We hypothesized that the classical PNS in this patient was triggered or exacerbated through a postvaccinal aberrant autoimmunity.
The pathogenesis of PNS is incompletely understood, but it is believed to be associated with antibody and T-cell responses against the expression of shared epitopes in the nervous system and the tumors.[sup] The fact that this patient did not have such a postvaccinal response before suggests an altered adaptive immunity in the presence of an ovarian tumor.
2) Postvaccinal adverse events of the central nervous system:
Other classifications of postvaccinal reactions can be found in the literature, some of which put an emphasis on the neurological symptoms, while others emphasize the immunological mechanisms.
describing neurological complications, have included as "minor"--mild or severe postvaccinal reactions, occurring up to 48 hours after injection and disappearing without leaving permanent sequelae, the following: prolonged crying, restlessness and hyperactivity, apathy with increased sleepiness, high body temperature, a temporary mild increase in intracranial pressure manifested by a throbbing crown of the head, "cerebral cry" (sometimes included among "major" complications) [5-7].
Among the "major" neurological complications, usually manifesting more than 48 hours after vaccination and which might be the cause of permanent damage to the central nervous system (CNS), the following are listed: seizures especially if there is no increase in body temperature, hypotonic-hyporesponsive episodes, postvaccinal encephalitis, postvaccinal encephalopathy [6, 8-11] and autism [10, 12-14].
Konior and Strozik  have proposed their own classification of postvaccinal reactions taking into account the contribution of the immune system in the vaccinated children.
unrelated to the immune system--patients whose postvaccinal reactions may be related to the toxic effects of the vaccine components or may result from the vaccine virus turning virulent, resulting in complete or abortive symptoms of the disease.
The last four events are classified as confirmed on the basis of diagnostic testing (e.g., histopathology); confirmation of events thought to be immunologically mediated (i.e., erythema multiforme, myo/pericarditis, postvaccinal
encephalitis, or encephalomyelitis) does not establish causality.