Brain tissue immunoglobulins in adrenoleukodystrophy: a comparison with multiple sclerosis and systemic lupus erythematosus

Abstract

Immunoglobulin (Ig) concentrations were investigated in white matter samples of two adrenoleukodystrophy (ALD), three multiple sclerosis (MS), two systemic lupus erythematosus (SLE), one rheumatoid arthritis, and three control brains obtained at autopsy. "Free" Igs were extracted at pH 7.4; subsequently, bound Igs were extracted at pH 2.5 and 10.8, respectively. Igs were quantified by radial immunodiffusion. In ALD material there was an increase of free IgG and IgA, in one sample also of IgM, as compared to controls. No significant amounts of Igs were detected in the pH 2.5 and 10.8 extracts of ALD brain. Similarly to ALD, an increase of free IgG and IgA was a characteristic finding in MS brain; in contrast to ALD and control material, significant amounts of bound Igs (IgG) extractable at acid or alkaline pH, respectively, were present in MS tissue. In both SLE brains increase of free IgM was conspicuous. Preliminary studies on binding of Igs extracted at pH 7.4 from brain to frozen sections of normal human and bovine brain tissue revealed different binding properties of Igs from ALD, MS, SLE, and control brains. Immunochemical findings in ALD indicating pathologic accumulation of Igs in brain tissue were paralleled by immunocytochemical observations demonstrating accumulation of lymphoid cells staining for IgG, IgA, and IgM, respectively, mainly in areas of recent demyelination. Participation of Igs in the pathogenesis of ALD lesions may be considered but needs further confirmation.