Initial information was received on 11/13/06 from the aforementioned literature citation. A 62 year old male pt, with a past medical history of hypertension and alcoholic liver cirrhosis, for which he underwent orthotopic liver transplantation, received an influenza vaccination on an unspecified date. The trade name, manufacturer or lot number were not reported. Two weeks after receiving the vaccine, the pt developed progressive generalized weakness and was diagnosed with Guillain [[name]]e Syndrome. He was seen in a hospital one week after the onset of symptoms, where he was found to have an elevated FK506 level (18.1 ng/ml, and the dose of FK506 was adjusted. His weakness worsened, and he was admitted to another hospital two weeks after th onset of the symptoms. The pts liver transplantation as six months prior to admission. Since then, he had been on FK506 and a low dose of prednisone without any complications. He denied any precedent episodes of diarrhea, nausea, vomiting, or other gastrointestinal or upper respiratory illness. Neurological examination on admission revealed normal mental status, bilateral facial weakness, dysphagia, hypophonia, quadriplegia ( 1-2/5 by Medical research council scale), throughout, and absence of muscle stretch reflexes in all extremities. Blood chemistry showed blood urea nitrogen 34 mg/dl, creatinine 0.9 g/dl, albumin 4.5 g/dl, aspartate aminotransferase 78 u/l, alanine aminotransferase 189 u/l, gamma glutamyl transpepitadase 160 u/l, alkaline phosphatase 146 mg/dl, total bilirubin 1.8 mg/dl, direct bilirubin 0.5 mg/dl, ammonia 47 ul/l, international normalized ration 0.91, and blood FK5506 level 7ng/ml. Serum immunoglobulin G was positive against herpes simplex virus 1, Epstein [[name]] virus and cytomeglaovirus, but neg against herpes simplex virus 2. Immunoglobulin M was neg against Epstein [[name]] virus and CMV in serum. The testing for Campylobacter Jejuni was not performed. Lumbar puncture revealed that the cerebrospinal fluid looked xanthochromic with red blood corpuscles 0/11^3, while blood cells 1/mm3, protein 358 mg/dl, glucose 88 mg/dl, lactic acid 2.7 mEq/l, and opening pressure of 25 cm cerebrospinal fluid. Cerebrospinal fluid venereal disease research lab slide test, gram stain, cyptococcal antigen, and cytology were neg. Herpes simplex virus, CMV, and Epstein [[name]] virus DNA were not detected by polymerase chain reaction test. Electrodiagnostic studies showed prolonged distal latencies and absence of late responses in all extremities. The component muscle action potential were reduced throughout with absence of component muscle action potential in the proximal tibial and peroneal nerves bilaterally. The conduction velocities were reduced in demyelination range in the median nerves bilaterally. There was a conduction block in median nerves bilaterally, in right ulnar and in right tibial nerves. These findings were consistent with acute inflammatory demyelination polyneuropathy. Shortly after admission, the pt was Intubated for airway protection and started on IV immunoglobulin 0.4 g/kg/[[name]] for three [[name]]s without significant improvement. Plasma exchange was not considered because of the pts hemodynamic status. His hospitalization course was complicated by the development of ischemic colitis secondary to dysautonomia, for which he under went subtotal colectomy. The pt expired three weeks after admission from septic shock and acute renal failure. The authors note although the temporal relationship between GBS and influenza vaccination is suggestive of causal relationship, it does not fully prove it.