Week 4 - Abnormalities of White Cells PDF

BMED12-118 LABORATORY MEDICINE ​John Leggett ​[email protected] ​ Week 4: Investigating Abnormalities of White Blood Cells At the end of this week students should be able to: Understand the major abnormalities of lymphoid cells Describe the common causes of leukopenia and leukocytosis...

BMED12-118 LABORATORY MEDICINE ​John Leggett ​[email protected] ​ Week 4: Investigating Abnormalities of White Blood Cells At the end of this week students should be able to: Understand the major abnormalities of lymphoid cells Describe the common causes of leukopenia and leukocytosis Explain the difference between lymphoid and myeloid neoplasms Understand the difference between leukaemias and lymphomas Describe the pathogenesis and diagnosis of acute | 3 Haematopoiesis ​Starts with a pluripotent stem cell ​Can give rise to separate cell lineages ​Are capable of self renewal ​Various cytokines & growth factors regulate the stem cells ​Control proliferation, differentiation and survival ​Differentiation into committed progenitor cells ​Lymphoid – T-cells & B-cells ​Myeloid – erythroid, granulocytic, megakaryocytic ​Haematopoietic malignancies are often associated with disruption of this well controlled process | 4  | 5 Plasma Cell Macrophage Role of White Blood ​White blood cells (leukocytes) can be divided into two very broad groups Cells ​Phagocytes (granulocytes) ​Neutrophils ​Monocytes (macrophages) ​Eosinophils ​Basophils ​Immunocytes (lymphocytes) ​Lymphocytes (T-cells & B-cells) ​Key role of both is protecting the body against infection | 6 Investigating ​Full Blood Count – White Blood Cells (WBCs) Disorders of White ​Looking for decreases or increases in total white cell count as well as changes in the percentage of Blood Cells each type of white blood cell making up that total. WBC Count % (x103/ul) Total 4.8-10.8 100 Neutrophils 1.4-6.5 40-60 Lymphocytes 1.2-3.4 20-40 Monocytes 0.1-0.6 2-8 Eosinophils 0-0.5 1-4 Basophils 0-0.2 0.5-1 ​Morphology – blood smear and bone marrow biopsy | 7 Investigating ​Morphology Disorders of White ​A blood smear is also performed to investigate changes in size & shape or observe the Blood Cells appearance of unusual morphological features (e.g. double nucleus in Hodgkins Lymphoma). ​Often if initial result indicate some kind of neoplasm then a bone marrow biopsy is required for diagnosis. ​Bone marrow has a unique structure that is organised in important ways to ensure appropriate function. Different cells at different stages of maturation can be found in specific places in the marrow. A network of thin-walled sinusoids. The interstitium has clusters of haematopoetic and fat cells. The structure of the marrow can be altered & fat cells can be reduced in tumours (and hyperplasia), or fibrosis can appear. ​The cells affected will be identified. More differentiated Bone Marrow Biopsy precursor cells can be identified by morphology. Otherwise, 1-4 = stages of megakaryocyte histo- and immunohisto-chemistry can be used to identify development the immature precursors. * = adipocytes > = sinusoids | 8 Disorders of White Blood Cells ​Leukopenia – reduced number of white blood cells ​Neutropenia ​Lymphopenia ​Can be due to increased use or decreased haematopoiesis. ​Leukocytosis – increased numbers of white blood cells ​Neutrophilia ​Lymphocytosis ​Monocytosis ​Eosinophilia ​Basophilia ​Due to increased production. | 9 Disorders of White ​Neutropenia Blood Cells ​Clinically significant as reduced numbers can lead to recurrent bacterial infections ​Ineffective granulopoiesis ​Suppression ​Aplastic anaemia ​Marrow infiltration by tumour ​Drugs (cytotoxics e.g. chemotherapeutics) ​Increased removal or destruction ​Immunological ​Splenomegaly ​Increased utilisation ​Overwhelming infection | 10 Disorders of White ​Lymphopenia Blood Cells ​Congenital immunodeficiency ​AIDS ​Treatment with steroids, cytotoxics ​Autoimmune disease | 11 Leukocytosis ​Increased production ​Chronic infection or inflammation ​Neoplasm ​Paraneoplastic – Hodgkin lymphoma – growth factor dependent ​Increased release ​Endotoxaemia ​Infection ​Hypoxia ​Decreased margination/extravasation ​Exercise ​Catecholamines ​Glucocorticoids | 12 Causes of Reactive Leukocytosis (non-neoplastic) Acute bacterial infections, especially pyogenic infections Neutrophilic Sterile inflammation leukocytosis Tissue necrosis (neutrophilia) Myocardial infarction Burns Allergic disorders Asthma Hay fever Eosinophilic Drug allergies leukocytosis Allergic skin diseases (eosinophilia) Parasitic infections Some forms of malignancy Hodgkin's lymphoma Basophilic leukocytosis (rare) Myeloproliferative disease Basophilia | 13 Causes of Reactive Leukocytosis (non-neoplastic) Chronic infections Tuberculosis Bacterial endocarditis Monocytosis Rickettsiosis Malaria Systemic autoimmune diseases, e.g. SLE Inflammatory bowel diseases, e.g. ulcerative colitis Chronic infections Tuberculosis Brucellosis Lymphocytosis Viral infections Hepatitis Cytomegalovirus infection Infectious mononucleosis | 14 Malignancies of WBCs Malignancies of ​Mutation of genes that control proliferation, differentiation or apoptosis can disrupt the tightly White Blood Cells controlled process of haematopoesis ​Can be caused by: ​Inherited genetic factors ​Viruses ​HTLV-1, EBV ​Chronic immune stimulation ​H.pylori ​Iatrogenic factors ​Chemotherapy, radiation Acquired ​spontaneous mutations during cell divisions | 16 Malignancies of ​Cancers are the most important white blood cell disorders clinically and can fall into the categories White Blood Cells of: ​Lymphoid Neoplasms: a diverse range of tumours of B-cell, T-cell or NK origin. ​ yeloid Neoplasms: tumours of various causes M that result in increased levels of one or more of the granulocytes. ​Can also be classified as leukemias or lymphomas ​Lymphoma is a solid tumour originating in solid tissue masses, usually lymph nodes (only involves lymphocytes (B & T cells)) ​ eukaemia involves the bone marrow and usually L a circulating peripheral blood component (can involve lymphocytes (lymphoid leukemia) and granulocytes (myeloid leukemia)) ​Many diseases have both solid and circulating phases and are named based on the usual tissue distribution at presentation. | 17 Acute vs Chronic ​Acute Leukaemia Leukaemia ​Characterized by a rapid increase in the numbers of immature blood cells ​Crowding due to such cells makes the bone marrow unable to produce healthy blood cells I​mmediate treatment is required due to the rapid nature ​Most common forms of leukaemia in children ​Chronic leukaemia ​Characterized by build up of relatively mature (but still abnormal) cells ​Slower disease progression (months or years) ​May not require immediate, aggressive treatment (may be monitored) ​Chronic leukaemia less common in children | 18 Myeloid Neoplasms - AML Myeloid Neoplasms ​Myeloid neoplasms all originate from hematopoietic progenitor cells and therefore involve primarily the bone marrow and to a lesser degree secondary organs such as the spleen, or lymph nodes. ​Three categories of myeloid neoplasms exist: Acute Myeloid Leukaemia: accumulation of immature myeloid cells in the bone marrow suppresses normal haematopoiesis Myelodysplastic syndromes: defective maturation of myeloid progenitors causes haematopoiesis to be ineffective Myeloproliferative Disorders: usually increased production of one or more types of myeloid cell The main factor influencing the manifestation of these neoplasms is where in the hierarchy of haematopoiesis is the faulty cell. Is it a stem cell or a more committed progenitor cell that has undergone some differentiation? | 20  ​A tumour of hematopoietic progenitors caused by Acute Myeloid mutations that impede differentiation. Many Leukaemia genes can be involved. ​This leads to accumulation of immature myeloid progenitors in the marrow and impedes haematopoiesis of other cells leading to anaemia, thrombocytopenia and neutropenia. ​Occurs at all ages but incidence rises throughout life (peaking after 60 years of age). ​Most patients present with symptoms such as: ​Fatigue ​Fever ​Spontaneous mucosal or cutaneous bleeding or haemorrhages ​Frequent infections ​Diagnosis - FBC ​- Low or High WBCs but always with low neutrophils | 21 ​- Low RBCs (Normochromic normocytic anaemia)  ​Diagnosis is by blood smear & bone marrow Acute Myeloid biopsy : Leukaemia ​AML is characterised by at least 20% myeloid blasts (progenitor cells) in the peripheral blood and/or bone marrow (see image) ​Flow cytometry is used to determine myeloid origin and extent of differentiation (see image) ​Molecular Genetics to determine specific gene mutations and treatment approaches Bone marrow aspirate of AML: Myeloblasts have more voluminous cytoplasm than lymphoblasts CD33 is a marker of immature myeloid cells| while22 and contain fine, granules. CD15 is a marker of mature myeloid cells. Indicates that these cells are immature myeloid Lymphoid ​Lymphoid neoplasms can involve T-cells or B-cells at any stage of their differentiation process. This Neoplasms may lead to disease mainly in tissues such as bone marrow and the blood (leukaemia) or mainly in the lymph nodes (lymphoma). Often the neoplasm will have involvement in both areas and classification becomes difficult. ​The World Health Organisation recommends classification of the neoplasm based on the cell of origin. ​Precursor B-cell neoplasms (immature B-cells) ​Peripheral B-cell neoplasms (mature B-cells) ​Precursor T-cell neoplasms (immature T-cells) ​Peripheral T-cell neoplasms (mature T-cells) ​Hodgkin Lymphoma (involves Reed-Sternberg cells) ​Note: any lymphoma not involving Reed-Sternberg cells is classified as non-hodgkins lymphoma) | 23 Lymphoid Neoplasms - CLL Lymphoid Neoplasms Naive B-cell Germinal Marginal Zone Centre B- (memory) B-cell cell | 25 Chronic lymphocytic leukaemia (CLL) ​Clinical Presentation ​Neoplasm of small round B-lymphocytes in the peripheral blood, bone marrow and lymph nodes. ​Cell of origin may be either memory B-cell or naïve B-cell. ​Represents 80% of lymphoid leukaemias making it the most common leukaemia in adults in the Western World. Generally occurs in older age group: >50 years old Men are affected more than women 2:1 Asymptomatic in more than 25% of cases and thus diagnosed on a routine blood film. Symptoms include splenomegaly, hepatomegaly, chronic fatigue, infections as a result of bone marrow replacement of normal cells with lymphocytes. Skin and organ infiltration. | 26 Chronic lymphocytic leukaemia (CLL) ​Diagnosis: Full Blood Count & Smear Lymphocytosis for more than 3 months. Lymphocytes appear morphologically normal. Blood film likely to show “smudge cells” with bare nuclei (fragile lymphocytes whose cytoplasm has been damaged whilst spreading the blood film). Normochromic normocytic anaemia and/or a thrombocytopenia not uncommon. These are a result of bone marrow replacement with lymphoid clone. Blood smear showing smudge cells Bone marrow biopsy is likely to show increased lymphocytes in interstitium (particularly due to naïve B-cell neoplasm) Lymph node biopsy will show | 27 destruction of nodal architecture Lymphoma  Hodgkin’s ​Covers a group of lymphoid neoplasms characterised by the presence of Reed-Sternberg Lymphoma (HL) cells. ​Reed-Sternberg cells are neoplastic, giant, binucleate cells derived from germinal centre B- cells. ​These cells release growth factors that cause accumulation of lymphocytes, macrophages and granulocytes in the lymph node causing significant swelling. ​Symptoms ​Most patients present with painless lymph node enlargement. ​HL arises in a single node and spreads in an orderly manner to adjacent lymph nodes (contiguous). Lymph biopsy showing Reed-Sternberg cell ​Later in the disease patients may present with fever, night sweats and weight loss. ​Average age of onset is 32 years. ​Diagnosis – Lymph node biopsy ​Will show increased WBCs and altered | 29 architecture.  ​Covers a group of lymphoid neoplasms that do Non-Hodgkin not present with Reed-Sternberg cells Lymphoma (NHL) ​Can be B-cell (80%) or T-cell (20%) derived. ​Symptoms (same as Hodgkins) i.e. any lymphoma that is not Hodgkins ​Most patients present with painless lymph node enlargement. ​ sually presents in multiple peripheral lymph U nodes. Does not spread in an orderly manner. ​ ater in the disease patients may present with L fever, night sweats and weight loss. ​Includes up to 61 different types such as: ​Follicular lymphoma ​Diffuse Large B cell lymphoma ​Burkitt lymphoma ​Diagnosis – Lymph node biopsy ​Features can be varied due to the different types of non-Hodkins lymphoma. ​Generally all have alterations in lymph node architecture and/or cell accumulation. ​No Reed-Sternberg cells present | 30 Stages of Both HL & NHL | 31 Hodgkin Lymphoma Non-Hodgkin Lymphoma More often localized to a single More frequent involvement of axial group of nodes (cervical, multiple peripheral nodes mediastinal, para-aortic) Orderly spread by contiguity Noncontiguous spread Extra-nodal presentation rare Extra-nodal presentation common Stage Distribution of Disease I Involvement of a single lymph node region (I) or a single extra-lymphatic organ or site (IE). II Involvement of two or more lymph node regions on the same side of the diaphragm alone (II) or localized involvement of an extra-lymphatic organ or site (IIE). III Involvement of lymph node regions on both sides of the diaphragm without (III) or with (IIIE) localized involvement of an extra-lymphatic organ or site. IV Diffuse involvement of one or more extra-lymphatic organs or sites with or without lymphatic involvement. All stages are further divided on the basis of the absence (A) or presence (B) of the following symptoms: unexplained fever, drenching night sweats, and/or unexplained weight loss of greater than 10% of | 32 normal body weight Summary ​Disorders of white blood cells can cause a decrease or an increase in their numbers. ​There are several non-cancerous events that can cause disorders in white blood cells including: ​Infection ​Toxins / drugs ​Nutritional deficiencies ​Inflammation (necrosis) ​There are several malignancies that affect the white blood cells. ​These tend to be categorised as myeloid or lymphoid neoplasms. ​The lymphoid neoplasms are further characterised as lymphomas (affecting lymph nodes) or leukaemias (affecting bone marrow and blood). | 33 Additional Reading ​White Blood Cells ​Chapter 13 of the Text Book (Pathological Basis of Disease) ​ ​RCPA manual ​https://www.rcpa.edu.au/Library/Practising-Patholo gy/RCPA-Manual/Items/Clinical-Problems | 34 Revision Questions 1) What are the principle causes of leukocytosis (there are 4) 2) List a specific causes for each of the following types of reactive leukocytosis: neutrophilia, monocytosis and lymphocytosis 3) What are the 3 major categories of myeloid neoplasms? 4) Describe the pathogenesis of Acute Myeloid Leukemia and how it is diagnosed. 5) What are the 5 major categories of lymphoid neoplasms? 6) Describe the features of a full blood count & smear in CLL 7) Describe the characteristics of the Hodgkin lymphoma group 8) What are the major differences between Hodgkins and non-Hodgkins lymphoma? | 35