What Is Combined Immunodeficiency (CID) Syndromes?

Combined immunodeficiency — also called combined immune deficiency or CID — is a genetic condition of the immune system. It's known as a "primary immunodeficiency."

Children inherit the gene for CID from their parents.

CID occurs when gene mutations cause defects in the immune system. This is the same disease process as severe combined immune deficiency (SCID), but CID is a less serious and aggressive form.

The immune system's main role is to fight infections and anything else it sees as foreign invaders to the body.

In CID, the body has little immune response. This means that children with this disease are highly at risk of getting infections, which become severe.

Bacteria, viruses, fungus, and other germs that aren't harmful to children with normal immunity can be fatal to children with CID.

Doctors see this disease in very young children. When babies are born, their systems have protective immunity from antibodies they received while in the womb.

As these antibodies from the mother leave the system over the first few months, the symptoms of CID begin.

CID, unlike SCID, worsens at a slower rate. And life-threatening complications may not appear for several years.

Combined Immunodeficiency Symptoms

Symptoms of CID are much the same as symptoms of other childhood illnesses. But, they may be longer-lasting and more severe.

CID symptoms are:

  • Respiratory infections that keep coming back, including sinus and lung infections.
  • Ear infections.
  • Overgrowth of yeast in the mouth (thrush) or severe diaper rash.
  • Infections on the skin that don't respond well to treatment.
  • Diarrhea.
  • Slow growth or slow weight gain.

Complications of CID

Children with primary immune deficiencies like CID are:

  • More prone than others to infections.
  • Slower to clear infections when treated.

Infections that wouldn't have much effect on other kids can become life-threatening in those with CID.

Diagnosing Combined Immunodeficiency

Most states now screen newborns for CID because, although it's rare, it's crucial to treat it early.

Doctors diagnose CID with a blood test that measures lymphocytes (a type of white blood cell) in the blood.

Further blood tests can show what type of CID your child has and what immune cells aren't working properly.

Combined Immunodeficiency Treatment

The goal of treating CID is to prevent your child from getting infections, which can become life-threatening.

Enzyme-replacement therapy can treat certain types of CID. This treatment does not cure the disease.

The most accepted treatment for CID, which cures the disease, is bone marrow transplant or stem cell transplant.

A lung transplant might also be appropriate if your child also has severe lung damage from frequent pneumonia or other lung infections.

The Hillman Center for Pediatric Transplant has the only program in the world that offers tandem lung and bone marrow transplants.

We also pioneered a reduced-intensity bone marrow transplant program. The program helps reduce the adverse effects a bone marrow or stem cell transplant has on the body's organs.

Because transplants are high-risk treatments, your child may need to take medicine for the rest of his or her life.

Paul Szabolcs, MD

Chief, Bone Marrow Transplant and Cellular Therapies

Dr. Szabolcs is a pioneer in reduced-toxicity/intensity unrelated donor cord blood transplant for inborn errors of the immune system. He's the first to prove the feasibility of sequential lung and bone marrow transplantation from the same unrelated deceased donor.

Your Child's CID Consult and Care: What to Expect

If a doctor diagnosed your child with combined immunodeficiency, we want you to know you're not alone. The Center for Rare Disease Therapy is here to help.

To make an appointment for your child or refer a patient for CID care, contact us by:

Here’s what you can expect when you come to us for your child's first CID consult.

How soon can I get an appointment for my child's combined immune deficiency?

In most cases, we can see a new patient within 1 to 2 weeks.

We'll ask the referring doctor to send your child's records so we can review them before your visit.

What should I expect at my child's first visit for CID?

Your first visit will take between 4 and 6 hours.

Your child will have a full evaluation from Paul Szabolcs, MD, chief of Bone Marrow Transplant and Cellular Therapies.

Dr. Szabolcs will make or confirm a precise diagnosis and find out how much the disease has progressed.

Because we work as a team here at the center, other doctors and staff might see your child during your visit.

These may include specialists in:

  • Genetic diseases
  • Brain diseases
  • Child development
  • Hearing
  • Physical therapy

What are the next steps after my child's visit to the center for CID care?

Before you leave the center, you'll have a CID care plan tailored to your child’s needs.

Members of your child's CID care team will talk with you about:

  • Likely next steps for your child.
  • Treatment options for your child's combined immunodeficiency.
  • Ways to care for your child at home to help improve his or her quality of life.

If surgery might be an option for treating your child's CID, we'll go over all the details. We'll let you know how you and your child can prepare.

We'll also schedule a follow-up visit in 3 months.

You'll meet our nurse practitioner (NP). You can contact our NP by phone or video conference with any concerns you have between now and your next appointment.

Before you leave, please feel free to ask us about your child's CID diagnosis, treatment, or anything else on your mind.

How soon will I get my child's CID test results?

We'll call you within 2 weeks to discuss the test results and next steps for your child's CID care.

You can also find your child's test results if you signed up for MyCHP — Children's patient portal.

MyCHP lets you manage your child's health online. It's free for patients of UPMC Children's Hospital of Pittsburgh and their parents or guardians

Partners in Your Child's CID Care

When a child has a rare disease like combined immune deficiency, it affects the whole family.

At the Center for Rare Disease Therapy, we see each family member as our partners.

The best care happens when we merge our CID expertise with your knowledge of what’s best for your child.

Contact us to learn more about CID or make an appointment for your child:

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Learn how families are finding help and hope at the Center for Rare Disease Therapy at Children’s Hospital of Pittsburgh of UPMC. Read stories from patients of the Center for Rare Disease Therapy. »



Clinical Studies

*Immunodeficiency and End-Stage Lung Disease Treatment with BOLT+BMT Procedure

Bilateral Orthotopic Lung Transplant (BOLT) in Tandem With CD3+ and CD19+ Cell Depleted Bone Marrow Transplant (BMT) From Partially HLA-Matched Cadaveric Donors

Read more

*Non-Malignant Marrow Disorder Treatment using Reduced Intensity Conditioning – Phase II

Study of Reduced-Intensity Conditioning In Patients With Non-Malignant Disorders Undergoing Umbilical Cord, Bone Marrow, or Peripheral Blood Stem Cell Transplantation

Read more

*Original research initiated by investigators at UPMC Children’s Hospital of Pittsburgh.