Primary Immune Dysregulation in Subacute Sclerosing Panencephalitis: A Case-Control Study

ObjectiveThe primary objective was to study the pattern of immune dysregulation in cases with subacute sclerosing panencephalitis (SSPE). The secondary objective was to assess the correlation between the measured immunological variables and disability/death at 6 months,BackgroundSSPE is a chronic progressive neurological condition caused by a defective measles virus. It is postulated that immune-dysregulation might result in persistent infection (immune evasion) as well as initiation of autoimmune phenomenon (via natural killer cells) leading to panencephalitis.Design/MethodsThis was a prospective observational study conducted at a tertiary-case referral-facility from January 2020 to September 2021. Thirty consecutive patients fulfilling the Dyken's criteria for SSPE and 30 age-and-sex-matched healthy controls were enrolled. Immunological profile constituted by lymphocyte subset analysis, immunoglobulin levels and complement levels were done in all cases and controls. Cases were staged as per Jabbour's system; disability was assessed using the modified Rankin Scale (mRS).ResultsPatients with SSPE had a mean age of 14.76 years (± 6.9 years). There were 25 males and 5 females; 6.7% cases belonged to Jabbour's first stage, 40% to second stage and 53.3% to third stage. Levels of absolute lymphocyte count, B-cells, T cells, helper T-cells and cytotoxic T-cells were significantly higher in cases. IgG, IgM and IgE levels were significantly higher while IgD levels were significantly lower in cases. At baseline, 13.3% of cases had a mRS score of 0-2 and 86.7% had a score of 3-6; at 6 months 10% had a mRS score 0-2 (favorable outcome) while 90% had a mRS score 3-6 (poor outcome). No correlation of immunological parameters with outcome was found.ConclusionsSignificant immune dysregulation in terms of lymphocyte subsets and immunoglobulin levels seem to exist in SSPE. These findings may pave way for targeted immunomodulator therapy that can be targeted in a larger cohort of patients.