Cytokine profile and case series of tract-specific myelitis following SARS-CoV-2 infection

<b>Background:</b> The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a potential trigger for central nervous system (CNS) autoimmune disorders. The most common type of spinal cord pathology following novel coronavirus infection is immune-mediated/autoimmune transverse myelitis (TM); however, there are also rare forms of spinal cord pathology ‒ tract-specific myelitis ‒ previously considered as non-autoimmune-originated. <b>Methods:</b> The current study includes case series of 5 patients with a rare type of myelitis with predominant involvement of the dorsal and lateral columns following coronavirus disease 2019 (COVID-19). We aimed to analyze cytokines parameters in cerebrospinal fluid (CSF) of affected patients. In order to support the autoimmune origin of the disease, CSF cytokine profiles were compared to patients with TM following COVID-19 (n = 12). Scale variables were compared between two independent groups using t-test or Wilcoxon-Mann-Whitney test depending on the distribution. <b>Results:</b> In contrast to patients with TM, patients with tract-specific myelitis demonstrated higher levels of a proliferation-inducing ligand (APRIL), B cell activating factor (BAFF), interleukin (IL)-11, and thymic stromal lymphopoietin (TSLP). The BAFF/APRIL system is renowned for its involvement in the genesis and advancement of autoimmune disorders, and its pronounced increase in this case supports the autoimmune origin of the disease. <b>Conclusion:</b> The heightened activation of BAFF and APRIL cytokines, which promote B-cell maturation, suggests an autoimmune origin of tract-specific myelitis, thereby informing prognosis and treatment strategies for affected patients.