AQP1 and myeloid sarcoma: Interestingly, the AQP1-Abs in the three patients with typical MS phenotype (no. 20–22 in Table 2), practically did not bind to the intact AQP1-expressing cells (negative indirect CBA) while they bound to the cytoplasmic AQP1 Loop-B; i.e., these antibodies most probably do not play a pathogenic role, consistent with the absence of NMOSD phenotype-like findings in these patients.