What is Transfusion Selective IgA Deficiency?
Selective IgA deficiency is a condition where levels of a specific type of antibody, called IgA, are reduced but other antibodies, IgM and IgG, are at normal levels. This is the most commonly found immune system disorder. Interestingly, even though this deficiency is quite common, most patients with this condition don’t show any symptoms when they receive a blood transfusion. This is largely because most of these patients don’t produce anti-IgA antibodies. Even though it isn’t definitively proven that anti-IgA antibodies cause transfusion reactions, some reports point to their significant role in this context. However, in some patients where anti-IgA antibodies are produced, they may experience a severe allergic reaction, or anaphylaxis, when receiving a blood transfusion.
What Causes Transfusion Selective IgA Deficiency?
Anaphylactic transfusion reactions are severe allergic reactions that can occur within an hour of receiving a transfusion of blood products that contain plasma. This specific reaction is called a ‘selective IgA deficiency mediated anaphylactic transfusion reaction’ and can affect people who lack a certain type of protein (IgA) in their blood and have antibodies that react against this protein.
There is some evidence suggesting that reactions in individuals with selective IgA deficiency occur because of these so-called ‘anti-IgA antibodies’. In a certain report, these antibodies were found in about 76.3% of people with IgA deficiency who had a history of severe transfusion reactions, while only in 21.7% of those with the same deficiency but without any symptoms.
However, the exact role of anti-IgA antibodies in causing reactions is still being debated. For example, there have been cases when IgA deficient individuals have received blood products containing these antibodies without any adverse effects. Similarly, transfusion of blood products containing IgA protein does not always result in reactions in presence of anti-IgA antibodies. Therefore, while anti-IgA antibodies do seem to have some association with transfusion reactions in people lacking IgA, more research is needed to fully understand their role.
Risk Factors and Frequency for Transfusion Selective IgA Deficiency
Selective IgA deficiency, a health condition, happens in roughly 1 in 600 individuals in the western world. However, these numbers can vary greatly among different ethnic groups. It’s been estimated that roughly 1 in 1200 people with IgA deficiency have anti-IgA antibodies. In terms of blood transfusion reactions triggered by anti-IgA antibodies, it’s estimated that these occur in about 1.3 out of every million blood products transfused.
Signs and Symptoms of Transfusion Selective IgA Deficiency
Before a blood transfusion, health workers must take a detailed history. They should ask if the patient has undergone blood transfusions in the past and whether they have experienced any reactions because of them. Patients with a condition called selective IgA deficiency are more likely to have transfusion-related reactions.
If an extreme allergic reaction, known as an anaphylactic reaction, happens after a blood transfusion, patients can show skin, lung, heart, and sometimes, stomach symptoms. They generally experience hives, difficulty breathing, low blood pressure, and diarrhea. Although these reactions are serious and could be life-threatening, some patients might have less severe symptoms, or none at all.
Testing for Transfusion Selective IgA Deficiency
At the present time, there aren’t clear rules across the board about when to check for antibodies against a protein called IgA. Just because someone has these antibodies doesn’t mean they’re definitely going to have a severe allergic reaction. It’s possible that a person who tests positive for these antibodies could be mistakenly labeled as being in danger. They could then have to use special blood products that lack IgA for the rest of their life, possibly leading to harmful delays.
So, one proposed solution is to only test people for the antibodies if they’re in a high-risk group before they receive blood products. However, anyone who’s had a severe allergic reaction to a blood transfusion in the past should have a lab test for IgA and the antibodies against it.
Treatment Options for Transfusion Selective IgA Deficiency
If you have a condition called selective IgA deficiency and you undergo a blood transfusion, typically you’ll have no symptoms. However, in rare cases, an extreme allergic reaction known as anaphylaxis can occur. In these emergency situations, the transfusion is stopped immediately, and a medication called epinephrine is given. If you have low blood pressure, you may need fluids through an IV. It’s also necessary to monitor and ensure easy breathing, possibly providing oxygen. In severe cases, a tube may need to be inserted into your windpipe to help maintain an open airway (this is called “intubation”), and medications to increase blood pressure, known as ‘vasopressors’, might be needed.
It’s also important to note that anaphylaxis symptoms can come back a few hours after the initial episode, so patients should be watched for up to 24 hours after the symptoms have eased off.
If a patient who has never been diagnosed with IgA deficiency experiences an anaphylaxis during a transfusion, it’s believed that IgA anaphylaxis might be the cause, but additional transfusions are needed, there may not be enough time to check for anti-IgA antibodies (immune proteins that react against IgA). In such cases, the safest way to continue the transfusion is to use washed red blood cells and plasma or platelets from donors known to have IgA deficiency.
If a platelet transfusion is needed quickly and platelets from an IgA deficient donor are not available, the platelets can be washed–although this is a skill-demanding procedure. If fresh frozen plasma is needed quickly and plasma from IgA deficient donors is not at hand, then the transfusion can be started slowly under careful monitoring. This is generally considered safe since not all suspected IgA anaphylaxis cases actually involve anti-IgA antibodies.
If you have confirmed IgA deficiency and anti-IgA antibodies and you need blood products from an IgA deficient donor, but these are not readily available, then a medication called ‘recombinant activated coagulation factor VII’ (rFVIIa) can be considered. This medication doesn’t contain IgA and hence, is generally safe for patients with IgA deficiency.
For patients with anti-IgA antibodies who require replacement of their Ig (immunoglobulins–proteins that your immune system uses to fight infections), a medication called subcutaneous immunoglobulin (SCIG) is a safe alternative. In a previous study, four patients with anti-IgA antibodies had no side effects when given SCIG. In some cases, the anti-IgA antibodies disappeared, and these patients were able to receive intravenous immunoglobulin (IVIG), injected directly into the veins.
If you have IgA deficiency, have had reactions to IVIG in the past, and SCIG is not a good choice for you, then a different type of IVIG with low IgA content can be considered. There’s also a potential approach wherein patients are gradually made less sensitive to IgA-containing blood products, in a process called ‘desensitization’. In one case, a patient was successfully desensitised to IgA, allowing them to receive standard blood products without complications. They achieved this via a continuous drip of gradually increasing concentrations of IgA-containing immunoglobulins.
What else can Transfusion Selective IgA Deficiency be?
When identifying selective IgA deficiency in patients who have had a blood transfusion, doctors need to think about and look for signs of various reactions that could happen after a transfusion. These could include:
- Anaphylactic transfusion reaction (a severe allergic reaction)
- Acute hemolytic transfusion reaction (a reaction where the body attacks the new blood cells)
- Transfusion-related acute lung injury (an injury to the lungs related to the transfusion)
- Circulatory overload (too much blood leading to heart problems)
- Sepsis (severe infection spreading through the body)
- Interaction with ACE inhibitors (a type of blood pressure medication)
- Simultaneous exposure to other allergens
- Urticarial transfusion reaction (rash or hives resulting from the transfusion)
- Febrile non-hemolytic transfusion reaction (fever and other symptoms without blood cell destruction)
- Primary hypotensive reaction (a severe drop in blood pressure)
What to expect with Transfusion Selective IgA Deficiency
An allergic reaction that occurs from a blood transfusion, which is known as an IgA-mediated anaphylactic transfusion reaction, can be extremely serious, even potentially life-threatening. Looking at data from 2006 to 2009, it was estimated that about 0.3% of people in the United States who were hospitalized or visited the emergency department because of this severe allergic reaction, unfortunately, did not survive the incident.
Even though this statistic signifies a relatively low rate, it remains essential for medical personnel to respond quickly and effectively when they suspect a patient might be experiencing an IgA-mediated anaphylactic transfusion reaction. That is because the faster the appropriate treatment is given, the better the chances are for the patient to have a successful recovery.
Possible Complications When Diagnosed with Transfusion Selective IgA Deficiency
The biggest risk connected with IgA-related transfusion reactions is a severe allergic response called anaphylaxis. Anaphylaxis is an extremely dangerous health emergency that can potentially be deadly. Because of this, it’s crucial that any instances of anaphylaxis are addressed immediately.
Common Risks:
- Severe allergic reaction (Anaphylaxis)
- Potential fatality
Preventing Transfusion Selective IgA Deficiency
People with a condition called selective IgA deficiency should consider wearing a medical alert bracelet. This bracelet should clearly indicate their health condition and that they are more prone to getting allergies from certain blood product transfusions. This advice is meant for individuals with this condition regardless of whether they have developed anti-IgA antibodies or not. Anti-IgA antibodies are immune system cells that mistakenly target a protein called IgA in our bodies.
At this time, there are no specific guidelines detailing how often people with IgA deficiency should be checked for the emergence of anti-IgA antibodies. However, one long-term study did find that about 12% of people with very low IgA levels (less than 0.05 mg/dL) developed these antibodies over a period spanning 16 to 21 years. So, patients must understand that even after a long time, there’s still a chance of experiencing an allergic reaction.
