Comparison of the indirect fluorescent antibody test with agglutination, complement-fixation, and Coombs test for Brucella antibody.

A comparison is made of a Brucella fluorescent antibody test with four standard tests on 342 normal, 86 diagnostic, and 41 known positive human sera. Where positive titres of accepted significance were obtained in standard tests, a titre of 1/10 or more was achieved in the fluorescence test.

Validation and standardization of Kveim test suspensions prepared from two human sarcoid spleens.

Single lots of a Chase-Siltzbach type I Kveim test material from each of two sarcoid spleens and designated lot 5 of spleen K12 and lot 1 of spleen K13 have been validated alongside a single lot (lot 10) of a 'standard' suspension provided by Dr L. E. Siltzbach and prepared identically from the spleen of patient J (SPLEEN J) in New York. Additionally, a half-dilution of lot 5, K12, was included in this comparison. The reactivity of each suspension was assessed among patients with active and inactive sarcoidosis. The selectivity of each suspension for sarcoidosis was assessed similarly by comparison with results in patients with active and quiescent pulmonary parenchymal tuberculosis and in healthy subjects. All patients were closely matched and two Kveim tests were made in each subject according to a prearranged statistical design. The reactivity of the K12, K12 1/2 dilution, and K13 suspensions among patients with active and inactive sarcoidosis was closely similar to that with the 'standard' S10 suspension and in accordance with the expected proportions of reactions in patients at different stages of sarcoidosis. The K12, K13, and 'standard' S10 suspensions yielded a negligible proportion of positive reactions among patients with active and quiescent pulmonary tuberculosis and among healthy subjects: thus, as judged by these tests each suspension showed a high degree of selectivity for sarcoidosis. The results of this validation study are discussed in relation to the results of other studies in which lots 5 and 14 of K12 and early and late batches of a suspension prepared from another sarcoid spleen at the Commonwealth Serum Laboratories designated CSL and provided by Dr T.H. Hurley in Melbourne were employed. Using lot 5 of K12 positive reactions were found in an appreciable proportion of patients with Crohn's disease, ulcerative colitis, and tuberculous lymphadenitis. A closely similar rate of positive reactions was encountered among patients with Crohn's disease following tests with batch 0025 of CSL suspension and with another lot (lot 14) derived from spleen K12. A close concordance of results was obtained with lot 5(K12) and with batch 0042 CSL among patients with ulcerative colitis, but at a lower rate of reactivity. We conclude that positive reactions also occur in some diseases other than sarcoidosis and consider that the difficulties in determining the criteria for an acceptable test suspension become increasingly apparent as additional Kveim tests are made with one particular lot and with seqential lots of material from a 'validated' tissue source.

Splenomegaly and splenectomy in sarcoidosis.

The natural history of 30 patients with sarcoidosis who showed histological evidence of granulomatous involvement of the spleen has been studied; 24 patients had splenomegaly, 16 of whom had splenectomy. The main indication for splenectomy was splenomegaly and resultant discomfort. Corticosteroids reduced spleen size but reduction or withdrawal of the relatively high dosage required resulted in rebound splenomegaly within a period of three months to three years. Haematological abnormalities were controlled by splenectomy in all patients so affected, but the natural history of their sarcoidosis remained unaltered.

The Kveim test: analysis of results of tests using colindale (K 12) materials.

Results of an analysis are presented of the salient clinical, pathological, and Kveim-test data of importance in the diagnostic assessment of 839 patients in whom a Kveim test was made as part of their routine clinical investigation. From these analyses the following significant observations can be made: 1) The age distribution and negative tuberculin results in patients with sarcoidosis were in keeping with the diagnosis of sarcoidosis, whereas for those in whom a diagnosis other than sarcoidosis was made, they were not. 2) The findings of 64% positive tuberculin results in cases of confirmed sarcoidosis of less than 2 yr known duration and only 39% in those of greater than 2 yr duration are closely similar to those found in international Kveim-test studies reported by Siltzbach in 1966 and Hurley and Bartholomeusz in 1971. 3) The use of the material was helpful in confirming a diagnosis of sarcoidosis in patients with extrathoracic lesions, for positive results were obtained in 33% of those with uveitis 40% of those with erythema nodosum only (findings which are in keeping with those of other studies in the United Kingdom, and 60% among 27 patients presenting with lesions in various sites, including 2 with cranial nerve lesions and one with cardiac arrhythmia. 4) We found only 2 positive reactions (less than 1%) among 221 patients in whom a diagnosis other than sarcoidosis was reached. Clearly these findings show that the Kveim test material. Lots 19 and 22, of spleen K 12 exhibited not only a high degree of reactivity and selectivity for sarcoidosis, but also that they were of considerable practical value as an aid to diagnosis. The finding of only 2(0.9%) positive Kveim tests among 221 patients with diseases other than sarcoidosis is of special interest. Of the different diseases that were ultimately diagnosed only 6 patients tested had lymphoma, only 11 had either pulmonary or lymphatic tuberculosis, and only one had Crohn's disease. Although these numbers are small, it is relevant to compare the Kveim-test data of Lots 19 and 22 of K 12 with those of Lot 5 and of Lot 14 of the same spleen. In validation studies Lot 5 yielded the expected proportion of positive reactions at different stages of sarcoidosis and a negligible proportion of positive reactions with active or quiescent pulmonary tuberculosis or among healthy subjects. However, in subsequent studies in special groups of patients, those with Crohn's disease, ulcerative colitis, or lymphatic tuberculosis, a proportion of the Kveim tests performed with these lots were positive. Within the context of the present field study, the results of these analyses confirm that the last lots of K 12 material exhibited a high degree of selectivity for sarcoidosis and that they emphasize again the practical value of the Kveim tests with suspensions that have undergone careful validation.

The serodiagnosis of human hydatid disease: 1. The routine use of latex-agglutination and complement-fixation in diagnosis.

The combined use of complement fixation (CF) and latex agglutination (LA) tests is reported on sera from 6328 patients with suspected hydatid disease; 191 were confirmed positive at operation ('known positives'). Results by LA are related to CF titres. Both tests were negative in 90% of specimens. Nine patients were subsequently found infected of whom 3 became positive in tests after operation. Of sera positive in both tests, 75% were from 'known positives'. The remainder were almost certainly from infected patients. Half the patients whose sera were LA positive/CF less than or equal to 1/4 were follow-up 'known positives' in whom CF titres had waned; 2 were early infections. Only 3% of the cases with an LA negative/CF titre of greater than or equal to 1/16 were 'known positives' and 6% where the CF titre was 1/8. The remaining CF results in the group were false positives and accounted for 1.2% of all sera tested. Findings show that a CF titre greater than or equal to 1/8 with positive LA indicates past or present infection; a negative CF test with positive LA usually indicates past infection; rarely, infection is present when a CF titre is greater than or equal to 1/8 and LA is negative. A rising CF titre and positive LA indicates current infection; reliable prognosis following treatment is given by CF.

False positive reactions in the indirect fluorescent antibody test for Legionnaires' disease eliminated by use of formolised yolk-sac antigen.

The indirect fluorescent antibody (FA) technique for the diagnosis of Legionnaires' disease was used to investigate an outbreak of respiratory disease in a military population. The outbreak was later shown to be caused by an adenovirus. High titres were obtained using the ether-killed antigen supplied by the Center for Disease Control (CDC), Atlanta, but not with a formolised yolk-sac antigen prepared in out laboratory. The reactivity of these sera with the CDC antigen was removed by absorption with a partly identified gram-positive bacterium, whereas sera from persons with true Legionnaires' disease were unaffected by such treatment, suggesting that such reactivity is not specific for Legionnaires' disease. The lack of reactivity with negative control sera and strong reactivity from a small group of patients in whom seroconversion was demonstrated has led us to conclude that formolised yolk-sac antigen is a reliable antigen for the diagnosis of Legionnaires' disease by the FA method. Measurement of the sensitivity and specificity of the formolised yolk-sac antigen is still in progress.

The derivation of a minimum immune titre of rubella haemagglutination-inhibition (HI) antibody. A Public Health Laboratory Service collaborative survey.

Ten laboratories collaborated in a study of minimum immune titre (MIT) of rubella haemagglutination-inhibiting (HI) antibody with one laboratory acting as a reference laboratory to provide a uniform basis for comparison of the HI results. The international unitage equivalent to the MIT used by the ten laboratories was found to vary from 24 to 98 units. Testing of the sera by immunofluorescence and by HI after flotation centrifugation indicated that residual non-specific inhibitors may interfere with HI antibody testing to an extent equivalent to 12-15 units. An acceptable MIT would therefore be equivalent to 24-48 units of rubella HI antibody. The single radial haemolysis (SRH) results on the sera indicate that this is a sensitive and specific test for rubella antibody.

Detection of Bordetella pertussis antibodies in human sera by complement-fixation and immunofluorescence.

The complement-fixation test, as commonly used in the diagnosis of viral infections, was studied for its possible application to the diagnosis of whooping cough and the detection of antibody following pertussis vaccination. The results were compared with those obtained in parallel immunofluorescence tests. CFTs were performed on sera from 41 patients with whooping cough (Bordetella pertussis isolated), 125 vaccinated persons, and 618 controls; parallel tests by IF were made on sera from 24 cases of whooping cough, 36 vaccinated persons and 37 controls. Results of both tests correlated closely and showed that titres of diagnostic significance were seldom found in control sera. They also showed that, in patients suffering from whooping cough, antibody in a single specimen or a rise in antibody between paired sera was almost always demonstrated. Titres in general were lower in infants less than 6 months of age. IgG antibodies were involved in both tests. Although the number of sera tested was small both tests appear to be reliable as means of demonstrating the presence of antibody formed during the course of infection and after vaccination.

Cellular immunity and circulating antibody to herpes simplex virus in subjects with recurrent herpex simplex lesions and controls as measured by the mixed leukocyte migration inhibition test and complement fixation.

Cellular immune responses and circulating antibody levels to herpes simplex virus were examined in patients with recurrent herpes simplex (HSV) infections and controls. Mixed leukocyte migration inhibition by herpes simplex antigen was less in affected patients than in controls but serum antibody levels were higher. There was no significant difference in leukocyte migration between patients with active or recent lesions and other herpes subjects, and the response in the mixed leukocyte migration test to phytohaemagglutinin (PHA) was similar in patients and controls. The data presented suggest that a localized defect in cell mediated immunity to herpes simplex virus may exist and be responsible for recurrent herpes simplex infections.

The serodiagnosis of human hydatid disease: 2. Additional studies on selected sera using indirect haemagglutination (IHA), enzyme linked immunosorbent assay (ELISA) and defined antigen substrate spheres (DASS).

Sixty-one serum samples selected on the basis of reactivity in the complement fixation (CF) and latex agglutination (LA) test, were further examined for sensitivity and specificity by indirect haemagglutination (IHA), enzyme linked immunosorbent assay (ELISA) and defined antigen substrate spheres (DASS). Twenty sera from healthy Europeans and 48 samples from patients with either schistosomiasis or trichinosis were also tested. Comparable levels of sensitivity were found between the CF and LA positive sera and IHA, ELISA and DASS. Of the CF positive LA negative group of sera, many were positive by DASS but only a few reacted in IHA and ELISA. Some cross reactivity was also observed in the schistosomiasis sera tested by IHA and ELISA.

WHO collaborative study on the sero-epidemiology of rubella.

Under the auspices of WHO an investigation was made by 9 laboratories in different parts of the world on the distribution of rubella antibodies in girls and women of child-bearing age. In the first part of the study the objective was to determine the reliability and reproducibility of the tests employed. It was found that there were no significant differences in the variability of the titres obtained in different laboratories when the results were compared with those obtained by repeatedly testing the same sera in one laboratory.In the second part of the study sera were obtained from girls in schools and women attending clinics and health centres. They were not taken from random samples of the populations. In most of the studies the pattern of development of antibody was similar. About half the persons had antibody at 6-8 years of age and 80%-87% at 17-22 years of age, the percentage remaining relatively constant thereafter. The island populations of Trinidad and Jamaica and a rural area of Japan were, however, found to have significantly fewer women with antibodies than urban areas in Europe or the Americas.