Analogue to the findings in BAL-fluid, three studies (with 11, 48, and 66 neurosarcoidosis patients) found an elevated (≥five) or increased CD4:CD8 ratio in CSF, and one study found a normal ratio in five of eight evaluated neurosarcoidosis patients.18, 19, 20, 21 Single-cell RNA sequencing of CSF and blood in six probable neurosarcoidosis (4 treatment naïve) patients found interferon-mediated clonal CD8 T cell expansion instead of CD4 T cell expansion, but findings need to be confirmed.22 The gene discussed is CD4; the disease is neurosarcoidosis.