Pathology Lesson 3_ Leukemia PDF

# Leukemias 9 ## White Blood Cells (WBC)/Leukocytes * in immune system & defend * mainly in blood & lymphatic systems * 5 types categorized by physical look & function ## Hematopoietic Stem Cell: multipotent cell in bone marrow that becomes WBC ## WBC#: Between 4-11 × 10⁹/L (microli...

# Leukemias 9 ## White Blood Cells (WBC)/Leukocytes * in immune system & defend * mainly in blood & lymphatic systems * 5 types categorized by physical look & function ## Hematopoietic Stem Cell: multipotent cell in bone marrow that becomes WBC ## WBC#: Between 4-11 × 10⁹/L (microliters) * Make up 1% of total blood volume (thousands) ## Leukocytosis: # of WBC is above normal amount ## Leukopenia: # of WBC is below normal amount ## 2 Types of Leukocytes: * have chem mediators | Type of Leukocyte | Description | |---|---| | **Granulocytes** | have visible cytoplasmic granules | | **Agranulocytes** | don't have visible cytoplasmic granules | ### Granulocytes: (polymorphonuclear cell family PMNs) * Includes: basophil, neutrophil, eosinophil ### Neutrophil #### Granulocyte * **Number:** most common WBC (40-75%) * **Appearance:** stain neutral pink, multi-lobed (2-5 lobes) * **Function:** innate immune response, phagocytosis, degranulation (discharge of contents of a cell), guard skin & mucous membrane * **Lifespan:** 6 hrs-few days (short-lived) * **Production:** from stem cell in bone marrow * **2 diff types:** Segmented Neutrophil (segs) and banded neutrophils (bands) * **Response to:** inflammation, bacteria infections, env exposure, cancers, fungi (first responders) * **How they defend:** go to blood vessels, go towards site of damage, then to interstitial true to do phagocytosis * **Neutrophils are programmed for apoptosis:** (using perforin & granzyme) * **Perforin & Granzyme:** punch holes in cell membrane * **Chemotaxis:** Chem signals that guide cells (in this case neutrophil) to site of damage * ex: IL-8, C5a, fMLP, Leukotriene B4 ### Eosinophil #### Granulocyte * **Number:** make up 1-6% of WBC * **Appearance:** Stain Red & are bilobed but are transparent * Eosinophilic: "acid-loving" - have affinity for coal tar dyes * **Function:** degranulation, release enzymes, growth factors, cytokines * **Lifespan:** 8-12 days * **Production:** from hematopoiesis in bone marrow * **Response to:** parasites, allergic reaction, vertebrae infection (# eosinophil inc) * **Location:** thymus, lower GI, ovary, spleen, lymph nodes (if in lung, skin, esophagus, or internal organ it means infection) * **How they defend:** Not definition just what it does in eosinophil * **Degranulation:** Eosinophil releases chem mediators like histamine & proteins to defend (how you get allergic reaction) * **Produce Enzymes:** to attack parasites & modulate inflammation ### **Basophil** #### Granulocyte * **Number:** <1% WBC, least common * **Appearance:** Bi or trilobed, stain dark blue * Basophilic: "base-loving" like basic dyes * **Function:** degranulation, release histamine, enzymes, cytokines, chem mediators * **Lifespan:** not known (about few hours-few days) * **Production:** form mature in bone marrow * **Response to:** allergic tissues, inflammatory reaction, ectoparasite infections * **Location:** circulate in small # in blood * **How they defend:** releases heparin, histamine, use TLR for activation, carry receptor for IgE * activated by bacteria, virus, & parasite using TLR * **Heparin:** an anticoagulant that prevents blood from clotting too quickly * **Histamine:** vasodilator that promotes blood flow to tissues & amplifies innate response * **IgE activation:** releases histamine ### Monocyte #### Agranulocytes * **Number:** 2-6% of WBC * **Appearance:** kidney shaped, largest WBC, clear cytoplasm, amoeboid, unlobed * **Function:** turn into macrophages & dendritic cells to cause immune response (part of innate) * **Lifespan:** hours-days * **Production:** stored in the spleen in red pulps (Cords of Billroth), made in bone marrow * **Monoblast:** precursor to monocyte, bipotent cell differentiated from hematopoietic stem * **Response to:** inflammation & replace macrophage when # low, viral & chronic infections * **Location:** move to tissues thru out body ### Lymphocyte * any WBC in vertebrae immune system, mainly in lymph * 3 types: * **Shift to the left:** immature cells #### 1. **T cell** (Thymus cell) * **Function:** adaptive immune response * **Cell-mediated immunity & cytotoxic adaptive immunity:** * **Helper T:** Makes cytokines that have direct immune response * **Cytotoxic T:** makes toxic granules that have enzymes that kill cells #### 2. **B cell** (bursa-derived cell) * **Function:** Make large # of antibody & neutralize foreign objects, adaptive immune response * **Humoral & antibody drive adaptive response:** * **Both T & B cells do:** * **Antigen presentation:** recognize "non-self" antigen or generate response * **Memory cells:** remember antigens, made from B & T cells #### 3. **Natural Killer Cells (NK)** * **Function:** cell-mediated innate immunity by releasing cytotoxic granules * **React to:** tumors & infected cells * **How they defend:** find invaders by finding changes in Surface molecule major histocompatibility complex (MHC class1) * **Interferon:** family of cytokines that activate NK ### Cancer cell: * make up majority of the cell, smaller cytoplasm, many nuclei ## Leukemia: cancer of WBC ## Acute Lymphoblastic Leukemia (ALL) * **Peak age:** 2-5 yrs old * **Characterized by:** overproduction of lymphoblasts in bone marrow, blood, tissue & multiply * **Lymphoblast:** cancerous immature WBC that stop production of other cells (have different size morphology, etc) * **Diagnosis:** based on flow cytometric immunophenotyping (FCI), can have predominately bone marrow or extramedullary sites * **Cytogenetics:** Key in diagnosis of ALL * **Less B** * **Manifestations:** fever, night sweats, weight loss * **Symptoms:** Less functional blood cells, increase risk for infection, bleeding more, anemia, fatigue, headache, swollen lymph node * **CNS probs occur in 10% of pt (mostly in Bell ALL)** * **Common findings:** abdominal masses, tumor lysis syndrome, chin numbness * **3 types:** NK, T, B ALL * **Treatment:** MRD, PCR, generation sequencing * **Paller, tachycardia** * **Cell appearance:** Dis nucleus, multiple nuclei ## Measurable Residual Disease (MRD) * Residual leukemic blasts detected after cytoreductive chemotherapy despite 510 blasts in marrow * Assessed by: MFC & qPCR, Next Generation Sequencing (NGS) * MRD should be tested in bone marrow. ## Frontline Therapy * Made up of: Induction of remission, consolidation, maintenance, CNS prophylaxis * **Cause:** unknown, chromosomal translocation in fetal hematopoiesis maybe * **Allogenic Hematopoietic Stem Cell Transplantation:** pt with high risk features (Bort too high, PH or KMT2A translocation, etc.) ## B-cell Chronic Lymphocytic Leukemia (CLL) * **Most common leukemia in adults** * **Affects:** B-cell lymphocytes * **B cells grow out of control:** stay in bone marrow & blood * **Stage of SLL:** * **Small lymphocytic lymphoma:** B-cell lymphoma in lymph nodes * **Symptoms:** high WBC#, swollen lymph nodes, spleen, liver, anemia, infection * **Other symptoms:** fever, weight loss, night sweats, autoimmune hemolytic anemia, thrombocytopenia * **Wells syndrome:** skin reaction to insect bites w/ CLL * **Treatment:** chemotherapy, monoclonal antibodies * **Risk factors:** Genetic factors, Viral infection, chem exposure, immune system disorders * **Diagnosis:** more than 5000/microliter B cells in peripheral blood w/ cytometry, less than 55% being prolymphocytes * **B cell markers are:** CD19, CD20, CD23 * **Expansion of CDS:** * **(FISH) Fluorescent in situ hybridization:** detect molecular abnormalities * **Types:** * **Del (11q):** more prominent lymphadenopathy, advanced disease, poor chemotherapy response * **Del (17p):** more advanced disease, poor chemotherapy response, lack nuclei, smudge cells * **Appearance:** resemble mature lymphocytes, dense chromatin, scant cytoplasm, lack nuclei, smudge cells ## Acute Myeloid Leukemia (AML) * **Cancer of:** myeloid line of blood cells * **Most common:** acute leukemia * **Characterized by:** rapid growth of abnormal WBC that stay in bone marrow & stop production of other cells * **Genetics:** heterogeneous group of hematologic neoplasms w/ clonal proliferation of myeloid blasts * **Suppressed apoptosis of:** neoplastic blast cells * **Treatment:** cytogenetics, chemotherapy aimed at remission * **Symptoms:** tumor in extramedullary tissues, bone marrow, peripheral blood, decrease # of RBC, platelets, WBC, fatigue, shortness of breath, inc risk of infection, easy bleeding, acute myeloid rash * **Caused by:** replacement of bone marrow w/ leukemic cells * **Risk factors:** if have chromatin fragility disorder, cytotoxic therapies, alkylating agents exposure, radiation therapy * **Mutations w/ TP53 and:** agents that repair topoisomerase * **Diagnosis:** 20% or more myeloid blasts in bone marrow or peripheral blood * **Confirmed diagnosis:** flow cytometry immunophenotyping * **Myeloid sarcoma:** mass in extramedullary tissues that reveal AML * **Wright-Giemsa:** aspirate smears revealed >10 blasts found thru 500-cell manual count * **Appearance:** immature myeloblasts w/ many nuclei, linear red Auer rod made of crystalline granules * **Myeloid lineage:** myeloperoxidase (MPO) needed to differentiate, but AML lack * **Acute promyelocytic leukemia (APL):** sub-type of AML (next one on page) * **Risk stratification:** next step to find management / prognosis / therapy in AML. Depends on many factors (markers, age, status of disease) ## Next Generation Sequencing (NGS) (for AML) * **Illumina sequencing tech:** a type of NGS that detects single bases as they are being incorporated into DNA strands * **DNA polymerase:** adds dNTP to DNA template * **Library Preparation:** random fragmentation of DNA or cDNA sample, w/ 5' & 3' adapter ligation * **Cluster Generation:** library loaded into flow cell, where fragments are amplified into distinct clonal clusters through bridge amplification * **Now ready for sequencing** * **Sequence by Synthesis (SBS):** uses proprietary reversible terminater-based method to detect single bases incorporated to DNA * **Data Analysis:** Sequence is aligned to reference genome ## Acute Promyelocytic Leukemia (APL): * **Sub-type of AML** * **Cause:** translocation between RARA on chromosome 17 & PML on chromosome 15 * **PML-RARα** * **Clinical presentation:** bleeding diathesis from DIC, fibrinolysis * **Treatment:** all-trans-retinoic acid (ATRA) & arsenic trioxide (ATO) ## Chronic Myeloid Leukemia (CML) * **Age:** 160-65 * **Has diff types** * **Characterized by:** inc is unregulated growth of myeloid cells in bone marrow & stay in the blood, mature cells * **Clonal bone marrow stem cell disorder:** * **Proliferation of mature granulocytes & precursors:** into signaling pathway * **Cause:** chromosomal translocation of Philadelphia Chromosome (Ph) * **Philadelphia Chromosome:** from reciprocal translocation between chromosome 9 & 22, causes CML * **ABL1: ** of chromosome 9 * **BCR: ** of chromosome 22 * **Fusion transcript:** BCR-ABL1 * **BCR-ABL1 tyrosine kinase:** oncoprotein that activates downstream pathways, codes for BCR-ABL1 tyrosine kinase * **Treatment:** tyrosine kinase inhibitor (TKI) drugs * **Through FISH** * **ABL1-BCR** * **Diagnosis:** complete blood count shows inc granulocytes of all types & mature myeloid cells, find Philadelphia Chromosome w/ cytogenetics. * **Initial presentation:** leukocytosis ul shift left w/ myelocytes & metamyelocytes in peripheral blood * **Risk factors:** exposure to ionizing radiation * **Symptoms:** abnormal WBC#, bone pain * **Cells:** large malignant cells, some normal cells ## Myelodysplastic Syndrome (MDS) * **NOT ON EXAM** * **Characterized by:** ineffective hematopoiesis, inc risk of turning to AML * **Prognosis:** cytogenetics, stemness, epigenetic alterations * **Risk factors:** evidence of clonal hematopoiesis * **Diagnosis:** degree of cytopenia, # of blasts, cytogenetic & genetic alterations * **Cause:** unknown, but environmental & genetic factors increase risk ## Myeloproliferative Neoplasm (MPN) * **Group of diseases in bone marrow w/:** excess cells produced * **May evolve to:** MDS or AML * **Cause:** clonal genetic changes