MANF and type 1 diabetes mellitus: Stability of spiked MANF after 8 freeze-thaw cycles was 97.6 ± 10.4% and 105.2 ± 4.9% compared to MANF concentration in the samples with 1 freeze-thaw cycle in T1D (n = 4) and autoantibody-negative sera (n = 4), respectively (Fig. 1d).