Immunology clinical outcomes

The Immunology Department at Great Ormond Street Hospital (GOSH) offers a comprehensive diagnostic and treatment service for children up to the age of 16 years with suspected or confirmed primary immunodeficiency. Services are also provided for children with a variety of other immunological disorders (excluding allergy at present).

Primary immunodeficiency disorders (PIDs) form a group of rare disorders that vary widely in severity. The human body relies on the immune system – a uniquely complex family of specialised disease-fighting cells – to ward off attack from infectious agents, such as viruses and bacteria. Children with PIDs are compromised in their ability to fight these infections.

Infants and children at the mild end of the PIDs spectrum can be affected by frequent minor infections, while the more severe PIDs lead to life-threatening infections and other life-limiting complications. Those affected by the more severe PIDs may require inpatient care, and some require stem cell transplantation (SCT). A small and highly selected group of children also undergo gene therapy procedures or thymus transplantation.

GOSH is one of two specialist centres in the UK that treat children with severe PIDs, and is one of the largest centres worldwide. This service is provided by a close collaboration between the Immunology Department and Bone Marrow Transplant Unit.

PIDs at the severe and/or complex end of the spectrum are broadly divided in to two categories: Severe combined immunodeficiency (SCID) and other severe PIDs (called 'non-SCID' as a group).

Initial treatment as soon as the diagnosis is established involves medication with antibiotics, anti-fungals, and (in some cases) anti-viral medicines to protect against serious infection. Affected children are not able to produce their own antibodies to fight infection, so replacement antibody (called immunoglobulin) is given. Blood and platelet transfusions may also be needed.

Stem cell transplantation is the most usual treatment for long-term cure of severe PIDs. Healthy bone marrow is rich in stem cells, from which all the cells of the immune system develop, and it is possible to take bone marrow from a healthy individual and give it by transfusion into most children with severe PIDs.

In most cases preparatory treatment with chemotherapy and/or immunosuppressive medications are needed to prevent rejection of the transplanted bone marrow by any residual immune system. These are complex treatments that carry significant risks and complications, but, if successful, can result in cure.

For some disorders (SCID and non-SCID) it is possible to correct the defective gene in the patient stem cells. These gene-corrected stem cells can be returned by transfusion to the patient. This is called autologous SCT or gene therapy, and reduces the need for chemotherapy and immunosuppressive medications.

Bone marrow transplant (BMT) for the treatment of SCID offers the likelihood not only of long-term survival, but also long-term cure, with a normally functioning immune system. This is known as 'immune reconstitution'.

The chance of a successful outcome depends on a number of factors, including how early the diagnosis is recognised, complications at the time of diagnosis, and the closeness of the match between recipient and donor.

In Figures 1.1 and 1.2 below, we show our SCID transplant survival rates by year of BMT at 100 days and one year post-transplant. Our overall survival rate is comparable to other centres, both nationally and internationally.

Fig 1.1 SCID transplant survival rate at 100 days, 2008 to 2021

Fig 1.2 SCID transplant survival at one year, 2008 to 2021

Table 1.1 SCID transplant survival at 100 days and one year post gene therapy, 2020

BMT in the treatment of non-SCID has very high rates of survival and can also result in complete immune reconstitution. Figures 2.1 and 2.2 below show our non-SCID transplant survival rates by year of BMT at 100 days and one year post-transplant. Our overall survival rates are again comparable to other centres, both nationally and internationally.

Fig 2.1 Non-SCID transplant survival rate at 100 days, 2008 to 2021

Fig 2.2 Non-SCID transplant survival rate at one year, 2008 to 2021

Table 2.1 Non-SCID transplant survival at 100 days and one year post gene therapy, 2020

T-cells are one type of white blood cells that play an important role in the immune system. These cells originate in the bone marrow but complete their maturation in the thymus, a small gland that lies in the front of the heart.

Babies born without a thymus suffer from congenital athymia. They don’t have T-cells and are extremely vulnerable to infections. The problem can be corrected by transplanting thymus tissue from another baby, who has a normal immune system, but in whom part of the thymus needs to be removed during cardiac surgery.

GOSH is the only European centre performing this life-saving treatment. Congenital athymia is very rare and in most affected infants, it is due to a disorder called complete DiGeorge Syndrome.

Table 3.1 Congenital athymia survival at 100 days and one year post-thymus transplantation, 2020 to 2021

This information was updated in February 2023.