Complement C6 and C7 DNA polymorphisms analysed by PCR in seven ethnic groups and characterisation of the C6 MspI RFLP.

Five polymorphisms in the C6 and C7 genes have been investigated in seven ethnic groups. The allele frequencies are broadly similar in most groups except C7 M/N which is monomorphic in our group of Africans, and C6 MspI and C7 S367T where the allele frequencies in African and Cape Coloured subjects are very different from the other ethnic groups. There is very little allelic association except between C6 A/B and C6 MspI. Seventeen of the 32 possible haplotypes have been observed, suggesting that much recombination has taken place. We describe a new method for the investigation of the MspI RFLP located in intron 3 of C6 (approximately 3 kbp 3' from exon 3 and 1.5 kbp 5' from exon 4) and its molecular basis, together with an improved method for the isolation of DNA from stored serum.

Complement component C7. Assessment of in vivo synthesis after liver transplantation reveals that hepatocytes do not synthesize the majority of human C7.

C7 M/N typing, the determination of the allotypes of the recently described C7 M/N protein polymorphism, was conducted on serum samples from donors and recipients of 100 liver transplantations to determine whether the liver is the predominant site of in vivo synthesis of human complement protein C7. Twenty-one cases were informative as the recipient was transplanted with the liver obtained from a donor with a different C7 M/N allotype. The determination of the C7 levels and phenotypes of up to 10 post-transplantation (p.t.) samples revealed that there was at most only a 50% contribution of the transplanted liver toward the C7 M/N allotype at 2 to 3 wk p.t.; that influence decreased with time and was approximately 10% in the samples obtained later than 6 wk after transplantation. C7 is thus the only terminal complement component not predominantly synthesized by hepatocytes, which is compatible with the observation that C7 is not an acute phase reactant. The transient contribution of the donor phenotype appears to be attributable to cells of the mononuclear phagocyte lineage, Kupffer cells in particular that are replaced by cells of recipient origin. Various cells of that lineage that are known to synthesize C7 in vitro, therefore, contribute more toward the C7 concentration than previously anticipated. Enhanced local C7 synthesis at the site of inflammation might add further to the basic C7 level especially because C7 is often the limiting factor for terminal complement complex generation.

Tissue typing, heart and heart-lung transplantation.

The effects of HLA matching and the presence of pre-existing anti-HLA antibodies, together with cross-match results, on heart and heart-lung transplants are discussed. Prospective HLA matching of donor and recipient is not usually performed for heart and heart-lung transplants. In a multi-centre study statistically significant improved survival with the better-matched heart grafts was found. In a small series of heart grafts it was also found that the improvement with HLA matching was confined to male recipients who were not blood group O. Heart graft recipients with wide panel reactive antibody had worse graft survival one year after transplant than the unsensitized. In several studies patients with a positive cross-match had a significantly lower survival rate than those with a negative cross-match. It is suggested that, minimally, pre-transplant screening and prospective cross-matching of highly sensitised patients is necessary.

Transfusion-associated graft-versus-host disease in patients with Hodgkin's disease and T cell lymphoma.

Two patients, one with Hodgkin's disease and one with peripheral T cell lymphoma, developed transfusion-associated graft-versus-host disease 16 and 8 days after transfusion of red cell and platelet concentrates. Fever and skin rash were followed rapidly by an elevation of liver enzymes and the onset of diarrhoea and pancytopenia. Despite treatment with high-dose methylprednisolone and anti-lymphocyte globulin, commenced within 7 and 2 days of the onset of rash, grade IV GvHD persisted and both patients died with severe pancytopenia. HLA types of peripheral lymphocytes of the patient with Hodgkin's disease were inconsistent with those of her parents and siblings, but HLA typing of her fibroblasts revealed that her true type was consistent with those of her parents and that her circulating lymphocytes were not genetically her own. The HLA types of the patient with T-cell lymphoma were inconsistent with those of her siblings which suggests, but, in the absence of other evidence, does not prove, chimaerism.

Lack of complementation between xeroderma pigmentosum complementation groups D and H.

The construction of permanent hybrid cell lines between xeroderma pigmentosum (XP) cells from different complementation groups allows analysis not only of the degree of repair correction but also of the restoration of biological activity to the UV-irradiated cells. With use of an immortal human cell line (HD2) that expresses excision repair defects typical of XP group D, a series of permanent hybrid cells has been produced with XP cells from groups A to H. Excision repair, as measured by incision analysis and unscheduled DNA synthesis, is restored to normal or near normal levels in crosses involving HD2 and cells from XP groups A, B, C, E, F, G, and I. All these hybrids show complementation for the recovery of normal UV resistance. As expected, hybrids expressing poor incision and hypersensitivity to UV were produced in crosses between HD2 and XPD fibroblasts, but they were also produced without exception when XPH was the partner. In the permanent HD2 x XPD or XPH hybrids, analysis of incision capacity reveals abnormally low activity and therefore that there has been no complementation. The true hybrid nature of HD2 x XPH cells has been confirmed by HL-A and -B tissue typing; moreover, detailed kinetic analysis of incision in these cells shows that the XPH phenotype, rather than the XPD, is expressed, i.e. breaks accumulate at low UV fluence of 1 J/m2. To help confirm these findings, another immortal XPD cell line was used in fusions involving HD2, XPH, or XPI. Cells resistant to ultraviolet were produced only with XPI fibroblasts. These data are discussed in terms of whether XPD and H mutations are likely to be allelic with respect to incision.

Definition of 15 equine leucocyte antigens.

Fifteen equine leucocyte antigens were defined by absorption and titration analysis of alloantisera obtained by natural sensitisation through pregnancy and by planned experimental immunisation. Definitive sera were tested on the cells of 90 unrelated horses and members of eight equine families. The family data suggested that 13 specificities were coded by a single locus (first locus) and one specificity (Eq 14) was coded by a second linked locus. The remaining specificity (Eq 7) was controlled by a third locus unlinked to the first or second loci. Tests on the cells of unrelated horses showed that two first locus specificities (Eq 16 and Eq 17) had a supertypic relationship to other first locus antigens. No individual was found to possess more than two first locus antigens, excluding the supertypic specificities.

Differential kidney graft survival associated with interaction between recipient ABO group and pretransplant blood transfusion.

In 1973 we reported significantly superior survival of kidneys transplanted to blood group O recipients compared with recipients of those from blood groups A, B, and AB taken together. In this extended series, the difference between these categories was less prominent and no longer significant. In the present study, blood transfusion significantly improved the survival of kidney grafts in patients of blood group O, but not of combined A, B. and AB groups. The difference between the graft protecting effect of transfusion in group O and combined groups A, B, and AB recipients was also significant. This suggests that the improvement in subsequent graft survival after transfusion is either confined to blood group O recipients, or is much stronger in them than in recipients of other groups. Our previous policy of restriction of blood transfusion is seen as one of the causes of the reduced superiority of group O over other groups in this extended series in comparison with our 1973 series. It seems that transfusion of group O recipients can markedly improve the prognosis of a subsequent first kidney graft.

Parallel studies of HLA antigens in patients with rheumatic heart disease and scleritis: comparisons with three control populations.

Parallel studies were carried out on HLA antigens in patients with rheumatic heart disease and scleritis. Comparison with one control population showed a significant excess of BW15 in both disease samples, while a comparison with two other control populations, showed the excess not to be significant. Possible reasons for this discrepancy are discussed, together with the effect on statistical significance of a small percentage of false antigen assignments in one of the samples. A small systematic serological false assignment of an antigen can, by itself, produce a significant result more easily if the frequency of the antigen being detected is low than if it is high. It is suggested that this effect may contribute to the discrepant significant results obtained by different workers in some HLA and disease studies.

An indirect anti-immunoglobulin rosetting reaction to detect alloantibodies to human lymphocytes.

A test is reported which detects alloantibody, absorbed onto the surface of human lymphocytes from multiparous antisera, by means of a red cell rosette assay. The red cells, trypsinised ox, are coupled with anti-immunoglobulin using chromic chloride. The antiglobulin used is rabbit anti-human IgG (Fc), chosen to avoid reaction with the surface immunoglobulin naturally present on human B lymphocytes. The reaction is termed the Indirect Anti-immunoglobulin Rosetting Reaction (IARR). The IARR is shown to be specific in the following ways: anti-immunoglobulin coupled ox cells do not react with normal human lymphocytes nor with lymphocytes treated with non-reactive serum. Red cells coupled with normal rabbit IgG do not react with normal or alloantibody coated lymphocytes. Multiparous sera (reactive with other individuals) do not react with cells of the serum donor in the IARR. Finally, the coupled red cells do not usually react with lymphocytes which have absorbed immune complexes onto their Fc receptors. The IARR is shown to be more sensitive than a standard cytotoxic test for detection of alloantibody. Several possible applications of the IARR are discussed.

HL-A antigens in patients with guttate psoriasis.

Tissue typing was performed on lymphocytes of sixty-two patients with guttate psoriasis, in forty-four of whom this was the first manifestations of the disease. In 84% of cases, the guttate psoriasis was preceded by a clinical infection. A highly significant excess of antigen W17 (HLA-BW17) was found in patients when compared with healthy population. In common with some other studies antigens HL-A13 (HLA-B13), W15 (HLA-BW15) and W21 (HLA-BW21) were found in excess but these became non-significant after correction for the number of antigens studied. 68% of patients who had guttate psoriasis de novo, subsequently developed persistent plaque psoriasis.

Kidney transplantation: analysis of 200 cases.

The first 200 renal allograft operations performed at Addenbrooke's Hospital, Cambridge, have been analysed. At the time of writing the fractional graft survivals at one, two, and three years were 53%, 49%, and 39% respectively, and these showed no observable change through the seven years of the programme. On the other hand, the survival of patients undergoing renal transplantation steadily improved, the most recent survival rates at one, two, and three years being 83%, 78%, and 67%, whereas the overall rates were 74%, 66%, and 54% respectively. The survival of second allografts was similar to that of first allografts. Ninety per cent. of the patients whose allografts functioned for a year or more returned to active and gainful employment. The return of children to school and of housewives to running a household was similarly gratifying. We conclude on both social and economic grounds that renal transplantation is fully justified as a therapeutic procedure.