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L05 Blood Leucocytes in disease

Leucocytes in disease

Status: S1LectNotes Time: 2025-03-13 Tags: lecturenotes Links:

Content:

Blood tests

Marrow aspirate Marrow trephine blood film automated blood test

blood lineages

myeloid vs lymphoid

neutrophil maturation

  1. myeloblast
  2. promyelocyte
  3. myelocyte
  4. metamyelocyted
  5. band neutrophil
  6. neutrophil neutrophils are in the bone marrow for 10 day in the blood for maybe 5 in the tissues for 3-5

margination

half of neutrophils are marginated (rolling on endothelial cells)

inflammation leads to transmigraion through integrins

neutrophil behaviour and end

stimulated bycytokines opsonised bacteria immune complexes fungi and ecm components

die via apoptosis or NETosis

Conditions

neutrophilia

infection

  • associated features
    • shift to immaturity
    • toxic changes to neutrophils
    • vacuolation (eating itself) steroid induced neutrophilia
  • steroids trigger demargination chronic mild neutrophilis
  • chronic infalmation

Neutropenia

mild: 1-1.9 x 10^9 /L

  • not clinically important
  • History: medication, chronicity, viral infections, African & Middle Eastern ethnicity (Duffy null blood group)
  • We check the rest of the blood count and the blood film

Severe: < 0.4 x 10^9/L

  • watch closely for fever/elevated CRP (give intravenous antibiotics if febrile)
  • consider protective isolation
  • occasionally treat with G-CSF

Causes:

  • part of pancytopenia
    • eg chemo
  • drug side effects: marrow suppressors
  • viral infection (Common usually mild)
  • genetic neutropenia
  • Duffy null (blood group)
    • low neutrophils but protects against malaria
  • Fulminant bacterial infections
    • uses up all the neutrophils real fucken quick

Functional neutrophil defects

Acquired

  • diabetes
  • alcoholism
  • renal failure Steroid medication
  • demargination makes it difficult for the neutrophils to reach the tissues genetic defects are really rare

Eosinophilia

eosinophils play multiple and broad roles in the immune system and tissue homeostasis (We dont know what the hell they do)

associated with

  • parasitic infection or
  • allergic reactions (drug allergy is included)

Monocytes & Monocytosis

10-15% of cells in all organs!

monocyte are in the blood on the way to become macrophages in tissues Different names based on the location unfortunately:

  • connective tissue (histiocytes),
  • liver (Kupffer cells)
  • lung (alveolar macrophages)
  • brain (microglial cells)
  • serous fluids (pleural and peritoneal macrophages)
  • skin (Langerhans cell)
  • bone (osteoclasts)

Reactive chronic inflammation states

  • chronic bacterial infections
  • myelodisplactis syndromes

Basophiles

we dont know what they do

Leukoerythroblastic state

Immature cells are “pushed out” by a full marrow

  • Marrow replacement from leukaemia or lymphoma
  • Marrow infiltration by metastatic cancer
  • Myelofibrosis (a marrow cancer) But can also occur in:
  • Severe hypoxia + infection (e.g., pneumonia)

leukoerythroblastic blood film

lymptocytes

Mostly T cells but also B cells

Lymphocytosis causes in Children

  • Viral infections
  • Pertussis
  • acute lymphoblastic leukemia Young adults
  • EBV

any age

  • Cytomegalovirus Older patients
  • Older patients:
  • Less common causes:
  • EBV, CMV, acute lymphoblastic leukaemia
  • More common causes:
  • Chronic lymphocytic leukaemia (CLL)
  • Some lymphomas (most lymphomas don’t show circulating cells)

Malignancy

lymphoid blood cancers and myeloid cancers

  1. Acute myeloid leukaemia
    1. death in weeks
    2. marrow will get filled with blasts
  2. Myeloproliferative neoplasms
    1. Mainly red cells Polycythemia vera
    2. mainly platelets essential thrombocythemia (decades)
    3. mainly grandulocytes chronic myeloid leukaemia (decades)
  3. myelodysplastics syndrome (dysplasia = abnormal growth) (decades with nrew treatments)
    1. defectibve myeloid cells

lymphoma precursor lymohoid neoplasms

  1. acute lymphoblastic leukaemia mature lymphoid neoplasms
  2. lymphoma (usually solid)
    1. usually in lymph nodes
  3. chronic lumphocytic leukaemia
  4. plasma cell myeloma

malignant bone marrow diseases can cause cytopenia

Graph View