HEPATITIS-B TRANSMISSION FROM CONTAMINATED CRYOPRESERVATION TANK

Over a 25-month period, six multiply transfused patients undergoing cy totoxic treatment for haematological or other malignant disorders deve loped icteric acute hepatitis B virus (HBV) infection. Bone marrow or peripheral-blood stem cells had been harvested from all six patients a nd stored in the same cryopreservation tank for possible future transp lantation. Human DNA, HBsAg, and HBV DNA with sequences identical to t hose from four patients with related infections were subsequently foun d in the liquid nitrogen. Leakage of the cryopreservation bags used to store bone marrow harvested from the first patient when acutely infec ted with HBV led to contamination of the tank and its contents with HB V and subsequent transmission to patients after transplantation. This incident emphasises the continuing need to screen donors of tissue to be cryopreserved for bloodborne virus infections. It also reinforces t he requirement for primary containers used to cryopreserve human tissu e to be sealed in a way which prevents exchange of material between th e specimen and the liquid nitrogen.