Pietruczuk et al. (2019) showed that patients in remission had decreased serum TNF-α and increased IL-6 and IL-10 compared to healthy people. Also, the level of IL-17A was significantly lower in patients in depression or remission. Karthikeyan et al. (2022) showed no differences between BD patients and healthy people in serum IL-6 or TNF-α. This evidence concerns the gene IL6 and depressive symptom measurement.