Differences in immunoglobulin subclasses between dye exclusion and 51Cr release complement-dependent lymphocytotoxicity assays.

Paradoxical differences previously noted between lymphocytotoxicity detected by dye exclusion at room temperature (CDCE) or by 51Cr release (CDC51Cr) at 37 degrees C in maternal antipaternal complement-dependent lymphocytotoxicity have suggested that CDCE and CDC51Cr at 37 degrees C, but not at 20 degrees C, may detect different immunological antibody-antigen interactions. Reactions in the two test systems against the same target cells were compared in sera from known immune dialysis patients, secondary aborting women, and refractory platelet recipients before and after heat treatment of sera, absorption with solid-phase heparin, anti-light-chain augmentation, and the addition of murine monoclonal anti-IgG subclass antibodies. The results demonstrate significant differences between the two tests using the same target and sera. Further, the results imply the presence of an inhibitor and an inhibitor of inhibitor in sera. The involvement of different immunoglobulin subclasses was shown in the two tests. These data demonstrate the necessity for further study of the nature of the differences in the mechanisms of these clinically important antibody-detecting systems.

Association of parvovirus B19 with plasma cell-rich myocardial infiltrates after heart transplantation.

In this report we describe the development of plasma cell-rich myocardial infiltrates in association with a parvovirus B19 infection in a heart transplant patient. We hypothesize that the virus, either alone or in association with the cardiac allograft, may polarize the immune response in the direction of T helper 2 (Th2) cells rather than the expected Th1 cells. This favors the development of a humoral immune response and infiltration of the graft with plasma cells.

Utility of DRB1 subtyping: a case report.

The purpose of presenting this case is to illustrate the importance of high-resolution DNA Class 2 typing when assignment of MHC antigens is of extreme importance (i.e. bone marrow transplantation); suggest this test as a substitute for the mixed lymphocyte culture (MLC), and provide evidence that DRB1 subtype mismatches may be clinically significant. Initial serological and monoclonal HLA Class 1 and low-resolution DNA-SSP Class 2 typing of a potential bone marrow transplant patient and two sisters revealed all to be HLA identical with apparent homozygosity for DRB1 x 04. High-resolution DNA-SSP Class 2 typing was then performed and revealed electrophoretic banding patterns which were not specific for any DRB1 x 04 subtype. One sister and the patient had identical patterns, while the other sister had a different pattern. Complete HLA Class 1 and high-resolution DNA-SSP Class 2 typing of the parents was performed. The mother was found to be heterozygous for Class 1 and Class 2 antigens and possess the DRB1 x 0404, 0405 subtypes. In contrast, the father was found to be homozygous for Class 1 antigens, heterozygous for Class 2 antigens and possess the DRB1 x 0404, 0407 subtypes. This led to the initial false assumption of HLA identity for the patient and her two sisters. However, assignment of haplotypes revealed one sister to be HLA identical with the patient and the other sister to be a one-haplotype five-antigen match with the patient, mismatching for one DRB1 allele. Bone-marrow transplantation was performed utilizing the latter sister, which resulted in intractable acute graft vs. host disease that resulted in the patient's demise.

Report of a new DRB1*13 allele: DRB1*1336.

This brief communication describes the characterization of a new allele, DRB1*1336.