Presentation on theme: "Immuno-Mycologics, Inc."— Presentation transcript:
1Immuno-Mycologics, Inc. Serodiagnosis of MycosesSean K. Bauman, Ph.D.V.P. OperationsImmuno-Mycologics, Inc.
2Outline Why use serology? Mechanisms of different tests Serology of specific mycoses
3Why Use Serology For Case Finding? Antigens and antibodies are easier to detectthan finding the organism directly.Antibodies are produced in large quantitiesand circulate in the blood even though they arenot usually protective against mycotic agents.Soluble antigens frequently enter thecirculation of the host and are sometimesexcreted in the urine. They are produced indiscrete infected lesions.Culture is relatively Insensitive due to the lowconcentration of the agents in tissues. Multiplecultures are usually required.
15Qualitative vs Quantitative Immunodiffusion AgCSPt1243Screening TestQUALitativeUndil.1:21:81:4AgCSPatient 1QUANTitativeUndil.1:21:81:4AgCSPatient 3QUANTitativePositive Undiluted1:4Identity & Partial Identity bands are considered POSITIVE
16Complement Fixation Serum without antibodies Serum with Antigen binds to antibodiesUnboundantigenDay 1Complementbinds to Ag/AbcomplexUnboundcomplementHemolysin sensitizedred blood cellsserve as an indicatorDay 2No lysisPositiveLysisNegative
29Aspergillosis The Organism Primary etiologic agents A. fumigatus A. flavusA. nigerA. terreusAspergillus spp. have a global distribution
30Aspergillosis The Disease Infection initiates by inhalation of Aspergillus sporesA. niger fruiting bodyin a lung cavity(Aspergilloma)Forms of the DiseaseAllergic Bronchopulmonary Aspergillosis (ABPA)Pulmonary Aspergilloma (fungus ball)Invasive Aspergillosis (IA) (usually immunocompromised)
33Blastomycosis The Organism Etiologic agent: Blastomyces dermatitidis B. dermatitidis is endemic to theOhio and Mississippi river valleysl
34Blastomycosis The Disease Infection initiates by inhalation of the organism
35Blastomycosis Antibody Test DiagnosisImmunodiffusion‘A’ antigen (a.k.a. WI-1)120-kDa glycoprotein25-amino acid tandem repeat is immunodominant epitopePrecipitin band indicates current/recent B. dermatitidis infectionSensitivity 100%Specificity 100%J. Med. Vet. Mycol. (1995) 33:123Complement FixationSensitivity 40%Specificity 100%J. Clin. Micro. (1986) 23:294
36Candidiasis The Organism Primary etiologic agent: Candida albicans C. albicans is part of the normal human flora~80% have positive DTH reactions toCandida antigens by 1 year of age
37Candidiasis The Disease Immunocompromised states susceptible to CandidiasisNeutropeniaCorticosteroidsDiabetes mellitusHIV infectionCancerOropharyngeal (thrush)Antibiotic therapySystemic/InvasiveInfection types:Vaginal
38Candidiasis Antibody Test DiagnosisImmunodiffusion 1 band indicates current/recent infectionSystemic candidiasis should be suspected whenNumber of precipitins increases on serial specimens-or-Seroconversion (i.e. negative patient becomes positive)Sensitivity 80% in immunocompetent individuals* Manual of Clinical Laboratory Immunology, 6th EditionSensitivity is less in immunodeficient individuals
43Coccidioidomycosis Antibody Test DiagnosisImmunodiffusionIDTP120-kDa glycoprotein (BGL2)3-O-methylmannose (3-O-MM) is immunodominant epitopeHeat stable antigen (60°C, 30 min)Predominantly IgM reactivity in early primary casesIDCF47-kDa chitinase enzymeHeat labile antigenPredominately IgG reactivityClosest to the antigen wellSensitivity 100%Specificity 100%J. Clin. Micro. (1995) 33:618
44Cryptococcus neoformans CryptococcosisThe OrganismEtiologic agent:Cryptococcus neoformansC. neoformans is encapsulated yeast with aglobal distribution often found in soil andbird droppings
45Clinical microbiology made by M. Gladwin and B. Trattler CryptococcosisThe DiseaseImmunocompromised (e.g. AIDS) are most susceptiblePigeonMeningitisCryptococcusneoformansAIDSAdapted fromClinical microbiology maderidiculously simpleby M. Gladwin and B. Trattler
47Histoplasmosis The Organism H. capsulatum is endemic to the Etiologic agent:Histoplasma capsulatumH. capsulatum is endemic to theOhio and Mississippi river valleys
48Histoplasmosis The Disease Infection initiates by inhalation of the organismIntracellular proliferation
49Histoplasmosis Antibody Test DiagnosisImmunodiffusionM Antigen81-kDa glycoprotein (catalase)M precipitins first to appear in acute diseaseClosest to the antigen wellH Antigen93-kDa glycoprotein (b-glucosidase)H precipitins occur later in infection(likely extrapulmonary dissemination)Closest to the serum wellSensitivity 90%Specificity 94%J. Clin. Micro. (1976) 2:77
52Paracoccidioidomycosis The OrganismP. brasiliensis is endemic toMexicoCentral AmericaSouth AmericaDoctorfungus Corporation?Etiologic agent:Paracoccidioides brasiliensis
53Paracoccidioidomycosis The DiseaseInfection initiates by inhalationof the organismUlcerative lesions are commonDoctorfungus Corporation
54Paracoccidioidomycosis Antibody Test DiagnosisImmunodiffusionUp to 3 precipitin bands are observedgp43 Antigen43-kDa glycoproteingp43 is the immunodominant antigen (closest to Ag well)(a.k.a. E2 or A)Most prevalent and longest lasting of the major precipitinsSensitivity = >90%* Manual of Clinical Laboratory Immunology, 6th Edition
55Why Use Serology For Case Finding? Antigens and antibodies are easier to detectthan finding the organism directly.Antibodies are produced in large quantitiesand circulate in the blood even though they arenot usually protective against mycotic agents.Soluble antigens frequently enter thecirculation of the host and are sometimesexcreted in the urine. They are produced indiscrete infected lesions.Culture is relatively Insensitive due to the lowconcentration of the agents in tissues. Multiplecultures are usually required.
56The Fungal Diagnostic Specialists Do one thing, do it well!