Benign Disorders of WBCs PDF

Benign Disorders of WBCs Leukopenia: Decrease in # of WBCs • Types: o Neutropenia o Lymphocytopenia Neutropenia: Decrease in circulating neutrophils • Mild (1000-1500/mm) • Mod (500-1000/mm) • Severe (<500mm): risk of serious infection increases as absolute neutrophil count (ANC) drops severely • Ag...

Benign Disorders of WBCs Leukopenia: Decrease in # of WBCs • Types: o Neutropenia o Lymphocytopenia Neutropenia: Decrease in circulating neutrophils • Mild (1000-1500/mm) • Mod (500-1000/mm) • Severe (<500mm): risk of serious infection increases as absolute neutrophil count (ANC) drops severely • Agranulocytosis: ANC <100 Absence of neutrophils in peripheral blood • Granulocytopenia: Reduced number of blood granulocytes (neutrophils, eosinophils, basophils) • Etiology: o Reduced production o Increased destruction o Increased peripheral utilization o Congenital • Treatment o Antibiotics o Colony stimulating factor o Granulocyte transfusion o Splenectomy for Felty Syndrome (combination of rheumatoid arthritis, splenomegaly, and neutropenia) and neutropenia w recurrent bacteria infection, systemic lupus w autoimmune agranulocytosis Chediak-Higashi Syndrome: • Autosomal recessive Lysosomal storage disorder • Signs: o Recurrent bacterial infections o Abnormal NK function o Hypopigmentation of skin, eyes, hair • Pathogenesis: o Mutation of LYST/CHS1 o Defective lysosome functions o Delayed fusion of phagosomes with lysosomes o Decreased cytotoxicity of NK cell and T cell • Clinical Features: o Nonpigmented/hypopigmented skin o Gingivitis • Lab Findings: o Reduced/absent NK cytotoxicity o Larger and irregular lysosomes Autoimmune Neutropenia • Most common in children • Occurs due to neutrophil antibodies include IgG against: o CD 16b (most common) o HNA1 (most common) o HNA4 (less common) Shwachman-Diamond Syndrome • Autosomal recessive • Associated with mutations in the SBDS gene • Characterized by: o Exocrine pancreatic insufficiency o Bone marrow dysfunction (defect in bone marrow stroma and stem cell) o Skeletal abnormalities Leukocytosis • Increase in WBC • Reaction to physiological or pathological process • Left shift: Release of stored leukocytes and increase in immature leukocytes in circulation • Leukemoid rxn: o á immature cells, particularly more myelocytes than in left shift o á leukocyte alkaline phosphatase score than leukemia • Leucoerythroblastic rxn: leukemoid rxn + nucleated red blood cells à common in myelofibrosis • Diagnosis is confirmed via blood smear: o Myeloid o Increased blasts o Lymphocytosis Neutrophils • Made in bone marrow • Immobilize or kill pathogens through releasing neutrophil extracellular traps (NETs) • Neutrophilia: Higher than normal # of neutrophils o Shift neutrophilia: Shift of marginal to circulating, NO left shift o True Neutrophilia: left shift present o NO leukocytosis in certain infections, such as typhoid fever, paratyphoid fever, mumps, measles and TB o Drugs: Cortical steroid Eosinophils: • Participates in: o Antiparasitic and bactericidal activity o Immediate allergic reactions • Eosinophilia: o Parasite infections o Allergic reactions o Neoplasms Basophils: • Irregular bilobed nuclei • Contain histamines (vasodilation) and heparin (anticoagulant) • Basophilia: o Occasionally seen in allergic reactions o Most commonly associated with neoplastic disorders especially myelogenous leukemia Monocytes: • Kidney or C-shaped nuclei • Migrate to tissueà transformed into macrophages • Monocyte-macrophage system (single functional unit) consisting of: o Kupffer cells in liver o Microglia in CNS o Osteoclasts in bone • Increased in infections, autoimmune disorders, and neoplasms • Reduced in marrow failure, AIDS and hairy cell leukemia • Monocytosis: Associated with neoplastic lesions especially myeloproliferative disorders Lymphocytes: • T cells, B cells or NK cells • B cells: from bone marrow (responsible for humoral immunity) • T cells: from bone marrow but mature in thymus (responsible for cell-mediated immunity) • Lymphocytosis: Absolute count gets high o Reactive: Polyclonal o Clonal: Monoclonal B cell lymphocytosis Morphological Abnormality of White Cells Toxic Granulation: Seen in severe infection/inflammatory states Dohle Bodies: Remnants of Rough ER Hypersegmentation: Defined as increased lobes: 3 cells have 5 lobes or a single cell with 6 lobes Benign Disorders of Lymph Nodes Acute Lymphadenitis • Most commonly due to S. aureus infection • Also associated with cat-scratch disease, IV drug use • Usually superficial lymph nodes o Enlarged lymph nodes that are soft and tender o Overlying skin red and edematous o Histologically granulocytes are seen Chronic Lymphadenitis • Painless enlargement of lymph nodes • Tingible-body macrophages commonly present • Diagnosis: Flow cytometry to rule out monoclonal lymphocytic proliferation Splenomegaly: • Hyperfunction of spleen • Etiology: o RBC destruction: Hereditary spherocytosis, thalassemia o Ectopic hematopoiesis: Myeloproliferative neoplasm, etc • Clinical Features: o Nucleated red cells o Teardrop red cell shape Hyposplenism: Reduced spleen • Due to congenital abnormalities • Peripheral blood abnormalities o Howell-Jolly bodies o Pappenheimer bodies o Target cells Acute is painful Chronic is painless