Se estudió la incidencia de déficits del sistema complemento en pacientes con enfermedad meningocócica, detectándose 4 pacientes con déficit completo en la actividad hemolítica mediada por el complemento (ensayo de CH50). Tres de ellos tenían un déficit completo del factor C8, dos de los cuales pertenecían a la misma familia, y el cuarto paciente presentaba un déficit parcial de C3, secundario a la presencia de un factor activador de la vía alterna del complemento, conocido con factor nefrítico, o C3-nef. En los casos con déficit de C8 se llevó a cabo un estudio familiar, detectándose otro individuo más con déficit de C( y nueve sujetos con déficit parcial (inviduos heterocigotos). Así mismo se analizaron los niveles de complejos inmunes circulantes, mediante dos tecnicas diferentes: la fijación a C1q y la unión a células Raji. Los resultados no muestran asociación entre los niveles de CIC y la severidad del cuadro clínico. / We analyzed the incidence of complement deficiencies in patients with acute meningocococcal disease. We detected four patients with recurrent meningococcal infections having a complete lack of serum haemolitical activity (CH50 assay). Three of then had a complete absence of CD8 in serum and the four patient had an aberrant activation of the alternative complement pathway due to the presence of C3-nef. Familial studies were done in the cases of C8 deficiencies, in which a fourth member was identified, together with nine individuals with a partial (heterocygotic) C8 deficiency. Finally we evaluated the levels of circulating immune complexes (CIC) by binding to C1q or to Raji cells. Our results showed a lack of association between the severity of the disease and the levels of CIC.

Octapharma tillverkar Octagam, en lösning innehållande humant immunglobulin för intravenös administrering, vars huvudkomponent är immunglobulin G (IgG). Aggregerade IgG förknippas med aktivering av komplementsystemet i frånvaro av antigen. Denna ospecifika aktivering av komplement har tidigare rapporterats orsaka biverkningar hos patienter. För att undvika detta använder Octapharmas laboratorium för kvalitetskontroll en metod som kallas test av antikomplementär aktivitet, för kontroll av batcher av Octagam innan de släpps ut på marknaden. Denna metod har flera problem, t.ex. låg tillgänglighet av viktiga reagens. Syftet med detta projekt var därför att undersöka om en alternativ metod, CIC-C1q ELISA, kunde mäta aktiveringen av komplementsystemet på immunglobuliner genom att testa olika batcher av IgG och värmebehandlade IgG-prover för att bedöma om det fanns en korrelation mellan resultaten från de två metoderna. Resultaten visade att det inte fanns någon korrelation mellan ACA-testet och CIC-C1q ELISA. Varken normala IgG-batcher eller värmebehandlade prover uppvisade någon tydlig korrelation. Den enda fördelen som C1q kan ha är att den gav ett högt resultat för en batch som tidigare har rapporterats orsaka biverkningar hos patienter, medan svaret i ACA-testet var relativt normalt. CIC-C1q ELISA metoden har dock visat sig ha sina egna problem eftersom standardprover ger inkonsekventa värden och mer tester behöver utföras för att hitta spädnings-linjäritet. / Octapharma manufactures Octagam, a liquid preparation of highly purified human immunoglobulin for intravenous administration, the main component of which is immunoglobulin G (IgG). Aggregated IgG is associated with activation of the complement system in the absence of antigen. This non-specific activation of complement has been reported to cause adverse reactions in patients. To avoid this, Octapharma's quality control laboratory uses a method called the determination of anti-complementary activity (ACA) in Immunoglobulin, for control of all batches of Octagam before release. This method has several problems, such as low availability of critical reagents. Therefore, the aim of this project was to investigate whether an alternative method, CIC-C1q ELISA, could measure the activation of the complement system on immunoglobulins by testing different batches of IgG and heat-treated IgG samples to assess whether there is a correlation between the results of the two methods. The results showed that there was no correlation between the ACA test and the CIC-C1q ELISA. Neither normal IgG batches nor heat-treated samples showed a clear correlation. The only advantage the C1q may have is that it gives a high response for a batch that has been reported to cause adverse reactions in patients, while the response in the ACA test was relatively normal. If this can be demonstrated by testing similar batches, it may be beneficial to continue testing the C1q ELISA. However, this method has also been shown to have its own problems, such as the standard sample giving inconsistent values, and more work is needed to find the linearity of the dilution.

In this study, we demonstrated that membrane immunofluorescence (MIF) with canine erythrocytes is a much more sensitive diagnostic technique compared with the Coombs test to detect auto-antibodies on RBC. We also demonstrate how the evaluation of the MIF test can be made more precisely which results in a more clear interpretation. Till nowadays the Evans syndrome (combined thrombocytopenia and anemia) is not very well diagnosed in dogs. Only a few studies with low animal numbers tested auto-antibodies on RBC and thrombocytes. Here we describe the frequency of Evans syndrome based on the evaluation of a large data set with 557 dogs. The novelty of the thesis also lies in making a research of the amount of CICs in sera of AIHA/AITP patients is described as well as the cytotoxic potential of patient’s sera for canine leucocytes. These new aspects of diagnosis (AIHA) and pathogenesis (AIHA/AITP) are not only relevant for dogs but also for humans and can be used for better differential diagnosis in medicine. The new findings with respect to circulating immune complexes and cytotoxicity are also offer new therapeutic concepts. Besides, the study has resulted in the characterization of monoclonal antibodies which allow for the detection of so far undetectable canine differentiation antigens (CD molecules) on canine erythrocytes (CD235) and thrombocytes (CD42a). The identified mAbs are useful in the identification of relevant target structures for autoantibodies on these cells.