IL13 and asthma: Furthermore, an IL-13-producing cTfh13 subset is elevated in peanut allergy and asthma, correlated with IgE, and airway hyperreactivity (60), suggesting the crucial role of cTfh13 in high-affinity IgE in allergy, consistent with GC-Tfh13 (113), calling for studies on the relationship of cTfh2 and cTfh13.