Dilutions and specificity analysis of pretransplant sera

Six serial dilutions of 51 sera from pretransplant patients were reacted against T and B lymphocytes at 5 degrees C and 37 degrees C. By the use of defined panels of T and B lymphocytes it could be shown that 10% of the 51 positive sera contained T-warm antibodies against HLA-A, -B, and -C specificities. There were 28% of the sera that had antibodies against non-HLA antigens reactive to B lymphocytes in the cold. Other sera contained mixtures of HLA and non-HLA antibodies. By dilution analysis of the sera, the mixtures could be detected and the HLA specificities identified. This ability to distinguish between HLA and non-HLA antibodies should be important in classifying pretransplant patients into high- and low-risk patients. Prior evidence that we have presented suggests that the non-HLA antibodies may be enhancing antibodies.

Enhancement of human kidney allografts by cold B-lymphocyte cytotoxins

The sera of 233 kidney transplant patients before transplantation were tested by cytotoxicity against a panel of B and T lymphocytes at 5 degrees C and 37 degrees C. The results divided the patients into four groups: those whose sera reacted with B lymphocytes at 5 degrees C; those reacting with B lymphocytes at 5 degrees C and 37 degrees C; those reacting with T lymphocytes at 37 degrees C; and those with no antibodies. The patients with pre-transplant antibodies reactive with B lymphocytes at 5 degrees C had a significantly higher kidney-transplant survival rate at 6 months (70%) and 1 year (65%) than patients who had no antibodies (47% and 46%, respectively). Patients with antibodies reactive at 37 degrees C had a 6-month survival-rate of 38% when reactive against B cells and 43% when reactive against T lymphocytes. The cold cytotoxins were IgM.

Autoantibody against B lymphocytes

The sera of 20 out of 99 (20%) normal males and females were shown to have antibodies that kill their own B lymphocytes. The sera were specifically cytotoxic to B lymphocytes and not T lymphocytes. Allogeneic B lymphocytes were also killed by these autocytotoxins. Maximum killing of B lymphocytes occurred when the incubation temperature in serum was 5 degrees C and complement incubation temperature was 20 degrees C. Under these cold conditions, some sera reacted up to a dilution of 1/16. These results suggest that positive B-lymphocyte crossmatches found in kidney transplantation do not detect alloantibodies. Since the B-cell autoantibodies tend to appear at the time of immunisation, their role as autoregulators of the antibody response is an intriguing possibility.

Relation between HLA-DW and the b-lymphocyte specificities

Homozygous DW typing cells were tested for six B-lymphocyte specificities. All four of the second locus specificities of B lymphocytes were strongly associated with the DW specificities. DW1 typing cells were B group 6, DW2 were B4, DW3 were B5, and LD107 were B3. The first B-cell locus antigens 1 and 2 tended to be uniform within the DW groups. From an analysis of the typing responses of a panel of cells to the homozygous typing cells, it has become apparent that the first B-locus specificity present on the homozygous typing cells also plays a role in determining whether a typing response is obtained or not. Thus, the DW3 typing cells were themselves B2 and B5, and cells having B2-B5 were most frequently nonreactive to DW3 in mixed lymphocyte culture. Homozygous typing cells therefore mainly detect the second B-cell locus antigens and, to a lesser degree, the first locus specificities. Stated another way, homozygous typing cells do not define a single specificity, but rather the presence of two B-lymphocyte specificities, even though their responses often reflect matching of only the second B-locus specificity.

B-lymphocyte haplotypes in asthma families

Thirty families in whom at least one member had asthma were typed for five new B-lymphocyte specificities, as well as the antigens of the A and B loci of HLA. The B-cell reactions were consistent with the concept that they were determined by genes linked to the HLA-A and HLA-B loci. Between 22 HLA-identical siblings and 16 two-haplotype different siblings, a significant difference in concordance of reactions for the B-cell groups was noted. The data obtained were most compatible with B-groups 1 and 2 being determined by one locus and B-groups 3, 4, and 5 by another locus. The superhaplotypes of HLA-A, HL-B, and B-cell loci 1 and 2 were then determined. The most striking linkages noted were for the second B-cell locus and the HLA-B locus: B-cell group 3 with HLA-B12, B-cell group 4 with HLA-B7, and B-cell group 5 with HLA-B8, B17, and Bw35.

The role of B-lymphocyte antigens in MLC stimulation

A total of 950 MLC combinations were set up out of which 259 were classified as low MLC response. An attempt was made to predict which of the combinations would give low response by matching the B-lymphocyte specificities and the HLA-A and -B antigens. A statistically significant prediction of a low response was noted for the B-lymphocyte specificities as well as for HLA-A and -B antigens. The fraction of the low response, which was correctly found, was, however, greater with the B-cell specificities than the HLA-A and -B locus antigens. It is concluded that the B-lymphocyte specificities may be either identical or closely linked to the DW specificities. To what extent they are associated with the strong transplantation antigens of man remains to be determined.

Strong association between B-lymphocyte group-2 specificity and asthma

30 families in which at least one member has asthma were tested for five new specificities of B lymphocytes as well as for twenty-five HLA antigens. 41 other asthmatic patients were also tested. HLA-B8 was slightly less common than normal in the 71 patients with asthma and there was a trend towards an increased frequency of HLA-A2 in these patients. However, 88% of the 30 asthma patients had B lymphocyte group 2 compared with 24% of the 109 controls. This strong association between asthma and B lymphocyte group 2 was not completely paralleled by linkage with a postulated susceptibility gene of the HLA complex in 9 families whose members were investigated in detail.

Multiple sclerosis and high incidence of a B lymphocyte antigen

Multiple sclerosis patients were tested for six new antigens present on human B lymphocytes. The group 4 specificity occurred in 83.9% of the 56 patients as compared to 32.5 percent in 72 healthy controls (P less than .003). The antiserums defining the five other B lymphocyte specificities reacted at a lower frequency to B cells from multiple sclerosis patients, showing that increased reactivity to group 4 antiserum was specific. Linkage of a hypothesized multiple sclerosis susceptibility gene with certain haplotypes of HLA-A3, HLA-B7 HLA-DW2, and the new B group 4 can be inferred.