65 Eosinophils and Their Disorders Flashcards
Most specific eosinophilopoietic growth factor
IL-5
Eosinophils persist in the circulation for ______ hours
25 hours
Granular proteins uniquely expressed by eosinophils
EPX and MBP-2
Majority of mature eosinophilic granules are
Secondary (specific) large granules
The smaller primary granules of eosinophils contain
Charcot-Leyden Crystal protein (Galectin-10)
Cell surface markers of eosinophils using flow cytometry
EMR-1, Siglec-8, and CCR3 (CD193)
In tissues, eosinophils can be detected by immunohistochemistry using
MBP, ECP, and EPX stains
Eosinophilia is defined as
Exceeding the upper limit of normal and an absolute eosinophil count (AEC) of 0.35–0.5 ×10 9 /L
Severity of eosinophilia
Mild (AEC <1.5 ×10 9 /L)
Moderate or marked (AEC 1.5–5 × 10 9 /L)
Severe or massive (AEC >5 × 10 9 /L)
Hypereosinophilia (HE) is defined as
Persistent eosinophilia greater than 1.5 × 10 9 /L
Divided into primary (clonal or neoplastic), secondary (reactive), hereditary (familial), or HE of undetermined significance
Hypereosinophilic syndrome (HES)
(a) a persistent eosinophilia of greater than 1.5× 10 9 /L for longer than 6 months or death before 6 months associated with the signs and symptoms of hypereosinophilic disease
(b) a lack of evidence for parasitic, allergic, or other known causes of eosinophilia; and
(c) presumptive signs and symptoms of organ involvement
Idiopathic HE or HE of undetermined significance
Patients with an absolute eosinophil greater than 1.5 × 10 9 /L are asymptomatic with no end-organ damage
Gene rearrangement associated with myeloid/lymphoid neoplasms with eosinophilia
PDGFRA, PDGFRB, and fibroblast growth factor receptor (FGFR) 1, PCM1-JAK2
Incidence of FIP1L1–PDGFRA fusion with idiopathic HE or HES
10%
Most common clinical manifestations at presentation of HES
Skin (37%)
Lungs (25%)
GI tract (14%)
At table: Hematopoetic, heart, skin, nervous system
Rare HES-like hereditary immune deficiencies characterized by an elevated IgE level, eczema-like skin rashes, characteristic facial and dental abnormalities, and recurrent infections
Hyper IgE syndromes
Mutations in Hyper IgE syndromes
Autosomal dominant mutations- STAT3 (Job syndrome)
Autosomal recessive mutations- DOCK8, PGM3, SPINK5, or TYK2
An elevated serum vitamin B12 level is commonly seen in primary HES/CEL, NOS, caused by __________
Increased production of the haptocorrins
Useful screening test in patients with HE
Tryptase
Useful in the diagnosis of lymphocyte-variant HE/HES
Testing for clonal T lymphocytes by flow cytometry and polymerase chain reaction (PCR)/next-generation sequencing (NGS)
TRUE OR FALSE
Given its dire consequences, all patients with HE and HES should be screened for cardiac involvement with troponin (T or I) looking for myocarditis and an echocardiogram (+/- N-terminal pro B-type natriuretic peptide [NT-BNP]) to evaluate the presence of cardiomyopathy.
TRUE
In using FISH in the diagnosis of primary HES, this is a surrogate for FIP1L1-PDGFRA fusion gene
CHIC2 deletion
Interstitial submicroscopic microdeletion on the long arm of chromosome 4
Immunohistochemical staining to identify increased numbers of neoplastic mast cells
CD117, tryptase, and CD25
Translocations that warrants FISH testing for PDGFRA, PDGFRB, FGFR1, JAK2, or FLT3
4q12, 5q31~33, 8p11~12, 9p24, or 13q12
In patients with elevated tryptase, testing should be undertaken for________
KIT D816V mutation
Most common gene partner of:
PDGFRA: _________
PDGFRB: _________
FGFR1: __________
JAK2: _________
ABL1: _________
FLT3: _________
PDGFRA: FIP1L1
PDGFRB: ETV6
FGFR1: ZMYM2
JAK2: PCM1
ABL1: ETV6
FLT3: ETV6