The phenomenon of lymphocyte regression of phytohemagglutinin is a symptom of protein losing gastroenteropathy syndrome, also known as protein losing gastroenteropathy, or protein leaking gastroenteropathy or exudative gastroenteropathy. It is a syndrome caused by the loss of plasma protein, especially albumin, from the gastrointestinal mucosa due to various reasons. The main clinical manifestations are generalized swelling and hypoplasmosis. Small intestinal lymphangiectasis is often associated with immunoglobulin loss and abnormal cellular immunity, and the lymphocyte repertoire of phytohemagglutinin is diminished, making it susceptible to pulmonary infections. The differential diagnosis of lymphocyte repertoire of phytohemagglutinin: 1. Food allergy and intolerance: Food allergy refers to the recurrence of symptoms after eating a specific food that has been shown to have an immune basis (IgE antibodies to food), food intolerance is a complex allergic disease, which is an overprotective immune response of the human immune system to certain foods that enter the body. It can cause chronic symptoms in various systems of the body. 2, digestive malabsorption syndrome: digestive malabsorption syndrome is a disease caused by the nutrients of food can not be normally absorbed into the blood by the small intestine. Under normal circumstances, after digestion of food, its nutrients are mainly absorbed into the blood in the small intestine. If a disease affects the digestion of food or directly affects the absorption of nutrients, malabsorption syndrome can occur.