The Relationship Between Disease Activity and Platelet Indices in Pemphigus: An Observational Preliminary Study.

Tests which have proven their efficacy and reliability in the follow-up of pemphigus patients are used only on a limited scale or take time to complete due to a lack of technical facilities in several centers. Therefore, more accessible methods are being considered for monitoring disease activity. We aimed to investigate the relationship between platelet function and disease activity based on the change in proinflammatory cytokine profile in pemphigus pathogenesis. The size of platelets correlates positively with their activity. Platelet sizes can be evaluated by the platelet volume index consisting of mean platelet volume (MPV), platelet-crit (PCT), and platelet distribution width (PDW). These indicators can be easily measured in complete blood count (CBC) with automatic blood counting devices, which do not require additional costs and are readily available. Patients diagnosed with pemphigus between April 2010 and February 2016 (n=18) in our center were retrospectively included in the study. Demographic data, follow-up period, clinical variants of the patients, platelet parameters (MPV, PDW, PCT), and platelet count (PLT) in CBC analysis with concurrent clinical activity, as well as indirect immunofluorescence (IIF) findings (positive highest titer) at the 6th and 12th month were recorded for each patient. MPV changes were consistent with the course of the disease. A statistically significant decrease in PCT levels was observed at the 12th month compared with the baseline levels (P<0.05). According to the baseline measurement, a statistically significant positive correlation (58.9%) was found between the 12-month difference measurements of IIF and PCT. Our data demonstrated that PCT decrease is correlated with IIF values. The significant correlation between PCT and IIF values in our study is important in showing the possible role of platelet index in the measurement of disease activity.