Abstract
Purpose :
to measure (a) the apoptotic response to oxidative stress in lymphocytes of OAG, OH and controls, (b) the prevalence of T-reg (Cd4-Cd25) lymphocytes in OAG and controls and (c) correlate them with the 10-yr rate of field progression
Methods :
consecutive patients referring to the Glaucoma Clinic were screened. 56 patients with POAG, 56 matched controls and 41 ocular hypertensives were enrolled in the "apoptotic response study". 18 patients with POAG and 18 matched controls were enrolled in the "autoimmunity" study. Blood samples were processed as follows: (a) "apoptotic response": 2-hrs incubation of Lymphocytes, upon amplification with PHA, with increasing concentrations of H2O2 (up to 100 mM) , 16-hr recovery, apoptosis evaluated by DNA fragmentation test and Annexin V test;(b)"autoimmunity ":Flow cytometriy to determine the CD4+CD25+FOXP3 lympho population. After magnetic cell separation of CD4+CD25-(Tresp) and Treg cells, the suppression function of Tregs was assessed using the in vitro suppression test (Treg suppression Inspector, Miltenyi Biotec).
POAG and OH were followed up to 10 years.The following data were collected every 6 months:(a)visual field (SAP 24/2 SITA st),(b)optic disc (HRT2-3),(c)IOP and CCT,(d)visual acuity,(e)blood pressure,(f) medications and concomitant systemic therapies.Main outcome:rate of progression of visual field (RoP).Secondary outcome(s):(a) progression of optic disc,(b) changes of therapy,(c) conversion from OH to POAG.RoP was calculated by trend analyses of (a) the MD and (b) the glaucoma hemifield clusters.
Results :
Both the basal apoptotic index and the response to peroxide were higher in POAG vs controls and OH, whose values were superimposable. The % reponse to peroxide correlated significantly with 10-yr VF RoP (r2 = 0.746) .After a multivariate analysis, the following factors were significantly associated with faster RoP: % respose to peroxide, > 2 changes of therapy and age.CCT was protective.
The median value of Tregs (%) in POAG patients was 5.55 vs. 4.28 in controls (p=0.005).No significant difference in the suppression activity of Tregs was observed between POAG controls (88 and 94% of suppression in the 1:1 co-colture, p=0.118).MD RoP was 0,794+0,71 dB /year in glaucoma patients.The RoP correlated with the % T-regs in the individual patients (r = 0.774, p < 0.001).RoP proved surprisingly unrelated to the mean IOP.
Conclusions :
peripheral lymphocytes can provide biomarkers for POAG
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.