Leukocyte Disorders and Immune Response

Leukocyte Disorders

• Categorized as either quantitative or qualitative.
• Quantitative disorders result from decreased bone marrow production.
• Qualitative disorders involve disrupted cell function.

Leukocytosis

• Leukocyte count is higher than normal.
• Normal protective response to stressors like infection, exercise, emotional changes, temperature changes, anesthesia, pregnancy, drugs, hormones, and toxins.

Neutrophilia

• Describes granulocytosis.
• Neutrophils are the most numerous granulocytes.

Cranial Psychosis

• Increase in granulocytes released from bone marrow.

Shift to the Left (Leftward Shift)

• Demand for mature neutrophils exceeds supply.
• Bone marrow releases immature neutrophils.
• Increases immature leukocytes number in blood.

Eosinophilia

• Absolute increase in circulating eosinophils.
• Associated with allergic disorders like asthma, hay fever, and drug reactions, also parasitic infections.

Monocytosis

• Increase in circulating monocytes number.
• Commonly linked to bacterial infection.

Lymphocytosis

• Occurs most commonly in acute viral infections.

Infectious Mononucleosis (IM)

• Benign, acute, self-limiting lymphoproliferative clinical syndrome.
• Caused by acute viral infection of B lymphocytes.
• Caused by EBV, a type of herpes virus.
• EBV transmitted usually by saliva through personal contact (kissing disease).

Leukemia

• Disorder of leukocytes in bone marrow, and usually blood.
• Uncontrolled proliferation of malignant leukocytes.
• Decreased production and function of normal hematopoietic cells.
• Acute leukemia: undifferentiated or immature cells, abrupt and rapid onset, short survival time.
• Chronic leukemia: more differentiated cells, not functioning normally, relatively slow progression.
• Acute leukemias: acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML).
• ALL: aggressive, fast-growing leukemia with too many lymphoblasts.
• AML: aggressive, fast-growing leukemia with excessive myeloblasts in bone marrow and blood.
• Chronic leukemias: chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL).
• CLL: slow-growing cancer with too many immature lymphocytes, mainly in bone and bone marrow.
• Leukemia reappearance statistically significant in families.
• Increased risk in adults with exposure to cigarette smoke, benzene, and ionizing radiation.

Lymphoma

• Lymphadenopathy: increase in size and number of lymph node germinal centers.
• Large neck nodes are characterized by being palpable and often tender.
• Localized lymphadenopathy: drainage of area with inflammation, or infection.
• Generalized lymphadenopathy: result of malignant or non-malignant disease.
• Lymphomas develop from proliferation of malignant lymphocytes in lymphoid system.
• Hodgkin and non-Hodgkin lymphoma occur in children and adults.
• Hodgkin lymphoma: derived from B cell in germinal center that has not undergone successful immune immunoglobulin gene rearrangement.
• Hodgkin lymphoma clinical manifestations: fever, weight loss, night sweats, pruritus, fatigue, large, painless neck.
• Non-Hodgkin's lymphoma manifestations: progressive clonal expansion of B-cells, T cells, and natural killer cells.
• Non-Hodgkin's lymphomas most likely caused by mutations in cellular genes, possibly environmentally induced.
• Burkitt lymphoma: aggressive B-cell non-Hodgkin lymphoma (30% of childhood lymphomas worldwide).
• EBV associated with almost all cases.
• Lymphoblastic lymphoma: rare variant of non-Hodgkin lymphoma (2-4% incidence).

Multiple Myeloma

• Biologically complex disease with wide range of genetic alterations and individual differences in responses.
• Has poor prognosis.
• Median survival is three years.
• Untreated individuals with multiple bone lesions rarely survive more than 6 to 12 months.

Splenic Function

• Splenomegaly seen in 7-15% of individuals.
• Overactive spleen results in hematologic alterations.
• Overactive spleen causes a reduction in circulating blood cells.
• Spleen can sequester up to 50% of red blood cell population, potentially creating anemia.