Immunodeficiency pneumonitis is a syndrome of impaired immune defense mechanisms due to congenital, hereditary and other causes. Its symptoms are mainly as follows. 1. Congenital X-linked dysgammaglobulinemia: Children usually do not develop the disease in the first 3-4 months of life due to the temporary protection of maternal antibodies. However, as the child grows, it shows increased susceptibility to pathogenic bacteria, with respiratory tract infections being the most common; 2. Generalized variable immunodeficiency: the etiology is unclear. Unlike X-linked agammaglobulinemia, most patients have normal or increased numbers of B lymphocytes, but fail to develop secretory plasma cells. The clinical manifestations of the disease are similar to those of X-linked agammaglobulinemia, but most present with symptoms after the age of 30 years. Recurrent respiratory infections are the main manifestation in half of the patients; 3. Selective immunoglobulin deficiency: the patient’s B-lymphocytes, although morphologically mature, are unable to make and secrete IgA into serum or secretions. Symptomatic IgA-deficient patients often have atopy, asthma and allergy to food, especially milk. 1/3 of the patients have recurrent respiratory tract infections. If you feel unwell, it is recommended that you go to a regular hospital for examination and treatment in time to avoid delaying your condition.