A Controversial New Approach to Address Hematological Parameters in Hashimoto's Thyroiditis

Background: Hashimoto's thyroiditis (HT) is a common autoimmune disorder. Genetic, environmental, and immunological factors all play a role in the pathogenesis of HT, but the effects of lymphocytes and platelets on the pathophysiology of HT are still unknown. In this study, we evaluated the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV) in HT groups and HT subgroups with low cardiovascular risks. Methods: This study included 92 patients with HT and 38 control subjects. Among the HT patients, three subgroups were formed according to thyroid function: overt (n = 12), subclinical (n = 38), and euthyroid (normally functioning thyroid; n = 42). Results: Age and gender distributions were similar between the patient and control groups. Body mass index was higher in the patient group than in the control group. The C reactive protein level was higher in patients than controls (p = 0.064). The thyroid stimulating hormone (TSH) level was higher and the mean free thyroxine level lower in the patient group than in the control group (p < 0.05). There were no differences between the groups with regard to leukocytes, neutrophils, platelets, or MPV (p > 0.05). The NLR and PLR were significantly different in one subgroup of HT patients relative to healthy subjects (p < 0.05). However, we did not find any statistical differences in the MPV among the three subgroups (p = 0.547). A positive correlation was found among the NLR, anti-thyroglobulin (TG) antibodies, and anti-thyroid peroxidase (TPO) antibodies (p < 0.01), although there was a negative correlation between the PLR, TSH, anti-TPO, and anti-TG (p < 0.001). Conclusions: A single marker or panel of biomarkers is not a consistent indicator of HT, but NLR combined with PLR testing may offer a more reliable diagnosis.