Page 258 - Haematologica Atlas of Hematologic Cytology

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Figure 12 Leukocyte inclusions in in in in MYH9-related MYH9-related disease disease A constant finding of MYH9-related MYH9-related disease disease is is is the presence of of of clumps of of of M H9 protein in in neutrophils cytoplasm (Pecci et al al 2018) Immunofluorescence analysis recognizes these aggregates in all all neutrophils of all all patients and this test has therefore very high sensitivity for for diagnostic purposes Specificity is is is also very good since the MYH9 protein is is is distributed homogeneously both in in in healthy subjects and patients with other forms of acquired or or inherited thrombocytopenia (A) Mutations in in the the tail of MYH9 usually result in one or few large aggregates aggregates possibly associated with small aggregates aggregates (B) while mutations in in in the head (motor domain) of MYH9 results in in in many small aggregates (C) In May-Grünwald-Giemsa stained blood films the aggregates (named Döhle-like inclusion bodies) are recognized in in in a a a a a a a a small percentage of neutrophils in in around 50% of of patients The large aggregates due to mutations in in the tail of of M H9 are easily iden- tified as
round or or spindle-shaped light blue corpuscles usually located at at the cell periphery (D-F arrows) The small aggregates due to to mutations in the head of MYH9 (G-I arrows) are more difficult to to identify 245