A new alloantigenic system on human lymphocytes

Immunological observations following vasectomy

Lymphocytotoxic antibodies (LCA) against panels of normal lymphocytes and leukemic B-cells were demonstrated in vasectomized men. Since vasectomy is known to induce antibody formation to spermatozoa, the demonstration of these lymphocytotoxic antibodies may be related to antigenic constituents of spermatozoa such as HLA or B-cell alloantigens. Long term follow-up is needed to clarify the clinical significance of these antibodies.

Association of HLA-B8, DRw3, and anti-acetylcholine receptor antibodies in myasthenia gravis

Twenty-eight patients with myasthenia gravis (MG), five with and 23 without thymoma, and 47 normal controls were typed for serologically defined HLA-A, B, C, and DRw antigens. Sera from all patients were titered for antibodies to acetylcholine receptors (AChR). The frequency of HLA-B8 and DRw3 in the non-thymoma MG patients was significantly higher than in the normal population. Most of the non-thymoma patients with AChR titers higher than the average level were positive for HLA-B8 and/or DRw3, while the majority of the HLA-B8(-) and/or DRw3(-) non-thymoma patients demonstrated AChR titers below average. These findings support the possibility of the existence of immune response genes in the HLA-B, DRw segment of the major histocompatibility complex which are concerned in the response to or recognition of autoantigens.

Renal transplantation and a positive serological cross-match

A renal transplant involving a recipient with a positive serological cross-match against donor lymphocytes generally results in hyperacute rejection of the graft. 13 cadaveric renal transplants were performed in recipients with a known positive serologic cross-match against donor B lymphocytes. 12 of these serological cross-matches were positive against donor blood, node, or spleen lymphocytes, but the reactivity was directed against donor B lymphocytes only. 3 transplants failed, 2 because of rejection and 1 because of renal-artery thrombosis. 10 transplants are functioning, 6 to 42 weeks after the operation. Of these 10 successful grafts, 3 had no acute rejection episodes, while 7 had an early acute rejection episode which responded to treatment. Histologically, the grafts showed a cellular rejection, similar to that in enhanced renal allografts in the rat. It is possible to transplant a kidney in a high-risk patient with a positive B lymphocyte cross-match with a low risk of failure. In addition active enhancement of the graft might sometimes occur.

New groups and segregant series among B-cell alloantigens of the Merrit system. A study of leukemia cells, peripheral B cells, and lymphoblastoid cell lines

On the basis of reactions with a chronic lymphatic leukemia cell panel, evidence for 6 new specificities of the Merrit B-cell alloantigenic system in man is presented, bringing the number of provisionally defined specificities to 19. These can be roughly divided into two segregant series. The system is well represented on both homozygous and heterozygous B-type lymphoblastoid cell lines. In the cell lines some specificities show a suggestive but inexact correlation with HLA-D locus factors. This correlation is represented also on peripheral blood B cells, on the non-T variety of acute lymphatic leukemia cells, and on acute myeloid leukemia cells. Although great similarities exist, each of the cell populations may manifest differences other than or in addition to mere differences in B-cell antigen frequencies.

Cytotoxic antibodies to cultured human lymphoid cells in polytransfused thrombocytopenic patients: association with reduced survival of allogeneic transfused platelets

Four out of 8 thrombocytopenic patients without detectable cytotoxic antibodies to human peripheral lymphocytes contained cytotoxic antibodies to cultured human lymphoid cells. The presence of such antibodies was associated with reduced survival of infused allogeneic platelets in these patients. The antibodies reacted in a distinct fashion with a panel of cultured human lymphoid cells and are directed to B cell antigens. Cytotoxic antibodies to cultured human lymphoid cells did not react in vitro with platelets suggesting that the antibodies play no significant role in the accelerated destruction of infused allogeneic platelets, although their presence predicts it. Therefore, screening of sera with cultured human lymphoid cells appears to be a useful test in addition to those now used to select patients for transfusion of allogeneic platelets. Sera from polytransfused patients without cytotoxic antibodies to peripheral lymphocytes may be a useful source of antibodies to B cell antigens.

Chemotherapy--one of the causes of transient loss of HLA antigens and lymphocyte polyreactivity in patients with blood diseases and malignancies

Modifications of HLA antigens (transient loss or polyreactivity) were found in thirty-two of fifty-five examined patients with blood diseases (leukaemia, reticulosis, reticulo- and lymphosarcoma, lymphogranuloma, erythroblastoma) and malignant tumours. In two cases of acute myelosis transient alteration of HLA-A 2 antigen in HLA-A 28 was demonstrated. The relationship of HLA antigenic modification to chemotherapy was established, both by analysis of individual cases and by statistical evaluation of serological results in patients with or without chemotherapy (0-01 greater than P greater than 0-001). Chemotherapy is thus one of the causes for the development of HLA antigen modifications in blood diseases and malignant tumours.

Normal human sera cytotoxic to cells of human acute leukemia

Eight human sera from healthy individuals with no history of immunization with human transplantation antigens have demonstrated complement dependent cytotoxicity to cells of some patients with active acute leukemia. The antigen(s) detected by these sera are absent from normal and remission lymphocytes and appear most often in ALL patients with a high peripheral lymphoblast count. Some B and T lymphoblastoid cell lines carry the antigen(s) as evidenced by their ability to react with and absorb the antileukemia activity. The data support the existence of at least two overlapping specificities detected by these antileukemia sera. The leukemia antigen(s) show no strong correlation with any known HLA antigen. These observations provide evidence for a human leukemia blast associated antigen or set of antigens which may be immunogenic in man. Their relationship to normal HLA antigens of loci other than A, B or C is unknown.

B-cell antibodies, Ia-like determinants, and their relation to MLC determinants in man

The HLA supergene is located in the 6th chromosome. Its position to the centromere and the position of a number of polymorphic isoenzymes has been elucidated. The HLA supergene codes not only for determinants present on all nucleated cells, but also for determinants present on B cells and absent from T cells and platelets. These determinants can be recognized by serology, and evidence is presented that some of them are coded for by a hither to unrecognized locus Ag, which is very closely linked to the MLC determinants of the D locus can be recognized with the help of the MLC test using unprimed cells, homozygous for the MLC determinants, so-called typing cells primed against one MLC determinant in the PLT test. So far, 8 MLC determinants have been recognized. Significant disease-association studies in different racial groups appear to be especially informative. They already indicate that the association found so far must rest on different mechanisms. Whether some of them could be caused by partial deficiency for one or more of the complement factors remains to be proven.