Early recovery from cow's milk allergy is associated with decreasing IgE and increasing IgG4 binding to cow's milk epitopes

Abstract

Background: The dynamics and balance of allergen-specific IgE, IgG4, and IgA binding might contribute to the development of tolerance in patients with cow's milk allergy (CMA). Profiling of antibody binding to cow's milk (CM) protein epitopes might help in predicting the natural history of allergy.

Objective: We sought to investigate differences in IgE, IgG4, and IgA binding to CM epitopes over time between patients with early recovery or with persisting CMA.

Methods: We studied serum samples at the time of diagnosis (mean age, 7 months), 1 year later, and at follow-up (mean age, 8.6 years) from 11 patients with persisting IgE-mediated CMA at age 8 to 9 years and 12 patients who recovered by age 3 years. We measured the binding of IgE, IgG4, and IgA antibodies to sequential epitopes derived from 5 major CM proteins with a peptide microarray-based immunoassay. We analyzed the data with a novel image-processing method together with machine learning prediction.

Results: IgE epitope-binding patterns were stable over time in patients with persisting CMA, whereas binding decreased in patients who recovered early. Binding patterns of IgE and IgG4 overlapped. Among patients who recovered early, the signal of IgG4 binding increased and that of IgE decreased over time. IgE and IgG4 binding to a panel of alpha(s1)-, alpha(s2)-, beta-, and kappa-casein regions predicted outcome with significant accuracy.

Conclusions: Attaining tolerance to CM is associated with decreased epitope binding by IgE and a concurrent increase in corresponding epitope binding by IgG4.

FIG 1

Differences in IgE binding to cow's milk peptides (black curve) between children with persisting cow's milk allergy at the age of 8-9 years (P, red) and those recovering early by the age of 3 years (E, green) at three time points: A) T:0 the time of diagnosis, B) T:1 one year later, C) T:9 follow-up at the age of 8-9 years. Arrows point to regions with significant (>0.1 or <-0.1) difference between groups. The x-axis depicts amino acid sequences of the five proteins (β-LG stands for β-lactoglobulin), and the y-axis relative signal strength. The temporal differences in IgE binding intensity are shown D) within study groups and E) between groups; red denotes regions with significantly (>0.1) increased and blue regions with significantly (<-0.1) decreased binding intensity.

FIG 2

Differences in IgG4 binding to cow's milk peptides (black curve) between children with persisting cow's milk allergy at the age of 8-9 years (P, red) and those recovering early by the age of 3 years (E, green) at three time points: A) T:0 the time of diagnosis, B) T:1 one year later, C) T:9 follow-up at the age of 8-9 years. Arrows point to regions with significant (>0.1 or <-0.1) difference between groups. The x-axis depicts amino acid sequences of the five proteins (β-LG stands for β-lactoglobulin), and the y-axis relative signal strength. The temporal differences in IgG4 binding intensity are shown D) within study groups and E) between groups; red denotes regions with significantly (>0.1) increased and blue regions with significantly (<-0.1) decreased binding intensity.

FIG 3

A) Differences in IgA binding to cow's milk peptides (black curve) between children with persisting cow's milk allergy at the age of 8-9 years (P, red) and those recovering early by the age of 3 years (E, green), at the time of follow-up at the age of 8-9 years (T:9). Arrows point to regions with significant (>0.1 or <-0.1) difference between groups. The x-axis depicts amino acid sequences of the five proteins (β-LG stands for β-lactoglobulin), and the y-axis relative signal strength. The temporal differences in IgA binding intensity are shown B) within study groups and C) between groups; red denotes regions with significantly (>0.1) increased and blue regions with significantly (<-0.1) decreased binding intensity.

FIG 4

Differences in overlap of antibody binding intensity to cow's milk peptides between children with persisting cow's milk allergy at the age of 8-9 years (P) and those recovering early by the age of 3 years (E). Time points are denoted as follows: T0 the time of diagnosis, T1 one year later, T9 follow-up at the age of 8-9 years. Red denotes regions where the difference of binding intensity between IgE and IgG4 (4A) or between IgE and IgA (4B) is greater (less overlap) in group P compared with group E, and blue denotes the opposite. Differences >0.1 or <-0.1 are considered significant.