Patients with CVI present with recurrent bacterial infections of the respiratory tract, such as sinusitis, otitis media, bronchitis and pneumonia. The most common etiologic agents are encapsulated bacteria such as Streptococcus pneumoniae and Haemophilus influenzae. The onset of these abnormally frequent infections may occur at any age but most patients do not come to medical attention until the second or third decade. This is in contrast to X-linked agammaglobulinemia, where recurrent infections develop in the first 2 years of life. The recurrent bacterial infec tions in CVI are a direct result of the deficiency in antibody production (specifically immunoglobulin G, IgG) that is the hallmark of this syndrome. If CVI goes undiagnosed (and hence untreated), recurrent pulmonary infections can lead to irreversible chronic lung disease with bronchiectasis. Septicemia and recurrent infections of the skin, urinary tract, joints or central nervous system also occur in patients with CVI, but are less frequent. In rare instances, patients with CVI can become infected with a variety of opportunistic fungi, mycobacteria and Pneumocystis carinii. An unusual syndrome of severe enteroviral meningoencephalitis is seen in patients with primary antibody-deficiency syndromes. This type of infection is most commonly associated with X-linked agammaglobulinemia, but several well-documented cases have occurred in patients with CVI. Other viral infections that can occur with increased frequency in CVI include recurrent attacks of herpes simplex and herpes zoster.
Patients with CVI suffer from a variety of infectious and noninfectious gastrointestinal disorders. The protozoan Giardia lamblia is a common cause of infectious diarrhea in these patients. Malabsorption, of unknown etiology, leading to severe weight loss and diarrhea, is another major gastrointestinal
Table 1 Clinical features of common variable immunodeficiency
Sinusitis, otitis media, pneumonia
Streptococcus pneumoniae Haemophilus influenzae Giardia lamblia Salmonella spp. Campylobacter spp. Cryptosporidium Dysgonic fermentor-3
Staphylococcus aureus Mycoplasma spp. Haemophilus influenzae
Streptococcus pneumoniae Haemophilus influenzae Neisseria meningitidis Enteroviruses Pneumocystis carinii
Systemic lupus erythematosus Sjogren's syndrome Ulcerative colitis Crohn disease
Lymphadenopathy Splenomegaly Nodular lymphoid hyperplasia Bronchiectasis
Malignancy Cholelithiasis Idiopathic malabsorption Sarcoid-like granulomatous disease manifestation of CVI. Small bowel biopsy reveals flattening of the villi with a lymphocytic infiltration in the lamina propria. Neoplasms of the gastrointestinal tract (specifically, adenocarcinoma of the stomach and intestinal lymphomas) appear to occur with increased frequency in CVI.
Approximately 25% of patients with CVI will develop one or more autoimmune diseases, indicating that CVI is a disease of abnormal immune regulation as well as immunodeficiency. Autoimmune (Coombs'-positive) hemolytic anemia and idiopathic thrombocytopenic purpura (ITP) are the two most common autoimmune diseases seen. Neutropenia is also seen in a significant number of patients with CVI, and in some cases antigranulocyte antibodies have been demonstrated. A variety of other autoimmune diseases can occur in association with CVI (Table 1).
Patients with CVI frequently develop lympho-proliferative disorders, which can take several forms. Malignant lymphoma occurs with increased frequency in these patients, although the exact magnitude of this increase is unclear. This high incidence of lymphomas (and cancers in general) is an indication that some patients with CVI may have clinically important defects in cell-mediated as well as humoral immunity. More common than malignant lymphoma is the occurrence of benign lymphoid hyperplasia manifested by one or more of the follow ing: splenomegaly; diffuse lymphadenopathy; or nodular lymphoid hyperplasia of the intestinal tract.
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