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DO FAT BOYS GET BURNED ?
826
frequency of blood-group B in the control sample. The expected number of children with blood-group B would, therefore, be 7-8 individuals in the combined sample as compared to the one observed. This deficit was due to a decreased frequency of mothers with the B allele. Although the frequency of type A was slightly increased in the C.H.D. group the deficiency of B was of relatively greater magnitude. Department of Pediatrics, University of Colorado Medical Center, Denver, Colorado 80220, U.S.A.
patients who had high but non-rising
c.F.
are
antibody titres
The results of the nasal smears and the shown in the accompanying table.
(gl/160).
serology
COMPARISON OF SEROLOGICAL FINDINGS AND FLUORESCENT-ANTIBODY TECHNIQUE FOR IDENTIFICATION OF INFLUENZA-A INFECTION
M.-L. LUBS J. J. NORA H. A. LUBS.
DO FAT BOYS GET BURNED ?
SiR,-Major
Wilmore and Colonel Pruitt
(Sept. 23,
p. 631) show that burned boys in Texas between 2 and 13 years old are heavier than percentile growth charts, compiled for a different population some years ago, would predict. Their conclusion is that fat boys get burned, which may be true and interesting. Equally, however, Texas boys may be fat: could the authors set our minds at rest by comparing the weight of unburned Texas boys with
the
same
percentile
charts ?
Clinical Research Centre, Harrow, Middlesex HA1 3UJ.
J. S. GARROW.
Copositivity 16/28=57 conegativity 12/18=67;. Overall correlation 28/46=61 %.
The fluorescent-antibody technique was not a sensitive method for the diagnosis of influenza-A infection either in this group of patients or in another study.1 6 patients aged between 54 and 77 years had influenza-A antigen in their nasal smears but negative serological results. These patients had influenza-like illnesses and it is possible that influenza-A positive cells in the nose have some significance in the serologically negative patient. Tateno et al.2 also found positive nasal smears in 68% of serologically negative
patients. FLUORESCENT-ANTIBODY DIAGNOSIS OF INFLUENZA-A INFECTION SiR,—The report by Dr. Brocklebank and others (Sept. 9, p. 497) on the use of the fluorescent-antibody technique for the early diagnosis of influenza-A infection in children prompts us to report some different findings with this technique on older patients during an influenza A2/Hong Kong/68 outbreak in January and February, 1972.
patients (mean age 65 years) were admitted to hospital with exacerbations of chronic lung or heart disease, but the clinical diagnosis of influenza in some of these patients was uncertain. 16 patients, mostly medical and nursing staff (mean age 29 years), with influenza-like illnesses were also investigated. 68 nasal swabs were taken from the 46 patients within two days of onset of symptoms or on the day of admission to hospital. Each swab was rolled on to two separate areas on a microscope slide which was then dried, fixed in acetone for ten minutes, and coded. Each area was overlaid with chicken anti-influenza A or B serum (W.H.O. International Influenza Center for the Americas, Atlanta, Georgia) for one hour at 37 °C, washed, and stained with fluorescein-conjugated rabbit anti-chicken serum (Nordic Diagnostics) for forty-five minutes at 37 °C. All sera used in the test were absorbed with HEp2 cells and used at optimal dilutions. Antibody to influenza A or B was measured in acute and convalescent sera from all patients using the overnight complement-fixation (c.F.) test and the hsemagglutination-inhibition (H.i.) test. Influenza-A specific IgM was measured by the indirect fluorescentantibody technique in sera from those patients who had non-rising influenza-A antibody titres and in those patients who had influenza-A positive nasal smears but negative serological findings. Positive serological results are defined as a fourfold or greater rise of C.F. or H.I. antibody, or the presence of influenza-A specific IgM in sera. A virus similar to influenza A2/Hong Kong/68 was isolated from throat-swabs obtained from 3 patients.
More vigorous but more distressing methods of taking specimens might reduce the number of negative nasal smears in serologically positive patients. We thank Dr. M. S. Campbell, Dr. T. T. Fulton, Dr. J. S. Logan, Dr. J. F. Pantridge, and Dr. J. A. Weaver for access to their patients.
Royal Victoria Hospital and Department of Microbiology, Grosvenor Road,
DOROTHY THOMSON C. F. STANFORD J. H. CONNOLLY.
Belfast BT12 6BN.
30
Positive influenza-A fluorescence in nasal smears was obtained up to ten days after the onset of illness. All nasal smears were negative for influenza-B antigen, and influenzaB antibody rises were not detected in any patient. Influenza-A specific IgM was only found in the sera of 3
M.E.M. TEST FOR MALIGNANT DISEASE SiR,—The independent confirmation by Pritchard et al.3 of our original finding4 that lymphocytes from patients with malignant disease are sensitised to encephalitogenic factor (E.F.) seems an appropriate moment at which to draw attention to some difficulties and pitfalls in the use of the macrophage electrophoretic migration (M.E.M.) test and which have become apparent in the light of our now much extended experience with cancer basic protein as well as E.F.
(1) In addition to the difficulties raised by coexistence of neurological disease, a background of intrinsic asthma provides a
response to
E.F.
within the
cancer
range."
(2) Exposure of either patients (or guineapigs used as a source of macrophages) to influenza virus may give rise to false-positive results. It is important that guineapigs should be healthy and tested if necessary for prior sensitisation to E.F.7 (3) Cancer may be present for some years before diagnosed,’ so that some patients in the " silent phase " will appear as false positives. Time alone will resolve their situation. Since wellsubstantiated cancer occasionally regresses spontaneously such, too, may be expected to add to a group of false positives. On the other hand, there is a very small number of apparently normal 1. 2. 3. 4.
5. 6. 7. 8.
Liu, C. Am. Rev. resp. Dis. 1961, 83, 131. Tateno, I., Kitamoto, O., Kawamura, A. New Engl. J. Med. 1966, 274, 237. Pritchard, J. A. V., Moore, J. L., Sutherland, W. H., Joslin, C. A. F. Lancet, Sept. 23, 1972, p. 627. Field, E. J., Caspary, E. A. ibid. 1970, ii, 1337. Caspary, E. A., Feinmann, L., Field, E. J. Unpublished. Field, E. J., Caspary, E. A. Lancet, 1972, i, 963. Diengdoh, J. V., Turk, J. L. Internat. Archs Allergy, 1968, 43, 297. Field, E. J., Caspary, E. A., Shepherd, R. H. T. Br. med. J. 1972, iii, 641.
frequency of blood-group B in the control sample. The expected number of children with blood-group B would, therefore, be 7-8 individuals in the combined sample as compared to the one observed. This deficit was due to a decreased frequency of mothers with the B allele. Although the frequency of type A was slightly increased in the C.H.D. group the deficiency of B was of relatively greater magnitude. Department of Pediatrics, University of Colorado Medical Center, Denver, Colorado 80220, U.S.A.
patients who had high but non-rising
c.F.
are
antibody titres
The results of the nasal smears and the shown in the accompanying table.
(gl/160).
serology
COMPARISON OF SEROLOGICAL FINDINGS AND FLUORESCENT-ANTIBODY TECHNIQUE FOR IDENTIFICATION OF INFLUENZA-A INFECTION
M.-L. LUBS J. J. NORA H. A. LUBS.
DO FAT BOYS GET BURNED ?
SiR,-Major
Wilmore and Colonel Pruitt
(Sept. 23,
p. 631) show that burned boys in Texas between 2 and 13 years old are heavier than percentile growth charts, compiled for a different population some years ago, would predict. Their conclusion is that fat boys get burned, which may be true and interesting. Equally, however, Texas boys may be fat: could the authors set our minds at rest by comparing the weight of unburned Texas boys with
the
same
percentile
charts ?
Clinical Research Centre, Harrow, Middlesex HA1 3UJ.
J. S. GARROW.
Copositivity 16/28=57 conegativity 12/18=67;. Overall correlation 28/46=61 %.
The fluorescent-antibody technique was not a sensitive method for the diagnosis of influenza-A infection either in this group of patients or in another study.1 6 patients aged between 54 and 77 years had influenza-A antigen in their nasal smears but negative serological results. These patients had influenza-like illnesses and it is possible that influenza-A positive cells in the nose have some significance in the serologically negative patient. Tateno et al.2 also found positive nasal smears in 68% of serologically negative
patients. FLUORESCENT-ANTIBODY DIAGNOSIS OF INFLUENZA-A INFECTION SiR,—The report by Dr. Brocklebank and others (Sept. 9, p. 497) on the use of the fluorescent-antibody technique for the early diagnosis of influenza-A infection in children prompts us to report some different findings with this technique on older patients during an influenza A2/Hong Kong/68 outbreak in January and February, 1972.
patients (mean age 65 years) were admitted to hospital with exacerbations of chronic lung or heart disease, but the clinical diagnosis of influenza in some of these patients was uncertain. 16 patients, mostly medical and nursing staff (mean age 29 years), with influenza-like illnesses were also investigated. 68 nasal swabs were taken from the 46 patients within two days of onset of symptoms or on the day of admission to hospital. Each swab was rolled on to two separate areas on a microscope slide which was then dried, fixed in acetone for ten minutes, and coded. Each area was overlaid with chicken anti-influenza A or B serum (W.H.O. International Influenza Center for the Americas, Atlanta, Georgia) for one hour at 37 °C, washed, and stained with fluorescein-conjugated rabbit anti-chicken serum (Nordic Diagnostics) for forty-five minutes at 37 °C. All sera used in the test were absorbed with HEp2 cells and used at optimal dilutions. Antibody to influenza A or B was measured in acute and convalescent sera from all patients using the overnight complement-fixation (c.F.) test and the hsemagglutination-inhibition (H.i.) test. Influenza-A specific IgM was measured by the indirect fluorescentantibody technique in sera from those patients who had non-rising influenza-A antibody titres and in those patients who had influenza-A positive nasal smears but negative serological findings. Positive serological results are defined as a fourfold or greater rise of C.F. or H.I. antibody, or the presence of influenza-A specific IgM in sera. A virus similar to influenza A2/Hong Kong/68 was isolated from throat-swabs obtained from 3 patients.
More vigorous but more distressing methods of taking specimens might reduce the number of negative nasal smears in serologically positive patients. We thank Dr. M. S. Campbell, Dr. T. T. Fulton, Dr. J. S. Logan, Dr. J. F. Pantridge, and Dr. J. A. Weaver for access to their patients.
Royal Victoria Hospital and Department of Microbiology, Grosvenor Road,
DOROTHY THOMSON C. F. STANFORD J. H. CONNOLLY.
Belfast BT12 6BN.
30
Positive influenza-A fluorescence in nasal smears was obtained up to ten days after the onset of illness. All nasal smears were negative for influenza-B antigen, and influenzaB antibody rises were not detected in any patient. Influenza-A specific IgM was only found in the sera of 3
M.E.M. TEST FOR MALIGNANT DISEASE SiR,—The independent confirmation by Pritchard et al.3 of our original finding4 that lymphocytes from patients with malignant disease are sensitised to encephalitogenic factor (E.F.) seems an appropriate moment at which to draw attention to some difficulties and pitfalls in the use of the macrophage electrophoretic migration (M.E.M.) test and which have become apparent in the light of our now much extended experience with cancer basic protein as well as E.F.
(1) In addition to the difficulties raised by coexistence of neurological disease, a background of intrinsic asthma provides a
response to
E.F.
within the
cancer
range."
(2) Exposure of either patients (or guineapigs used as a source of macrophages) to influenza virus may give rise to false-positive results. It is important that guineapigs should be healthy and tested if necessary for prior sensitisation to E.F.7 (3) Cancer may be present for some years before diagnosed,’ so that some patients in the " silent phase " will appear as false positives. Time alone will resolve their situation. Since wellsubstantiated cancer occasionally regresses spontaneously such, too, may be expected to add to a group of false positives. On the other hand, there is a very small number of apparently normal 1. 2. 3. 4.
5. 6. 7. 8.
Liu, C. Am. Rev. resp. Dis. 1961, 83, 131. Tateno, I., Kitamoto, O., Kawamura, A. New Engl. J. Med. 1966, 274, 237. Pritchard, J. A. V., Moore, J. L., Sutherland, W. H., Joslin, C. A. F. Lancet, Sept. 23, 1972, p. 627. Field, E. J., Caspary, E. A. ibid. 1970, ii, 1337. Caspary, E. A., Feinmann, L., Field, E. J. Unpublished. Field, E. J., Caspary, E. A. Lancet, 1972, i, 963. Diengdoh, J. V., Turk, J. L. Internat. Archs Allergy, 1968, 43, 297. Field, E. J., Caspary, E. A., Shepherd, R. H. T. Br. med. J. 1972, iii, 641.