Background and objectives: Commercially available gel test microtubes are not available with antisera for the determination of IgG subclasses. The aim of this study was to adapt the gel technique for this purpose and apply it to the investigation of patients with autoimmune haemolytic anaemia (AIHA). Materials and methods: We studied 66 red cell samples from 49 patients with AIHA of the warm-active IgG type. Standard serologic and haematologic methods were used. We adapted the DiaMed gel test by using IgG-subclass antisera. Results: We found the adapted test useful in determining the subclass of autoantibodies in eluates. We could identify the IgG subclass in all the AIHA patients, even those that were ‘Coombs-negative’, with less than 200 IgG molecules bound in vivo per red cell. Comparison of the gel test with the standard spin tube test and the microtiter plate test showed the superiority of the gel test, i.e., detection of IgG subclasses was much better than with the tube test and the results were more clearcut than those of the microplate test. The gel test is also the simplest and least time-consuming and permits a later reading of results. Application of the test in our 66 samples confirmed that IgGl was the most frequent (96%). In 59% of the cases it was accompanied by IgG of other subclasses. Multiple subclasses were most common in the cases with stronger in vivo IgG red cell sensitization and severe haemolysis. Accompanying IgG3 was detected only in patients with obvious haemolysis. Conclusion: The gel test is more sensitive than other procedures for the determination of IgG subclass and has the advantages of simplicity, rapidity, low cost, and stability of the agglutinates.

In the four tests, correlation between expected and obtained results was appropriate (CCC ̴1). Each test had some advantage and limitation in any clinical situation. Therefore, it is best to have opportunity to perform two or three assays in the laboratory.

The gel test is more sensitive than other procedures for the determination of IgG subclass and has the advantages of simplicity, rapidity, low cost, and stability of the agglutinates.

Summary. Congenital dyserythropoietic anaemia type II (CDA II) is well known for glycosylation abnormalities affecting erythrocyte membrane glycoconjugates that encompass hypoglycosylation of band 3 glycoprotein and accumulation of glycosphingolipids: lactotriaosylceramides, neolactotriaosylceramide and polyglycosylceramides. These abnormalities were not observed in erythrocytes from patients with CDA of either type I or III. Recently, however, we have described a CDA type I patient in Poland with identical, though less pronounced, glycoconjugate abnormalities to those observed in patients with CDA type II. The abnormalities included partial unglycosylation of O-linked glycosylation sites in glycophorin A. These abnormalities are now reported in three Bedouin patients from Israel with CDA type I. In addition, the erythrocyte membranes of these patients exhibited highly increased globotetraosylceramide content. Glycoconjugate abnormalities were also present in erythrocyte membranes from three patients from Northern Sweden with CDA type III but they almost exclusively affected glycosphingolipids. In erythrocytes of all patients examined including one with CDA type II, polyglycosylceramides were significantly hypoglycosylated although, on a molar basis, their contents in erythrocyte membranes were increased. Thus, glycoconjugate abnormalities of varying intensity occur in erythrocyte membranes from all patients with CDA that were investigated.

StreszczeniePrzed transfuzją krwinek czerwonych wykonuje się rutynowe testy immunohematologiczne, dzięki którym przetacza się biorcom serologicznie zgodną krew dawców. Wyzwaniem dla serologów jest dobór koncentratu krwinek czerwonych (KKCz), gdy uodpornieni biorcy mają alloprzeciwciała z powodu wcześniejszych transfuzji lub ciąż albo wytworzą autoprzeciwciała w niedokrwistościach autoimmunohemolitycznych (NAIH). Wyzwaniem dla klinicystów jest pilna, ratująca życie transfuzja bez próby zgodności. Są to przetoczenia nagłe (krwawienie) oraz sytuacje, gdy brak jest krwi o wyjątkowych fenotypach. Ważne jest tworzenie narodowych rejestrów rzadkich dawców krwinek czerwonych i uczestnictwo w rejestrze międzynarodowym oraz przekazywanie informacji o skutkach niezgodnego przetoczenia i leczeniu ograniczającym hemolizę. Inne problemy dotyczą szczególnych grup biorców krwi, czyli: płodów, noworodków, niemowląt i pozostałych dzieci. Różnią się one cechami hematologicznymi i immunologicznymi, więc testy zgodności muszą się też różnić. Skomplikowane są transfuzje po transplantacjach komórek krwiotwórczych i narządów, gdy z powodu immunologicznego chimeryzmu dochodzi do hemolizy. Ścisła współpraca między klinicystami i immunohematologami jest konieczna, by zapewnić bezpieczeństwo transfuzji w wymienionych sytuacjach klinicznych opisanych w prezentowanej publikacji.