J. J. van Rood

LEUKOCYTE GROUPING. A METHOD AND ITS APPLICATION

This study describes the development of a method for the recognitionnand definition of leucocyte group Four. The method can also benapplied to the detection of other leucocyte groups. Essential factorsnin the method were:na) the use of leucocyte agglutinins formed during pregnancy;nb) an insight into the shortcomings of the agglutination test;nc) the use of statistical methods to overcome these shortcomings; andnd) the use of a panel consisting of the leucocytes of the women whonhad formed the agglutinins, and of those of their husbands.

Anti HL-A2 inhibitor in normal human serum.

THE finding that allogeneic pig liver transplants frequently survive for a significantly prolonged period of time even without immunosuppression has led to a new line of research1,2. Calne and his colleagues have shown that the recipient of an allogeneic liver transplant showed partial tolerance towards kidney, and to a lesser extent towards skin transplants, when these were obtained from the same animal as was the liver.

Immunogenetics of human minor histocompatibility antigens : their polymorphism and immunodominance

Minor Histocompatibility (mH) antigens are polymorphic endogenously synthesized products that can be recognized by alloreactive T cells in the context of major histocompatibility complex molecules. In transplant situations where tissue donor and recipient are matched for HLA, mH antigens may trigger strong cellular immune responses. To gain insight into the polymorphism of mH antigens we studied their frequencies in the healthy population. Five HLA class I restricted mH antigens recognized by distinct cytotoxic T-cell (CTL) clones were used in the population genetic analysis consisting of a panel (N=100) of HLA typed target cells. Three mH antigens showed phenotype frequencies of 69% or higher, this contrasted the frequencies of two other mH antigens with 16 and 7% respectively. To gain insight into the “functional” polymorphism of the T-cell response to mH antigens, we analyzed the specificity of CTL clones within individuals. Three out of five individuals investigated shared a CTL response to one single HLA-A2 restricted mH antigen. These results indicate limited allelic polymorphism for some mH antigens in the healthy population and are suggestive of the existence of immunodominant human mH antigens.

Leucocyte Antibodies in Sera of Pregnant Women

1 The leucocyte agglutinins arising during pregnancy are isoantibodies directed against an antigen present on the leucocytes of the husband and some of the children. 2 With the aid of such sera it is possible to recognize leucocyte groups. 3 These antibodies can cause transfusion reactions. 4 The antigens against which these antibodies are directed are found not only on the leucocytes but also on the thrombocytes, and in placental tissue. They are not found on the erythrocytes. 5 The possible significance of these antibodies in connection with spontaneous abortion is mentioned.

Epidemiological study of HLA and GM in rheumatoid arthritis and related symptoms in an open Dutch population.

This report deals with the question of whether or not the established association of HLA-DR4 with rheumatoid arthritis (RA) can also be detected in cases of RA as diagnosed in a population survey. For this purpose 6584 persons older than 19 years living in a single community in The Netherlands were investigated for the presence of rheumatoid arthritis and related abnormalities. After five years 83 patients with RA, 30 with only erosive abnormalities on radiological examination (Rad), and 48 with only rheumatoid factor (RF) were reinvestigated and typed for HLA and allotypes of immunoglobulin G heavy chain (GM). On the classification of the initial survey no significant association of HLA-DR4 or GM could be detected in any of the three categories. When the information of the follow-up investigation was taken into account, a reappraisal of the classification resulted in 53 cases with RA, 18 with Rad only, and 35 with RF only. The frequencies of HLA-DR4 and GM in the three categories were also about the same as those in normal controls. However, an increase in the frequency of HLA-DR4 was observed in cases of RA positive for Rad, RF, or both. We found no evidence for an interaction between HLA-DR4 and GM. Our results suggest that rheumatoid arthritis is a heterogeneous disorder, only a fraction of which is associated with HLA-DR4. At present no single determinant of RA such as Rad or RF can characterise the HLA-DR4-associated, and most probably more severe, type of RA.

Failure of lymphocyte-membrane HLA-A and -B expression in two siblings with combined immunodeficiency.

A diagnosis of partial combined immunodeficiency was made in two Turkish siblings with a history of multiple pyogenic infections and persistent candidiasis. They demonstrated severe hypo-γ-globulinemia, with B-lymphocytes, but deficient plasma cell differentiation. T-Lymphocytes were decreased in number and did not respond to antigens, but did proliferate in cultures with lectins and allogeneic cells. HLA-A and -B determinants were not detected on blood lymphocytes, but they were expressed by cultured lymphoblasts, cultured fibroblasts, and were present in serum. MLR-Stimulatory capacity was intermediate and only two of six anti-HLA-DRw7 antisera demonstrated B-cell reactivity. β-2-Microglobulin (B2M) was not detected on the surface of T-lymphocytes, but was found in cross-sectioned T-cell membranes. B-lymphocytes carried B2M normally. The absence of HLA-A and -B determinants on lymphocytes of patients with similar immunodeficiency syndromes suggests a role for HLA determinants in lymphocyte differentiation.

Influence of non-inherited maternal HLA antigens on occurrence of rheumatoid arthritis

Many HLA-associated diseases occur in patients not carrying the putative predisposing antigen. The suggestion that this might be due to disease heterogeneity is not sufficiently supported by available data. We hypothesise that HLA-DR4-associated genetic susceptibility to rheumatoid arthritis is due to an effect of DR4 on T-cell receptor repertoire expression and that the presence of antigen in the mother is capable of producing this effect in her children, even when DR4 is not inherited by them. To investigate this possibility we HLA typed 94 rheumatoid arthritis patients and their parents and 86 control families. An increased frequency, compared with controls, of non-inherited maternal HLA-DR4 was found predominantly in the mothers of DR4-negative patients. Unexpectedly, we also found an increased frequency of non-inherited maternal HLA-DR6 and a decreased frequency of non-inherited maternal HLA-DR3 in the mothers of DR4-positive patients. The results of our analyses are consistent with our hypothesis.

An HLA-DQ alpha allele identified at DNA and protein level is strongly associated with celiac disease

An HLA-DQ alpha cDNA probe showed upon hybridization a highly significant discrepancy between the RFLP of celiac disease patients and healthy controls. The 4.0-kb Bgl II restriction fragment was present in 97% of celiac disease patients (n = 30), compared to 56% in a healthy control population (n = 72) (RR = 14.9; p less than 0.0005). At the product level all celiac disease patients tested to date have one DQ alpha chain in common, designated HLA-DQ alpha 2.3, which is associated with the 4.0-kb Bgl II fragment. This HLA-DQ alpha allele identified at the DNA level and product level seems to be a better marker for genetic susceptibility to develop celiac disease than those available to date.

Neonatal tolerance revisited

Of the many thousand patients who are waiting for a kidney transplant an increasing percentage cannot be transplanted because they have formed broadly reactive leucocyte antibodies. Broadly reactive leucocyte antibodies are here defined as antibodies that react with more than 85°70 of a panel of at least 50 unrelated donors. At present the percentage of such patients in Eurotransplant is over 10070. In the rest of Europe it is nearly 15070 [1]. These patients are very difficult to transplant because the crossmatch with potential donors is nearly always positive. Only if donor and recipient are HLA-A and -B identical or compatible is there a reasonable chance for a negative crossmatch and a successful transplant. However, even with more than six thousand patients on the waiting list of Eurotransplant we are not able to provide an HLA identical graft for more than 5-8070, and this is only possible if the HLAo phenotype of the patient is relatively frequent. It is therefore important to determine whether those patients who often react not only to 85070 of the panel but to almost all panel cells (a so-called 100070 panel reactivity) have formed antibodies against all HLA antigens or whether there remain some antigens towards which they have not formed antibodies. There are two protocols with which one can identify so-called permissible mismatches for these highly immunized patients. We call such anti-

Two different T-cell systems in humans, one of which is probably equivalent to Qa or Tla in mice

Two different alloantigenic systems, expressed mainly on TG and TM lymphocytes and called TCA and TCB, respectively, are described. Alloantisera from parous women are absorbed with Epstein-Barr virus-transformed B cell lines from the husband of the serum producer to remove all anti HLA-A,B,C and DR antibodies. The absorbed sera are tested against a random panel and against lymphocytes from families. Family studies indicate that the TCA system might be encoded by a gene linked to HLA and located on the telomeric side of HLA-A. The total lod scores for the material of 15 informative families is +3.301 at a recombination fraction of 15%. Furthermore we can show that the TCA molecule is associated with beta 2-microglobulin by blocking with turkey anti-beta 2 microglobulin. The antigens are dimers of peptides with a molecular weight of approximately equal to 42,000 daltons and 12,000 daltons, respectively. This implies that TCA might be equivalent to either Qa or Tla in the mouse. For the TCB system no evidence is found for linkage with any known genetic marker. Only in random population studies is an association seen between TCB and Gm.