Transcript IMMUNITY MEDIATED BY B LYMPHOCYTES AND ANTIBODIES

FAILURE OF HUMAN
DEFENSE MECHANISMS
FAILURE OF HUMAN DEFENSE
MECHANISMS
* Mechanisms of Failure
* Evasion and subversion of the immune system
by pathogens
* Immunodeficiencies
* Inherited (Primary)
* Acquired (Secondary)
*
*
*
*
Malnutrition
Drugs
Radiation
Pathogens
MECHANISMS OF EVASION AND
SUBVERSION BY PATHOGENS
* Genetic variation (antigenic differences)
* Numerous different surface antigens (serotypes /
serovars) without modification
* Streptococcus pneumoniae
* 90 serotypes (capsular polysaccharides)
* Salmonella species
* 2,500 serotypes (cell wall polysaccharides)
* Rhinoviruses
* 100 serotypes (capsid proteins)
* Poliovirus
* 3 serotypes (capsid proteins)
MECHANISMS OF EVASION AND
SUBVERSION BY PATHOGENS
* Genetic variation (antigenic differences)
* Few different surface antigens with frequent modification
* Influenza viruses
* Classification into “types” on nucleoprotein
* A, B and C
* Classification of Influenza A virus into “subtypes
* Hemagglutinin (HA or H)
* Avian (16) and Human (3)
* Neuramindase (NA or N)
* Avian (9) and Human (2)
* Influenza A subtypes (H3N2, H1N1, H5N1)
MECHANISMS OF GENETIC
CHANGE IN INFLUENZA A VIRUS
* Antigenic Drift
* Point mutations in HA and NA genes
* No proofreading of replication
* Minor antigenic change resulting in new “strains”
* Antigenic Shift
* Re-assortment of gene segments from avian and human viruses in
same host (swine or humans)
* Major antigenic change resulting in new “subtype” of Influenza A
virus
MECHANISMS OF EVASION AND
SUBVERSION BY PATHOGENS
* Establishment of a dormant state (latency) with
reactivation
* Blocking of antigen processing and presentation
*
*
*
*
*
*
MHC I degradation
Interference with proteasome
Interference with TAP
Interference with Tapasin
Retention of MHC 1 in ER
Interference with NKG2A receptor
* Inhibition of humoral immunity
MECHANISMS OF EVASION AND
SUBVERSION BY PATHOGENS
* Characteristic of the Herpesviruses
*
*
*
*
*
*
*
*
Herpes simplex virus, type 1 (HSV-1)
Herpes simplex virus, type 2 (HSV-2)
Varicella-Zoster virus (VZV)
Epstein-Barr virus (EBV)
Cytomegalovirus (CMV)
Human herpesvirus 6 (HHV-6)
Human herpesvirus 7 (HHV-7)
Human herpesvirus 8 (HHV-8)
HUMAN HERPES VIRUS 8 (HHV-8)
* One of seven oncogenic viruses
* History of stealing human genes
* IL-6, BCL-2, cyclin D
* Etiologic agent
* Kaposi’s sarcoma
* Multicentric Castleman’s Disease
* Non-malignant tumor in lymph nodes
* Hyperproliferation of B cells
HUMAN HERPES VIRUS 8 (HHV-8)
* Target cell for latency
* B lymphocyte
* Mechanism of latency (genes and proteins)
* Cyclin D
* LANA (latency associated nuclear antigen)
* K 13
* Blocks Fas apotosis pathway
* Target cell for Kaposi’s sarcoma
* Spindle cell
MECHANISMS OF SUBVERSION OF
THE IMMUNE SYSTEM
* Production of exotoxins (superantigens)
* Staphylococcus aureus
* Streptococcus pyogenes
* Staphylococcus aureus superantigens
* Toxic shock syndrome toxin-1 (TSST-1)
* 75% of cases (99% M and 40% NM)
* Staphylococcal enterotoxin B (SEB)
* 20% of cases
* Staphylococcal enterotoxin C (SEC)
MECHANISMS OF SUBVERSION OF
THE IMMUNE SYSTEM
* Streptococcus pyogenes superantigens
* Streptococcus pyrogenic exotoxins A, B and C
* Exotoxins produced primarily from M types
* 1 and 3
* Mechanism of action
* Activation of 5 to 30% of T cells
* Cytokine storm
TOXIC SHOCK SYNDROME (TSS)
* Staphylococcal TSS
* First reported in 1978 followed by outbreak in 1980
* Clinical manifestations (acute onset)
* Fever (>102 F), chills, headache
* Hypotension (<90 mmHg)
* Diffuse macular erythroderma rash
* Myalgias
* Nausea, vomiting and diarrhea
* Cutaneous desquamation (palms and soles)
IMMUNODEFICIENCY DISEASES
* A group of diseases where one or more
components of the immune system are either
absent or defective
* Classification
* Primary (Inherited)
* Gene defects may be autosomal or X-linked
* Secondary (Acquired)
* Malnutrition, diseases, drugs, radiation, microorganisms
COMPONENTS OF THE IMMUNE SYSTEM
AND CLINICAL PRESENTATION IN
IMMUNODEFICIENCY DISEASES
* Humoral
* Persons with history of recurrent infections with
encapsulated bacteria
* Streptococcus pneumoniae
* Haemophilus influenzae
* Cellular (Cell mediated)
* Persons with history of recurrent infections with
opportunistic pathogens
* Pneumocystis jiroveci (carinii)
EVALUATION OF PATIENTS WITH
IMMUNODEFICIENCY DISEASES
* Humoral
* Measure antibody levels by nephelometry
* IgM
* IgG + subclasses
* IgA + subclasses
* Measure absolute number and percent of B cells by
flow cytometry
* Cellular
* Measure absolute numbers and percentages of T
lymphocytes by flow cytometry
PRIMARY IMMUNODEFICIENCY
DISEASES
* WHO currently recognizes 100 primary
immunodeficiency diseases
* < 20 account for >90% of all cases
* General Classification
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*
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Primarily humoral deficiency
Primarily cellular deficiency
Combined humoral and cellular deficiency
Phagocyte dysfunction or deficiency
Complement deficiency
MHC deficiency
PRIMARY IMMUNODEFICIENCY
DISEASES
* Prevalence of primary immunodeficiency diseases
*
*
*
*
*
*
B cell
T cell
B and T cells
Phagocytes
Complement
NK
(50 to 60%)
(5 to 10%)
(20%)
(10 to 15%)
(2%)
(< 0.1%)
PRIMARY IMMUNODEFICIENCY
DISEASES
* Most common primary immunodeficiency
diseases
* B cell
* T cell
*
*
*
*
B and T cells
Phagocytes
Complement
NK
Selective IgA deficiency
DiGeorge syndrome
ZAP-70 deficiency
SCID
Chronic granulomatous disease
Immune complex disease
Viral infections and tumors
PRIMARY IMMUNODEFICIENCY
DISEASES
* Gene defects
* Autosomal recessive or dominant
* X-linked
* Examples
*
*
*
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CVID (autosomal dominant)
Selective IgA (autosomal dominant)
Hyper-IgM (autosomal recessive or X-linked)
Classic complement (autosomal recessive)
* First PID described in 1952
* Bruton’s X-linked agammaglobulinemia
CASE STUDY – 13 YEAR OLD MALE
* Bone marrow transplantation (BMT) for SCID
* BM from sister was unmatched
* 3 months later developed
*
*
*
*
Fever
Nausea, vomiting and diarrhea
Abdominal pain
Intestinal bleeding
* Autopsy revealed
* Hundreds of intraabdominal malignant tumors
CASE STUDY – DAVID P. VETTER
* Parents – David J and Carol Ann
* Children
* Katherine (1968)
* David J III (1970)
* Died of SCID at 7 months
* Advised of risk of another male child
* David P born on September 21, 1971
* Unmatched BMT on 12/21/83
* Died of SCID on 2/22/84
SELECTIVE IgA DEFICIENCY
* Most common and mildest of PI
* Prevalence
* 1 in 700 caucasians
* 1 in 18,000 Japanese
* Majority of patients are asymptomatic
* Clinical presentation
* Recurrent sinopulmonary and GI disease, allergy, autoimmunity
SELECTIVE IgA DEFICIENCY
* Incidence of allergy and asthma is increased
* Food allergy
* Asthma may be more severe
* Allergic rhinitis
* Incidence of autoimmune disease is increased
* Rheumatoid arthritis (RA)
* Systemic lupus erythematosus (SLE)
* Mechanism is unclear
* 30% of patients have Anti-IgA (IgG > IgM > IgE)
SELECTIVE IgA DEFICIENCY
* IgA deficiency significant risk factor for
* Anaphylactic transfusion reactions
* Mechanism is unclear
* Classic anaphylaxis involves IgE
* Anti-IgA, IgG most prevalent
* Definition
* Deficiency (< 7 mg/dL)
* Severe deficiency (<0.05 mg/dL)
SELECTIVE IgG DEFICIENCY
* Selective IgG subclass deficiency
* IgG2 in children
* IgG3 in adults
* Combined deficiency relatively common
* IgG2 with IgA
* IgG1 and IgG3
* IgG2 and IgG4
* Clinical presentation
* Recurrent upper and lower respiratory tract infections
SELECTIVE IgG DEFICIENCY –
CASE STUDY
* 9 year old male presented to family physician by
his mother for evaluation of short stature and
recurrent infections
* Past medical history
* Recurrent URI and LRI with
* Streptococcus pneumoniae, Haemophilus influenzae, Influenza
virus, Respiratory Syncytial Virus, Parainfluenza virus
* 2 to 3 each year since age 1
* Recurrent diarrhea since age 4
SELECTIVE IgG DEFICIENCY –
CASE STUDY
* Laboratory results for total serum antibodies
* IgG of 6.0 gm/L
* IgA of 0.9 gm/L
* IgM of 0.6 gm/L
(5.4 to 16.1 gm/L)
(0.7 to 2.5 gm/L)
(0.5 to 1.8 gm/L)
* Laboratory results for IgG subclasses
*
*
*
*
IgG1 of 4.6 gm/L
IgG2 of 0.1 gm/L
IgG3 of 0.5 gm/L
IgG4 of 0.2 gm/L
(3.6 to 7.3 gm/L)
(1.4 to 4.5 gm/L)
(0.3 to 1.1 gm/L)
(0.1 to 1.0 gm/L)
CORRECTION OF GENETIC
DEFECTS OF IMMUNE SYSTEM
* Many immunodeficiencies affect hematopoietic
cells
* Correction of deficiency by transplantation of
* Bone marrow (hematopoietic stem cells)
* Success depends on degree of HLA matching between donor
and recipient
* Major complication graft-versus-host disease (GVHD)
* Somatic gene therapy
* Functional copy of defective gene inserted into patients stem
cells
SECONDARY (ACQUIRED)
IMMUNODEFICIENCY DISEASES
* Malnutrition
* Diseases
* Diabetes, nephrotic syndrome, protein-losing enteropathy
* Drugs
* Corticosteroids
* Hydrocortisone, methylprednisolone, prednisone
* Immunosuppressants
* Azathioprine, tacrolimus, cyclosporine A
ACQUIRED IMMUNODEFICIENCY
DISEASES
* Radiation
* Microorganisms
* Human T-cell lymphotropic virus, type I (HTLV-I)
* Mycobacterium leprae
* Lepromatous leprosy
* Cytomegalovirus (CMV)
* Epstein-Barr virus (EBV)
* Human immunodeficiency virus (HIV)
CASE STUDY –
20 YEAR OLD MALE
* Presented to ER of Southeast Regional Medical Center in
Lumberton, NC
* Headache, fever, chills, AMS and nuchal rigidity
* Blood cultures collected, but lumbar puncture was
unsuccessful
* Treated with single 2 gram dose of ceftriaxone
* Transferred to New Hanover Regional Medical Center in
Wilmington, NC
CASE STUDY (20 M) –
PHYSICAL EXAMINATION
* VITAL SIGNS
* Temperature 100 F, PR 92, RR 20, BP 120/60
* HEENT AND NECK
* Pupils equal, round and light reactive
* Nuchal rigidity is positive
* LYMPH NODES
* No lymphadenopathy
* ABDOMEN
* Soft. No distention, tenderness, organomegaly
* EXTREMITIES
* Bilateral upper and lower clubbing
* NEUROLOGIC
* Babinski is negative and Kernig is positive
CASE STUDY –
20 YEAR OLD MALE
* Past medical history
* Recurrent infections (age 10)
* Sinusitis
* Pneumococcal pneumonia and bacteremia
* Specimens collected for culture at NHRMC
* Blood, CSF and ear drainage
* Treatment at NHRMC
* Ceftriaxone (2 grams IV q12) and vancomycin (1 gram IV
q12)
CASE STUDY (20 M) – COMPREHENSIVE
METABOLIC PANEL (CMP)
*
*
*
*
*
*
*
*
*
*
*
*
*
Glucose
BUN
Creatinine
Sodium
Potassium
Chloride
Calcium
Total Protein
Albumin
Bilirubin (T)
AST
ALT
Alk Phos
Patient
172
7
0.7
139
3.8
106
8.3
4.8
2.6
0.6
7
22
63
Reference
72 - 112
mg/dL
7 - 18
mg/dL
0.5 - 1.2
mg/dL
136 - 146 mmol/L
3.7 - 5.2
mmol/L
98 - 108 mmol/L
8.5 - 10.5 mg/dL
6.1 - 8.0
mg/dL
3.5 - 4.8
g/dL
0.0 - 1.0
mg/dL
15 - 37
U/L
19 - 55
U/L
50 - 136
U/L
CASE STUDY (20 M) –
CBC WITH DIFF
*
*
*
*
*
*
*
*
*
*
WBC
RBC
Platelets
HGB
HCT
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Patient
19.8
4.2
278
11.5
33.6
85
7
7
0
0
Reference
4.8 - 10.8 K/uL
4.9 - 6.1 M/uL
145 - 400 K/uL
14.0 - 18.0 g/dL
40 - 52
%
40 - 74
%
15 - 47
%
0 - 12
%
0-6
%
0-2
%
CASE STUDY (20 M) –
URINE DRUG SCREEN
*
*
*
*
*
*
*
*
*
PCP
Benzodiazepine
Cocaine
Amphetamine
THC
Opiates
Barbiturates
Methadone
Tricyclic Antidepressants
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
Negative
CASE STUDY (20 M) –
COAGGULATION/HEMATOLOGY
* PT
* INR
* PTT
* Fibrinogen
* Haptoglobin
* Sed rate
Patient
16.6
1.93
42.8
711
425
60
Reference
10.7 - 13.5 seconds
0.86 - 1.34 seconds
25 - 38
seconds
160 - 440
43 - 212
0 - 15
mg/dL
mg/dL
mm/hr
CASE STUDY (20 M) –
CEREBROSPINAL FLUID
*
*
*
*
*
*
*
*
*
Glucose
Protein
Lactic acid
WBC
RBC
Neutrophils
Lymphocytes
Monocytes
VDRL
0
314
17.6
568
373
73
11
16
Negative
40 - 70
15 - 45
< 2.8
mg/dL
mg/dL
mmol/L
uL
uL
%
%
%
Negative
CASE STUDY (20 M) – MICROBIAL
ANTIGENS (CSF)
*
*
*
*
*
*
Haemophulus influenzae, type B
Streptococcus pneumoniae
Streptococcus agalactiae (GBS)
Neisseria meningitidis (C, W135)
Neisseria meningitidis (A, Y)
Neisseria meningitidis (B)/ E.coli
* Cryptococcus neoformans
Negative
Negative
Negative
Negative
Negative
Negative
Negative
CASE STUDY (20 M) –
CULTURE AND SMEAR (CSF)
* Routine
* 2 to 6 WBC/HPF
* No organisms seen on gram stained smear
* Acid-fast bacilli
* No acid fast bacilli (AFB) seen on fluorochrome stained
smear
* Fungus
* No fungal elements seen on PAS stained smear
CASE STUDY (20 M) –
CBC WITH DIFF (DAY 2)
Patient
* WBC
14.5
* RBC
3.73
* Platelets
302
* HGB
10.0
* HCT
30.0
* Neutrophils
76
* Lymphocytes
16
* Monocytes
8
* Eosinophils
0
* Basophils
0
Reference
4.8 - 10.8 K/uL
4.6 - 6.1 M/uL
145 - 400 K/uL
14.0 - 18.0 g/dL
40.0 - 52.0
%
40 - 74
%
15 - 47
%
0 - 12
%
0-6
%
0-2
%
CASE STUDY (20 M) –
CMP (DAY 2)
*
*
*
*
Glucose
Protein(T)
Albumin
AST
Patient
129
5.2
2.3
2.0
Reference
72 - 112 mg/dL
6.1 - 8.0
g/dL
3.5 - 4.8
g/dL
15 - 37
U/L
All other analytes within reference ranges
CASE STUDY (20 M) –
CSF STUDIES (DAY 3)
*
*
*
*
*
*
*
Glucose
Protein
WBC
RBC
Neutrophils
Lymphocytes
Monocytes
* Bacterial antigens
Patient
34
100
576
14
42
28
30
Negative
Reference
40 - 70 mg/dL
15 - 45 mg/dL
uL
uL
%
%
%
Negative
CASE STUDY (20 M) – CSF
CULTURE AND SMEAR (DAY 3)
* Routine
* 0 to 1 WBC/HPF
* No organisms seen on gram stained smear
* Acid-fast bacilli
* No acid fast bacilli seen on fluorochrome stained smear
* Fungus
* No fungal elements seen on PAS stained smear
CASE STUDY (20 M) – MOLECULAR
MICROBIOLOGY (DAY 3)
* Cerebrospinal fluid (CSF) by PCR
* HSV-1 and HSV-2 DNA
* Enterovirus RNA
* Borrelia burgdorferi DNA
Negative
Negative
Negative
CASE STUDY (20 M) – MICROBIOLOGY
AT NHRMC (DAY 3)
* Ear drainage growth
* Pseudomonas aeruginosa
* Blood cultures
* Negative at day 3 and day 5
* Cerebrospinal fluid cultures
* Negative
CASE STUDY (20 M) –
BLOOD CULTURES (SRMC-DAY 3)
* Streptococcus pneumoniae
*
*
*
*
*
*
*
*
Penicillin G
Ceftriaxone
Azithromycin
Trim/Sulfa
Chloramphenicol
Moxifloxacin
Tetracycline
Vancomycin
Resistant
Resistant
Resistant
Resistant
Susceptible
Susceptible
Susceptible
Susceptible
CASE STUDY (20 M) IMMUNOLOGY (DAY 3)
* Consultation between infectious disease and
clinical microbiology
*
*
*
*
*
*
Monospot test
RPR
Antinuclear antibody (ANA)
Complement (T)
HIV-1/2 antibody
Serum protein electrophoresis (SPE)
CASE STUDY (20 M) IMMUNOLOGY (DAY 3)
* Monospot test
Negative
* RPR
Negative
* Antinuclear antibody (ANA)
Negative
* Complement (T)
48 U/mL
* HIV-1/2 antibody
Invalid
* Serum protein electrophoresis
Severe hypogammaglobulinemia
[31 – 66 U/mL]
PRINCIPLES OF HIV-1/2 ANTIBODY
TEST
* Lateral flow immunochromatographic procedure
* Antigens and antibody immobilized onto nitrocellulose
membrane in T and C zones
* Test (T) Zone
* Synthetic peptides from HIV envelope region
* Control (C) Zone
* Goat anti-human IgG
* Developer solution
* Facilitates flow of specimen onto test strip
* Rehydrates protein-A gold colorimetric reagent
CASE STUDY (20 M) – IMMUNOLOGY
(DAY 4)
Patient
Reference
* Immunoglobulin A (IgA)
< 15.0
81 - 463 mg/dL
* Immunoglobulin G (IgG)
< 60.0
694 - 1618 mg/dL
* Immunoglobulin M (IgM)
< 5.0
48 - 271 mg/dL
CASE STUDY (20 M) – DIFFERENTIAL
DIAGNOSIS
* Bruton’s X-linked agammaglobulinemia (XLA)
* Common variable immunodeficiency (CVID)
* Severe combined immunodeficiency (SCID)
* Omenn syndrome (OS)
CASE STUDY (20 M) - MOLECULAR
PATHOLOGY (FLOW CYTOMETRY)
*
*
*
*
*
CD3+/CD5+
CD4 lymphocytes
CD8 lymphocytes
CD19+/CD20+
CD3-/CD56+
Patient
Reference
79%
45%
30%
18%
3%
52 – 84%
30 – 61%
12 – 42%
5 – 25%
5 – 30%
CASE STUDY (20 M) –
FLOW CYTOMETRY
Percent
* Lymphs (CD45)
* T-Lymphs (CD3)
* % T-Lymphs
(CD3/CD45)
1175
687
45
Reference
1000 - 4800
690 – 2540
55 – 84
76
* T-Helper lymphs
(CD3+CD4)
* %T-Helper lymphs
(CD3+CD4/CD45)
Cells/uL
1540
410 – 1590
31 – 60
CASE STUDY (20 M) – CLINICAL
MANIFESTATION (DAY 5)
* Herpetiform vesicles on erythematous base
* Side of head
* Lower lip
* External ear
* CN V3 herpes zoster reactivation
CASE STUDY (20 M) – DISCHARGE
DIAGNOSES (DAY 5)
* Pneumococcal meningitis with bacteremia
* Pseudomonas aeruginosa otitis externa
* Common variable immunodeficiency (CVID)
* CN V3 herpes zoster reactivation
COMMON VARIABLE
IMMUNODEFICIENCY (CVID)
* Most prevalent primary immunodeficiency
* Heterogeneous group of immunologic disorders
* Unknown etiology
* Characterized by marked deficiency of
* IgG and IgA
* IgM and T-cell dysfunction
* Generalized lymphadenopathy and splenomegaly
CVID – PATHOPHYSIOLOGY
* Number of mechanisms for defective antibody production
* B-cell defects
* Differentiation of B-cells into plasma cells
* T-cell defects
* Low level expression of CD40 ligand
CVID – EPIDEMIOLOGY
* Prevalence of 1 case in 10,000 to 50,000 population
* Female to male ratio of 1
* All races
* Age at diagnosis
* 1 to 5 years
* 16 to 20 years
* 21 years and greater (60%)
CVID – COMPLICATIONS AND RISKS
* Recurrent infections
* Upper and lower respiratory tract
* Streptococcus pneumoniae and Haemophilus
influenzae
* Herpes labialis (HSV)
* Herpes zoster (VCV)
* Autoimmune diseases (RA, AHA, ATP)
* Malignancy
* Non-Hodgkin’s lymphoma
* Malignant lymphoma