engleski

The utility of HLA class I sera screening among Croatian pregnant women

The human immune system is very efficient at distinguishing between &#8220; self&#8221; and &#8220; non-self&#8221; antigens that are presented by major histocompatibility complex (MHC) cell surface proteins. The MHC molecules are continually monitored by lymphocytes to ensure that the correct self-antigens are presented ; the presence of any non-self antigens triggers an immune response. Donor specific human leukocyte antigen (HLA) antibodies can be detected in individuals who have been immunized as a result of blood transfusion, pregnancies or failed transplants. Antibodies directed to paternal HLA mismatches are found in 15-30% of women who have been pregnant. The alloimmunization against rare HLA antigens (rare HLA antigen &#8211; gene frequency <3% in general population) is of special interest because of great importance for donor selection in clinical transplantation. For this analysis we tested 123 sera from 103 women who had produced antibodies against the paternal HLA class I antigens. The sera were selectively chosen taking into account the possible presence of antibodies against rare paternal HLA antigens (anti-HLA-B53, -B56, -B55, -B70, -B49, -B63, -A23, -A2403). The sera were tested in a serologic crossmatch against the lymphocytes of the father and in a screening against a panel of 62 HLA typed individuals. The specificity of the anti-HLA antibodies was detected using the standard complement dependent microlymphocytotoxicity test (MLCT). The HLA phenotype of all women was determined using MLCT. Their husbands were typed using PCR-SSP DNA class I typing. Among 123 sera tested, 69 (56.1%) contained monospecific HLA antibodies (coefficient of correlation = 1) while for the rest of the sera coefficient of correlation was in the range of 0.5-0.9 (43.9%). Further analyses revealed that monospecific sera was always produced when the allosensizitation is due to HLA-B41 antigen, while on the other hand the allosensizitation to B51 antigen mostly results in bi- or oligo-specific sera. The alloimmunization against rare HLA antigens (B41, B50, B52, B60, B63) was detected in 8 women and was in concordance with the fathers&#8217; HLA phenotype. This study of HLA antibody profiles after the pregnancy can be beneficial for the screening analysis of highly sensitized patients on the waiting list for kidney transplantation.

HLA class I antibodies; screening; sensitization

nije evidentirano