Plasma and B cells are implicated in multiple sclerosis (MS) and produce free light chains (FLC) that are excreted in urine.
To confirm that demyelinating diseases (DD) cause increased urinary FLCs.
Urinary FLC in 50 patients with DD were compared to 20 patients with posterior uveitis (PU), 19 with AIDS, 34 with rheumatoid arthritis (RA) and 19 normal controls (NC).
Subjects with DD, PU, RA and AIDS have higher urinary FLCs than NC (p<0.01). Urinary FLCs did not correlate with gadolinium-enhancing lesions on MRI.
Urinary FLCs are raised in DD. Further studies are required to see if they correlate with disease activity.