Expression of CD4 on peripheral blood granulocytes. a novel finding in a case of myelodysplastic syndrome in association with t(5;12)

Impact of preanalytical variables on granulocytic surface antigen expression: a review

BACKGROUND

There is a gradual but steady increase in the use of granulocytic surface marker studies to diagnose several inherited and acquired blood and bone marrow disorders. Diagnosis and follow-up of patients with inflammation and infection are other areas of quantitative flow cytometric application. Despite the increased use of flow cytometry to study granulocytes, there seems to be no well-established standards regarding specimen handling for these studies.

METHODS

This review summarizes the effect of preanalytical variables on granulocytic surface markers.

RESULTS AND CONCLUSIONS

Storing specimens in sodium heparin at room temperature for up to 72 h seems satisfactory. Other anticoagulants, although acceptable, may have a shorter storage time. Storage time could be prolonged further with the use of some preservation media. Lysed whole blood is the preferred technique. Techniques should avoid major temperature change and excessive manipulation and should maintain storage and methodologic temperature with minimal fluctuation. Fixation before staining with the antibody may result in decreased expression of some surface antigens.

Flow cytometric study of neutrophilic granulopoiesis in normal bone marrow using an expanded panel of antibodies: correlation with morphologic assessments

Flow cytometry studies of surface markers of neutrophils have been performed mostly on peripheral blood, and for a limited spectrum of diseases. Studying maturation defects on developing neutrophils in the bone marrow (BM) may be helpful in BM diseases, such as myelodysplastic syndromes and Shwachman-Diamond syndrome. We applied an expanded panel of antibodies to examine normal maturation patterns in 26 control samples of BM together with microscopic correlation. Promyelocytes correlated well with the CD24(-) and CD11b(-) populations, and metamyelocytes correlated well with the CD16(+) population (intermediate positivity). An excellent correlation was also identified between the sum of bands and segmented neutrophils and each of the following: CD16(++) (strong positivity), CD35(+), CD87(+), and CD64(-). Although visually identified segmented neutrophils paralleled CD10 positivity, there was an appreciable difference between both methods. We conclude that neutrophilic granulocyte maturation in the BM is accompanied by a change in surface antigens that reflects certain stages of development. A successful strategy for detecting maturation defects is to include several antibodies that are known to be expressed or absent at the same stage of maturation, such as CD16, CD35, CD64, and CD87.

CD87 as a marker for terminal granulocytic maturation: assessment of its expression during granulopoiesis

BACKGROUND

Understanding the normal surface maturation pattern of granulocytes is essential for the recognition of abnormal patterns, which in turn may be of diagnostic or pathogenetic significance in disorders such as myelodysplastic syndromes and inherited bone marrow failure disorders. CD87 plays a role in cellular interaction, cell migration, and inflammatory response. Surface expression of this antigen has not been adequately studied on bone marrow granulocytes, and the small number of previous studies has provided conflicting data.

METHODS

Bone marrow aspirates from 11 control subjects were studied by flow cytometry and a lysed whole blood technique to compare surface expression of CD87 on marrow granulocytes with those of CD11b, CD16, CD35, and CD10, which are expressed at the myelocyte, metamyelocyte, band, and segmented stage of neutrophilic development, respectively. Four sorting experiments of CD87(+) granulocytes were also performed.

RESULTS

Our study showed no statistical difference between surface expression of CD35 and CD87 (P > 0.3), whereas significant differences existed between CD87 and the other antibodies (P < 0.004). Sorting experiments showed that more than 80% of CD87(+) cells were bands and segmented neutrophils. Dual staining for CD87 and CD35 showed that most CD87(+) granulocytes coexpress CD35.

CONCLUSIONS

CD87 is expressed on granulocytes at the band and segmented neutrophil stage of development and can be used to study normal and abnormal granulopoiesis.

Assessment of CD24 expression on bone marrow neutrophilic granulocytes: CD24 is a marker for the myelocytic stage of development

The understanding of normal surface maturation pattern of granulocytes plays an essential role in identifying abnormal patterns, which may be of diagnostic or pathogenetic significance in some disorders, such as myclodysplastic syndromes. CD24, which is expressed only on granulocytes and not on monocytes, has not been adequately studied. Surface marker studies on eight control marrows indicate that CD24 is expressed on bone marrow granulocytes in a pattern that is similar to CD11b while much different than the more mature markers, CD16b and CD35. Three sorting experiments show that the majority of CD24(-) cells are promyelocytes. We conclude that CD24 is expressed on the neutrophilic granulocytes at the stage of myelocytes, and hence it could potentially be used to study normal and abnormal maturation of granulocytes.

Surface antigen changes during normal neutrophilic development: a critical review

Neutrophil surface molecules function in part as biological sensors. Surface antigens undergo several changes during neutrophilic maturation to accommodate the cell's function. Surface antigens may appear with neutrophilic maturation, such as CD16b, CD35, and CD10; disappear with maturation, such as CD49d and CD64; be maintained during maturation, such as CD32, CD59, and CD82; or disappear with maturation but reappear after neutrophilic extravasation, such as CD49b. This article reviews the alterations in surface antigen expression during normal neutrophilic granulopoiesis.