Demonstration of a Blocking Factor in the Plasma and Spinal Fluid of Patients With Subacute Sclerosing Panencephalitis

Abstract

Conflicting reports on the immune responsiveness of patients with subacute sclerosing panencephalitis (SSPE) have been reported. This report shows that the leucocytes from four SSPE patients exhibited strong sensitivity to both measles and SSPE virus preparations as measured by the macrophage migration inhibition test, mixed lymphocyte virus infected cell culture test, and the lymphotoxin assay. Earlier suggestions that a factor may be operating to suppress cellular reactivity are confirmed by the demonstration that the response of lymphocytes from SSPE patients could be blocked by the addition of SSPE spinal fluid or plasma. It was determined that the blocking factor was stable at –20°C, heat labile at 56°C for 30 minutes, trypsin and neuraminadase sensitive, and had a mol wt greater than 150,000 as determined by Sephadex G-200 gel chromatography. The blocking factor appeared to be specific for SSPE virus and did not block the response of lymphocytes to nonspecific mitogenic agents and other viral and bacterial agents.

The Raji cell radioimmune assay for detecting immune complexes in human sera.

“…It may be that in these patients, mechanisms other than immune complexes are responsible for C activation and damage of the vascular walls, or that immune complexes, after their formation, are rapidly removed from the circulation and deposited on the arterial walls., Sera as well as cerebrospinal fluids from a limited number of patients with SSPE were also found to contain immune complexes by the Raji cell assay. Measles virus has been implicated in the pathogenesis of this disease (67), and SSPE sera reportedly contain blocking factors removed by anti-C3 or rheumatoid factor (68). Furthermore, IgG and C3 deposits have been noted in the vessels of patients with SSPE (69).…”

Cell-Mediated Immunity in Measles Using the Leucocyte Migration Test

“…These have been demonstrated in a number of diseases including subacute sclerosing pan encephalitis [21], As many of our measles patients were malnourished and as the in cidence of kwashiorkwor is high in this en vironment, some critical factor which is necessary for the reaction of the lympho cytes may be lacking in the serum of mal nourished children.…”

Human T-cell heterogeneity as delineated with a specific human thymus lymphocyte antiserum. In vitro effects on mitogen response mixed leukocyte culture, cell-mediated lymphocytotoxicity, and lymphokine production.

“…As more is learned about cellular immune dysfunctions in various disease states and the pathophysiologic role of various cell types in immune disorders, the hypothesis given regarding T-cell subpopulations may tend to group certain disorders. One such example is in the case of subacute sclerosing panencephalitis, where cells were shown to liberate LT and MIF on antigenic stimulation, but did not transform (20) to a viral preparation. The cell types involved and the area in the cellular immune system where these factors operate will be most useful in the further delineation of T-cell subsets.…”