Anti-Co(a) implicated in severe haemolytic disease of the foetus and newborn.

The Colton (Co(a)) antigen is of high frequency; its incidence in Caucasians is about 99.8%. Reports on haemolytic transfusion reactions and haemolytic disease of the foetus/newborn (HDFN) due to anti-Co(a) are rare. We report a severe HDFN due to anti-Co(a). The first child of the mother was healthy. The second died a few hours after delivery because of hydrops fetalis, likely due to HDFN; anti-Co(a) in the maternal serum, the father typed as Co(a+). The third pregnancy was followed up by the measurements of anti-Co(a) titre (additional antibodies were excluded), its functional activity by the chemiluminescence test (CLT) and the Doppler flow in the middle cerebral artery of the foetus. Increased values of antibody titre up to 128, the CLT to 30% and multiplex of median of the peak systolic velocity to 1.71 indicated haemolytic disease and the necessity for an intrauterine transfusion. The foetus received the maternal red blood cells (RBCs). Delivery had to be by Caesarean section for obstetrical reasons at 34-week gestation. The newborn (anti-Co(a) on red cells and in plasma, the rise of the bilirubin concentration up to 333 micromol L(-1)) had four exchange transfusions: the first of maternal RBCs, the remaining of donor's Co(a+) cells and one top-up transfusion. The baby was discharged in good health. Anti-Co(a) was responsible for severe HDFN. Proper monitoring during pregnancy and antenatal and post-natal therapy were successful. This is the second severe published HDFN due to anti-Co(a).

A clue to the basis of allelic enhancement: occurrence of the Ax subgroup in the offspring of blood group O parents.

Apparent deviation from Mendelian rules of blood group inheritance is rarely observed. Blood group O parents with children expressing weak A subgroups have occasionally been described but not explained. A detailed serological investigation of such a family is described here. The ABO locus was analysed by PCR-ASP/restriction fragment length polymorphism genotyping and DNA sequencing. The propositus' RBCs were very weakly agglutinated with monoclonal anti-A but distinctly with polyclonal anti-A,B, i.e. typical for Ax. Serum anti-A1 (titre 4) and -B were present. Her parents' blood groups were both clearly O, with titres of serum anti-A1, and -A at 16 and 4, respectively. Adsorption/ elution studies demonstrated A antigen on the daughter's cells only. The ABO genotypes were: mother, AxO1; father, O1vO2; and propositus, AxO2. The Ax allele was an A1-O1v hybrid allele with a crossing-over breakpoint between positions 235 and 446 in intron 6 (Ax-4). Compared to the A1 glycosyltransferase, this allele predicts a protein with two amino acid substitutions (Phe216Ile and Met277Val) known to yield either weakly expressed or no A antigen on RBCs. This study suggests that the nature of the ABO allele in trans can influence A antigen expression, a phenomenon previously described as allelic enhancement (or reinforcement). Potential mechanisms for this are discussed.

[Evaluation of microtest in dextran gel for blood group serology]. / Ocena mikrometody z zastosowaniem zelu dekstranowego w serologii grup krwi.

Microtest in gel was compared to the traditional, immunohaematological methods. Blood samples of 1.032 persons were tested. From the results presented in this paper we conclude that Gel-test is specific, clear, easy to perform and more sensitive than the traditional methods. It can be used for red cell phenotyping and antibody detection as well. By this technique it was possible to establish the specificity of antibodies of Rh system not found by any other method. The advantage of this test is that nearly all unspecific reactions could be eliminated. The disadvantage concerned the high sensitivity in the detection of cold, clinically insignificant allo- and autoantibodies. Therefore, some modifications for the elimination of these unfavourable reactions were introduced.

[Value of using polyethylene glycol in the indirect antiglobulin test with erythrocytes]. / Wartosc stosowania glikolu polietylenowego w posrednim tescie antyglobulinowym z krwinkami czerwonymi.

A series of comparative investigations was carried out for establishing the value of the indirect antiglobulin test (IAT) in its first phase. The results showed that PEG, in relation to NaCl solution of low ionic strength, increased the reactivity of various antibodies of different specificity present in 72 studied sera. A significant superiority of IAT-PEG to IAT-BISS was noted in 45.8% of these sera. In search for antibodies in sera of 1160 patients IAT-PEG detected 7 antibodies not reacting in the IAT-LISS, and 5 of them had Rh system specificity, one was anti-K and one anti-Jka. Although the IAT-PEG was more sensitive than IAT-LISS in the detection of anti-Rh antibodies, it was less sensitive in this range than the enzymatic LEN test with which not only 5 of these antibodies were demonstrated but which detected also 8 antibodies not demonstrated in IAT-PEG or IAT-LISS. All 5 antibodies not detected by the IAT-PEG but demonstrated in the IAT-LISS were specific for the Lewis system. The per cent of reactions regarded as non-specific in the IAT-PEG was 1.3%. The IAT-PEG modification may be recommended as a sensitive, simple and specific method extending the possibilities of immunohematological diagnosis, especially in cases of post-transfusion reactions and in difficulties of interpretation connected with the occurrence of weakly positive reactions in the IAT-LISS.

[Remarks on routine use of the enzyme test LEN (LISS Enzyme) in immunohematological studies]. / Spostrzezenia nad rutynowym stosowaniem testu enzymatycznego LEN (LISS-Enzym) w badaniach immunohematologicznych.

The authors report one-year experience with the enzymatic test LEN (LISS-Enzym) replacing the one-step papain test in the compatibility testing, and in place of the two-step papain test in the detection and identification of red cells allo-antibodies. A wide range of investigations confirmed the usefulness of this test in the detection and antibodies specificity, mainly from the Rh system which are often undetectable by means of the indirect antiglobulin tests. It is concluded that in compatibility tests the LEN test should replace the low-sensitivity one-step papain test used as yet. It is stressed that in case of positive reactions only in the LEN test suggesting presence of autoantibodies the test should be repeated bringing to 37 degrees C the reacting components before their mixing. This makes possible elimination of clinically not significant cold autoantibodies.

[Value of the LEN (LISS-enzyme) technic in detection of alloantibodies to erythrocytes]. / Wartosc techniki LEN (LISS-Enzym) w wykrywaniu alloprzeciwcial przeciw krwinkom czerwonym.

The reported study was done for assessment of the value of the enzymatic technique LSE/LISS Spin Enzyme proposed by Odell et al. using a solution of NaCl of low ionic strength (LISS) for detection of incomplete alloantibodies to erythrocytes, especially those from the Rh system. The results of the study demonstrated that the LSE test, called by the authors LEN (LISS-Enzyme) is a sensitive and specific method comparable in its effectiveness to the two-step papain test (2-Pap) used widely in this country. In routine studies the LEN technique is simple, easy and rapid. Washing of papain treated erythrocytes is not necessary. The time from enzyme addition to erythrocytes to result reading is about 15 minutes, that is it is four times shorter than the time in the 2-Pap technique (60 minutes). A significant was the preparation of one type of erythrocyte suspension in LISS solution for two tests: enzymatic and antiglobulin, carried out in parallel. For these reasons the LEN test may be recommended in place of 2-Pap for detection and identification of antibodies. It is also a practical methods for matching test in place of the one-step papain test. The LEN test should be widely introduced in laboratories of transfusiological immunology in this country. Attention is called ti various technical details necessary for obtaining of unequivocal and reproducible results.

Adherence to human monocytes of red cells from autoimmune haemolytic anaemia and red cells sensitized with alloantibodies.

Red cells sensitized with autoantibodies are able to adhere in vitro to autologous monocytes and monocytes from healthy individuals. A direct relationship between the degree of sensitization and the percentage of rosettes was not observed, while such a correlation was found if red cells sensitized with anti-Rh alloantibodies were used. Sometimes the adherence of red cell from AIHA was observed although the sensitization was weaker than that of the control erythrocytes sensitized with anti-CD serum which did adhere to monocytes. In patients with AIHA some relation was found between the adherence assay, haemolysis in vivo and treatment with prednisone.