Component-resolved analysis of IgA, IgE, and IgG4 during egg OIT identifies markers associated with sustained unresponsiveness

BACKGROUND

In a previously reported CoFAR study, 55 subjects with egg allergy underwent randomized, placebo-controlled egg oral immunotherapy (eOIT). Active treatment induced desensitization in most and sustained unresponsiveness (SU) in a smaller subset. We hypothesized that component-resolved analysis of IgE, IgG4, IgA, IgA1, and IgA2 may identify potential biomarkers of SU in OIT subjects.

METHODS

Longitudinal samples for 51 egg-allergic subjects (37 active and 14 placebo) were available. Egg white (EW)-, ovalbumin (OVA)-, and ovomucoid (OVM)-specific levels of IgA, IgA1, and IgA2 were quantified by ELISA. IgE and IgG4 to these antigens were quantified using ImmunoCAP^® . Clinical responders achieved SU to egg; all others were considered nonresponders. Between-group comparisons were made among active and placebo, as well as responders and nonresponders.

RESULTS

No placebo subjects achieved responder status. Through month 48, among the 37 active subjects, baseline IgE-OVM was lower in responders (median 3.97 kU/l, n = 19) than in nonresponders (10.9 kU/l, n = 18, P = 0.010). Logistic regression analysis revealed that lower baseline IgE-EW (P = 0.038), IgE-OVM (P = 0.032), and a higher IgG4/IgE-OVM ratio (P = 0.013) were associated with clinical response. Relative increases in IgG4-EW, IgA-EW, and IgA2-EW were observed in responders (P = 0.024, 0.024, and 0.029, respectively). IgG4/IgE, IgA/IgE, and IgA2/IgE ratios for EW and IgA/IgE ratio for OVA were found to be significantly elevated among responders (P = 0.004, 0.009, 0.028, and 0.008, respectively).

CONCLUSIONS

Increased IgG4-EW, IgA-EW, and IgA2-EW during eOIT are associated with clinical response to eOIT. Lower pretreatment IgE-EW and IgE-OVM are also associated with SU. Future studies are needed to evaluate and validate these potential biomarkers.

Applicability of NINDS-sponsored studies to community-based physician involvement

Background: The National Institute of Neurological Disorders and Stroke (NINDS) Clinical Trials Group established the Clinical Research Collaboration (CRC) Project in 2005 to increase community-based physician involvement in NINDS-sponsored research.

Methods: We assessed a random sample of 112 of the more than 1,000 current NINDS-sponsored clinical research studies to determine which could involve community physicians in enrollment or follow-up. Scoring factors were based on the premise that participation is feasible for noninvasive studies with simple screening, and follow-up criteria and visit frequency consistent with usual care. Scored studies included 26 Phase III, 31 Phase I/II, and 55 nonclinical trials.

Results: Overall, 41% of the sampled research studies were considered conducive to community physician participation that exceeds referral only; 21% with participation in all study activities and 20% with ability to provide some follow-up. Specialized neuropsychological or neurologic scale testing was judged to exclude community physician participation in 16% of studies.

Conclusion: Many National Institute of Neurological Disorders and Stroke studies are available in which community-based physicians could participate. Involving community physicians may increase efficiency of completing clinical research and encourage application of research findings in community practices.