CD40LG and type 1 diabetes mellitus: On the other hand, comparison of anti-SARS-CoV-2 IgG titers between RT-PCR-negative adolescents with T1D and RT-PCR-negative healthy controls, regardless of SARS-CoV-2 IgM and IgG test results before the first vaccination, showed no significant difference in anti-SARS-CoV-2 IgG titers between the two groups after the second vaccination.