You Ask , They Answer
Q
: What are primary immunodeficiency diseases ( PID ) and which symptoms are associated with them ?
A
: PID are caused by hereditary defects involving genetic mutations that affect the immune system . They result in increased susceptibility to infections , changes in molecular control of immune processes ( immune dysregulation ), chronic systemic inflammation ( autoinflammatory ), uncontrolled production of white blood cells ( lymphocytes ), and / or lymphoma ( blood related cancer ).
Q
: In which cases should babies or children get tested for primary immunodeficiency disease ?
A
: Those who have a family history of primary immunodeficiency diseases should get tested , as should those with clinical manifestations suggestive of PID , such as unusual infections or opportunistic infections , which tend to occur in people with weakened immune systems . Opportunistic infections , such as the fungus Pneumocystis jiroveci , may be a clue for PID .
The Jeffrey Model Foundation has introduced 10 warning signs for parents and paediatricians to identify PID :
• four or more new ear infections within one year
• two or more serious sinus infections within one year
• two or more months of oral antibiotic treatment with little effect
• two or more episodes of pneumonia within one year
• failure to thrive
• recurrent , deep skin or organ abscesses
• persistent thrush in mouth or fungal infection on skin
• need for intravenous antibiotics to clear infections
• two or more deep-seated infections , including septicaemia or blood poisoning
• a family history of PID
Q
: What are the treatment options for the disease and how effective are they at keeping it at bay ?
A
: Treatments include antibiotic prophylaxis ( to avoid infections ), aggressive treatment of infections with intravenous antibiotics or antifungal / antiviral remedies depending on the micro-organism isolated from blood cultures , and immunoglobulin replacement therapy ( for those with primary antibody defects ). Some may benefit from curative treatments , such as allogeneic bone marrow transplantation , depending on their PID gene defect .
Immunoglobulin replacement therapy is a lifelong treatment and involves regular 3-4 weekly infusions of immunoglobulin G , a type of antibody . This is indicated for those with primary antibody defects where they have defective antibody production leading to no antibodies or cases where the antibodies that were produced malfunctioned .
Q
: When is a stem cell transplant recommended , how does it work , and is it curative ?
A
: Stem cell transplant is recommended for some type of PID , such as severe combined immunodeficiency diseases ( SCID ). Data from a multicentre study in the United States showed that the best survival outcome for SCID patients undergoing transplant occurs when performed before the age of 3.5 months with no active infection upon transplantation . The procedure works by replacing the defective hematopoietic stem cells in SCID patients with normal and functioning stem cells from another matched donor . Hematopoietic stem cells are responsible for the body ’ s ability to manufacture blood cells . Stem cell transplants offer a greater chance of cure for SCID patients . Many PIDs are successfully cured by this type of hematopoietic stem cell transplantation ( HSCT ), with the survival rate having increased from 50 percent to 90 percent in the last 20 years .
Q
: How can parents avoid passing down the faulty gene to their offspring ?
A
: Because of the nature of the disease , it might be difficult to avoid passing down the faulty gene to one ’ s offspring . Depending on the type of genetic mutations , we can predict and detect them early at birth and do the necessary workup to confirm the diagnosis . This is crucial as early intervention and treatment can save lives .
Dr Intan Juliana Abd . Hamid
Dr Intan Juliana Abd . Hamid is a Consultant Paediatrician and Clinical Immunologist ( Institut Perubatan & Pergigian Termaju , Universiti Sains Malaysia ) and an executive committee member of the Malaysian Paediatric Association .
10 MARCH 2022 GlobalHealthAsiaPacific . com