199 DETECTION OF HEPATITIS-B CORE ANTIBODY
SIR,—There is a growing interest in the detection of hepatitis-B core antibody (anti-HBc) as a serological marker of human hepatitis-B virus infection.’ Existing methods using 4 complement fixation,2 radioimmunoassay,3 or immune adherences all require the purification of hepatitis-B core antigen (HBcAg): this prerequisite step has precluded their use by most laboratories. A method not requiring the purification of HBcAg was developed and evaluated. The principle is a specific staining inhibition of a peroxidase-labelled antl-HBc serum by the serum to be tested, using as a substrate a human liver rich in HBcAg. The liver from a chronic HBsAg carrier who died with postnecrotic cirrhosis was obtained at necropsy and frozen. It was shown by electron microscopy to contain nuclear virus-like panic1es.6 6fLm serial sections of this frozen liver were used immediately after post-fixation.7 The anti-HBc used was obtained from an asymptomatic HBsAg chronic carrier. After labelling with peroxidase,8 it stained the nuclei of the above substrate, and this staining was completely inhibited in a blocking test with an unlabelled reference rhesus anti-HBc serum (no. V-805-501-563, gift from the National Institutes of Health, Bethesda, Maryland) but was unaffected by absorption with purified HBsAg (Electronucleonics, Bethesda). With this peroxidase-labelled anti-HBc diluted at 1/20, the specificity and sensitivity of the inhibition method was evaluated by testing 225 coded human sera previously tested for HBsAg by radioimmunoassay. Sera were tested by batches of 16, together with known positive and negative control sera. Unknown sera giving complete or partial inhibition were read as anti-HBc positive. Results are given in the accompanying table.
BY IMMUNOPEROXIDASE INHIBITION ACCORDING TO DIAGNOSIS AND
being readily used
P. COUTU G. RICHER
1058 St. Denis Street, Montréal H2X 3J4, Canada
HÆMOPOIETIC STEM CELLS
SIR,—Smith and Ekert’ described
a significant improveperipheral-blood neutrophil-count after hypertransfusion of children with malignant disease. Predictably, this was associated with significantly less infection.2 However, to conclude that the evidence points to "stem-cell competition"
is untenable. Although there have been a number of reports describing remission in acute leukaemia after blood-transfusions, no satisfactory explanation has been proposed.3-6 All the children in Smith and Ekert’s study had marrow involvement—indeed most had acute lymphoblastic leukaemia, a disease which m most cases probably originates in the bone-marrow.’ The recorded findings may simply reflect a shift in the distribution of granulocytes to the circulating pool. There is no information on the absolute and differential marrow cellularity, marrow granulocyte reserve, or marginated granulocyte pool, and the growth of bone-marrow in culture in vitro. Without such information Smith and Ekert are quite unjustified in their claim. Furthermore, the two groups studied were dissimilar in the anti-leukæmic therapy received before randomisation (their table I). It is quite possible that patients in group A were on their way towards remission when they were entered into the man
hypertransfusion protocol. As hard data on the primitive haemopoietic cells in healthy man continue to be gained,’ it is surely a retrograde step to indulge in pure speculation on the basis of scanty results obtained from patients with intrinsic marrow disease. of Pathology,
University Department Royal Infirmary,
RONALD D. BARR
Aberdeen AB9 2ZB
National Institutes of Health,
Bethesda, Maryland, SEYMOUR PERRY
CORYNEBACTERIUM PARVUM TOXICITY
SIR,-Ossorio tients ever,
From these results, it appears that this method is specific for anti-HBc detection, since all positive sera were from HBsAgpositive subjects, except for one with a drug-induced hepatitis but with a history of acute hepatitis six years before. The results in chronic HBsAg carriers, either asymptomatic or with chronic liver disease, corroborate the findings of others with complement fixation.2 But the fact that only 5 of the 25 acutephase sera from patients with type-B hepatitis were found positive appears to be a clear indication of a lower sensitivity of the present method. The immunoperoxidase inhibition method does not offer the sensitivity of the existing methods,2-5 but it is specific and has
a1.9 have described toxic reactions in pa-
given Corynebacterium parvum intravenously. Howadult experience may not be directly applicable to
children. In an evaluation of C. parvum at a dose of5 mg/m2 we found that the intravenous route was tolerated much better than the subcutaneous route. Severe toxicity due to pain and suppuration was noted in patients after multiple courses of subcutaneous C. parvum. Subcutaneous C. parvum had to be discontinued in five out of fifteen patients because of unacceptable toxicity (suppuration or malaise or both). In one child a dose reduction to 0.5 mg/m2 still resulted in large 10 ml; sterile abscesses. Mild to moderate fever apart, intravenous C. parvum was well tolerated, and no severe toxicity was noted in six children. Pediatric
Hematology/Oncology Service, Children’s Memorial Hospital, Oklahoma City, Oklahoma 73190, U.S.A.
1 Hoofnagle, J. H., Gerety,
J., Barker, L. F. Am J.
C. L. SEXAUER R. NITSCHKE G. B. HUMPHREY
J H., Gerety, R. J., Barker, L. F. Lancer, 1973, ii, 869. H, Germ, J. L., Almeida, J. B., Holland, P. V. Intervirology, 1974, 2, 231. 4 Moritsugu, Y., Gold, J. W. M., Wagner, J. A., Dodd, R. Y., Purcell, R. H. J Immun. 1975, 114, 1792. 5 Tsuda, F , Takahashi, T., Takahaski, K., Miyakawa, Y., Mayumi, M. ibid. 1975, 115, 834 6 Lamothe, F, Laurencin-Piché, J., Côté, J., Guévin, R., Viallet, A., Richer, G. Gastroenterology, 1976, 71, 102. McLean, I W , Nakane, P. K J. Histochem Cytochem. 1974, 22, 1077. 2 Hoofnagle, 3. Purcell, R
8 Nakane, P. K, Kawoi, A. ibid p. 1084.
1 Smith, P. J., Ekert, H. Lancet, 1976, i, 776. 2. Bodey, G. P., Buckley, M., Sathe, Y. S., Freireich, E. J
Ann intern. Med. 1966, 64, 328. 3 Hayhoe, F. G J., Whitby, L. Br J Hœmat 1955, 1, 1. 4 Wetherley-Mein, G., Cotton, D. G. ibid 1956, 2, 345 5. Dreyfus, B. Rev. Hemat. 1948, 3, 29. 6. Bessis, M., Dausset, J. ibid. 1950, 5, 188. 7 Barr, R. D., Sarin, P. S., Perry, S. M. Lancet, 1976, i, 508 8. Barr, R. D., Whang-Peng, J. Science, 1976, 190, 24. 9. Ossorio, R. C., Fahey, J. L., Wilson, W., Plotkin, D., Brossman, S., Skinner, D Lancet, 1975, ii. 1090