presence of cells with the regulatory phenotype, i.e. CD25⁺Foxp3⁺ cells, constituted only 0.32% of CD8⁺ T cell subset. Regarding the expression of CD25, AH CD8⁺ T cells were an exceptional population in that nearly 85% of these cells expressed this molecule without concomitant Foxp3 expression. Despite having this phenotype, they should not be viewed as activated cells because most of them co-expressed CD127, which indicates that they are naive lymphocytes. With regard to the markers applied in the present research, CD8⁺CD25⁺CD127⁺Foxp3^- T cells represent the most numerous subset of AH CD8⁺ cells. The results suggest that eye chambers in mice are an element in the normal migratory pathway of naive CD8⁺ T cells. The study presented herein demonstrated only trace presence of CD4⁺ cells in the eye chambers, as the mean percentage of these cells was just 0.56. Such selective and specific homing of CD8⁺ and CD4⁺ cells to the eye chambers is most clearly engaged in the induction and maintenance of ocular immune privilege.

Immunomodulatory effects of Longdan Xiegan Tang on CD4+/CD8+ T cells and associated inflammatory cytokines in rats with experimental autoimmune uveitis

Longdan Xiegan Tang (LXT) is a mixture of herbal extracts commonly used in traditional Chinese medicine that may exert immunomodulatory effects for the treatment of autoimmune diseases. However, the detailed mechanisms that mediate the actions of LXT are unclear. The present study induced an experimental autoimmune uveitis (EAU) model in Lewis rats via injection of IRBP1177‑1191 emulsion. The model was used to investigate the effects of LXT on EAU rats and assess the efficacy of LXT by measuring clinical manifestations and histopathological changes caused by EAU. Additionally, alterations in the ratio of CD4+/CD8+‑T cells were determined by flow cytometry, and the expression of interferon (IFN)‑γ, interleukin (IL)‑17, IL‑10 and tumor necrosis factor (TNF)‑α were measured using reverse transcription‑quantitative polymerase chain reaction and enzyme‑linked immunosorbent assay analysis. The results of the present study demonstrate that LXT can efficiently alleviate the symptoms of EAU, inhibit the differentiation of uveitogenic CD4+ T cells and reduce the expression of proinflammatory cytokines, including IFN‑γ, IL‑17 and TNF‑α. Furthermore, LXT promotes the production of IL‑10 and accelerates the recovery of EAU, indicating that the immunomodulatory effects of LXT may potentially be used for the treatment of uveitis.