IL2 and infection: Although the frequency of IL-2 monofunctional CD4+ T cells was statistically significantly lower against BA.1 peptides (p < 0.001), there was only a 19.7% decrease from ancestral SARS-CoV-2, suggesting that after natural infection of highly immunized transplant patients with Omicron BA.1, homotypic and heterotypic CD4+ T-cell responses to spike peptides are generally similar.