The fatty acyl chain composition of human normal and leukaemic lymphocytes and its modulation by specialised...

Thirty species of fatty acyl chain have been quantitatively identified in human normal peripheral blood lymphocytes (four donors) and lymphocytes circulating in eight patients with chronic lymphocytic leukaemia (CLL). Towards the aim of influencing cell behaviour by lowering membrane fluidity, reaction conditions for catalytic hydrogenation at physiological temperature and pH have been established that effect reduction of the unsaturated species, and preferentially the polyunsaturated forms, but this has not yet been accomplished without killing the cells. That saturation of ethylenic linkages per se is the cause of death is indicated by separate findings showing that the lymphocytes are capable of withstanding hydrogen gas at the requisite high pressure (9 atm.) or exposure alone to the rhodium catalyst [chlorotris (sodium diphenylphosphinobenzene-m-sulphonate)-rhodium(I) tetrahydrate]. It remains feasible that future use of these two agents in combination under milder conditions to produce much lower degrees of hydrogenation than those reported here will permit the cells to survive. Concerning fatty acyl chain composition, the lymphocytes from most of the patients exhibited an inversion in the level of palmitic and stearic acid. A consistently abnormal pattern exhibited by the patients was a rise in oleic acid and a fall in arachidonic acid content. This same alteration has been demonstrated elsewhere in transformed/neoplastic cell types and hence it could well represent phenotypic expression in the CLL lymphocyte of malignant change. Fatty acyl chain composition remained unchanged in lymphocytes reconstituted after cryopreservation in liquid nitrogen.