According to the current state of science, there are various therapies that are considered to be about equally effective: the administration of cortisone as a tablet, the administration of immunoglobulins via the vein (IVIg) and plasma exchange (PE), a form of blood washing. All therapies aim to change the immune system and in particular to eliminate or reduce harmful auto-antibodies and have proven themselves over many years in the treatment of CIDP. In severe cases, additional so-called immunosuppressants (these include drugs such as azathioprine, methotrexate, cyclophosphamide, and rituximab) must sometimes be given in order to control the disease. The aim of therapy is to prevent further progression of the disease; In some of the patients, an improvement in symptoms can also be achieved. However, it has been shown that not all patients respond equally well to a certain therapy, and in some cases several therapy options have to be tried out until the individually best therapy option is found.

The administration of cortisone as a tablet is usually the first attempt at treatment for CIDP. In many cases this therapy is very effective, but sometimes the disease progresses despite cortisone therapy. Another problem with cortisone therapy is that cortisone, when given in higher doses for a long period of time, can often cause side effects such as weight gain, increases in blood sugar levels, stomach ulcers and psychological problems. In another part of the patients, cortisone therapy is out of the question due to certain concomitant diseases such as severe diabetes. In these situations the question arises as to which therapy should be used next. This question is to be answered within the scope of this study - only patients are included in the study who are out of the question for a cortisone therapy due to one of the reasons mentioned above.

The immunoglobulins are an infusion that is administered over a period of 5 days via a peripheral access (eg into a vein in the arm). The mechanism of action of the immunoglobulins is not exactly known, but it is believed that in this way the harmful effects of the antibodies in the blood can be alleviated. The main risks of this procedure are often allergic reactions (in rare, severe cases, these can be life-threatening) and occasionally an increased risk of thrombosis, which in rare cases can lead to life-threatening pulmonary embolism. Previous studies have shown that immunoglobulins are effective in most patients, comparable to cortisone therapy.

Plasma exchange replaces part of your liquid blood (called blood plasma) with a protein solution. This removes the proteins in the blood plasma (including harmful antibodies) from the blood. The procedure requires venous access to a deep jugular vein (a so-called central venous catheter or Shaldon catheter), which is applied under local anesthesia. The treatment will then be carried out daily for 5 days, with your blood being drawn out through the venous access. The main risks of this procedure are (rarely) thrombosis or bleeding due to the loss of coagulant or anticoagulant proteins as well as complications from the Shaldon catheter such as (rarely) damage to the nerves, vessels or the lung membrane (pneumothorax). The studies available also suggest that plasma exchange is equally effective in comparison to cortisone therapy in the majority of patients.

In addition to these three therapies, a further type of blood washing has proven itself in neurological autoimmune diseases, the so-called immune adsorption. Immune adsorption is similar to plasma exchange in many ways. The main difference is that the blood plasma is not replaced by a protein solution, but is passed through a special device that filters the antibodies out of your blood while other proteins are largely retained; After the blood plasma has passed through the device, the blood plasma with all remaining proteins is returned to your body through the same venous access.

This results in some advantages compared to plasma exchange: due to the extensive retention of coagulation-promoting and inhibiting proteins, thrombosis and bleeding occur less often, and overall immunoadsorption (due to the sparing of most plasma proteins) is considered to have fewer side effects compared to plasma exchange. The above-mentioned side effects (thrombosis, bleeding, injuries to blood vessels, nerves or pulmonary membrane as part of the Shaldon catheter system) also occur during immune adsorption. A disadvantage, on the other hand, is that proteins may also remain in the blood as a result, which, in addition to the antibodies, can be involved in the disease process. In addition, because of its novelty, the procedure is less well-tested than plasma exchange, and there are fewer studies showing its effectiveness. Accordingly, the procedure is not yet listed as a treatment option for CIDP in the current guidelines of the German Society for Neurology.

Previous publications, which mostly relate to the use on a few patients, so far indicate a good effectiveness of the immunoadsorption in CIDP. In our clinic, around 50 CIDP patients were treated with immunoadsorption by 2020. According to our previous experience, the therapy can partially improve the symptoms of patients who have only had CIDP for a few months. In patients with a long-term course of the disease, on the other hand, long-standing symptoms can usually not be influenced or only slightly influenced, the therapy here aims at stabilization, ie the disease symptoms should not worsen further if possible, which, according to our previous experience, usually works.

It is very important to know that all of the mentioned therapies usually have to be repeated at regular intervals, as CIDP is a chronic disease and the effect of the therapies only lasts for a limited time (weeks to months).

This study is being carried out because there is currently no clear indication which of the therapies mentioned has the best effect on the symptoms of CIDP. In particular, the effectiveness of immune adsorption in CIDP has not yet been compared with other therapeutic methods. In the context of this study, the immunoadsorption in patients who are not eligible for cortisone therapy is therefore to be compared with one of the other more established methods, namely the administration of immunoglobulin.