IMMUNOGLOBULIN M, γM, is not detectable by immunoprecipitation techniques in normal cerebrospinal fluid (CSF).1 In early studies, this immunoglobulin was shown to be a macroglobulin with a sedimentation coefficient of 19S.2,3 In recent studies,3-13 however, smaller proteins with antigenic determinants identical with the heavy chain (μ) of 19S-γM (HMW-γM) have been demonstrated. These lower molecular weight forms of γM (LMW-γM) occur in patients with a variety of disorders including systemic lupus erythematosus (SLE),6,7 ataxia-telangiectasia,7 antibody deficincy syndromes,5,7,12,13, malignancy of the plasma-cell-lymphatic system,10 and as an M protein in a lymphomatous disorder.9 Some LMW-γM proteins have been shown to have antinuclear and incomplete isohemagglutinin activity.7 To date, LMW-γM has not been demonstrated in the CSF.
This report presents a case characterized clinically by recurrent central nervous system (CNS) symptoms and skin findings typical of SLE, in whom LMW-γM was found in
Griggs RC, Strober W, McFarlin DE. Recurrent Encephalopathy: Associated With Low Molecular Weight γM in the Serum and Cerebrospinal Fluid. Arch Neurol. 1969;21(3):303–314. doi:10.1001/archneur.1969.00480150093012
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: