Leukocyte Sedimentation

LEUKOCYTE SEDIMENTATION represents a phenomenon analogous to the sedimentation of erythrocytes; already during the routine performance of the erythrocyte sedimentation reaction with salted plasma, one can see above the upper boundary of the settled erythrocytes in various cases either a dense, well-settled narrow white layer (consisting under the microscope predominantly of leukocytes), or a more delicate, grayish film, or finally the entire plasma layer appears homogeneously turbid. Schilling studied leukocyte sedimentation more in detail in citrated blood in very narrow tubes with a special device for observation under a low-power microscope system [later a special Schilling-Schultz-Kunin apparatus was constructed]. According to the character of the leukocyte suspension under the microscope, Schilling distinguishes 4 degrees of leukocyte sedimentation: 1) normally isolated suspended leukocytes—a normal phenomenon; 2) individual clumps of leukocytes—insignificant sedimentation; 3) clear clumps of leukocytes—accelerated leukocyte sedimentation; 4) very large clumps—strong acceleration of leukocyte sedimentation. Determination of the rate of leukocyte sedimentation by the dimensions of the transparent plasma zone succeeds only late—2-4 hours after the sedimentation of the main mass of erythrocytes—or is normally impossible altogether. Bauer proceeds differently: he mixes defibrinated blood with 2% acetic acid, centrifuges, repeatedly washes the leukocyte sediment with physiological solution, shakes the sediment in physiological solution for 2-3 minutes, and leaves the leukocyte suspension to settle in wide tubes; after 2-4 hours, a strip of transparent solution in millimeters is noted. The larger and the sooner leukocyte sedimentation occurs, the more it is accelerated in infectious processes; leukocyte sedimentation is not parallel to erythrocyte sedimentation, in particular it is not accelerated in blood diseases and cachexias. Leukocyte sedimentation is of importance for the prognosis of infections and for the discovery of infectious foci; however, in all these cases, changes in the hemogram are more sensitive. Leukocyte sedimentation depends on the degree of agglutinability of leukocytes, does not depend on their number, and does not depend on the ratio of blood protein fractions, but rather on some special substances (Schilling). According to data from the Obukh Institute (Bauer, Zaitchenko), the acceleration of leukocyte sedimentation completely coincides with the toxicity of leukocytes determined by E. Freyfeld's method; Schultz and Barta note such a coincidence only in ¹/₃ of cases.