Immunology clinical outcomes

Clinical outcomes are broadly agreed, measurable changes in health or quality of life that result from our care. Constant review of our clinical outcomes establishes standards against which to continuously improve all aspects of our practice.

About the Immunology Service

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

Clinical outcomes for severe PIDs treated by SCT

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.

1. Post-transplant survival rate for SCID

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 2015

SCID transplant survival rate at 100 days, 2008 to 2015

Fig 1.2 SCID transplant survival at one year, 2008 to 2015

SCID transplant survival rate at 1 year 2008 to 2015

2. Post-transplant survival rate for non-SCID

BMT in the treatment of non-SCID has very high rates of survival and can also result in complete immune reconstitution. Tables 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 2015

Non-SCID transplant survival rate at 100 days, 2008 to 2015

Fig 2.2 Non-SCID transplant survival rate at one year, 2008 to 2015

Non-SCID transplant survival rate at 1 year, 2008 to 2015
 

3. IgG levels in immunoglobulin replacement treatment

Some children have a form of PID for which transplantation is not appropriate, and in a small group of the transplantable PIDs a suitable donor is not available. These children receive long-term supportive treatment. The mainstay of this is immunoglobulin replacement. Immunoglobulin is a solution of human antibodies which have been purified from normal blood or plasma donations. It provides protection against infection and it is given either intravenously (into a vein) or subcutaneously (injection into the skin).

Treatment focuses on preventing infection and complications, and maximising health-related quality of life. International research confirms that infection rates decrease with higher IgG levels. Although there isn't international agreement on ideal levels, UK centres aim for IgG levels of greater than (>) 8 G/L.

Table 3.1 shows the IgG levels for children with Primary Antibody Deficiency (PAD) who have been on home subcutaneous immunoglobulin therapy through Great Ormond Street Hospital for more than a year. The table shows the number and percentage of patients with IgG levels equal to or greater than 8 G/L and those below 8 G/L.

Table 3.1 IgG levels for children with Primary Antibody Deficiency, 2013

IgG levels 2013 Number of Patients
>= 8 80 (88%)
<= 8 11 (12%)
Total 91 (100%)

This information was published in June 2017.