Differentiation of Common Variable Immunodeficiency From IgG Deficiency.

BACKGROUND: Common variable immunodeficiency (CVID) and IgG deficiency are 2 of the more prevalent primary humoral immune defects. The former is defined by consensus with criteria for quantitative and qualitative antibody defects, whereas the latter is used to describe patients with reduced IgG, who commonly have recurrent sinopulmonary infections but do not fulfill CVID criteria. However, these patients are often given this diagnosis. OBJECTIVE: To compare immunologic findings and clinical manifestations of 2 large cohorts of patients with CVID or IgG deficiency to better delineate differences between these syndromes. METHODS: We extracted clinical and laboratory data from electronic medical records of patients at our institution who had received International Classification of Disease codes for either CVID, or IgG deficiency. We gathered immunoglobulin levels, lymphocyte subpopulation counts, and serological vaccine responses. In some patients, we performed flow cytometry to determine percentages of memory and switched-memory B cells. We compiled and statistically compared clinical data related to infectious manifestations, bronchiectasis, autoimmune diseases, infiltrative inflammatory processes, and lymphoid malignancies. RESULTS: In contrast to IgG-deficient patients, we found that patients with CVID had lower IgG levels, greater unresponsiveness to most vaccines, lower percentages of memory and isotype switched-memory B cells, and lower CD4 T-cell counts. Clinically, patients with CVID presented similar rates of sinusitis and pneumonias, but a significantly higher prevalence of bronchiectasis and especially noninfectious complications. CONCLUSIONS: CVID and IgG deficiency do not share the same disease spectrum, the former being associated with immunodysregulative manifestations and markers of a more severe immune defect. These data may allow clinicians to distinguish these conditions and the management differences that these patients pose.

The prevalence and characteristics of food allergy in urban minority children.

BACKGROUND: Urban minority children are known to have high rates of asthma and allergic rhinitis, but little is known about food allergy in this population. OBJECTIVE: To examine the prevalence and characteristics of food allergy in an urban pediatric population. METHODS: A retrospective review of electronic medical records from children seen in the hospital-based general pediatric clinic at Mount Sinai Hospital serving East Harlem, NY, between July 1, 2008 and July 1, 2010 was performed. Charts for review were selected based on diagnosis codes for food allergy, anaphylaxis, or epinephrine autoinjector prescriptions. RESULTS: Of 9,184 children seen in this low-income, minority clinic, 3.4% (313) had a physician-documented food allergy. The most common food allergies were peanut (1.6%), shellfish (1.1%), and tree nuts (0.8%). Significantly more black children (4.7%) were affected than children of other races (2.7%, P < .0001), which consisted primarily of Hispanic and multiracial children. Anaphylaxis was most frequently documented for peanut (15.1%), fish (12.5%), and milk (11.1%). Among food-allergic children, asthma (50%), atopic dermatitis (52%), and allergic rhinitis (49%) were common. Fewer than half had confirmatory testing or evaluation by an allergy specialist, and although most had epinephrine autoinjectors prescribed, most were not prescribed food allergy action plans. CONCLUSION: This is the largest study of food allergy prevalence in an urban minority pediatric population, and 3.4% had physician-documented food allergy. Significantly more blacks were affected than children of other races. Fewer than half of food-allergic children in this population had confirmatory testing or evaluation by an allergy specialist.