PIGR and nutritional deficiency disease: In malnourished children, it was shown that malnutrition induced altered B cell differentiation status in bone marrow and a predominance of plasma cells in the small intestine lamina propria lymphocytes, decreased pIgR expression, and reduced secretory IgA in mucosal sites, which can be a reason for poor protective immune responses to oral vaccines in malnourished children in developing countries (43).