Serum folate in viral and mycoplasmal infections.

The concentration of serum folate in 260 patients with viral and mycoplasmal infections was determined (305 samples). In 60% the serum folate concentrations were found to be below 3 micrograms/l. The incidence of low serum folate varied slightly. According to the infections diagnosed, low values were: for influenza A 50% (50 patients), influenza B 42% (45 patients), human parvovirus 67% (76 patients), rubella 62% (13 patients), infectious mononucleosis 60% (15 patients), Mycoplasma pneumoniae 73% (45 patients). For a group of undiagnosed rashes it was 81% (16 patients). The cause of low concentrations of serum folate in these patients is discussed.

Psittacosis/ornithosis in Cambridgeshire 1975-1983.

In a population of approximately 300 000 there were 150 illnesses attributable to chlamydial infection from January 1975 to June 1983 and nearly all were presumed due to Chlamydia psittaci. Diagnosis was based on the complement-fixation (CF) test, the disadvantages of which are discussed, especially anamnestic responses. There were 73 cases of pneumonia, 37 febrile respiratory infections, 35 miscellaneous conditions and five asymptomatic seropositive contacts. The annual number of cases was lowest in 1976 (3) and increased to a maximum in 1980 (28) followed by a sustained high level. No seasonal variation was observed. A presumptive bird source was present in only 17% and detailed consideration of cases in one rural practice suggests that the infection may possibly be more endemic than zoonotic.

Antibody assays for varicella-zoster virus: comparison of competitive enzyme-linked immunosorbent assay (ELISA), competitive radioimmunoassay (RIA), complement fixation, and indirect immunofluorescence assays.

The competitive ELISA test was compared with competitive RIA, complement fixation, and indirect fluorescent antibody test for the detection of antibody to varicella-zoster virus (VZV). ELISA and RIA were the most sensitive tests, being tenfold as sensitive as indirect immunofluorescence and 20 times as sensitive as complement fixation, which was surprisingly inadequate for detecting anti-VZV in sera from regular haemodialysis patients. The ELISA test was found to be the most suitable assay, employing a routine complement fixation test (CFT) grade viral antigen and not requiring radiolabelling and counting facilities, which are unavailable in most virology laboratories.

Disseminated toxoplasmosis in cardiac transplantation.

The first case of disseminated toxoplasmosis following cardiac transplantation in the UK is described, with details of Toxoplasma antibody tests made on other cardiac transplant patients. Sixteen of 40 (39%) of recipients had Toxoplasma antibody before operation. Eleven of 30 (37%) of donors had Toxoplasma antibody. The were four occasions when a negative recipient received a heart from a positive donor. Three survived the immediate postoperative period and two became infected with toxoplasmosis. The implications of this are discussed. Disseminated toxoplasmosis appears much more often when heart muscle from a dye test positive donor is given to a dye test negative recipient. Antibiotic therapy is limited by the fact that the antitoxoplasma drugs available are static in their effect, and need to be given for prolonged periods postoperatively.

Hepatitis B in the Cambridge dialysis and transplant unit 1966-1983.

The results of hepatitis B surveillance of the Cambridge dialysis and transplant units from June 1969 to July 1983 are reported. On admission 34/528 (6.44%) haemodialysis patients had anti-HBc. Preadmission screening excluded 19 HBs Ag carrier patients and two carrier staff. Eight patients became antigenaemic after admission and two others were found to be antigenaemic post-transplantation but pretransplant sera were not available from them. These two had active hepatitis and of the others, seven had asymptomatic carriage and one had acute hepatitis during haemodialysis. Two infected patients were admitted temporarily and one antigenaemic organ donor identified retrospectively. No cross infection occurred on the unit and the only instance of accidental infection of a member of staff was from an outpatient.

Tonometer disinfection and viruses.

Tonometer disinfectants in current use are frequently inactive against viruses and enable transfer of infection between patients. We selected sodium hypochlorite as a readily available alternative which is active against viruses and bacteria. At 500 p.p.m. it destroys herpes simplex, adenovirus 8, and enterovirus 70 within 10 minutes. A simple technique is described which is clinically acceptable and has been in daily use for one year.

Use of normal immunoglobulin in an echovirus 11 outbreak in a special-care baby unit.

An epidemic of echovirus 11 infections occurred in the Cambridge special-care baby unit during August to October, 1982. There were 21 confirmed infections in babies; 1 died, 1 recovered after resection of a kidney, 5 had meningitis, and 6 had respiratory symptoms. Normal human immunoglobulin which contained antibody to echovirus 11 was administered intramuscularly (250 mg) to give protection. None of the children given immunoglobulin immediately after delivery (205 doses) developed symptoms or ill-effects. Serological studies reinforced earlier evidence for the protective action of antibody, and it is considered that immunoglobulin is a valuable safeguard for exposed newborn infants.

Antibody moieties within circulating immune complexes in heart transplant recipients.

Circulating immune complexes were isolated from the sera of cardiac allograft recipients by bovine conglutinin/anti-conglutinin co-precipitation, or by gel filtration and protein A-Sepharose affinity chromatography. The antibody moieties within these isolated immune complexes were tested for specificity against heterologous anti-thymocyte globulins by solid phase radioimmunoassay, and bacterial and viral antigens by indirect immunofluorescence. The results showed that in addition to possessing specific anti-equine anti-thymocyte globulin antibodies, immune complexes also contained cross-reacting antibodies to rabbit anti-thymocyte globulin and vice versa, despite the patients only having received antibody of one species. Similarly, antibodies directed against bacteria or viruses (cytomegalovirus, Herpes simplex, virus, Epstein-Barr virus) were found within immune complexes obtained during overt infection, but also where infection was not detected. These results demonstrate the heterogeneous nature of immune complexes in heart transplant sera, and suggest that various stimuli, including ATG therapy, infection and possibly polyclonal B cell activation, may be involved in their generation in cardiac transplantation.

An immunoradiometric assay of serum interferon using a monoclonal antibody.

An immunoradiometric assay for human interferon-alpha (HuIFN-alpha) has been adapted for the assay of low concentrations of HuIFN-alpha in human serum. The sensitivity of the assay is 5 to 10 IU/ml and the coefficient of variation less than 10%. The assay was shown to compare well with a biological (antiviral) assay in the measurement of serum interferon following intramuscular injection of HuIFN-alpha in nine volunteers. Serum interferon was also measured in the serum from 250 normal human donors. Two donors appeared to have detectable levels of HuIFN-alpha.

An ELISA test for the detection of antibodies to Legionella pneumophila.

An enzyme-linked immunosorbent assay (ELISA) test has been developed to detect antibodies to Legionella pneumophila serogroup 1. There is good correlation between indirect fluorescent antibody (IFA) and ELISA titres but ELISA is more sensitive.

Fatal infection with echovirus 11.

Twenty-four fatal cases of echo 11 infection in the eleven years 1968-78 are presented. All were children, and could be divided into two groups according to age at death and clinical presentation. The first group comprised 12 babies who died aged between 5 and 11 days after a short illness characterised by collapse, acidosis, and bleeding. At necropsy there was evidence of disseminated intravascular coagulation with haemorrhage into many organs including the renal medulla, suprarenal glands, gastrointestinal tract, and central nervous system. Six cases showed hepatic necrosis which was massive in three. Virus was present in many tissues. Infection was probably acquired from the mothers at delivery in 3 cases. Low maternal neutralising antibody titres and prematurity were thought to be adverse factors in the outcome. The second group consisted of 12 children aged between 9 weeks and 4 years 10 months who died suddenly. Pathological findings included upper respiratory tract infection, pneumonia, encephalitis, and gastroenteritis. Six of this group had been classified as 'cot deaths'. The role of echo 11 in the death of some of these older children is unknown. This report shows the danger of echo 11 to neonates, especially if unprotected by maternal antibody.

Low molecular weight IgM in cytomegalovirus infections and cardiac patients.

When 71 ischaemic heart disease and cardiomyopathy patients' sera were examined by the IFA (indirect fluorescent antibody) test, 18 of the 49 (36%) with CMV (cytomegalovirus) CF antibody appeared to contain a specific LMW (7S approx) IGM. This IgM was unrelated to the presence of RF (rheumatoid factor) demonstrable by agglutination of IgG-coated latex and by an immunofluorescence test, was not absorbed by heat-aggregated IgG and latex, nor did its demonstration appear to be complement dependent. It was demonstrable in acute CMV infection and in some cardiac patients, binds to HSV (herpes simplex virus) and CMV-infected cells.

Observations on 10 years' HBs antigenaemia after renal transplantation.

A renal transplant patient became a carrier of HBs Ag within four weeks of a successful transplant. The level of antigenaemia was extremely high, and approximately 3% of the particles were 42 nm Dane particles, although the anti-HBe was present from at least 20 months after transplant. After four years the antigenaemia declined to a low level, and five years later HBs Ag became undetectable for the first time. During the past 18 months, no antigen has been detected although immunosuppression continues and the original kidney is still functional.