Frequency of tumour necrosis factor alpha receptor superfamily 1A multiple sclerosis-associated variants in patients with rheumatoid arthritis with anti-tumour necrosis factor therapy-related demyelinating complications

Tumour necrosis factor alpha (TNFα) is a key cytokine in inflammatory rheumatic diseases but is also implicated in multiple sclerosis (MS) where TNFα is elevated in demyelinating plaques. However, TNFα inhibitors (TNFi) have opposite effects: they have revolutionised the treatment of chronic rheumatic diseases but may cause flares of MS.1 Several studies have suggested an association between TNFi use and occurrence of demyelinating disorders.2 3 Their incidence is estimated up to 4% after 18 months of treatment in a recent prospective study with systematic neurological examination before and after treatment initiation.4 In addition, two TNF receptor superfamily 1 ( TNFRSF1A ) single nucleotide polymorphisms, (SNPs) rs1800693 and rs4149584 (TNFRSF1A R92Q), have been shown to increase the risk of developing MS.5 The rs1800693*G allele leads to a dysfunctional TNFα soluble receptor that inhibits TNFα signalling.6 Rare variants of TNFRSF1A locus have also been implicated …