Cyril A. Clarke

Experimental Studies on the Prevention of Rh Haemolytic Disease

In the context of haemolytic disease of the newborn, ABO incompatibility means that the father’s blood is unsuitable for transfusion into the mother, and our interest in this stems from the work of Levine (1943), who noted a deficiency of such mating types in the parents of affected children. He deduced, therefore, that ABO incompatibility affords a degree of protection against Rh haemolytic disease, and this has been confirmed by many workers. Of particular interest are the experiments of Stern et al. (1956), who showed that male volunteers could be much more easily sensitized to Rh if the injected blood were ABO compatible.

Further Experimental Studies on the Prevention of Rh Haemolytic Disease

In a previous report (Finn et al., 1961) we gave reasons for thinking that the rapid removal of Rh-positive foetal erythrocytes from the circulation of a mother who was Rh-negative would prevent her from becoming immunized and producing Rh antibodies. We have now investigated the matter further, and the present paper describes the completed results of the earlier work (Experiment I) and then gives details of some subsequent observations (Experiments II and III). The reasoning involved and the scope of the investigations are first discussed.

P.T.C. taste response and thyroid disease.

The deaths from leukaemia in England and Wales for the period 1945 to 1957 have been classified under three headings-acute leukaemias of all types, chronic myeloid leukaeniia, and chronic lymphatic leukaemia. The age-specific mortality rates have been calculated for each type of leukaemia, for each sex, and for three periods of time-1945 to 1949, 1950 to 1954, and 1955 to 1 957. A study of these data suggests that the principal feature in the real increase in leukaemia is a change in the incidence of acute leukaemia. This is compatible with the concept that an increased exposure to ionizing radiations plays some part in the changed incidence of the disease.

A Local Survey of the Distribution of Industrial Melanic Forms in the Moth Biston betularia and Estimates of the Selective Values of these in an Industrial Environment

The survey shows that there is a rapid decline in the frequency of the industrial melanic carbonaria of the moth Biston betularia from a value of about 97 % in Liverpool to less than 10 % 50 miles to the west in North Wales. The decline in the frequency of the intermediate phenotype insularia in this area, controlled by an allelomorph at the same locus, is from about 14% on the Wirral (no reliable frequency is available for Liverpool) to about 4 % 30 miles to the west. The frequency of carbonaria has declined in one locality (Caldy) since 1959, perhaps as the result of the introduction of smokeless zones to the east of it. It is argued on the basis of experimental data that the typical form is not at an advantage with respect to visual predation by birds at this locality, but it is at less of a disadvantage than formerly. The increase in its frequency is explained by postulating a com pensating non-visual disadvantage of the carbonaria homozygote, for which there is independent evidence. This disadvantage may be of the order of 15 %. Experiments using dead moths placed in life-like positions on tree trunks at Caldy and in Liverpool confirmed that carbonaria is better camouflaged on the blackened tree trunks of industrial areas. Estimates of the selective disadvantage of the typical form in Liverpool, using data from the survey and these experiments, together with a variety of assumptions, indicate values of the order of 60 %, which is somewhat higher than previous estimates. At Caldy the typical form appears to have been at a disadvantage of about 50 % prior to the introduction of the smokeless zones and is now at about a 20 % disadvantage, using assumptions similar to those in the Liverpool estimates. Although these estimates are subject to considerable error, there is little doubt that they reflect the correct order of magnitude of the relative selective values.

Prevention of Rh-Haemolytic Disease: A Third Report

In two papers (Finn et d., 1961; Clarke it al., 1963) we described experiments which were successful in preventing Rh immunization in Rh-negative male volunteers. The basis of the procedure was to remove rapidly from the circulation previously injected chromium-tagged Rh-positive red cells by giving hightitre incomplete anti-D either as an infusion of plasma or as gamma3-globulin. In our second paper we stated that the next steps should be to find out whether foetal red cells could be cleared equally well as adult and whether female volunteers could be protected in the same way as men. The results of experiments to test these points form the first part (I) of the present paper. The second part (II) concerns two factors of great importance in the application of the technique to preventing Rh immunization due to pregnancy. These are the frequency with which transplacental haemorrhage from foetus to mother occurs during pregnancy as distinct from at delivery, and the relation of the production of immune antibodies to the size of transplacental haemorrhage assessed after delivery. In the third part of the paper (III) we discuss some of the details of the clinical trial, recently started in Liverpool, of anti-D gamma2-globulin injection given to Rh-negative Women after delivery.

Prevention of Rh-haemolytic disease

Between 1970 and 1976 in the Yorkshire region the incidence of Rh antibodies in Rh-negative pregnant women fell by 70%. This decrease occurred in both old (long-standing) and new (first-affected) cases, which emphasised that the reduction in numbers was as much due to fewer pregnancies among Rh-negative mothers as to administration of anti-D immunoglobulin. Nevertheless, the incidence has begun to level out. The continued incidence of first-affected cases is caused by three main factors: failure of administration of anti-D immunoglobulin after normal deliveries and abortions; a steady incidence of antibodies in primigravidae; and cases in which administration of anti-D immunoglobulin had failed to protect. Administering anti-D antenatally might reduce the incidence of new cases among primigravidae who are sensitised before anti-D is normally given. Even without routine antenatal administration of anti-D, the incidence of severely affected Rh babies in the Yorkshire region could be reduced to one or two isolated cases a year in a population of three to four million by administering anti-D after all Rh-negative deliveries and after every abortion.

INTENSIVE PLASMAPHERESIS AS A THERAPEUTIC MEASURE IN RHESUS-IMMUNISED WOMEN

Abstract Intensive plasmapheresis of pregnant and non-pregnant women, immunised to the Rh or Kell isoantigen, lowered the concentration of plasma-proteins, including total IgG and individual antibodies. The lowering of antibody concentration was detected by a method using radioactive anti-D gamma-globulin but not by a conventional agglutination technique. In general, the antibody content mirrored the IgG level during plasmapheresis, although in one pregnant woman the serum anti-D antibody content fluctuated despite a consistent fall in IgG. This patient may have been undergoing stimulation by Rh-positive fetal erythrocytes at the time of plasmapheresis. In all, eight pregnant women were treated by plasmapheresis in addition to conventional therapy. Of these, five gave birth to live infants, of which four survived the early postnatal period. Three non-pregnant women also received plasmapheresis.

Consequences for fetus and neonate of maternal red cell allo-immunisation

AIMS To study the distribution of clinically important red cell antibodies in pregnancy, and the associated fetal and neonatal morbidity and mortality. METHODS The case notes of women with clinically important red cell antibodies identified in their serum during pregnancy were reviewed. RESULTS During a 12 month period 22 264 women were referred for antenatal screening. Clinically important red cell antibodies were detected in 244 (1%). Of these, 100 were anti-D and 144 were non-RhD antibodies. There were three intrauterine deaths, three fetuses required intrauterine transfusion, 10 neonates were transfused, 27 others had phototherapy, and 27 with a positive direct antiglobulin test received no treatment. Early fetal losses occurred in the presence of both high and low levels of anti-D. CONCLUSIONS Anti-D remains the most common clinically important antibody in pregnancy, and accounts for the greatest fetal and neonatal morbidity and mortality. Of the other antibodies detected, anti-c was associated with most neonatal morbidity. The production of many of the non-D antibodies detected could be avoided by the use of selected red cells when transfusing pre-menopausal women.

Further studies on the industrial melanic moth Biston betularia (L.) in the northwest of the British Isles

The frequencies of the three phenotypes carbonaria, insularia and typical of the moth Biston betularia are given for a number of new localities and new samples from old localities in northwest England and the Isle of Man. In one locality (Caldy) the frequency of carbonaria has been decreasing at the rate of 1% per three years since 1959, probably due to the introduction of smokeless zones. Two methods have been used to measure the relative degree of camouflage at Caldy, where the melanic is common, and in the Isle of Man where it is much rarer. In Caldy carbonaria was the better camouflaged, but there was no evidence for this on the Isle of Man. One possible selective agent not previously reported is the bat, P. pipistrellus The rôle of moth movement over land and water is discussed in relation to the maintenance of the polymorphism and the steepness of the clines between North Wales and Liverpool.

All-Female Broods in the Butterfly Hypolimnas bolina (L.)

It has been known since 1924 that a proportion of females in the butterfly H. bolina produce only daughters, whereas others produce a 1:1 sex ratio. The present results confirm this, and show also that occasionally a few males are produced. The production of broods with a disturbed sex ratio is inherited entirely through the female line. By sexing the embryos and larvae cytologically and observing mortality in the embryos and late pupal stage we have obtained evidence that the deficiency of males is due to their very high mortality in the pre-adult stage. It is suggested that the abnormal sex ratio is due to an infective cytoplasmic factor (the presence of spirochaetes, as in Drosophila, having been ruled out), in contrast to Acraea encedon where meiotic drive of the Y chromosome has been postulated. The view is put forward that the polymorphism in H. bolina is maintained by the ‘infected’ females being at a slight disadvantage and that their numbers are maintained by contagion from an unidentified reservoir species.