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R Blasczyk

Publications and source records attributed to R Blasczyk.

81 records · Page 5Linked to original sources
PubMed1995

Strong association between the responder status of the FC gamma II receptor and recurrent spontaneous abortion.

Several models exist for the aetiology and therapy of recurrent spontaneous abortion (RSA). They are based in part on the assumption that an increased materno-fetal histocompatibility results in an insufficient maternal immunological recognition of the fetus, and thus renders the maternal immune system unable to sustain the pregnancy. The involvement of the FcgammaII receptor (FcgammaIIR) in RSA was suggested, since FcgammaIIR-blocking antibodies, present in normal pregnancies, could not be found in patients suffering from RSA. The FcgammaIIR is known to be functionally and structurally dimorphic, which results in a responder, respectively non-responder pattern. We used an in vitro proliferation assay to distinguish between FcgammaIIR responder and non-responder phenotypes. In 29 RSA couples we found 97% (28/29) of RSA patients and 100% (29/29) of their partners to be responders, whereas 50 fertile couples and a further 100 unrelated controls revealed distributions of responder vs. non-responder of 73% vs. 27% and 70% vs. 30%, respectively. These differences (RSA vs. controls) are highly significant (P less than or equal to 0.0001). Our results suggest further that the FcgammaIIR dimorphism might be involved in the pathogenesis of RSA.

Abortion, Habitual↗
PubMed1994

Microbiologic contamination of peripheral blood stem cell autografts.

We have determined the incidence and clinical significance of positive microbiologic cultures in a series of 290 peripheral blood stem cell concentrates in 95 patients undergoing multiple apheresis procedures for autologous stem cell rescue. Specimens for bacterial cultures were obtained after processing of the autografts just prior to freezing. The incidence of microbial contamination was 4.5% (n = 13). The predominant pathogenic microorganism cultured was coagulase-negative Staphylococcus (n = 11). From 8 patients with contaminated leukapheresis products 6 underwent autologous stem cell transplantation. Five patients received 1-5 culture-positive stem cell concentrates without serious sequelae, whereas the sixth patient was autografted with noncontaminated leukapheresis products, 1 concentrate contaminated with Aspergillus fumigatus being not reinfused. No microorganism present in the stem cell autograft was recovered in vivo in the posttransplantation period, although fever as a sign of infection occurred in all but 1 patient. Peripheral blood stem cell collection and ex vivo processing for cryopreservation may result in microbiologic contamination. However, our data show that infusion of contaminated stem cell autografts does not play a significant role as a source for infections in the clinical setting of autologous stem cell rescue.

Adolescent↗
PubMed1994

HLA-DPB1 typing by PCR-SSO reverse dot blot hybridization after group-specific amplification.

BACKGROUND: The allelic diversity of HLA-DPB1 antigens can be determined at the DNA level after PCR amplification. The pattern of polymorphism at the DPB1 locus makes it difficult to unambiguously assign all genotypes in a typing system using one single pair of generic primers. MATERIALS AND METHODS: We apply here a simple technique based on the reverse dot blot analysis to the typing of HLA-DPB1 alleles. In order to increase its resolution, a group-specific amplification based on sequence variations of the polymorphic region F was used subdividing the HLA-DPB1 alleles in 2 nonoverlapping families. A separate analysis was then performed within each group of alleles. RESULTS: Using these 2 primer pairs, 21 group 1 and 30 group 2 alleles were separately amplified. From 1,378 possible allele combinations for DPB1*0101-5301 only 33 gave ambiguous typing results compared to 61 using a single pair of generic primers. CONCLUSIONS: This procedure provides a rapid and simple HLA-DPB1 genotyping. Especially in heterozygotes the hybridization patterns were easier to interpret. The utilization of group-specific amplification substantially reduced ambiguous typing results.

Alleles↗
PubMed1993

Soluble CD4, CD8, and HLA molecules in commercial immunoglobulin preparations.

CD4 and CD8 exist in membrane-bound and soluble forms. These antigens are the physiological ligands for molecules of HLA classes I and II, which we have found in soluble form in commercial immunoglobulin preparations. We measured concentrations of soluble CD4 and CD8, as well as soluble HLA-ABC and HLA-RQP in sixteen immunoglobulin preparations by enzyme immunosorbent assays. Only two preparations contained detectable CD8, and nine had soluble CD4 in varying amounts. There was great variation in concentrations of soluble HLA molecules. It is possible that the immunomodulating effects of immunoglobulin therapy in disorders with immune aetiology are due, at least partly, to these contaminating molecules.

CD4 Antigens↗
PubMed1992

Soluble HLA class I and class II concentrations in commercial immunoglobulin preparations.

Soluble HLA class I (sHLA-ABC) and class II (sHLA-RQP) molecules were quantitated in 16 commercially available immunoglobulin (Ig) preparations by enzyme-linked immunosorbent assays. Whereas three Ig preparations contained no detectable sHLA-ABC, all preparations showed concomitant sHLA-RQP molecules. There was a considerable variability with regard to the individual sHLA concentrations. For sHLA-RQP the values exceeded that found in human plasma of healthy individuals, suggesting that the extraction procedure may concentrate not only Ig, but also HLA class II molecules. Based on the total dosage of intravenously administered immunoglobulins (i.v.Ig), contaminating sHLA molecules may become immunogenic. Furthermore, sHLA molecules are discussed in terms of participation in the well-known immunomodulating effects of i.v.Ig therapy.

Enzyme-Linked Immunosorbent Assay↗
PubMed1991

Fc receptor blocking antibodies after active immunization for the treatment of recurrent spontaneous abortion.

In a prospective study 140 couples who had at least three spontaneous abortions (RSA) were studied for the presence of Fc receptor blocking antibodies detected by the erythrocyte antibody rosette inhibition (EAI) assay, for anti-paternal cytotoxic antibodies (APCA), and for mixed lymphocyte culture inhibiting (MLCI) antibodies before and after active immunization with paternal lymphocytes. The comparative analysis revealed the EAI assay to possess a higher sensitivity than the APCA and/or MLCI tests in monitoring the specific immune response after active immunization. The success of pregnancy in EAI positive post-immunization patients was not influenced by the presence or absence of APCA or MLCI. In the light of a successful pregnancy outcome of 85.7% (n = 37) in this study we conclude that the monitoring of Fc receptor blocking antibodies is useful in active immunization protocols for RSA patients.

Abortion, Habitual↗
PubMed1990

Further characterization of the EAI factor induced by alloimmunization for treatment of recurrent abortion.

In order to remove the EAI "blocking" activity, EA inhibition positive sera from patients with recurrent abortions were absorbed after alloimmunization with paternal lymphocytes by the lymphoblastoid cell line (LCL) of the husband. To avoid non-specific binding via the Fc-receptor, the cells were first fixed with 0.05% glutaraldehyde. Absorption was performed for 3 h at 4 degrees C. For subsequent elution, the cells were incubated with 0.1 M glycine-HCl, pH 2.3, for 30 min at 4 degrees C. After each step, EAI assay was carried out to determine the "blocking" activity in the supernatants. Furthermore, 10% SDS-PAGE and immunoblotting with goat antihuman IgG of the whole serum and the supernatants were performed. The results obtained give evidence that the EAI "blocking" activity can be absorbed by and eluted from the LCL of the immunizing husband, and is due to an IgG antibody directed against an antigen present on the LCL. Further absorption experiments with trophoblast cells will show whether this antigen is also displayed by the trophoblast.

Abortion, Habitual↗
PubMedDate not supplied

Simultaneous genotyping of human platelet antigens (HPA) 1 through 6 using new sequence-specific primers for HPA-5.

BACKGROUND: Polymerase chain reaction using sequence-specific primers is widely used for genotyping human platelet antigens (HPA). However, the results of HPA-5 genotyping are still problematic. STUDY DESIGN AND METHODS: New sequence-specific primers were designed for HPA-5 that, together with already published primers, allow simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6. The reliability of the described protocol was determined by using reference DNA samples as well as samples from healthy blood donors. RESULTS: All primers produced specific amplification products. The genotype and the previously ascertained phenotype of the tested specimens were in concordance in all cases. CONCLUSION: The described polymerase chain reaction protocol allows rapid, reliable, simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6.

Alleles↗