When autoimmune diseases emerge, the human body’s immune response produces autoantibodies that attack its own cells, tissues or organs due to an immune system malfunction. A category of autoimmune diseases, auto-immune haemolytic anaemia (AIHA) is a disorder where the immune system malfunctions by producing auto-antibodies to self’s red blood cells (RBC) as well as other cells (Gurpreet et al., 2004). This unregulated increased destruction primarily affects premature RBC reducing their lifespan of 120 days coupled with the bone marrow unable to compensate to this destruction rate (Gurpreet et al., 2004). Clinical findings that result from this inapt immune response are usually directly related to an abnormally reduced RBC quantity and function. These include a lower haemaglobin count, a high indirect bilirubin count, a reduction in plasma levels, a low haptoglobin, a positive direct antiglobulin test (DAT) and reduced gas exchange rates among the lungs and tissues. As these clinical effects occur after a few hours or a few days before detection, not all clinically related typical features may be present complicating the AIHA diagnosis. Based on the characteristics and pathogenesis of these auto antibodies present, AIHA is classed as warm antibody haemolytic anaemia (WAIHA), cold antibody haemolytic anemia (CAIHA), drug indcuced haemolytic anemia or the rare paroxysmal cold haemoglobinuria (Lechner & Jager, 2012). Analyzing AIHA classification and pathogenesis is important when attempting to apply transfusion treatment, other therapeutic applications or providing further clinical recommendations.
Although the true aetiology of the disorder in uncertain, the cause may be either primary or secondary (Lechner & Valent et al., 2008). The primary AIHA is idiopathic accounting for half of AIHA cases (Gupta et al., 2011) whilst secondary AIHA occur due to other illnesses. Despite the unknown cause, it can be detected by increases in auto antibodies attached to the red blood cells along with a decreased red blood cell quantity (Melve et al., 2004).
Various indicators of a person suffering from AIHA are examined upon clinical presentation through analyzing signs and symptoms. As AIHA is still considered an anemia subtype, anemic symptoms usually occur among those suffering from the condition particularly a massive RBC destruction. If destruction of RBCs is mild and steadily developing, the patient may show no symptoms (Lichtin 2009). Although if severe among affected patients, the symptoms are similar to those that occur with other types of anemia especially fever, weakness, headaches and shortness of breath after exercising (Zeeleder et al., 2011). These particular symptoms are related to the AIHA classification as a warm AIHA usually due to primary causes and IgG class antibodies. When RBC destruction is rapid, severe jaundice may develop whilst long term AIHA results in splenomegaly causing abdominal fullness and discomfort among patients. AIHA secondary causes show symptoms of underlying disorders like swollen lymph nodes and fever (Lichtin 2009).
Established AIHA diagnostic criteria are used for analysing and evaluating AIHA severity in addition to applying appropriate therapy. This criterion (Petz et al.,) uses the clinical history in conjunction with diagnostic methods to evaluate findings of AIHA. Succeeding methods for diagnosis like the direct antiglobulin tests (DAT) confirm the concentration of antibodies attached to the RBCs whilst the indirect antiglobulin test (IAT) help confirm if antibodies are bound to the liquid portion of the blood. In addition Sokol et al., (1992) found that half of the warm antibodies are idiopathic anaemias usually causing AIHA whereas most cold antibodies less commonly identified account for most of the secondary anaemias. Using these guidelines, the specific criteria for AIHA diagnosis are occurring RBC destruction, the presence of autoantibodies in patient plasma, low haemaglobin quantification and a positive DAT. Furthermore, the significance of antibody diagnostic features can be used in conjunction with more compatibility testing to ensure appropriate match of donor and recipient prior to administering transfusion.
As a requirement, those suspected with AIHA should have compatibility testing done within six hours in order for the transfusion process or other appropriate treatment to commence (Garraty et al., 1998). The compatibility testing aims to determine patient’s plasma and potential donor RBCs compatibility and the presence and relevance of auto or allo-antibodies through adsorption studies. Normally compatibility testing includes an ABO and Rh typing, antibody screening and specificity, cross-matching, elution, adsorption analytical methods and other antibody investigation methods (Hoffman 2009).
Serological tests are undertaken for the analysis of warm and cold AIHA in the laboratory to assess the presence of an auto-antibody in addition to evaluation of potential treatment methods like transfusion. Upon sample presentation to the transfusion laboratory, they are initially grouped and screened to confirm patient’s ABO and Rh blood group (Zeerleder 2011). The succeeding DAT screening for antibody detection test is then performed which determines if the RBC has been coated with antibodies primarily IgG or complements like c3d or even both (Valent & Lechner 2008). This is done with the use of a poly-specific anti-human-anti-globulin which binds human antibodies likely causing the autoimmune haemolysis. This particular procedure will investigate whether haemolysis is immune related or not. A positive DAT indicates immune haemolytic anaemia whilst a negative DAT usually occur in non-immune haemolytic anaemias (Lawrence et al., 2004). WAIHA would usually show positive reactions with antisera to IgG regardless of complement activation whilst the CAIHA antisera would react to complements and irregularly to IgG.
Narrowing down the basis of a positive DCT results, the specificity is tested using mono-specific reagents of C3d or IgG to decide if RBC are coated a specific antibody or complement class. A warm acting antibody is found to cause the WAIHA when the DAT mono-specificity indicates the findings of an IgG antibody (Zeerleder 2011). For further antibody specificity testing of a WAIHA, elution is performed on patient’s RBC and the resulting eluate (or removed antibody) is tested for auto-antibody specificity (Lawrence et al., 2004). The eluate which contains the auto-antibody which was bound to the RBCs is obtained through alterations of ionic bonds among the antigen-antibody complex formation. This elution study will determine the auto-antibody reactivity and its specificity with cells other than the patient’s own (Valent & Lechner 2008). The eluate is tested against a panel of red cells to determine if it is directed only against the patient’s own red cells. Assessment of the elution studies results determines the reactivity and specificity of the antibodies of an AIHA patient. Antibodies that are reactive will react to the applied panel cells in a specific or non-specific manner while antibodies that are non-reactive are suspected to be only specific to patient’s red cells (Zeerleder 2011). These specific antibodies are commonly targeted towards parts of the different blood group systems while the non-specific antibodies would usually react with most or all panel red cells tested. Knowing the specificity of the patients auto-antibodies is significant in transfusion management but does not determine the expected outcome of the transfusion as transfusion of RBC that contain these targeted antigens are sometimes still tolerated just like RBC without the antigen. Contrariwise, CAIHA serological procedures are similar although the antibody is usually IgM and within the periphery binds in cold and dissociates in warm settings. The antibody screening and determination of underlying allo-antibody techniques can also be used for WAIHA and CAIHA (Zeerleder 2011).
As the patient may present with an auto-antibody that reacts with all panel red cells from the screen, these auto antibodies may mask the availability of alloantibodies in the blood, making transfusion increasingly difficult. Alloantibodies may be present and cause a reaction in the occurrence of haemolytic transfusion or increase the damage on the RBC. Patients may be at risks of producing clinically significant allo-antibodies if previously transfused or pregnant. These undetected allo-antibodies increase haemolytic reactions in the body giving a fake illusion of severe AIHA. Even though these can be uncovered through the IAT method, allo-adsorptions and auto-adsoprtions should be performed with an understanding of the patient’s previous transfusion history.
Allo-genenic adsorptions are undertaken when underlying allo-antibodies are a suspected cause which can be due to recent transfusion (within the last three months) or less patient RBCs available as there are multiple populations of RBCs in the patient. On the contrary, auto-adsorption may be performed to adsorb the auto-antibody out of the patient plasma leaving only the allo-antibodies providing the patient has not been recently transfused as introduction of new red blood cell population can cause interferences (Lawrence et al., 2004). During auto-adsorption, the patient’s RBC are initially treated to boost interactions with the suspected auto-antibody then subsequently added to the patient’s plasma before incubation. After adsorption by the described process, the antibody screen can now be done to determine if the reactivity. No reactivity concludes that patients RBC’s do not contain allo-antibodies present and appropriate matching units can be selected for the pre-transfusion testing and transfusion or other preferred therapy. Despite this progressive pre-transfusion testing outcome, reactivity may occur in the antibody screening of the auto-adsorption. The positive auto-adsorption screening result is of clinical significance and must be followed up by antibody identification techniques along with thoughtful interpretation especially when investigating the complete removal of auto-antibodies (Ruddman 2005). Allogeneic adsorption techniques contrast by using blood samples that lack certain blood group antigens. This process comprises the use of allogeneic RBCs which can also be treated by enzymes to adsorb the antibody. The adsorbing RBC may possibly be different from the patient’s own RBC therefore carefully selection must be done so there is no accidental adsorption of both allo-antibodies and auto-antibodies from the patient’s plasma (Lawrence et al., 2004). With this, in order to rule out the majority of allo-antibodies, a minimum of three phenotypical appropriate RBC which contains blood group phenotypical antigens that are absent is used (Ruddman 2005). If the RBC is treated with an enzyme, this will help the possible detection of anti Fya, Fyb and S. The red cells usually used are K negative cells, R1R1, R2R2 and rr individual cells as well as one of the cells lacking Jka and another cell lacking Jkb (Ruddman 2005). The timing of the compatibility testing, antibody identification and adsorption studies is an important factor and must be correctly followed in order for the appropriate transfusion or alternative therapy to commence.
AIHA patients usually have severe anaemia that requires blood transfusion for therapy however one should avoid transfusion unless necessary because of the risks like alloantibody formation. Determining if patient’s health status and requirements would benefit from a transfusion requires proper communication between clinicians and laboratory scientist’s in order to review the urgency, difficulties and apply transfusion therapy with correct timing. Usually considerations for transfusion of fresh blood units should be made for persons above 50 years old who are suffering from cardiovascular diseases. Other vital parameters analyzed before the application of transfusion include cardiac function, renal function and diuresis. When there is no vital indication for a transfusion immunohaematological tests must be assessed before selection of appropriate blood units and transfusion may be applied (Ruddman 2005).
Depending on the AIHA class, transfusion and several treatment methods may be applied for therapeutic purposes (Lawrence et al., 2004). Providentially CAIHA is usually mild and treatment is usually not required. The only applied treatment is keeping warm by protection against the cold. If transfusions or surgery are applied, they are done under 37 oC (Zeerleder 2011). The criteria for choosing the correct blood products are still similar to the WAIHA practice. Compared to CAIHA, the transfusion of patients with WAIHA class is critical due unit selection for transfusion and complicated by the presence of an auto-antibody showing specificity (McClatchey 2002). For example, deciding whether to transfuse e negative or e positive blood to an R1R1 phenotypical patient. During compatibility testing, e negative blood will likely react in the cross match as incompatible and if the haemolysis is caused by anti-e, transfusion of these units will worsen the case. Whilst in this same case, e positive units are expected not to react but may cause the patient to making anti-e which may complicate antibody identification and blood transfusion. In the occurrence of transfusion, the blood products must be compatible with respect to allo-antibodies in the serum which may activate complement. Selected blood units should be negative for the antigens the allo-antibodies have been identified for during compatibility testing whilst preventing the development of new allo-antibodies (Ruddman 2005). Minimal requirements for selected transfusion units have been suggested to be Kell and Rhesus compatible and if possible consideration of auto-antibody specificity (Ruddman 2005). Timing is a critical factor in transfusion settings and in emergency cases prevention of the allo-antibody formation is the most important factor. Despite this, transfusion of a WAIHA patient is usually avoided unless ordered by a haematologist consultant. Alternative methods like immunosuppressive or steroid therapy are preferred (Hillyer 2009).
The transfusions of pateints with AIHA have been shown to be present with other commonly occurring problems. Broadly reactive antibodies from the patient can cause units of RBCs to be imcompatible adding a factor of uncertainty when assessing the risks and benefit of a potential transfusion (Hillyer 2009). The difficulty that frequently emerges in most cases is the presence of auto-antibody in the patient’s serum which may also cover the presence of allo-antibodies capable of causing haemolytic transfusion reactions (HTR) (Hillyer 2009). In addition, other common difficulties in AIHA management of patient transfusion is the reluctance to transfuse when possible complications outweigh the benefits of the transfusion and uncertainty regarding the effectiveness and safety of the patient receiving incompatible RBC units (Zeerleder 2011). Undoubtly HTR occurs due to clinically significant antibodies but if incompatibility is due to only the presence of a RBC antibody, the survival expectation is shown to be as effective as that of the patient’s owns RBCS. This is applicable providing appropriate compatibility testing is done to identify alloantibodies. In support, evaluation of many transfusion related clinical cases have shown that the correct examination of patients need for a transfusion is more essential than the results from compatibility testing (Ruddman 2005).
Evidence of the current knowledge of AIHA pathogenesis has helped to provide frameworks for clinical applications and prognosis of related compatibility testing and transfusion methods although the underlying aeitology is not certain. As previously discussed with precision, the compatibility testing of AIHA investigation, allo and auto-antibody studies, and the use other appropriate diagnostic routines and their timing is critical in order for application of the most suiting cells for transfusion or other therapeutic method.

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