SEROLOGY (PT4) (page 10-14)

hepatitis a (infectious hepatitis)

• may be transmitted by clotting factor concentrates

hepatitis b (serum hepatitis)

• dane particle: complete hbv that causes infection

• hbeag: infective

• hbeab: recovery

hepatitis c (nonA-nonB hepatitis)

• aka post transfusion hepatitis

• surrogate tests for hcv: inc. alt, (+) antig hbc

• specific tests for hcv: (+) anti hcv

hepatitis d

• requires hbd infection

• coinfection: simultaneously

• superinfectionL sequentially

hepatitis e

• associated with fulminant liver failure in pregnant women

human immunodeficiency virus

• retrovirus containing rna and reverse transcriptase

• target helper cd4 t cells

• hiv 1 utilizes 2 major co-receptor along with cd4 to bind and enter target cells

r5 strains

• ccr5 as their co-receptor (expressed on monocytes, t cells)

x4 strains

• use cxcr4 as their co-receptors (expressed on t cells)

r5×4 strains

• use both ccr5 and cxcr4 as their co-receptors

antibody to p24

• is the first to appear during infection (hiv)

seroconversion

• is the change of a serological test from negative to positive as a result of developing the measurable antibodies in response to infection or immunization

first generation elisa

• solid phase indirect - assay using viral lysate antigens from hiv 1

• detects antibodies to hiv 1only

second generation elisa

• indirect binding assay using highly purified recombinant or synthetic antigens from both hiv 1 and hiv 2

• detects antibodies to hiv 1 and hiv 2

third generation elisa

• sandwich technique

• detects hiv antibodies of diffrent ig classes, including igm

fourth generation elisa

• detcts hiv 1 antibodies, hiv 2 antibodies, and p24 antigens

p55

• precursor protein which forms core proteins

reverse transcriptase (p66, p51)

• transcribes rna to dna (hiv)

integrase (p31)

• inserts viral dna to host dna (hiv)

protease (p10)

• cleaves protein precursors (hiv)

g110

• cleaved to form gp120 and gp41 (hiv)

g120

• binds to cd4 on t cells (hiv)

gp41

• transmembrane protein (hiv)

cytomegalovirus

• most important infectious agent associated with organ transplantation with infectious resulting from reactivation of cmv in the recipient or transmission of cmv from the donor organ

• most common cause of congenital infections

• identification of cmv or cmv dna in amniotic fluid after the 20th week of gestation is considered the gold standard for confirmation of fetal infection

• transmission: close, prolonged contact with infectious body secretions; intimate sexual contact; blood transfusions; solid organ transplants; perinatal exposure from infected mother to infant

infectious mononucleosis

• is a self-limiting disease caused by epstein barr virus

• the disease may be confused with diptheria, pharyngytis, vincent’s angina, lymphadenitis, scarlet fever, hepatitis, or pertussis

• classic symptoms: fever, lymphadenopathy, sore throat

• transmitted via saliva, blood transfusion, transplacental routes, and possible by mosquitos

• infects b cells, the variant lymphocytes produced in response to infection have t cell characteristics

• infection from blood transfusion is known as im post perfusion syndrome

• assoc with: burkitt’s lymphoma, nasopharyngeal carcinoma

• initial infection occurs in the orpharynx

• can integrate its dna into the genome of the cells it infects and transform them into cancer cells

• enlarged lymphocytes with atypical nuclei (downey cells) are characteristic

heterophile antibody

• cross react with any member of a group of similar antigens that can be found in unrelated animals or microorganisms

• igm that usually appears during acute phase of infectious mononucleosis

• reacts with horse, ox, sheep rbcs

• absorbed by beef erythrocytes but not absorbed by guinea pig kidney cells

• does not react with ebv specific antigens

paul-bunnell screening test

• hemagglutination test designed to detect heterophile antibodies in patient serum when mixed with antigen-bearing sheep rbcs

• useful screening test but cannot determine specificity

• heterophile antibody titer is reported as the reciprocal of the highest dilution showing agglutination

• normal titer: <= 56

davidsohn differential test

• distinguishes between heterophile antibodies associated with infectious mononucleosis, serum sickness, or forssman antigen

• absorption with guinea pig kidney and beef rbc > agglutination with sheep rbcs

monospot test/rapid differential slide test

• also differentiate but require absorption of the patient’s serum

• horse rbcs are agglutinated by heterophile antibodies of infectious mononucleosis

igm anti vca

• detectable early in the coarse of infection

igg anti vca

• detected after onset of signs and symptoms

• can present for life

igg anti ea d

• strongly indicates active infection

• rise in titer during reactivation of latent infection

• not consistent indicator of disease

igg anti ea r

• found in the serum of very young children but not in young adults during acute stage

ebna

• found in the nucleus of all ebv infected cells

• does not stimulate antibody until after incubation period of im

anti ebna

• appears during convalescence (ebv)