What Is Combined Immunodeficiency (CID)?

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 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 don't harm kids 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.

How Do You Diagnose Combined Immunodeficiency in Kids?

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.

If your child has severe lung damage from frequent pneumonia or infections, a lung transplant may also help.

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 (CRDT) at UPMC Children's Hospital of Pittsburgh 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.

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

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

These may include experts 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 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.

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 CRDT, 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.

Center for Rare Disease Therapy patient storiesMeet Our Rare Disease Center Patients

Learn how others are finding help and hope for their child’s rare disease through the expertise at UPMC Children’s.

View Center for Rare Disease Therapy patient stories »

Contact Us About Your Child’s CID

At the CRDT, every child diagnosed with a rare disease receives a tailored treatment plan and family-centered care.

For an appointment, consult, or referral, contact us:

We’ll be in touch within 2 business days.