Hematology and Clinical Microscopy Glossary - College of American ...
Hematology and Clinical Microscopy Glossary - College of American ...
Hematology and Clinical Microscopy Glossary - College of American ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Coarse stippling, on the other h<strong>and</strong>, is clinically significant<br />
<strong>and</strong> suggests impaired hemoglobin synthesis. The<br />
punctuation is readily visible <strong>and</strong> made up <strong>of</strong> relatively<br />
evenly distributed blue-gray granules. Coarse stippling<br />
results from abnormal aggregates <strong>of</strong> ribosomes <strong>and</strong><br />
polyribosomes in reticulocytes. Iron-containing<br />
mitochondria in the aggregates may further<br />
accentuate the stippling. Lead poisoning, thalassemia,<br />
<strong>and</strong> refractory anemia are disorders commonly<br />
associated with coarse basophilic stippling.<br />
Heinz Body (Supravital Stain)<br />
Heinz bodies appear as large (1 to 3 μm or greater),<br />
single or multiple, blue-purple (depending on the stain<br />
used) inclusions <strong>of</strong>ten attached to the inner surface <strong>of</strong><br />
the red cell membrane. They characteristically are seen<br />
at the edge <strong>of</strong> the red cell, stuck to the interior <strong>of</strong> the<br />
membrane <strong>and</strong> protruding into the cytoplasm. They are<br />
visible only with the help <strong>of</strong> supravital stains such as new<br />
methylene blue, Nile blue, crystal violet, or methyl violet.<br />
They are almost never visible in Wright-Giemsa-stained<br />
blood films, although bite cells are markers <strong>of</strong> their<br />
presence. Depending on the disease, the Heinz body is<br />
composed <strong>of</strong> precipitated normal hemoglobin (eg, G-6-<br />
PD deficiency) or structurally defective hemoglobin (eg,<br />
unstable hemoglobin).<br />
Hemoglobin C Crystal<br />
Hemoglobin C crystals within red cells are dense<br />
structures with rhomboidal, tetragonal, or rod shapes.<br />
They <strong>of</strong>ten distort the cell <strong>and</strong> project beyond its rim.<br />
The classic shape resembles the Washington monument.<br />
The crystals are <strong>of</strong>ten surrounded partly by a clear area<br />
or blister devoid <strong>of</strong> hemoglobin. Hemoglobin C crystals<br />
are readily seen after splenectomy in patients with<br />
hemoglobin C disease or SC disease.<br />
Hemoglobin H Inclusions<br />
Hemoglobin H inclusions represent precipitated excess<br />
beta hemoglobin chains, seen only after supravital<br />
staining. They are found in hemoglobin H disease, a<br />
form <strong>of</strong> alpha thalassemia (three alpha-gene deletion).<br />
Excess beta hemoglobin chains form tetramers that<br />
precipitate with the addition <strong>of</strong> brilliant cresyl blue stain.<br />
The deposits are small <strong>and</strong> evenly dispersed within the<br />
red cell, producing a “golf ball” or peppery<br />
appearance. The fine, deep-staining deposits are<br />
numerous, varying from 20 to 50 per cell. They are much<br />
smaller <strong>and</strong> more numerous than classic Heinz bodies.<br />
They are not visible with Wright-Giemsa stain.<br />
Howell-Jolly Body (Wright Stain)<br />
Blood Cell Identification<br />
Howell-Jolly bodies are small round objects about 1<br />
μm in diameter. They are larger than Pappenheimer<br />
bodies <strong>and</strong> are composed <strong>of</strong> DNA. They are formed in<br />
the process <strong>of</strong> red cell nuclear karyorrhexis or when an<br />
aberrant chromosome becomes separated from the<br />
mitotic spindle <strong>and</strong> remainsbehind when the rest <strong>of</strong> the<br />
nucleus is extruded. Normally, the spleen is very efficient<br />
in removing Howell-Jolly bodies from red cells, but if the<br />
spleen is missing or hyp<strong>of</strong>unctioning, they may be<br />
readily found in the peripheral blood. Howell-Jolly<br />
bodies are usually present singly in a given red cell.<br />
Multiple Howell-Jolly bodies within a single red cell<br />
are less common <strong>and</strong> typically seen in megaloblastic<br />
anemia.<br />
Pappenheimer Body<br />
Pappenheimer bodies are small, angular, dark<br />
inclusions appearing either singly or in doublets. They<br />
are less than 1 μm in diameter <strong>and</strong> thus are smaller<br />
than Howell-Jolly bodies. Unlike Heinz bodies, they<br />
are visible on Wright-Giemsa-stained smears. These tiny,<br />
generally angular inclusions stain positively with Prussian<br />
blue, indicative <strong>of</strong> the presence <strong>of</strong> iron. Wright-Giemsastain<br />
does not stain the iron, but rather the protein<br />
matrix that contains the iron. Pappenheimer bodies are<br />
formed as the red cell discharges its abnormal iron-<br />
containing mitochondria. An autophagosome is<br />
created that digests the <strong>of</strong>fending organelles. If the<br />
autophagosome is not discharged out <strong>of</strong> the cytoplasm<br />
or removed by the pitting action <strong>of</strong> the spleen, the<br />
inclusions will be visible on Wright-Giemsa-stained<br />
blood films. Their true nature is confirmed with an iron<br />
stain. Heinz bodies <strong>and</strong> Howell-Jolly bodies do not<br />
contain iron.<br />
Red Cell Agglutinates<br />
Red cell agglutination occurs when red blood cells<br />
cluster or clump together in an irregular mass in the thin<br />
area <strong>of</strong> the blood film. Usually, the length <strong>and</strong> width <strong>of</strong><br />
these clumps are similar (14 by 14 μm or greater). One<br />
must distinguish this abnormality from rouleaux<br />
formation. Individual red cells <strong>of</strong>ten appear to be<br />
spherocytes due to overlapping <strong>of</strong> cells in red cell<br />
agglutinates. This misperception is due to obscuring <strong>of</strong><br />
the normal central pallor <strong>of</strong> the red cells in the clump.<br />
Autoagglutination is due to cold agglutinins, most<br />
commonly an IgM antibody. Cold agglutinins can arise<br />
in a variety <strong>of</strong> diseases <strong>and</strong> are clinically divided into<br />
cases occurring afterviral or Mycoplasma infections,<br />
cases associated with underlying lymphoproliferative<br />
disorders or plasma cell dyscrasias (cold agglutinin<br />
disease), <strong>and</strong> chronic idiopathic cases that are<br />
800-323-4040 | 847-832-7000 Option 1 | cap.org<br />
11