Human B-lymphocyte antigens expressed by lymphocytic and myelocytic leukemia cells. II. Detection by human anti-B-cell alloantisera

The majority of human lymphocytic and myelocytic leukemia cells express a polymorphic antigen that is found on peripheral blood B-lymphocytes and cultured lymphoblastoid B-cell lines. These B-lymphocyte antigens were detected by 34 human alloantisera that were repeatedly absorbed with pooled platelets to remove all activity against HLA antigens and T-lymphocytes. Absorption studies indicated that a common antigen was present on both B-lymphocytes and positive leukemia cells. Leukemia cells could be subdivided into two groups based on the presence of the B-lymphocyte antigen. Fourteen of 18 acute myelocytic leukemia cells, 10 of 13 acute lymphoblastic leukemia cells, 4 of 6 chronic myelocytic leukemia cells, and 2 of 2 chronic lymphocytic leukemia cells were positive. This group of leukemia cells also reacted with rabbit anti-B-cell sera raised to papain digests of spleen cell membranes. F(ab')2 fragments of the rabbit antsera were shown to specifically block the reactions of the human antisera against B-cells and leukemia cells. These results suggested that the rabbit and human anti-B-cell sera were reacting with identical molecules. This conclusion was supported by immunoprecipitation data.

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.

Anti-B lymphocytotoxins in renal-allograft rejection

To determine the possible role of the B lymphocyte alloantigen system in renal-transplant rejection, we examined serum specimens from 81 allograft recipients for cytotoxic activity against a panel of normal B lymphocytes. Specimens from 22 of 25 recipients undergoing allograft rejection demonstrated strong B-lymphocyte cytotoxicity whereas only 13 of 56 recipients with normal allograft function showed similar B lymphocyte cytotoxocitiy (P less than 0.0001). In the serum samples of recipients with graft rejection who were followed sequentially, B-lymphocyte cytotoxicity preceded or was concurrent with the onset of functional impairment. The results show that anti-B-lymphocyte antibodies are associated with rejection, but it is quite possible that they are the products of rejection rather than the cause.

B-lymphocyte alloantigens in Caucasians

Human B lymphocytes have been shown to have at least five polymorphic specificities defined by 32 antisera. The antisera were produced by absorption with pooled platelets to remove HLA activity and were selected out of over 400 tested sera. The sera that defined the five specificities had high correlation coefficients within a group (generally in the range of 0.6-0.9). As shown by the fit in the Hardy-Weinberg equilibrium, the five specificities appear to be determined by alleles at one genetic locus. No association between these specificities and HLA was noted.

HL-A in cancer family "N"

Actual HL-A typing has been performed on 115 members of cancer family N, a large kindred (over 1000 members ascertained) showing the findings consistent with the cancer family syndrome. In the cancer-prone line (branches C and D) of the family, 20 of 21 members with cancer had one HL-A haplotype, HL-A2-HL-A12 (relative odds = 6.30), including some decreased family members who had haplotypes assigned. Eleven of 12 family members with cancer in branches C and D, actually typed, had HL-A2-HL-A12 (relative odds = 6.06). The single exception showing cancer and another haplotype in branch D is a child of a family member with haplotype HL-A2-HL-A12.

Lymphocyte-dependent antibody cross-matching for transplant patients

Cadaver donor transplant patients who had a negative complement-dependent cytotoxicity cross-match test were tested in parallel with the specific donor at the time of transplantation by the lymphocyte-dependent antibody (L.D.A.) test. Transplants were performed on the basis of negative standard and long (2-5-hour) ment-dependent cross-match tests and the results of the L.D.A. test were withheld from the transplant centres. Of the 57 transplants tested, 49 had a negative L.D.A. result with 74 percent one-month function whereas 8 had a positive L.D.A. Result with 25 percent one-month function (P smaller than 0-02). When the results were further divided into methods of preservation of donor kidneys, among L.D.A.-Negative transplants, of the 20 kidneys preserved by Collins Sacks solution, 95 percent were functional at one month, whereas of the 28 kidneys preserved on the Belzer machine, 64 percent were functional at one month (P smaller than 0-05). The risk of the most hazardous period of transplantation (i. e., the first month) may be reduced drastically by simple preservation methods and the se of L.D.A. cross-matching.

Utilization of cultured human lymphoid cells for detection of humoral sensitization in prospective recipients of kidney transplants

Prospective recipients of kidney transplants were tested for lymphocytotoxicity; from these we selected 102 sera that lacked cytotoxic antibodies against peripheral lymphocytes from at least 80 unrelated subjects. To detect humoral sensitization, we then reacted these with 17 cultured human lymphoid cell lines having different HL-A phenotypes. Cytotoxic antibodies reacting with these cultured cells were now detected in some of the sera. These antibodies were not directed against HL-A antigens, yet mediated lysis of target cells in the presence of rabbit but not of human or guinea pig complement. Furthermore, they activated the classical pathway of the rabbit complement system. Later, a significant association was found between occurrence of cytotoxic antibodies and rejection of the transplant. Thus, cultured human lymphoid cells, because of their great susceptibility to complement-mediated lysis, appear to be useful in detecting humoral sensitization in candidates for kidney grafts.