INTRODUCTION LAYOUT OF CHAPTERS (see centre panel)
Type IV hypersensitivity responses
Unlike the hypersensitivity responses discussed so far, type IV hypersensitivity, also known as
Medical registrars perceive Immunology as difficult to delayed hypersensitivity (DTH), is T-cell-mediated and not antibody mediated. As the name
suggests, the immune response is delayed (appearance of signs typically 48-72 hours after A.Core text (basic immunology knowledge)
understand with a daunting amount of literature and specialized exposure to antigen).
books available. After brief exposure to the subject in medical The prototypic DTH reaction is the tuberculin skin test (Mantoux skin test for tuberculosis). This
test is (or rather was) used to determine whether an individual has been previously infected with M
B.Boxes (specialized immunology knowledge)
school teaching there is poor recall and limited opportunity to tuberculosis but may also come up ‘positive’ in BCG-vaccinated persons. A mixture of Mtb
antigens (tuberculin) is injected intradermally. TH1 cells are stimulated by antigen-presenting cells
C.History boxes (knowledge of important persons and events)
update on the rapidly increasing knowledge. A fresh approach to
bridge this knowledge gap is planned with the CICC.
via MHC class II and release inflammatory cytokines eventually leading to a localised
inflammatory response at the site of injection. D.Clinical boxes (applied knowledge in Clinical Immunology)
E.Self-study questions (on-line test once certificate course is
Very similar reactions are observed in several cutaneous hypersensitivity responses. A prime
A one month practical rotation for Pathology Registrars in the example is the rash produced by contact with poison ivy. Other well-known contact
Immunology Unit NHLS Tygerberg with Clinical and Bench hypersensitivity reactions are caused by nickel or chrome. As with other allergic responses, a pre-
sensitisation is necessary. established)
Laboratory exposure was initiated in 2005. This now includes
Pathology registrars from other hospitals and the Infectious
Contact dermatitis is not always a purely allergic (DTH) response (see clinical link ‘latex allergy’).
Contact dermatitis or irritant dermatitis is a term for a skin reaction resulting from exposure to F.External links (where applicable)
allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis). Phototoxic dermatitis
Disease Subspecialists from Stellenbosch University and the occurs when the allergen or irritant is activated by sunlight. Photocontact dermatitis is divided into
two categories, phototoxic and photoallergic.
University of Cape Town on the common teaching platform. The reach of delayed-type hypersensitivity, goes far beyond allergic conditions. DTH is
As part of the rotation Immunology applied theory currently is responsible for pathological immune reactions in some infectious diseases (tuberculosis, leprosy,
etc / granuloma formation), autoimmune diseases (sarcoidosis, rheumatoid arthritis, multiple
taught informally via case history discussions on wardrounds, at sclerosis etc) and in the rejection of tissue transplants. We will re-visit DTH in these settings.
weekly journal club and a weekly interactive forum. The
registrar/rotator is required to engage in selfstudy for the
principles of basic Immunology. In vitro testing BOX Allergy diagnostics
The methodology for the market-leading RAST
(radioallergosorbent test) was invented and marketed by
Pharmacia Diagnostics and the acronymn RAST is a brand The skin prick test (SPT)
A novel structured assisted selfstudy course is planned to help name. This test has evolved into the current non-
radioactive ImmunoCAP Specific IgE (from Phadia).
Skin prick testing is a cheap, rapid and accurate
way of identifying the causative allergens in an
the student with acquiring basic and laboratory Immunology This in vitro test detects the amount of IgE in a patient
serum sample that reacts specifically with an allergen.
atopic individual. The test depends on the
introduction of allergen extract into the dermis - 13 out of 16 chapters intended have been completed or
resulting in an IgE-mediated response
principles linked to a clinical scenario. ImmunoCap Test Principle
The allergen of interest,
characterised by an immediate wheal-and-flare
reaction. The test is usually performed on the inner
outlined in MS Word (see ‘course outline’)
covalently coupled to the
ImmunoCAP, reacts with the
forearm. Positive (histamine) and negative controls
(saline) are included. Reactions should occur within - Informal student feedback confirms correct placing of learning
10-15 minutes. A wheal reaction of 3 mm greater
specific IgE in the patient
sample. than the negative control is regarded as positive.
- The core knowledge has been used successfully on other
teaching platforms (see ‘impact’)
After washing away non-specific
IgE, enzyme-labelled antibodies - Feasibility and structure of webbased course has been
against IgE are added to form a
Current impact of the project on teaching and learning
After incubation, unbound
enzyme-labelled anti-IgE is Delayed type hypersensitivity responses (DTH, see
1 Basic concepts A The Immunology Interactive Forum (IIF, Fridays 11:00,
washed away and the bound below) are sometimes diagnosed using the similar
Introduction complex is then incubated with
a developing agent.
‘skin patch test’ where the allergen is placed on the
skin (often the back) under a dressing. Typically, a
2 The range of infectious agents and positive response occurs after 48 hours.
Microbiology) is directed at rotating Medical Registrars
disease transmission (Pathology and Infectious diseases) and included also were
3 Cells and tissues; trafficking After stopping the reaction, the
fluorescence of the eluate is Pathology Hons, Microbiology Hons students and Immunology
4 Innate immunity I
measured. The higher the
Innate immunity fluorescence, the more specific
IgE is present in the sample. To
Technicians. The IIF structure is based on the Clinical
5 Innate immunity II: complement and evaluate test results, the
responses of patient samples Immunology Certificate Course and ‘cross-fertilisation’ between
are compared directly to the
responses of calibrators. the two structures has occurred and has been included in the
Acquired: B cells 6 Antigens and antibodies, antibody Pictures: Phaedia course material. We are currently compiling a database of talks
diversity given in the IIF, which will also be available to interested
7 B cell effector functions etc students and may be made available as external links in the
Acquired: T cells 8 Antigen-processing and presentation certificate course.
9 Regulation of immune responses (TH, B: Currently rotating registrars have received printouts of the
Treg, …); cytokines History box
Robert Royston Amos ("Robin") Coombs already completed chapters and have given constructive
10 Lymphocyte development; memory 9 January 1921 – 25 February 2006 feedback resulting in minor changes to the chapters. The overall
Clinical 11 Immunodeficiencies; chronic infection Co-discoverer of the Coombs test (1945) used for opinion was that the Certificate Course in its current form is well
Immunology 12 Hypersensitivity and allergy detecting antibodies in various clinical scenarios, such suited to teach immunology at a Pathology and Infectious
as Rh disease and blood transfusion.
13 Autoimmunity and transplantation Gell-Coombs classification of hypersensitivity reactions disease registrar level. The inclusion of clinical case illustration
14 Vaccines and cancer immunology (together with Philip George Howthern Gell). is welcome and considered very helpful as learning
Epilogue 15 Timelines: of immunology / ontology: supplements.
Picture: The Lancet
fetus to old age / phylogeny
16 Immunodiagnostics and research
Clinical link: Latex allergy
OBJECTIVES OF THE COURSE:
1.Enable the student to refresh and consolidate core
Immunology theory CONCLUSIONS AND FUTURE DEVELOPMENTS
2.Provide the student with a sound understanding of the Latex allergy is particularily important as an occupational allergy in a hospital and laboratory setting. About
10% of health professionals develop latex allergy predominantly through repeated wearing of latex gloves.
principles of immunology relating to disease states. Once individuals have become sensitised further exposure to latex must be avoided. Fortunately powder-
free and latex-free alternative products are available in the work-environment and at home.* The Clinical Immunology Certificate Course (CICC) has been well
3.Expose the student to the concepts of research in Immunology Latex is known to cause 2 of the 4 types of hypersensitivity responses:
received by participants and is well attended. Proposed
Type I: The most serious and rare form, type I is an immediate and potentially life-threatening reaction, not
4.Link the student to the existing webbased Immunology unlike the severe reaction some people have to bee stings. Such reactions account for a significant timeframe has been adhered to. CPD accreditation has been
proportion of perioperative anaphylactic reactions in pre-sensitised individuals.
teaching eg Immunopaedia. Type IV: Also known as allergic contact dermatitis. This involves a delayed skin rash that is similar to poison obtained for the IIF. Independent course structure for the CICC
5.Evaluate the students on completion of the rotation by ivy with blistering and oozing of the skin. This type is caused by components originating in the processing of
rubber products (mostly proteins from the rubber tree Hevia brasiliensis). will be implemented from 2010.
evaluation (Multiple Choice Question or other) and with logbook Irritant contact dermatitis: The most common type of reaction. This causes dry, itchy, irritated areas on the
skin, most often on the hands. Frequent washing of the hands, incomplete drying, exposure to hand Chapters have been completed so far in ‘MS Word’. The
completion of rotations. sanitizers, and the talc-like powder coatings (zinc oxide, corn starch etc) used with gloves can aggravate
‘Articulate’ package will allow us to break down the chapters
symptoms. Irritant contact dermatitis is not a true allergy.
6.To make the teaching material available in hardcopy and *PS For those concerned about latex allergy and condom useage: Once sensitised to latex, condom useage from MS word into MS Power Point slides (including pictures,
may indeed become a problem. However, non-latex condoms and sex toys are available – even in South
electronic format and webbased teaching. Africa!!! links, possibly animations) without requiring web-page design
skills. ‘Articulate’ then converts the Power Point slides into html
web-format useable on WebCT. Chapters can also be burned on
DVD for those users who have difficulties accessing the internet
List the 4 types of hypersensitivity responses according to the from the hospital (NHLS log-in).
Gell-Coombs classification system and describe the main Ultimately we plan to offer a CPD registered, accredited course
ACKNOWLEDGEMENTS immune mechanism for each type. with exit certificate.
Martie van Heusden (CHSE/ SGWO) This project is in allignment with the startegic initiatives of the
Dr JP Bosman (Centre for Teaching and Learning) Department of Pathology, SU to advance Immunology teaching
Fundig: Department of Education (DOE) External Link: Allergy Society of South Africa (ALLSA)
and training to strengthen the academic and research basis of
Fund for Innovation in Teaching and Learning (FIRTL/ FINLO) www.allergysa.org
the Immunology Unit.