The GAPDH SO3 tetramer strongly significantly correlated with the occurrence of the PRDX2 SO2/3 multimer, which again strongly supports the idea that sulfonylation of the GAPDH tetramer in OSA RBC after PAP reoxygenation might be associated with a higher decrease of RBC and HTC level. Here, PRDX2 is linked to obstructive sleep apnea syndrome.