Dados do Trabalho

Título

Yellow Fever Vaccination May Trigger Multiple Sclerosis Onset and Relapses

Objetivo

Although it is well accepted that a number of infectious agents may trigger multiple sclerosis (MS) onset and increase the risk of relapses, the association of MS with vaccination is still debated. Whereas activated vaccines are considered generally safe, some evidences suggest that atenuated vaccines may increase MS relapses. The yellow fever (YF) vaccine is a live attenuated vírus vaccine which has been associated with increased relapse risk in MS patients. Its association with MS onset, however, has not been reported. Here we describe four MS patients who had either disease onset or a new relapse following YF vaccination. We discuss the possible effects of YF vaccine on the pathophysiology of MS.

Relato do caso

All patients met the modified 2010 McDonald revised diagnostic criteria for MS. Patients had a history of YF vaccination within a few weeks prior to development of neurological déficits. Two mullato males aged 36 and 42 years developed the inaugural manifestations of MS two and six weeks following vaccination. In one of them MS onset followed immuniztion for YF, diphteria and tetanus, and was characterized by signs of involvement of the lower brainstem and upper spinal cord, associated with MRI lesions in these regions. The second patient presented cervical myelitis after YF vaccination. Follow-up showed relapses with motor, sensory, brainstem and sphincter disturbances. The other patients were mullato females aged 22 and 24 years. One of them had a long history of obstructive lung disease and allergic rhinitis. She developed hypoesthesia in left lower limb which lasted for about 4 weeks. Three months later she noticed diplopia due to left sixth nerve palsy, which occurred three weeks following.YF vaccination. The fourth patient had a 4-year history of MS with three previous relapses. A few days after YF vaccination she developed right sixth nerve palsy with diplopia. A repeated brain MRI disclosed disseminated T2-hyperintensities in the cerebral white matter and in the pons. Cerebrospinal fluid analysis in three patients showed oligoclonal bands (OCB) with no correspondence in the serum. One patient refused spinal tap. In all patients brain and spinal cord MRI showed typical MS lesions.

Discussão

The YF vaccine causes CD4+ and Treg lymphocytes activation, and secretion of gamma-interferon and of other inflammatory cytokines. These pro-inflammatory factors may play a role in the pathophysiology of the demyelinating complications.