Immunoglobulin G subclass deficiency and infection risk in 150 patients with chronic lymphocytic leukemia

Partial reconstitution of humoral immunity and fewer infections in patients with chronic lymphocytic leukemia treated with ibrutinib

“…4 Deficiencies in immunoglobulin G (IgG) and its subclasses, IgA, and IgM may be present. 5 Stage and duration of disease correlate with the severity of hypogammaglobulinemia. 4 Although other immune defects, such as impairments of T-cell function, also contribute to infection risk, CLL patients with lower serum immunoglobulin levels appear to be particularly susceptible to severe and recurrent infections.…”

Age-associated distribution of normal B-cell and plasma cell subsets in peripheral blood

“…Thereafter, the relative distribution of circulating PCs expressing different IgH isotypes and subclasses remained relatively stable, except for a transient increase in IgA 1 1 PC counts at 10 to 17 years, a decrease in IgG 3 1 PC counts in adults, and a progressive increment of smIgG 2 1 and smIgA 2 1 cell counts until 10 to 17 and 18 to 39 years, respectively (Fig 2, F). Finally, the relative number of smIgD 1 and smIgG 4 1 PCs was greater among 2-to 4-yearold (P 5 .001) and 5-to 9-year-old children (P 5 .01), respectively (Fig 2, F).…”

“…Interestingly, although MBC counts with smIgG 2 1 and smIgA 2 1 expression (IgH isotype subclasses of the third IGHC gene block) also increased in childhood, these counts continued increasing until adulthood, with significantly higher counts among 18-to 39-year-old adults versus younger subjects (P 5 .03 and P 5 .005, respectively). Despite representing a minor subset (<1% and <1 cell/mL for most donors), particularly among children, smIgG 4 1 MBCs peaked at 40 to 59 years (Fig 3 and see Table E4). …”

“…Results: IgH-switched MBCs expressing IgG 1 , IgG 2 , IgG 3 , IgA 1 , and IgA 2 were already detected in cord blood and newborns at very low counts, whereas CD27 Serum immunoglobulin levels are widely accepted as the most reliable surrogate marker for B-cell functionality in healthy donors and patients with different immune-related diseases. [1][2][3][4][5][6] Thus, reference serum immunoglobulin values per age group have been generally adopted as the measure of changes in B-cell immunocompetence through life. [7][8][9][10][11][12][13][14][15][16][17] Overall, increasing serum immunoglobulin levels are observed with age, although patterns vary for the distinct immunoglobulin heavy chain (IgH) isotypes and subclasses.…”

“…12 Finally, IgE serum levels peak around 10 years and decrease thereafter to adult levels. 21 A common feature for all serum IgH isotype subclasses (except for IgD, IgG 4 , and IgE) is that their levels accumulate with age. 7,8,11,12,16 Once maximum levels are reached, serum IgH isotype subclass levels remain remarkably stable, without significant changes in older subjects.…”