NK-92, a highly cytotoxic, interleukin-2 (IL-2)-dependent human natural killer (NK) cell line, has been of interest for basic and translational research. We report on a comprehensive analysis of NK-92 for factors implicated in NK cytotoxicity to elucidate factors underlying NK-92's high cytolytic activity and target range. Thus, we hope to develop a method to identify patients best suited to NK-92 immunotherapy. In addition, as a model system, we hope to increase understanding of the basis for the elevated activity exhibited by activated NK (ANK) cells. NK-92 exhibits an unusual receptor expression profile, expressing a relatively large number of activating (NKp30, NKp46, 2B4, NKGD, E, CD28) receptors. Conversely, it expresses few inhibitory receptors (NKGA/B, low levels of KIR2DL4, ILT-2), lacking most of the killer inhibitory receptors (KIRs) clonally expressed on normal NK cells. In addition, NK-92 expresses high levels of molecules involved in the perforin-granzyme cytolytic pathway as well as additional cytotoxic effector molecules including tumor necrosis factor (TNF)-superfamily members FasL, TRAIL, TWEAK, TNF-alpha, indicating the ability to kill via alternative mechanisms. NK-92 also expresses other molecules implicated immune effector cell regulation (CD80, CD86, CD40L, TRANCE) whose relevance in NK killing is unclear. This study provides initial data to develop a method to identify NK-92 susceptible cells (cells expressing ligands for NK-92 activating receptors ie CD48 for 2B4 and CD80/86 for CD28). Furthermore, this work suggests mechanisms that may contribute to ANK cell activity, including modulation of receptor expression to favor activation, up-regulation of cytotoxic effector molecules, and acquisition of new cytolytic pathways.

Summary:The role of ICU support in BMT patients is controversial. In an era of constrained resources, the use of prognostic factors predicting outcome may be helpful in identifying patients who are most likely (or unlikely) to benefit from this intervention. We attempted to define the survival of patients admitted to ICU following autologous or allogeneic BMT and to identify those factors important in determining patient outcome. A retrospective study of all adult BMT recipients admitted to intensive care over a 6 year study period was performed to determine overall and prognostic indicators of poor outcome. Pre-treatment, pre-ICU admission and ICU admission data were analyzed to identify factors predicting long-term survival. 116 patients were admitted to ICU on 135 separate occasions with the primary reasons for admission being respiratory failure (66%), sepsis associated with hypotension (10%), and cardiorespiratory failure (8%). No pre-ICU characteristics were predictive of survival. Univariate analysis identified the number of support measures required, the need for ventilation or hemodynamic support, the APACHE II score, the year of ICU admission and the serum bilirubin as significant predictors of post-discharge survival. On multivariate analysis the year of ICU admission, the need for hemodynamic support and the serum bilirubin remained significant. The APACHE II score significantly underestimated survival in the 46% of patients with scores less than 35, and could only be used to predict 100% mortality when it exceeded 45. Twenty-three percent of all BMT patients admitted to the ICU and 17% of ventilated patients survived to hospital discharge. Of the 27 patients surviving to leave hospital, 16 remain alive with a median follow-up of 4. was identified which could be used to predict futility but patients requiring both hemodynamic support and mechanical ventilation, and those with an APACHE II score greater than 45 have a very poor prognosis and are unlikely to benefit from lengthy ICU support.

In this work, we evaluated the potential of the natural killer (NK) cell line NK-92 and its IL-2-independent variants NK-92MI and CI, as immunotherapy for melanoma. In vitro, we found that NK-92 was much more cytotoxic to a number of human melanoma cell lines than lymphokine-activated killer (LAK) cells, particularly at low effector/target (E:T) ratios. In vivo treatment of mice challenged with MEWO melanoma cells with i.v. administered NK-92 and NK-92-MI resulted in a 1.5-2.5-fold increase in average length of survival. NK-92, MI, and CI were also effective against the WM1341 cell line, causing a 2-5-fold increase in survival when administered before the malignant cells. With s.c. injection, MEWO and WM1341 caused a primary tumor mass, secondary tumors, and metastatic cells. NK-92 cells reduced WM1341 primary tumor size by 40-90% and MEWO tumors by 30-75%. Similar results were seen with NK-92MI and CI. These data show that NK-92 cells are highly cytotoxic to human melanoma cells in vitro and in vivo and suggest that treatment with NK-92 cells may be a potentially effective immunotherapeutic modality in melanoma.