Patients who develop inflammatory polyarthritis (IP) after immunization are clinically indistinguishable from other patients with IP

Musculoskeletal symptoms may occur following various types of immunization, and it has also been suggested that, like infection, immunization may act as a trigger for rheumatoid arthritis (RA). A total of 48 of 898 (5.3%) patients with early inflammatory polyarthritis (IP) referred to the Norfolk Arthritis Register reported an immunization in the 6 weeks prior to symptom onset. There were no important clinical or demographic differences between the 48 immunized patients and 185 consecutive patients who did not report prior immunization. In addition, the frequencies of HLA-DRB1*01. *04 and the shared epitope in 33 of the immunized patients were similar to those in the 185 non-immunized patients and to those in 136 healthy controls. Further results from a case-control study suggest that the rate of immunization is higher amongst cases (5.5%) than age- and sex-matched controls (2.8%). In a small number of susceptible individuals, immunization may thus act as a trigger for RA.      

Effect of natural killer cells on syngeneic bone marrow: in vitro and in vivo studies demonstrating graft failure due to NK cells in an identical twin treated by bone marrow transplantation

Bone marrow transplantation for severe idiopathic aplastic anemia was undertaken in a patient, using his monozygotic twin brother as the donor. In spite of the use of syngeneic bone marrow, failure of engraftment occurred on two occasions. In vitro studies demonstrated that natural killer (NK) cells from the recipient markedly inhibited the growth of donor bone marrow granulocyte progenitor cells. On a third attempt, successful bone marrow engraftment was achieved following high-dose cyclophosphamide, which has previously been shown to be inhibitory to NK cells. We conclude that NK cell activity may play an important role in bone marrow failure as well as being responsible for at least some cases of aplastic anemia.     

Contrast medium precipitation during abdominal CT

Abdominal computed tomography (CT) scans of 55 patients who had ingested Gastrografin (meglumine diatrizoate and diatrizoate sodium) diluted to 2% with tap water and flavored with a commercial fruit juice base were reviewed. Twenty patients (36%) demonstrated intraluminal precipitation of Gastrografin shown by focal areas of markedly increased attenuation within the gastric lumen or trapped within gastric folds. Beam-hardening artifact produced by precipitation was observed, which limited the diagnostic value of some examinations. In vitro CT scans of the same Gastrografin solution titrated with hydrochloric acid or sodium hydroxide showed that by raising the pH of the solution, precipitation was virtually eliminated. Fifty-one CT scans of the abdomen using a buffered Gastrografin solution demonstrated precipitation in only five patients. Properly buffered dilute oral Gastrografin solutions should significantly decrease the prevalence of precipitation during abdominal CT examinations.