Immune Tolerance Clinic
Some hemophilia patients develop an inhibitor. Inhibitors are antibodies that the body makes which are directed against the missing or abnormal clotting factor. This inhibitor prevents the factor from doing its job during bleeding episodes. This serious problem is discovered either through routine laboratory tests or when a patient has a bleeding episode and factor does not seem to stop the bleed. The presence of an inhibitor requires a special infusion plan and close monitoring by a hematologist.
Once an inhibitor is detected, the patient may start immune tolerance therapy. The idea behind this is to infuse factor on a regular basis (sometimes as much as two times per day) so that the body will get used to the factor and stop making an antibody. Dependent upon the level of the inhibitor, additional infusion therapy may be required to stop bleeding when it happens.
The frequency of clinic visits for a patient on immune tolerance therapy is based upon each patient’s situation. Patients who are repeatedly bleeding while on immune tolerance therapy may require more frequent infusions and visits in order to manage these bleeding events.
During a routine clinic visit for a patient on immune tolerance therapy, a patient history will be obtained regarding bleeding episodes experienced and how well current therapy is working. If a central venous access device is present, issues related to that device will be reviewed and addressed. Oftentimes blood is drawn during clinic visits to determine if the inhibitor is still present and its level. At times, response to infusion therapy through a half-life study may also be obtained (half-life is the amount of time that factor survives in the body or circulation; it is measured in the amount of time it takes for half of the factor to disappear). This is accomplished by giving factor and then measuring factor levels at specific times such as one, two, four and six hours, etc., after infusion. Additionally, during the immune tolerance clinic visit, x–rays and other radiographic studies may be ordered based upon the patient’s particular history and problems.
A physician and nurse staff the IHTC immune tolerance clinic. A physical therapist is available, as are other members of the IHTC’s multidisciplinary team for any identified problems. Notably, the physical therapist tends to be fairly involved with patients with inhibitors.
