Primary immunodeficiencies

Primary immunodeficiencies are rare diseases, most often of genetic origin, in which part of the immune system does not function properly from birth. They affect both children and adults and may sometimes only become apparent later in life. They most commonly manifest as infections that recur frequently, last a long time or respond poorly to treatment; some are associated with autoimmune or inflammatory manifestations. Recognising these signs enables an appropriate diagnosis and management. In the event of unusual and recurrent infections, a specialist consultation, following referral by your general practitioner, is recommended.

Our Immunodeficiency Treatment Unit brings together internist-immunologists, paediatricians, biologists, pulmonologists, gastroenterologists and infectious disease specialists around the patient. The process begins with an immunological assessment: measurement of antibodies (immunoglobulins IgG, IgA and IgM), evaluation of the response to vaccines, analysis of immune cells and, when useful, genetic testing. This assessment enables an accurate diagnosis and identification of the type of deficiency. Care is personalised: prevention and rapid treatment of infections, appropriate vaccinations and, for many antibody deficiencies, replacement therapy with immunoglobulins administered in hospital (intravenously) or at home (subcutaneously). Regular follow-up aims to detect and treat any complications (autoimmune, pulmonary or digestive) and to adapt treatment over time. This coordinated, multidisciplinary approach, from childhood through adulthood, improves quality of life and reduces the risk of complications.

On a daily basis, simple measures help limit infections: keeping vaccinations up to date, good hand hygiene, regular dental care and prompt treatment of infections. Most episodes can be managed on an outpatient basis. However, you should seek medical advice without delay, or even go to the Emergency Department on the advice of our available specialist doctors, in the event of a high and persistent fever, breathing difficulties, a sudden deterioration in your general condition, neck stiffness or signs of a severe infection. If in doubt, contact your healthcare team: it is better to make one call too many.

1. First signs and referral — Recurrent, persistent or poorly responsive ENT, bronchial or pulmonary infections may suggest an immunodeficiency. The general practitioner or paediatrician then refers the patient to a specialist consultation.

2. Assessment and diagnosis — A blood test measures antibodies (IgG, IgA and IgM) and the response to vaccines; analysis of immune cells and, sometimes, genetic testing complete the assessment. These tests confirm the diagnosis and determine its type, such as common variable immunodeficiency (CVID), the most common form in adults.

3. Starting treatment — When an antibody deficiency is confirmed, replacement therapy with immunoglobulins is generally offered, either by intravenous infusion in hospital or subcutaneously at home. This is combined with prompt treatment of infections and appropriate vaccinations.

4. Long-term follow-up — Regular consultations are used to monitor treatment effectiveness, adjust doses and detect any autoimmune, pulmonary or digestive complications. Follow-up is coordinated between the various specialists.

5. Daily life and support — Therapeutic education, support from patient associations and, for children, planning the transition to the adult team help patients live as well as possible with the condition.

Many primary immunodeficiencies diagnosed in childhood require lifelong follow-up. To ensure a seamless transition, the move from paediatrics to adult medicine is prepared in advance, progressively and with support. The young patient meets the adult care team, gains a better understanding of their condition and treatment, and becomes more independent. Paediatricians and adult physicians share medical information so that the transition takes place smoothly, without any loss of information or interruption in care.

Our team participates in international research on inborn errors of immunity. The work of Jean-Christophe Goffard, conducted in collaboration with major academic networks, has notably helped explain why some people develop severe forms of viral infection: it has demonstrated the role of autoantibodies directed against type I interferons—key molecules in antiviral defence—and of underlying immune deficiencies, for example in severe COVID-19. This research improves the diagnosis of immunodeficiencies and paves the way for more personalised care.