WBC Disorders and Syphilis Serology

• an enzyme that breaks down sphingomyelin in phagocytes

• deficiency leads to Type A or B Niemann-Pick Disease

What is sphingomyelinase?

• a small area of inflammation that forms in response to infection

• created due to the immune system trying to isolate a foreign substance

What is a granuloma?

a genetic disease caused when a person acquires two copies of an abnormal gene (one from each parent)

What is an autosomal recessive disorder?

• condition where neutrophils are unable to reach the site of infection

• phagocytosis and bactericidal activity are normal, but motility and chemotaxis are defective

• patients suffer from repeated bacterial infections

• probably due to mutations in the cell’s actomycin system (used for cell motility)

What is lazy leukocyte syndrome?

• a rare, congenital autosomal disease

• causes altered granules in neutrophils

  • giant, azurophilic, and ineffective

• chemotaxis is impaired

  • results in delays in killing bacteria

• frequent skin infections, photosensitivity, and hypopigmentation

• fatal by age 7

What is Chediak-Higashi Syndrome?

• a hereditary disease (congenital)

  • autosomal and X linked (X linked is more common and severe)

• where phagocytes cannot produce superoxide, so no “oxidative bursts”

  • enzymes are unable to produce hydrogen peroxide for bursts

• results in recurrent catalase positive bacterial infections and fungal infections

• life threatening, patients live into their 40s

What is Chronic Granulomatous Disease (CGD)?

• rare autosomal recessive trait (congenital)

• adhesion deficiency of neutrophils

  • aggregation of neutrophils is decreased

  • results in decreased phagocytosis of opsonized organisms

• affects T cells

• causes: bacterial infections (skin, musoca, and gums), neutropenia, and decreased inflammatory response

What is Complement C3 Receptor Deficiency?

• can be inherited or acquired (congenital)

• most common phagocytic disorder

• granules are present in the cell, but MP is decreased or absent

  • MP is responsible for peroxidase activity within the cell

• defects in bacterial and fungal killing

• most patients are asymptomatic, but some may have increased Candida infections

What is myeloperoxidase deficiency (MP)?

• a rare autosomal recessive disorder (congenital)

• neutrophils are unable to synthesize specific granules during WBC differentiation in the bone marrow

• causes decreased inflammatory responses

• results in severe and chronic cutaneous infections (ulcers and abscesses) and recurrent lung infections (pneumonia)

What is Specific Granule Deficiency?

• a rare genetic disorder of monocytes and macrophages

• alpha-glucocerebrosidase deficiency

  • an enzyme that splits glucose from glucosylceramide in cells

  • causes an accumulation of cerebroside

• found in bone marrow but NOT in peripheral blood smears

  • cells are large, have 1-3 eccentric nuclei, and wrinkled cytoplasm

• types:

  • type 1: most organs are involved, but not the brain

  • type 2: brain involved

• some patients can live a possibly normal life while others have premature deaths

What is Gaucher Disease?

• a group of monocyte and macrophage diseases

• 3 types:

  • type A and B:

    • sphingomyelin accumulates in cells deficient in the enzyme sphingomyelinase, affecting the function of the involved organ

    • common in Eastern European and Jewish populations

  • type C:

    • inability to metabolize cholesterol, causes accumulation in the liver and spleen

    • common in Puerto Ricans and Spanish populations

• PBS shows pick cells, cells that have foamy-looking cytoplasm

What is Niemann-Pick Disease?

• a technique used to decrease the concentration of a solution in a sequence of dilutions with a constant dilution factor

• used in immunology to determine the titer of antigens or antibodies in a sample

What is serial dilution?

Treponema pallidum

What is the bacteria that causes syphilis?

• stands for T. pallidum Particle Agglutination

• it is a confirmatory test used to diagnose syphilis

• uses indirect/passive agglutination

  • the antigen used is gelatin particles sensitized with T. pallidum

  • the antibody we look for in patient serum is Anti-T. pallidum

What is TP-PA?

• stands for Rapid Plasma Reagin

• a test that screens for nonspecific reagin (antibodies produced in syphilis) in patient plasma

• indirect/passive agglutination test

  • charcoal particles are coated with antigen

• false positives are possible

What is an RPR test?

• Venereal Disease Research Lab test

• an indirect/passive test that screens for nonspecific reagin antibodies in patient sample

• procedure:

  • sample (either serum or CSF) is heated for 30 minutes to inactivate complements

  • reagin in patient sample combines with latex particles coated in cardiolipin antigens

  • flocculation is observed

• a positive result on CSF is diagnostic for neurosyphilis

What is a VDRL test?

• Fluorescent Treponemal Antibody Absorption test

• a confirmatory test for late neurosyphilis when patients have symptoms and a negative RPR test

• procedure:

  • whole treponemes are fixed to a slide

  • patient serum is mixed with non-T. pallidum antigen (to reduce cross reactivity) and added to the slide

  • fluoroscein-conjugated antihuman antibody is added

What is an FTA-AB test?

• T pallidum (variant)

• T. pertenue

• T. carateum

What are the three other species of T. pallidum?

• direct contact with skin or oral lesions

• sexually

• sharing a bed with an infected person

• through the placenta in pregnancy

How is syphilis transmitted?

• enters through the mucous membranes or broken skin

• spreads to every organ

• incubation period is 3 weeks

How does T. pallidum enter the body?

• Primary

  • painless chancre sore develops at entry site, highly contagious

  • diagnosed with darkfield microscopy

• Secondary

  • rashes and lesions 2-8 weeks after sores, highly contagious

  • NS abnormalities develop: meningitis, then neurosyphilis

  • diagnosed via RPR, VDRL, or TP-PA

• Latent

  • asymptomatic, relapse into secondary stage can happen

  • congenital transfer is the main route of transmission

  • typically not diagnosed at this stage

• Tertiary

  • granulomas (mass of immune cells) form, CV system and CNS become involved

  • diagnosed with CSF using the VDRL test

What are the 4 stages of syphilis?

• antitreponemal

  • antibodies the immune system produces specific to T. pallidum

• nontreponemal

  • antibodies produced in response to syphilis, but not specific to T. pallidum

  • also known as reagin antibodies: always produced in syphilis (may also be produced in other diseases too)

What is the difference between antitreponemal antibodies and nontreponemal antibodies?

• darkfield microscopy

• direct and indirect fluorescent antibody tests

• RPR test

• VDRL test

• TP-PA test

• DNA probes

  • harvested molecular material from the patient sample is matched to treponemal DNA

• ELISA

  • looks for anti-treponemal IgG antibodies in patient sample that have crossed the placenta to newborn

• FTA-AB test

What are the 8 ways to diagnose/screen for syphilis?

• nonreactive

  • patient does not have the disease, or the infection is in the early stages, could be wrong technique by tech or alcohol consumpton

• weakly reactive

  • can be caused by inferior technique by tech, early stage in infection, or biologic false positives

• reactive

  • patient has disease, or could be a biological false positive or inferior technique by tech

How are syphilis test results interpreted?

• a reaction that is due to the presence of an antibody not specific to the antigen in the test

• caused by another living organism or disease

  • like lupus, rheumatoid arthritis, hepatitis, etc.

• can be seen in RPR and VDRL tests, but NOT TP-PA

What are biological false positives?