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The presence of immunoreactive myelin basic protein peptide in urine of persons with multiple sclerosis

1987; Wiley; Volume: 22; Issue: 5 Linguagem: Inglês

10.1002/ana.410220516

1531-8249

John N. Whitaker,

Biochemical effects in animals

Abstract A polyclonal antiserum has been produced that can detect nanogram amounts of myelin basic protein (MBP)–like material in unconcentrated human urine. The urinary immunoreactive material is cross‐reactive with human MBP peptides 45–89 and 69–89, dialyzable, heat resistant, and is not an artifact of either degradation of radioligand or salt effect. An octapeptide, MBP peptide 82–89, was demonstrated to be the smallest peptide containing the main epitope against which this antiserum was directed. This epitope differed from the major epitope recognized by antisera detecting MBP‐like material in cerebrospinal fluid, implying that the MBP‐like material is altered, presumably degraded, in the kidney. Results of gel filtration and high‐performance liquid chromatography suggested a size of 1,000 daltons or less and a charge similar to that of human MBP peptide 80–89. In a group of 39 persons with multiple sclerosis, 48 with other neurological diseases, and 26 normal control subjects, the concentration of urinary MBP‐like material, related to the concentration of urinary creatinine, was significantly higher in the multiple sclerosis group (22.0 ng MBP‐like material/mg creatinine) than in the other neurological diseases or control groups, in which the values were 7.0 and 3.9 ng MBP‐like material/mg creatinine, respectively. Variations in the level of MBP‐like material appearing in the urine may provide a clinically feasible test for myelin damage. The precise identification of the chemical nature of the urinary MBP‐like material may also furnish a means for further analyzing the in vivo catabolism of the potentially autoantigenic MBP.