Question

Human patients suffering from severe allergies and/or life-threatening asthma conditions are increasingly being treated with drugs like relizumab and beralizumab. Both drugs are engineered antibodies that specifically deplete eosinophils from circulation. Unlike other conditions where patients lack one cell population or another (i.e. macrophage deficiency is associated with inflammatory bowel disorders; neutrophil deficiency leads to chronic infections with encapsulated bacteria), this deliberate induction of eosinophil deficiency is associated with no notable symptoms whatsoever. This observation has been duplicated in mice genetically engineered to lack eosinophils.

Hypothesize why eosinophil deficiency apparently has no observable effects on lab animals or in human patients receiving antibody treatment. Explain your reasoning.

Answer 1

Eosinophils are a type of granulocytes. They are also called acidophils. They are important in controlling infections with worms and allergies. Low eosinophil count can be due to cushing's syndrome and alcohol intoxication. If there is no disease in the individual, low eosinophil levels go unnoticed. This is because other WBCs present in sufficient numbers will take care of the functions of the defense. Problem arises if rest of the immune cells also are low in blood. Excess of eosinophils may be a sign of allergies. Some of the activities of eosinophils brings allergies and inflammation in the body. Asthma and other sever type of allergies are treated by administering IgE antibodies which lower the levels of eosinophils.Since the immune function eosinophils perform can be easily taken up by other immune cells, lack of eosinophils does not have any observable effect. It is of concern only if the other immune cells are also low.