SERPINA1 and systemic lupus erythematosus: In addition, the activation of the complement increases the capillary permeability and causes protein loss and which leads to a significant decrease in the serum ALB level.[17,18] We speculated the reason for this patient's diarrhea is due to intestinal damage caused by SLE, resulting in protein-losing enteropathy (diarrhea, bowel wall thickening, and mesenteric structural disorder), which needed to be confirmed by 99mTc-HAS (99m-labeled human serum albumin)[19] or alpha-1-antitrypsin clearance instool examination,[20] but which are not available at our hospital.