Subacute sclerosing panencephalitis and immune thrombocytopenia: More than a coincidence?

Subacute sclerosing panencephalitis (SSPE) is a progressive disease caused by persistent measles virus (MV). It has an incidence of 0.4-2.0/million in Turkey. Immune thrombocytopenia (ITP) is a bleeding disorder whose estimated incidence is 4.2/100.000 person/years in the pediatric age group. We observed three cases with ITP in our cohort of 315 pediatric SSPE cases, an incidence higher than coincidentally expected in the general population. We hypothesize an association between SSPE and ITP. Our three cases had measles 1-2 years before the onset of ITP and 8-10 years before first symptoms of SSPE. A common immunogenetic background creating susceptibility to infection and autoimmunity might play a role. Alternatively, chronic antigenic stimulation by the MV leading to synthesis of cross-reacting antibodies against platelets, or treatment of ITP with immunoglobulins or steroids might affect or alter the development and manifestation of SSPE. The co-occurrence of these two disorders of viral and immune pathogenesis may draw attention to similar observations and provide clues for their mechanisms.