Blood Cells PDF

White blood cells are divided into: 1. lymphocytes (lymphoid series): B that give plasma cell , T lymphocytes. 2. granulocytes (myeloid series): neutrophils-the most abundant- eosinophils, basophils White blood cells disorders...

White blood cells are divided into: 1. lymphocytes (lymphoid series): B that give plasma cell , T lymphocytes. 2. granulocytes (myeloid series): neutrophils-the most abundant- eosinophils, basophils White blood cells disorders Deficiencies (leukopenias) Proliferations (reactive or neoplastic). the decrease in WBC count , we can use CBC test ( complete blood cell count ) ( increase in WBC count ) can be divided to to measure the number of RBC , WBC, reactive (infection,inflammatory disorder ) or platelets, hemoglobin. neoplastic (tumors). Usually the WBC count is between 4000 and 11000 per microliter. 1. Leukopenia (Deficiencies) Type Causes Clinical Consequences - Decreased number of neutrophils, decreased granulocyte production due to: - Neutrophils are the first line of defense against * Chemotherapy Neutropenia / Agranulocytosis (More bacterial infections so deficiencies in it might lead * Aplastic anemia common) to severe and often fatal bacterial and fungal * Bone marrow replacement by tumors infections. * Immune-mediated destruction (e.g., drugs). -decrease number of lymphocytes due to: * Congenital immunodeficiency Lymphopenia (Less common) diseases - Increased susceptibility to infections. * Advanced HIV infection (acquired immunedeficiency virus) * High-dose corticosteroid therapy. 2. Reactive Leukocytosis Occurs due to inflammatory stimuli (microbial or non-microbial so it’s non specific). Type Cause Details - Acute bacterial infections (pyogenic organisms). Neutrophilia - Sterile inflammation (non-microbial). - Most common in bacterial infections.. - Tissue necrosis (e.g., myocardial infarction, burns). - Allergic conditions (e.g., asthma, hay fever). - Parasitic infections (selectively). - Elevated eosinophils indicate parasitic infections or allergic Eosinophilia - Drug reactions. disorders. - Certain malignancies. - Viral infections (e.g., CMV, EBV, hepatitis A). - Lymphocyte increase seen in viral infections. Lymphocytosis - Chronic immunologic stimulation (e.g., - HIV may decrease lymphocytes. tuberculosis, brucellosis).  Leukemoid Reaction: A severe increase in WBC count that mimics leukemia but arises as a result of reactive (non- neoplastic) processes. Reactive Lymphadenitis Lymph nodes Act as defensive barriers, filtering pathogens and abnormal cells from lymphatic fluid and they divide histologically into: cortical (B cells found in it) and paracortical(T cell found in it ) Reactive lymphadenopathy: Refers to the swelling of lymph nodes due to infections or non microbial inflammatory stimuli, distinct from tumor Types of Reactive Lymphadenitis: a. Acute Nonspecific Lymphadenitis Features: ◦ Can be localized (e.g., cervical or axillary regions) or generalized (involving multiple lymph nodes throughout the body). ◦ Lymph nodes are painful, swollen, and inflamed. ◦ Histology shows large germinal centers with numerous mitotic figures. Causes: ◦ Pyogenic bacterial infections often cause neutrophilic infiltrates + lymphoid follicle with germinal centers and abscess b. Chronic Nonspecific Lymphadenitis Shows specific histologic patterns: Pattern Description Associated Conditions Follicular Proliferation of B cells in lymphoid follicles. Rheumatoid arthritis, toxoplasmosis, early HIV infection. Hyperplasia Germinal centers appear enlarged. Paracortical Expansion of the paracortical zone due to T- Viral infections (e.g., EBV), post-vaccination responses (e.g., Hyperplasia cell proliferation. smallpox), drug-induced immune reactions (e.g., phenytoin). Sinus Prominent proliferation of sinus macrophages Commonly seen in lymph nodes draining cancers. Histiocytosis in lymph nodes. this is lymphoid follicles -rounded areas- this is the normal cell ( we call it resting normal including fainting areas in center these are lymph node) lymphoid follicular hyperplasia with germinal centers. *May occur in acute or in chronic. 3. Neoplastic Proliferations of White Cells Refer to the abnormal growth of white blood cells, which can lead to the formation of tumors. These proliferations are considered always malignant (in lymph nodes), with varying levels of aggressiveness (indolent vs. aggressive) and they occur at all ages. Type Description - Involve the bone marrow and peripheral blood. Leukemias - Characterized by the abnormal proliferation of white blood cells. Lymphomas - Produce masses in lymph nodes or other tissues. - From the lymphoid series (leukemias, non-Hodgkin and Hodgkin lymphomas, plasma cell neoplasms) Lymphoid Neoplasms - Occur in bone marrow (BM) or lymph nodes. - From the myeloid series (leukemia, myelodysplastic syndromes (MDS), myeloproliferative neoplasms). Myeloid Neoplasms - Typically occur in bone marrow. # Lymphoid neoplasms affect lymphocytes (B cells, T cells, and plasma cells) and include Hodgkin lymphomas and Non- Hodgkin lymphomas. These neoplasms disrupt immune function, increasing susceptibility to infections. Classification and Diagnosis of Lymphomas Aspect Details - Hodgkin lymphomas (Reed-Sternberg cells). Types - Non-Hodgkin lymphomas (B-cell or T-cell origin). - IHC (Immunohistochemical Stains): Detects surface markers like CD20, CD3, or CD30. Diagnosis Tools - FCM (Flow Cytometry): Helps classify the lymphoma. - CD20: B-cell lymphomas. CD Markers - CD3: T-cell lymphomas. - CD30: Hodgkin lymphoma RS cells. Comparison of Key Lymphomas Diffuse Large B Cell Lymphoma Feature Follicular Lymphoma Hodgkin Lymphoma (DLBCL) Germinal center-derived B-cell Classification Peripheral B-cell neoplasm. Peripheral B-cell neoplasm. neoplasm. Common in children and young Prevalence 40% of adult NHLs in the USA. Most common lymphoma in adults. adults. - Characterized by RS cells (tumor - Aggressive, high-grade tumor. giant cells) - Indolent, low grade. - Painless lymph node -enlargement at Key Features - Arises in single lymph nodes or - Painless, generalized lymphadenopathy. one or several sites, often extranodal chains. (mostly in GIT). 85% harbor t(14:18) (Bcl2 gene fuses Often high-grade from onset or Genetic Frequently involves Epstein-Barr with IgH gene)→ Bcl2 overexpression transformed from low-grade Changes virus (EBV). (antiapoptotic). lymphoma. Large RS cells with inclusion-like Diffuse sheets of malignant cells in Histological Follicular hyperplasia (nodular nucleoli, surrounded by lymph nodes or tissues but not in Appearance appearance) lymphocytes, macrophages, and blood and BM. eosinophils. Microscopic Small neoplastic cells with nodular Large, ugly cells with prominent Atypical RS cells: binucleate, Characteristics growth. nucleoli and high mitotic activity. abundant cytoplasm. Rs cell (It’s binucleated with 2 nucleoli) - Non-curable, but slow-growing. - 30-40% transform into diffuse large B Typically localized, Spread in cell lymphoma. Clinical Course Fatal if untreated. stepwise fashion to anatomically - the things we worry about the most is contiguous nodes. the transformation of follicular lymphoma into high grade lymphoma. Median Age Adults > 50 years. Median age: 60 years. Rs cell (It’s binucleated with 2 nucleoli)