Guillain-Barré syndrome following immunisation with Haemophilus influenzae type b conjugate vaccine.

The Guillain-Barré syndrome (GBS) is an immune-mediated disease often associated with viral or bacterial infections and with immunisation. IgM antibodies have been implicated as the main trigger event in GBS. So far, only four cases of GBS have been observed following immunisation with a conjugate vaccine against Haemophilus influenzae type b. We report another patient with GBS after this vaccination. We measured immunoglobulins against the H. influenzae type b polysaccharide (PRP) component of the vaccine. Surprisingly the anti-PRP IgM antibody level was markedly elevated (100 micrograms/ml) in the plasma of this patient. We speculate that an excessive anti-PRP IgM antibody response to the vaccine might be the cause of GBS.