CD40LG and COVID-19: Moreover, in the biological fingerprint region, the following intervals related to immunoglobins were detected, 1560–1464 cm−1 associated to IgG, 1420–1289 cm−1 and 1160–1028 cm−1 related to IgM, and 1285–1237 cm−1 designed to IgA (Fig. 1B), evidencing that the COVID-19 group exhibited higher absorbances than the healthy group.