5. Atypical Lymphocytes vs. Monocytes
These pictures (100x) depict the cytologic differences between
atypical lymphocytes (a & c) and monocytes (b). As can be
appreciated from these pictures, the differentiation is at times
difficult. However, the cytoplasm of monocytes usually is gray and
frequently contains vacuoles (not demonstrated in this example),
while the cytoplasm of atypical lymphocytes reveals the bluish tinge
previously described. Lymphocytes, typical or atypical, can be
differentiated by the expression of surface antigens. Monocytes
frequently express CD14, while T cells lack this antigen but express
CD3, CD4, CD5, CD7, CD8. B cells do not express any of these CD
antigens; instead, they often have CD19, CD20, and CD22. What trends
can you see regarding CD numbers and lymphocytes (T and B cells)?
Answer
