Establishment of age-dependent reference values for IgA subclasses

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

“…[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. At birth, serum contains low IgM and IgA levels, whereas maternal immunoglobulin molecules provide near-adult levels of serum IgG.…”

“…16,17 Similarly, production of IgG 4 appears to be delayed, but reference values per age group vary significantly among healthy subjects. 16,17 Furthermore, both IgA 1 and IgA 2 levels increase gradually during childhood, 8,19,20 reaching maximum IgA 1 production around the second decade of life, whereas IgA 2 serum levels keep increasing throughout adulthood. 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. 18 In contrast to serum immunoglobulin levels, more dynamic changes have been observed for total B-cell numbers and the composition of the B-cell compartment in peripheral blood (PB).…”

Feasibility Study for the Fractionation of the Major Human Immunoglobulin G Subclasses Using Hydrophobic Interaction Membrane Chromatography

“…11,12 In a more recent study, the competitive binding of the different subclasses on protein-G has been discussed. 13 However, the differences in binding were not significant enough to be exploited for subclass fractionation.…”

Antigen microarrays: descriptive chemistry or functional immunomics?

“…Although the large number of naïve B cells contribute to the plasma IgM and IgD pool, these antibodies are predominantly low-affinity binders and are therefore usually undetectable by antigen arrays. Recognizing that fluorescent signal-based antigen microarray technology can detect around 10 attomoles (1.5 pg) of bound IgG [6] and assuming that various clonal forms are evenly distributed and have sufficiently high levels of affinity to remain array-bound, we can estimate the maximum number of theoretically detectable clonal antibody forms (Figure 1a), based on the concentrations of various immunoglobulins in serum [13][14][15][16][17]. This is a simplistic approach because the latter two assumptions are not true and the spatial constraints of a microarray chip are ignored.…”