Primary Immunodeficiencies

Common Variable Immunodeficiency (CVID)

CVID increases risk of upper and lower respiratory tract infections caused by encapsulated bacteria, Mycoplasma species, and respiratory viruses. Chronic diarrhea with malabsorption suggests giardiasis or chronic norovirus infection.

Additionally, patients with CVID are at increased risk of autoimmune disease, inflammatory bowel disease, granulomatous disease (noncaseating granulomas in the lymphoid or solid organs), bronchiectasis, and malignancy.

Diagnosis of CVID

Several diagnostic criteria have been proposed for CVID, but all require documentation of low IgG levels, with variable presence of decreased IgA and IgM antibody, and demonstration of impaired antibody production to antigenic stimulation.

Antibody synthesis should be assessed by measuring antibody levels before and after pneumococcal polysaccharide and tetanus vaccinations.

Treatment of CVID

Immunoglobulin replacement therapy. Patients with CVID should receive appropriate immunizations with inactivated vaccines, recognizing that the immunologic response is likely to be blunted.

Severe Combined Immunodeficiency (SCID)

Inherited primary immunodeficiency involving both humoral and cellular immunity. Manifestations are chronic mucocutaneous candidiasis, recurrent and chronic diarrhea, and severe opportunistic infections such as PJP. This is a pediatric disease with few patients surviving to adulthood.

References

1. MKSAP 19