Ocular surface expression of inflammatory cytokines in GvHD and their association with disease development and clinical manifestations
Authors: Murphy Conor 
Published: January 2024

The aim of this study was to investigate the tear cytokine profiles of patients with chronic ocular graft versus host disease (GvHD) and evaluate their association with clinical disease severity. Consecutive patients attending the Haematology clinic with a known or suspected diagnosis of chronic ocular GvHD were invited to participate. To be included, patients had to fulfil either or both of the National Institute of Health (NIH) or the International Chronic Ocular Graft‐vs‐Host‐Disease Consensus Group (ICCGvHD) diagnostic criteria.Clinical parameters recorded included best correct visual acuity (BCVA), Schirmers I test, tear break up time (TBUT), and Oxford surface staining (OSS) along with the overall grading of ocular GvHD severity as defined by the ICCGvHD. Ocular tear samples were collected and levels of cytokine production (IFN‐γ, IL‐1β, IL‐2, Il‐4, IL‐6, IL‐8, IL‐10, IL‐12p70, IL‐13, and TNF‐ α) were assayed using Meso Scale Discovery (MSD) multi‐array technology. The results were compared to those of healthy matched controls using unpaired t test. Results were correlated with clinical parameters using Pearson r correlation.Thirteen patients took part in the study (8 male, 61.5%; 5 female, 38.5%) with an average age of 43.9 years (±13.4). With regards to ocular examinations, patients were found to be heavily dependent on lubricant eye drops (average 8.5 times/day). Patients suffered from both aqueous deficient and evaporative DED with an average Schirmer's measurement of 4.2 mm (±5.7, range of 0–21) and average TBUT of 3.8 s (±1.3, range 1–6). The average Oxford surface staining score was 7.9 (±4.2, range of 0–15). According to the ICCGvHD grading system, and using the average data across both eyes, seven of the patients had ‘Mild/Moderate’ disease (53.8%) and the remainder had ‘Severe’ disease (n = 5, 38.5%).The levels of IFN‐γ, IL‐1β, IL‐2, IL‐6, IL‐8, IL‐10, IL‐12p70, IL‐13, and TNF‐ α were found to be statistically elevated when compared to healthy age and gender matched controls (FDR p value<0.05). In those with early‐stage disease (n = 5), IFN‐γ was found to strongly correlate with lubricant usage (0.98, p = 0.03), and IL‐2 with the severity of ocular surface staining grade (1.00, p = 0.03), implying that these cytokines in particular may play a role in the development of chronic ocular GvHD and represent promising treatment targets for patients in the initial stages of disease.This study demonstrates that ocular tear cytokines are elevated in patients with chronic ocular GvHD, reiterating the role of inflammation in the pathogenesis of disease. Furthermore, the correlation of IFN‐γ and IL‐2 with clinical parameters of disease severity suggest that these cytokines play a role in early disease development. These findings support the implementation of anti‐inflammatory treatment such as topical calcineurin inhibitors, in conjunction with tear replacement and preservation to avoid irreparable damage to the ocular surface, and this may be best utilized in the initial stages of the disease development.