CVID3 due to CD19 D83.0

CVID3 is an immunodeficiency syndrome (see CVID; see also immunodeficiencies primary -antibody deficiency predominant) caused by a homozygous or compound heterozygous mutation in the CD19 gene (107265) on chromosome 16p11.2.

Van Zelm et al (2006) studied four patients from two unrelated families who had increased susceptibility to infection, hypogammaglobulinemia, and a normal number of mature B cells in the blood, indicating a B-cell antibody-deficient immunodeficiency disorder. The disorder was consistent with the clinical diagnosis of CVID.

One family included 3 siblings who were examined at ages 35, 33, and 49 years, respectively. All 3 siblings had had otitis media, sinusitis, and pharyngitis in childhood. In addition, one of the siblings had had pneumonia 4 times between the ages of 18 and 35 years. A Turkish girl was found to have recurrent bronchiolitis and bronchopneumonia from the age of 1 year, and meningitis at the age of 8 years. Lab: Hypogammaglobulinemia. At 10 years of age, a diagnosis of postinfectious glomerulonephritis was made, and she was found to have one. Van Zelm et al (2006) diagnosed homozygous truncating mutations in the CD19 gene (107265.0001 and 107265.0002). CD19 levels were undetectable in one patient and significantly reduced in the other three. Apparently, this mutation of the CD19 gene caused hypogammaglobulinemia , in which the response of mature B cells to antigenic stimulation is impaired.

Artac et al (2010) identified and examined 30 members of a family who were carriers of a heterozygous truncating mutation in the CD19 gene (107265.0001) and found that none of them showed clinical signs of immunodeficiency. Flow cytometric analysis of carrier lymphocytes revealed no significant difference in the number of B, T, or NK cell subsets between carriers and noncarriers. The expression levels of CD19 and CD21 (120650) on B lymphocytes were significantly decreased in carriers compared with noncarriers, and some carriers had decreased proportions of transitional and CD5+ B cells. The results suggest that carriers of CVID3 mutations have alterations in the naïve B cell division but no clinical signs of immunodeficiency or evidence of autoimmune phenomena.

Kanegane et al (2007) reported a Japanese boy with CVID3 characterized by recurrent infections, including pyelonephritis and gastritis, that began at age 5 years. Laboratory tests showed hypogammaglobulinemia and no antibody response to previous vaccinations. He also had mild thrombocytopenia. The patient's B cells showed absent CD19 membrane expression and decreased expression of CD21.

Van Zelm et al (2011) reported on a 6-year-old Moroccan boy born to consanguineous parents with CVID3. He had a history of recurrent respiratory bacterial infections and septicemia associated with hypogammaglobulinemia. He had a poor antibody response to vaccination but responded well to immunoglobulin therapy. T-cell and NK-cell function was normal. Flow cytometric analysis showed decreased numbers of memory B cells and lack of CD19 expression on B cells.

Kanegane et al (2007) identified a heterozygous splice site mutation in the CD19 gene inherited from his mother resulting in a truncated protein in a Japanese boy with CVID3 (107265,0003).

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6. van Zelm et al. (2011) Antibody deficiency due to a missense mutation in CD19 demonstrates the importance of the conserved tryptophan 41 in immunoglobulin superfamily domain formation. Hum Molec Genet 20: 1854-1863.