Questions & Answers
HIV EIA (3rd generation immunoassay) - ANSWER: Can use urine, saliva, or serum (most
accurate). Need to wait 12 weeks post-exposure to detect antibodies. >99% accurate.
4th generation immunoassay - ANSWER: "Gold standard"; detects both antibodies and
p24 antigen, can test 10 days post-exposure.
Mast cell - ANSWER: Cellular bags of granules in loose connective tissue near blood
vessels; activation initiates inflammation.
Histamine - ANSWER: Causes vasodilation, increases vascular permeability and blood flow
to injury site causing erythema and swelling.
Cytokines - ANSWER: Soluble factors regulating innate or adaptive immunity; can be pro-
or anti-inflammatory; act quickly or delayed.
Leukotrienes - ANSWER: Released during mast cell degranulation; prolong inflammation,
cause vasodilation, and attract neutrophils and monocytes.
Prostaglandins - ANSWER: Produced in arachidonic acid pathway during mast cell
degranulation; cause vasodilation, platelet aggregation, pain, fever.
Chemotactic factors - ANSWER: Chemicals attracting leukocytes to inflammation sites.
Neutrophils - ANSWER: Main leukocyte in early acute inflammation.
Monocytes - ANSWER: Circulate in blood, mature into macrophages in tissue; present
antigens to CD4 T cells and release cytokines IL-1, IL-6, TNF.
IL-1 function - ANSWER: Induces fever, activates phagocytes and lymphocytes, promotes
IL-6 release.
IL-6 function - ANSWER: Stimulates acute phase reactants, promotes RBC growth.
Causes of thrombocytopenia - ANSWER: Post-op hemodilution, splenomegaly, HIV
infection, bone marrow failure, hemolysis, multiple medications.
,Primary Immune Thrombocytopenic Purpura (ITP) - ANSWER: Autoimmune platelet
destruction; symptoms include petechiae, purpura, easy bruising, epistaxis, gingival
bleeding.
Heparin-induced thrombocytopenia (HIT) - ANSWER: Immune platelet destruction
triggered by heparin; Type 1 mild and transient, Type 2 severe with platelet drop 5-10 days
post heparin.
Hemophilia A - ANSWER: X-linked recessive; factor VIII deficiency; symptoms include joint
and GI bleeding; prolonged PTT.
Hemophilia B - ANSWER: X-linked recessive; factor IX deficiency; symptoms similar to
Hemophilia A; also called Christmas disease.
Disseminated Intravascular Coagulation (DIC) - ANSWER: Systemic coagulation
activation causing microthrombi and bleeding; triggers include sepsis, malignancy; labs
show prolonged PT/PTT, elevated D-dimer.
Complement system - ANSWER: Group of plasma proteins that opsonize pathogens,
promote inflammation, and form membrane attack complex.
Acute phase reactants - ANSWER: Proteins such as CRP, fibrinogen, and serum amyloid A
produced by liver during inflammation stimulated by IL-6.
Macrophage function - ANSWER: Phagocytosis, antigen presentation, cytokine secretion
initiating adaptive immunity.
T-lymphocytes (T cells) - ANSWER: Critical in cell-mediated immunity; differentiate into
CD4+ helper and CD8+ cytotoxic cells.
CD4+ T cells - ANSWER: Helper T cells that activate B cells, cytotoxic T cells, and
macrophages.
CD8+ T cells - ANSWER: Cytotoxic T cells that kill virus-infected and tumor cells.
B-lymphocytes (B cells) - ANSWER: Produce antibodies in adaptive humoral immunity.
Antigen-presenting cells (APCs) - ANSWER: Cells like macrophages and dendritic cells
that process and present antigens to T cells.
Humoral immunity - ANSWER: Immunity mediated by antibodies produced by B cells.
, Cell-mediated immunity - ANSWER: Immunity mediated by T cells directly acting on
infected or abnormal cells.
P24 antigen in HIV - ANSWER: Viral core protein detectable early in infection, before
antibodies develop.
Window period in HIV testing - ANSWER: Time between HIV infection and detectable
antibody or antigen levels; shorter with 4th gen tests.
Acute HIV syndrome symptoms - ANSWER: Fever, rash, lymphadenopathy, sore throat,
myalgia occurring 2-4 weeks post-infection.
Chronic HIV infection - ANSWER: Asymptomatic phase lasting years, gradual CD4 decline.
AIDS-defining illness - ANSWER: Opportunistic infections and cancers occurring with CD4
<200 cells/mm³.
Pneumocystis jiroveci pneumonia (PCP) - ANSWER: Common opportunistic infection in
AIDS causing pneumonia.
Mycobacterium avium complex (MAC) - ANSWER: Opportunistic bacterial infection in
AIDS affecting multiple organs.
Cytomegalovirus (CMV) - ANSWER: Opportunistic viral infection causing retinitis and
colitis in AIDS.
CD4 count significance - ANSWER: Indicator of immune function and HIV disease
progression.
Viral load in HIV - ANSWER: Measurement of HIV RNA to assess infection activity.
Antiretroviral therapy (ART) - ANSWER: Combination drugs that inhibit HIV replication;
reduces morbidity and mortality.
Classes of ART drugs - ANSWER: NRTIs, NNRTIs, PIs, integrase inhibitors, fusion inhibitors,
CCR5 antagonists.
HAART - ANSWER: Highly active antiretroviral therapy; multi-drug regimen.
Immune reconstitution inflammatory syndrome (IRIS) - ANSWER: Paradoxical worsening
of infections after starting ART due to immune recovery.