OPTIC NEURITIS AND CYTOKINES - NO RELATION TO MRI ABNORMALITIES AND OLIGOCLONAL BANDS

Acute unilateral monosymptomatic optic neuritis (ON) is a common first manifestation of MS if associated with multiple MS-like lesions on br ain MRI and oligoclonal IgG bands (OB) in the CSF, whereas ON patients lacking these laboratory abnormalities are considered to have a good prognosis regarding future MS development. Several cytokines involved in immune regulation are upregulated in blood and even more noticeable in CSF in MS. To study a possible relation between cytokine profiles and presence versus absence of MS-like brain MRI lesions and CSF OB, w e used in situ hybridization to examine mRNA expression of the proinfl ammatory interleukin-12 (IL-12), interferon-gamma, and tumor necrosis factor-alpha and the immune response downregulating IL-10, transformin g growth factor-beta, and IL-4 in blood and CSF mononuclear cells (MNC ) from 59 patients with untreated ON. There were no differences in num bers of MNC in blood or CSF expressing any of the cytokines under stud y, upon subgrouping the ON patients regarding presence (n = 31) versus absence (n = 28) of MRI lesions, presence (n = 45) versus absence (n = 14) of OB, or duration after onset of ON (<1 month, n = 30, versus > 1 month, n = 29). Similarly, no differences were observed for numbers of myelin basic protein-reactive blood MNC expressing any of these cyt okines after subgrouping according to these variables. Our findings su ggest that the cytokine profile, as examined in this study, is less us eful to determine the risk of future development of clinically definit e MS in ON patients or as indicator for therapeutic interventions in O N. An upregulation of both pro- and anti-inflammatory cytokines in ON patients seems to be more related to the CNS disease per se, whether L imited to the optic nerve or not, than to the inflammatory process cha racteristic for MS.