Edition no. 4

PATHCHby Dr Sylvia van den BergAT and Dr Cathy van Rooyen Endorsed by the Infectious Diseases Peer Group

Primary immunodefi ciencies: A diagnostic approach

Primary immunodefi ciencies are a group of • Absent thymic shadow on CXR

heterogenous genetic disorders that cause Most children referred for recurrent infections do not have an an enhanced susceptibility to recurrent and underlying immunodefi ciency. The majority of children will have severe infections. increased exposure, allergy (~30%), other chronic diseases (~10%) or an anatomic defect. Only about 10% will have an Features that suggest a primary immunodefi ciency. immunodefi ciency: Infections with certain sentinel

(First three features most predictive) organisms should set off the alarm bells and include the following: • Family history of immunodefi ciency or unexplained early death (<30 years) • Recurrent sinopulmonary infections with encapsulated • Failure to thrive bacteria (S. pneumoniae, H.infl uenzae type b, M. catarrhalis) • Need for IV antibiotics and/or hospitalisation to clear infection • Pneumocystic jirovecii pneumonia • Six or more new infections in one year • Pseudomonas aeruginosa infections • Two or more sinus infections or pneumonia in one year • Enteroviral meningoencephalitis • Four or more new ear infections in one year • Cryptosporidium enteric infections • Two or more episodes of sepsis or meningitis in a lifetime • Recurrent infections with S.aureus, coagulase negative • Two or more months of antibiotics with little or without an effect staphylococci, Serratia marcescens, • Recurrent or resistant Candida infections Chromobacterium violaceum or Aspergillus spp. • Recurrent tissue or organ abscesses • Recurrent herpes viral infections • Infection with an opportunistic pathogen • Infections with live vaccines (including BCG, oral polio • Structural damage due to infections vaccine, measles, rota virus, varicella) • Complications from a live vaccine • Prolonged or recurrent Candida infections • Chronic diarrhoea • Recurrent invasive neisserial infections • Non-healing wounds • Systemic or deep infections with nontuberculous • Extensive skin lesions mycobacteria • Persistent lymphopaenia • Unexplained fever or autoimmunity For more information or clinical queries, contact:

Dr Cathy van Rooyen Additional features in infants Tel: 012 678 0613/6 include the following: Email: [email protected] Dr Sylvia van den Berg • Delayed umbilical separation (>30 days) Tel: 012 678 0613/7 • Congenital heart defects Email: [email protected] • Hypocalcaemia

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Major subtypes of primary immunodefi ciencies* and expected clinical fi ndings:

Subtype: Age at onset: Pathogens: Infections: Humoral immunodefi ciencies: >6 months; can present Encapsulated bacteria Sinus infections X-linked or autosomal recessive aggamma- in adulthood; CVID can Fungi and parasites Otitis media globulinemia present in adolescence Giardia lamblia Bronchiectasis CVID Cryptosporidium Chronic conjunctivitis IgG subclass defi ciency species Pyoderma IgA with IgG subclass defi ciency Enterovirus Enteroviral infections Selective IgA defi ciency Infectious diarrhoea Specifi c defi ciency with normal immunoglobulins Transient of infancy Combined immunodefi ciencies: <6 months Mycobacterium species Opportunistic infections T-B+ SCID Viruses: Severe recurrent bacterial and viral T-B- SCID Cytomegalovirus infections Epstein-Barr Oral thrush CD40 ligand defi ciency Varicella virus Excessive diarrhoea ZAP-70 defi ciency Enterovirus, etc. MHC class I defi ciency Candida MHC class II defi ciency Pneumocystis jirovecii Complete DiGeorge Syndrome DOCK8 defi ciency Innate immunodefi ciencies: Childhood Mycobacteria and Recurrent sinopulmonary infections NK cell defi ciency other pyogenes with encapsulated bacteria AIRE defi ciency Candida albicans Mucocutaneous candidiasis NEMO defi ciency Histoplasma Herpes viral infections Herpes simplex encephalitis capsulatum Chronic mucocutaneous candidiasis Aspergillus fumigatus WHIM Coccidioides immitis Herpes viral infection Human papilloma virus Phagocytic disorders: Infancy or childhood S. aureus Skin, oral cavity and anorectal Chronic granulomatous disease Pseudomonas infections Leukocyte adhesion defi ciencies S. marcescens Poor wound healing Defects of neutrophil differentiation Nocardia Abscesses MSMD Klebsiella spp Salmonella serovar typhi Mycobacteria BCG Candida aspergillus Complement defi ciencies: Any age Neisserial infections Pyogenic infections with C1-9 defi ciencies S. pneumoniae encapsulated organisms Mannan binding lectin defi ciency H. infl uenzae type b Meningococcal and gonococcal Factor D, I and H defi ciencies Mycobacteria infections Legionnella Tuberculosis Legionnaire’s disease Hemolytic-uraemic Syndrome Well-defi ned syndromes with Infancy or childhood immunodefi ciencies: Wiskott-Aldrich Syndrome Ataxia-telangiectasia DiGeorge anomaly Hyper-IgE syndromes Dyskeratosis congenita *The major subtypes of immunodefi ciencies are provided with some examples. A complete classifi cation can be obtained from Al-Herz W, Bousfi ha A, Casanova JL et al. Primary immunodefi ciency diseases: An update on the classifi cation. International Union of Immunological Societies Expert Committee for Primary Immunodefi ciency. Frontiers in Immunology 2011: 2:1–26. (CVID: Common variable immunodefi ciency; SCID: Severe combined immunodefi ciency; MSMD: Mendelian susceptibility to mycobacterial disease; WHIM: Warts, hypogammaglobulinaemia, infections, myelokathexis)

Adapted from: Merritt TH, Segreti J. The role of the infectious disease specialist in the diagnosis and treatment of primary immunodefi ciency disease. Infectious diseases in clinical practice, 2011;19:316–325 and Al-Herz W, Bousfi ha A, Casanova JL et al. Primary immunodefi ciency diseases: An update on the classifi cation. International Union of Immunological Societies Expert Committee for Primary Immunodefi ciency. Frontiers in Immunology 2011: 2:1–26.

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Investigations 2. T-cell defects – these account for about 15% of Abnormal results need to be verifi ed by a repeat investigation when primary immunodefi ciencies the patient is well, as external factors like infections and medication T-cell defects usually present at a very young age with life- may have a transient infl uence on the test results. threatening infections due to a wide range of different pathogens, often opportunistic infections. Infections are persistent and severe, 1. Test for HIV, CMV, EBV, TB, disseminated BCGosis, PCP and other and viruses, fungi and intracellular bacteria are often involved. A infections where relevant family history of unexplained, especially infective deaths, should 2. FBC and differential count prompt further investi-gation. 3. CRP and ESR 4. Chest X-ray: To determine the presence of a thymic shadow • HIV ELISA or PCR in babies: done in all patients suspected of and to assess the presence of lung disease in children and having a T-cell defi ciency adults • FBC and differential: patients are usually lymphopaenic with 5. Screen for cystic fi brosis or allergies where indicated persistent absolute lymphocyte counts <1.5 X109 in older chil- dren and <2.5 X 109/l in younger children 1. Antibody (humoral) defi ciencies – these account • TREC PCR: neonatal screening on NBS or EDTA blood to ex- for about 70% of primary immunodefi ciencies clude SCID before administration of any live vaccines and for Patients suffering from antibody defi ciencies have a problem early diagnosis and search of bone marrow transplant with recurrent, severe upper (recurrent pneumonia) and lower • Lymphocyte immunophenotyping to enumerate the lympho- respiratory tract infections (i.e. recurrent otitis media, sinusitis), cyte subtypes (B-, T- and NK-cells) especially with pyogenic organisms, such as S. pneumoniae and • Lymphocyte proliferation tests to mitogens H. infl uenzae. - PHA - PMA Appropriate initial tests would be the following: - PMA+ionophore • Full blood count and differential - CD3 • KREC PCR – Neonatal screening on neonatal blood spot (NBS) - CD3 + IL-2 or EDTA blood to exclude agammaglobulinaemia before - CON A administering live oral polio vaccine - PWM • Quantitative immunoglobulins prior to the administration of immuno-globulins: • Lymphocyte proliferation tests to recall antigens IgG, M, A and E - Varicella zoster • IgG subclasses - Candida • Specifi c antibody titres to S. pneumoniae, H. infl uenzae, - Tetanus tetanus and diphtheria. If specifi c antibody levels are low, booster immunisations should be administered and titres For infants and young children, all of the lymphocyte proliferation measured again three to four weeks later. tests to mitogens should be ordered, whereas only LPT to candida, varicella zoster and PHA should be ordered in adults. Secondline testing: • Secretory IgA • Specialised immunopenotyping: - Naive and memory CD4- and CD8-cells Should any abnormality be detected, additional tests should be - Alpha/beta, gamma/delta T-cells done: - HLA DR • Lymphocyte immunophenotype: to determine total B-cell - Common gamma chain numbers - Interleukin 7 Receptor alpha • KREC PCR in patients with agammaglobulinaemia - Test repertoire will be expanded in the near future. Please • B-cell function testing for B-cell activation markers contact the laboratory for further information • Memory B-cells: fl ow cytometric assay to assess germinal B-cell • Genetic testing function in a patient with a humoral immunodefi ciency. Low memory B-cells are associated with more serious or frequent 3. Tests to determine neutrophil function infections, autoimmune disease and granulomatous disease These tests should be requested in patients with recurrent skin, soft • IL17: Decreased in Hyper-IgE syndrome tissue or deep abscesses, or recurrent infections with S. aureus, coagulase negative staphylococci, S. marcescens, P. aeruginosa, Diagnostic tests: Chromobacterium violaceum or Aspergillus. • Bruton’s Tyrosine Kinase: fl ow cytometric assay in patients with suspected X-linked aggamaglobulinaemia • FBC with differential count • CD 40 Ligand: fl ow cytometric assay in patients with suspected • Neutrophil oxidative burst, phagocytosis and chemotaxis hyper-IgM syndrome • Leukocyte adhesion studies: CD11 and CD18: in babies with • Genetic studies delayed umbilical cord separation (>30 days) and patients • Flow cytometric markers of B-cell maturation and subtypes of with recurrent bacterial infections, mainly involving the skin CVID will be available in the near future. Please contact the and mucous membranes, periodontitis, absent pus formation laboratory for further information. and impaired wound healing

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• Neutrophil : in suspected autoimmune mediated as live vaccines and infections can be fatal, and also greatly neutropaenia diminish the success rate of the bone marrow transplant.

4. Tests to determine complement function Neonatal screening assays are now available at Ampath The total heamolytic complement activity should be requested in to detect diseases hallmarked by the absence of T- or B- patients with recurrent neisserial and pyogenic infections. lymphocytes, classically seen in SCID and XLA/Bruton’s disease.

Low MBL levels may predispose patients to upper respiratory tract Neonatal PID screening tests: infections and they may have a higher risk for severe menigococcal • T-cell receptor excision circles (TRECs) – absent in SCID patients or pneumococcal infections. They may also be at increased risk of • Kappa-deleting receptor excision circles (KRECs ) – absent in developing tuberculosis and legionnaire’s disease. An increased XLA patients incidence of infectious disease is also seen in immunocompromised patients or immunological immature neonates and infants with A dried bloodspot on a Guthrie card obtained after a heel prick or concomitant MBL defi ciency. Immunocompromised hosts include EDTA blood shortly after birth is required. The test can also be used critically ill patients in the ICU, cystic fi brosis patients and patients later as supporting evidence to help make a diagnosis of SCID or XLA. receiving chemotherapy. Patients with concomitant MBL and humoral immunodefi ciency also tend to have more severe and 7. Tests for causes of secondary immuno- recurrent infections. It must be kept in mind that a wide range of MBL defi ciency serum levels have been observed in apparently healthy voluntary Secondary causes of immunodefi ciencies should always be blood donors and low levels are not necessarily clinically relevant. excluded and include HIV/AIDS and other viral infections nutritional defi ciencies, malignancies, infections, immunosuppressive Symptomatic patients with normal antibody and neutrophil tests medication, diabetes mellitus, dialysis and uraemia, protein- should be further evaluated by complement function testing. losing conditions, liver disease, malnutrition, trauma and burns, ionising and ultraviolet radiation, toxic chemicals, pregnancy, • Classic and alternate pathways (CH100 and ACH100) old age and severe stress. • Complement 3 and 4 levels • Mannan binding lectin (MBL) Conclusion As immunodefi ciencies may be complex and diffi cult to diagnose, 5. Natural killer cells it is recommended that advice be sought from immunologists, Natural killer (NK) cells play a crucial role in the host defence paediatricians, physicians, ENT surgeons and pulmonologists in against herpes virus infections, especially herpes simplex virus and the workup of diffi cult patients. It cannot be overemphasised varicella zoster virus reactivation and latency. that a high index of suspicion should always be maintained for possible immunodefi ciencies, as untreated immunodefi ciencies • Total NK cell numbers are life threatening, and the long-term prognosis depends on • NK cell function early diagnosis and intervention. Infections should be promptly • NK cell cytotoxicity (available soon) recognised and aggressively treated with appropriate antibiotics. IVIG or SCIG should not be given unless urgently indicated until 6. Neonatal screening there is a thorough evaluation of the immune system, as these It is crucial to make a diagnosis of SCID and X-linked will interfere with antibody investigations for months and have agammaglobulinaemia(XLA)/Bruton’s disease as early as possible, potential side effects. Only once the investigations are complete before the patients receive live vaccines or present with infections, should they be carefully considered.

Dear Doctor,

We would like to request your assistance for the PID Registry work of South Africa.

Primary immunodefi ciencies (PIDs) are inborn errors of immunity under-representation of case-reporting from other provinces, particularly resulting in susceptibility to severe, recurrent, atypical infections and the in black populations. consequences of immune dysregulation. Within a context of epidemic infectious disease rates, PIDs are orphan diseases often unrecognised or We invite you to contact us for further information, if you have identifi ed associated with delayed time to diagnosis. National and international new patients with probable or confi rmed PID diagnosis. We appreciate efforts are ongoing to increase awareness, improve case fi nding, and your time constraints and will assist you wherever possible. On the data- describe the prevalence of PID worldwide. Ethical consent to conduct this base, the patients will be refl ected under the relevant referring doctor/ research work is maintained at the universities of Stellenbosch, Cape Town institution. and the Witwatersrand. Thank you very much for your assistance. A South African database of patients with clinical, laboratory-based or genetically confi rmed PID diagnoses has been compiled in Excel format Kind regards as a registry since 2008. Patients are assigned IUIS classifi cation according to diagnosis. Both the names and diagnoses are coded and protected on a secured database. The data will also be entered anonymously on the Dr Monika Esser Ms Rina Nortje African (ASID) Registry and for international surveys. Head of Immunology Unit Secretary PID Register Local efforts in the Western Cape have increased awareness, diagnoses NHLS Tygerberg, [email protected] and reporting of PID since the Registry’s inception. However, there remains Stellenbosch University Fax: 021 938 4005; Tel: 072 210 0206

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