LEP and chronic bronchitis: In contrast, others have reported a significant partial correlation coefficient between leptin and soluble tumour necrosis factor receptor 55 (sTNF-R55), when adjusted for fat mass (FM) and oral corticosteroid use in the emphysematous subtype of COPD, but not in chronic bronchitis patients, while leptin levels were associated with FM in line with the reported feedback mechanism involved in the regulation of body weight [106].