The present study aimed to evaluate the applicability of PLR and NLR as biomarkers for the assessment of BD activity while using IBDDAM to score the disease status in each patient, carefully. Among Laboratory results CRP found to be higher in the participants than the laboratory normal range. Oral aphthae were the most common manifestation in the history of the disease, followed by ophthalmic manifestations and genital ulcers. While, active ocular manifestations, followed by active oral aphthae were the most common active manifestations of the disease at the time of last visit. Based on the history of manifestations, only NLR was significantly higher in patients with history of ocular manifestations. Moreover, NLR and PLR were both higher than normal in patients with active BD and active ocular manifestations. Our results indicate that only NLR correlated with overall disease activity (IBDAAM) and ocular activity (ocular IBDAAM).
ROC analysis determined the optimal cut-off value of PLR and NLR in classification of active/inactive BD and also classification of patients based on presence of active ocular manifestations. Results were significant, while only NLR showed a barely acceptable diagnostic ability (AUC: 0.690) for diagnosis of active ocular manifestations.
Several methods have recently been developed to evaluate systemic inflammation in patients; yet, additional specific and sensitive markers are still in demand. NLR has been receiving considerable attention as a new marker for inflammation, with several studies reporting high predictive and diagnostic value in cases of systemic inflammation (15, 20, 28-31).
White blood cells and platelets play a substantial role in the development of inflammation and inflammatory diseases (32); as a result, elevated levels of these parameters are expected in such diseases (33).
Recent studies illustrated that NLR as an independent prognostic factor in several chronic diseases and their manifestations, such as hyperlipidemia, cardiovascular and coronary artery diseases, atherosclerosis, inflammatory bowel disease, and arthritis (15, 20, 28-31).
BD, on the other hand, is defined as a form of inflammatory vasculitis that encompasses several organs and has a wide variety of clinical presentations, including mucocutaneous manifestations, recurrent deep vein thromboses, genital, ophthalmic, and gastrointestinal involvement, in all of which inflammatory processes have prominent roles and related biomarkers appear in higher levels in affected individuals as a result of chronic inflammation and endothelial dysfunction (34-37).
Utilizing WBC count to determine disease activity in BD patients was first discussed by Alan et al. (19) who categorized patients into three groups using NLR and PLR as a system of severity classification (Mild, Moderate and Severe disease). They reported higher NLR and PLR in patients with a currently active state of the disease in comparison with patients with an inactive disease state or healthy individuals. They, however, failed to find an association between the severity of the disease using BD Activity score criteria, PLR, and NLR.
On the contrary, Jiang et al. (38) measured the BD activity score using the simplified Behçet’s Disease Current Activity Form (BDCAF) and demonstrated acceptable diagnostic value for PLR with a cut-off value of 124.63. PLR was elevated in active BD as compared to inactive BD. It may be a reliable, cost-effective, and novel potential parameter to help evaluate disease activity in BD.
Our study yielded results similar to the one done by Alan et al. (19), as we did observe a significant increase in PLR and NLR, and were able to find a cut-off point for determining the disease activity status; yet, these values did not have adequate sensitivity for BD. In line with the previous studies, PLR and NLR lack strong correlation with IBDDAM scores, which prevented us from using them to predict the severity of disease activity.
To the best of our knowledge, this is the first study to evaluate the applicability of NLR and PLR for the assessment of BD activity and its clinical presentations with reference to IBDDAM scores of the patients. Avci et al. (39) had previously found NLR to have a stronger correlation with the development of anterior uveitis in comparison with PLR in an attempt to evaluate the efficacy of NLR and PLR for the diagnosis of BD. Another study by Erden et al. (39) demonstrated an increased risk of deep vein thrombosis in BD patients with higher NLR and PLR.
Considering the results of our study and the previous studies in the field, we recommend further investigation of PLR and NLR and their relationship with various manifestations of the disease separately, since specific associations between NLR and PLR and activity of BD seem to be existent but are not yet examined enough to be applicable for diagnostic purposes.
Since the study was a single-center cross-sectional work, the available data was limited. The duration of the treatment in each patient could have altered PLR and NLR which needs to be investigated in future studies. Despite these limitations, we were able to find a positive correlation between NLR and the activity of the disease as measured by IBDDAM. However, active BD manifestations (except for ocular) were found not to be associated with PLR and NLR, even though these ratios were higher in BD patients compared to normal laboratory ranges. Considering IBDDAM and the conventional physical examinations, laboratory tests, clinical settings, and statistical analyses, the study protocol could easily be applied to the other circumstances of BD.