- Email: [email protected]
PAEDIATRIC HIV INFECTION
108
experienced pathologist using
Grocott’s modification of Gomori’s
methenamine/silver-nitrate method. After treatment of BAL with hypochlorite containing 1 w/v free available chlorine (stock solution 12-5% w/v free chlorine; BDH), the cysts were concentrated, well separated, and brightly stained with the direct conjugate. The concordance of results (table) obtained by two examiners was 100%. In acute untreated PCP there were 10 to over 50 brightly fluorescent cysts per field, allowing immediate diagnosis. In specimens with low numbers of cysts, these were easily seen since they were the only organised structures persisting after hypochlorite treatment. Higher magnification (x 100 objective lens) permitted identification of the clearly delineated thick wall of the cysts and their internal structure. Although the volume of BAL we have been using was small, the sensitivity and specificity were at least as good as those of conventional staining. This simple, inexpensive, and safe procedure, which we are now evaluating for detection of P carinii in induced sputum, may allow many laboratories with no special experience to diagnose PCP accurately. The concentration of hypochlorite used and the time of exposure are critical. An indirect immunofluorescence kit containing PC22 is available from Northumbria Biologicals, Cramlington, Northumberland. Infectious Diseases Unit,
Hôpital Raymond Poincaré, Garches 92380, France
ERIC DOURNON
INSERM U13 and Central Laboratory of Microbiology, Hôpital Claude Bernard, Paris
PREMAVATHY RAJAGOPALAN
FRANÇOISE ALBERT
FRANÇOISE CAMUS CLAUDIE MARCHE
Hôpital Claude Bernard Division of Microbiological Reagents and Quality Control, Central Public Health Laboratory, London
JAMES MCLAUCHLIN DHANRAJ SAMUEL ANTHONY G. TAYLOR
Prospective evaluation of a monoclonal antibody in diagnosis of Pneumocystis carinii pneumonia. Lancet 1986; ii: 1-3. 2. Kovacs JA, Ng VL, Masur H, et al. Diagnosis of Pneumocystis carinii pneumonia: improved detection in sputum with use of monoclonal antibodies. N Engl J Med 1. Kovacs JA, Gill V, Swan JC, et al.
1988; 318: 589-93. J, McLauchlin J, Taylor AG,
3. Albert
et al Detection of Pneumocystis carinii cysts in broncho-alveolar lavage fluids from AIDS patients using a monoclonal antibody. PHLS Commun Dis Rep 1988; no 43: 3.
PAEDIATRIC HIV INFECTION
SiR,—The Italian Multicentre Study (Nov 5, p 1043) tries to cast a new light on an important issue: how perinatal HIV infection is transmitted and how it could be prevented. It seems to me that the data have been gathered in such a way that they cannot be properly analysed. 165 of 486 children born to HIV-positive mothers (33-9%) were considered infected. Since the source of information was a register for HIV infection in children, the proportion of children who were infected is certainly overestimated. The essential part of the report is the analsysis of the factors that might have contributed to infection (table n): data were available on 132 of 165 infected children (80%) but on only 81 of 321 uninfected children (25 %). Despite the lengthy and detailed questionnaire sent to all the 52 participating centres, information on the mode of delivery and feeding of most of the uninfected children was not obtained. It is possible that this small group of uninfected children was not representative of the whole group. 106 of 132 (80%) infected children in table u were delivered vaginally compared with 57 of 81 (70%) uninfected children. Vaginal delivery might seem tenuously associated with infection and one might think that with a larger number of children the difference would be statistically significant. An alternative
explanation would be that the 81 uninfected children were bom in centres where a higher proportion of caesarean sections was combined with
more willingness to cooperate in a multicentre retrospective study. The study group should say how the 81 uninfected children were
selected. A case-control
study would have been preferable.
46 Ash
Grove, Headington, Oxford OX3 9JL
GIUSEPPE E. BIGNARDI
*** This letter has been shown whose reply follows.-ED. L.
to
Dr Tovo and Dr de
Marinto,
’
SIR,-Dr Bignardi considers as uninfected the 321 healthy at-risk children in whom definitive proof of infection could not be obtained. But in our study, according to CDC criteria,! only 92 seronegative children aged over 15 months were regarded as uninfected, whereas in the remaining 229 infants the status of infection was indeterminate (PO class). Most of Bignardi’s figures were extrapolated without taking into account this important distinction. Consequently he assumes that information on the mode of delivery and type of feeding were available in only 25% of uninfected children, a poor representation of the whole group; he wonders how the 81 uninfected children were selected and speculates about disparity in methods between centres. In fact mode of delivery and type of feeding were also recorded in most of the 221 PO children, but the influence of these variables on perinatal HIV transmission could not be assessed. Furthermore, no selection among uninfected children was made because mode of delivery and feeding were known in 88% (81/92) of cases, which was not significantly different from the 80% known (132/165) among infected children. We would like to underline that the influence of vaginal delivery and breastfeeding on HIV transmission is a fundamental question about which our study may offer only a preliminary trend. The present data from 318 children with definite status of infection indicate a significant role for breastfeeding but not for vaginal delivery. Caution must, however, be used in interpreting these results because many variables may interfere. Such variables will be reduced but not removed by prospective studies, such as that which we are doing on over 400 children followed up from birth. Symptom-free children may be falsely classified as uninfected until sensitive and standardised methods for diagnosis of infection are available. Furthermore, the progression of disease in the mother, or, better, viraemia and immune deficiency, could increase the risk of HIV transmission,2 as well as the duration of breastfeeding. In contrast if infection occurs late in pregnancy, very premature children might be more protected. On the other hand a randomised case-control study is impossible, because caesarean section may prove necessary and we wonder if the risk/benefit ratio of breastfeeding newborn infants of seropositive mothers is today acceptable in a developed country when planning a specific study. Institute of Clinical Paediatrics, 10126 Turin, Italy; and Paediatnc Clinic III,
PIER-ANGELO TOVO MAURIZIO DE MARTINO,
Firenze, Italy
For the Italian Multicentre
Study
1. Centers for Disease Control. Classification system for human immunodeficiency virus (HIV) infection in children under 13 years of age. MMWR 1987; 36: 225-35. 2. Piot P, Plummer FA, Mhalu FS, et al. AIDS: an international perspective. Science
1988; 239: 573-79.
NEED TO CONFIRM HTLV-I SCREENING ASSAYS
SIR,-Dr Babona and Professor Nurse (Nov 12, p 1148) report a on antibodies to human T-lymphotropic virus type I (HTLV-I) among blood donors from Papua New Guinea. A screening test was used, without verification of antibody specificity by a confirmatory assay. We have used the same gelatin agglutination screening assay for HTLV-I (’Serodia’; Fujirebio, Tokyo) in a survey in Djibouti, but we confirmed all repeatedly positive sera by the more specific western blot (WE) (Diagnostic Biotechnology, Singapore). WB seropositivity was defmed by the presence of bands indicating antibodies to the p24 and the pig 19 gag viral proteins or to the p 19 protein plus antibodies to other relevant antigens, according to the manufacturer’s guidelines. All sera positive by WB were assayed twice, and results were reproducible. Of the 20 sera that were repeatedly reactive by agglutination testing, only 4 (20%) were confirmed by WB; 1 other serum gave an equivocal result. All 4 sera meeting the manufacturer’s requirements for HTLV-1 confirmed positivity also exhibited antibodies to gp46. Details of the epidemiological survey will appear survey
elsewhere.1
experienced pathologist using
Grocott’s modification of Gomori’s
methenamine/silver-nitrate method. After treatment of BAL with hypochlorite containing 1 w/v free available chlorine (stock solution 12-5% w/v free chlorine; BDH), the cysts were concentrated, well separated, and brightly stained with the direct conjugate. The concordance of results (table) obtained by two examiners was 100%. In acute untreated PCP there were 10 to over 50 brightly fluorescent cysts per field, allowing immediate diagnosis. In specimens with low numbers of cysts, these were easily seen since they were the only organised structures persisting after hypochlorite treatment. Higher magnification (x 100 objective lens) permitted identification of the clearly delineated thick wall of the cysts and their internal structure. Although the volume of BAL we have been using was small, the sensitivity and specificity were at least as good as those of conventional staining. This simple, inexpensive, and safe procedure, which we are now evaluating for detection of P carinii in induced sputum, may allow many laboratories with no special experience to diagnose PCP accurately. The concentration of hypochlorite used and the time of exposure are critical. An indirect immunofluorescence kit containing PC22 is available from Northumbria Biologicals, Cramlington, Northumberland. Infectious Diseases Unit,
Hôpital Raymond Poincaré, Garches 92380, France
ERIC DOURNON
INSERM U13 and Central Laboratory of Microbiology, Hôpital Claude Bernard, Paris
PREMAVATHY RAJAGOPALAN
FRANÇOISE ALBERT
FRANÇOISE CAMUS CLAUDIE MARCHE
Hôpital Claude Bernard Division of Microbiological Reagents and Quality Control, Central Public Health Laboratory, London
JAMES MCLAUCHLIN DHANRAJ SAMUEL ANTHONY G. TAYLOR
Prospective evaluation of a monoclonal antibody in diagnosis of Pneumocystis carinii pneumonia. Lancet 1986; ii: 1-3. 2. Kovacs JA, Ng VL, Masur H, et al. Diagnosis of Pneumocystis carinii pneumonia: improved detection in sputum with use of monoclonal antibodies. N Engl J Med 1. Kovacs JA, Gill V, Swan JC, et al.
1988; 318: 589-93. J, McLauchlin J, Taylor AG,
3. Albert
et al Detection of Pneumocystis carinii cysts in broncho-alveolar lavage fluids from AIDS patients using a monoclonal antibody. PHLS Commun Dis Rep 1988; no 43: 3.
PAEDIATRIC HIV INFECTION
SiR,—The Italian Multicentre Study (Nov 5, p 1043) tries to cast a new light on an important issue: how perinatal HIV infection is transmitted and how it could be prevented. It seems to me that the data have been gathered in such a way that they cannot be properly analysed. 165 of 486 children born to HIV-positive mothers (33-9%) were considered infected. Since the source of information was a register for HIV infection in children, the proportion of children who were infected is certainly overestimated. The essential part of the report is the analsysis of the factors that might have contributed to infection (table n): data were available on 132 of 165 infected children (80%) but on only 81 of 321 uninfected children (25 %). Despite the lengthy and detailed questionnaire sent to all the 52 participating centres, information on the mode of delivery and feeding of most of the uninfected children was not obtained. It is possible that this small group of uninfected children was not representative of the whole group. 106 of 132 (80%) infected children in table u were delivered vaginally compared with 57 of 81 (70%) uninfected children. Vaginal delivery might seem tenuously associated with infection and one might think that with a larger number of children the difference would be statistically significant. An alternative
explanation would be that the 81 uninfected children were bom in centres where a higher proportion of caesarean sections was combined with
more willingness to cooperate in a multicentre retrospective study. The study group should say how the 81 uninfected children were
selected. A case-control
study would have been preferable.
46 Ash
Grove, Headington, Oxford OX3 9JL
GIUSEPPE E. BIGNARDI
*** This letter has been shown whose reply follows.-ED. L.
to
Dr Tovo and Dr de
Marinto,
’
SIR,-Dr Bignardi considers as uninfected the 321 healthy at-risk children in whom definitive proof of infection could not be obtained. But in our study, according to CDC criteria,! only 92 seronegative children aged over 15 months were regarded as uninfected, whereas in the remaining 229 infants the status of infection was indeterminate (PO class). Most of Bignardi’s figures were extrapolated without taking into account this important distinction. Consequently he assumes that information on the mode of delivery and type of feeding were available in only 25% of uninfected children, a poor representation of the whole group; he wonders how the 81 uninfected children were selected and speculates about disparity in methods between centres. In fact mode of delivery and type of feeding were also recorded in most of the 221 PO children, but the influence of these variables on perinatal HIV transmission could not be assessed. Furthermore, no selection among uninfected children was made because mode of delivery and feeding were known in 88% (81/92) of cases, which was not significantly different from the 80% known (132/165) among infected children. We would like to underline that the influence of vaginal delivery and breastfeeding on HIV transmission is a fundamental question about which our study may offer only a preliminary trend. The present data from 318 children with definite status of infection indicate a significant role for breastfeeding but not for vaginal delivery. Caution must, however, be used in interpreting these results because many variables may interfere. Such variables will be reduced but not removed by prospective studies, such as that which we are doing on over 400 children followed up from birth. Symptom-free children may be falsely classified as uninfected until sensitive and standardised methods for diagnosis of infection are available. Furthermore, the progression of disease in the mother, or, better, viraemia and immune deficiency, could increase the risk of HIV transmission,2 as well as the duration of breastfeeding. In contrast if infection occurs late in pregnancy, very premature children might be more protected. On the other hand a randomised case-control study is impossible, because caesarean section may prove necessary and we wonder if the risk/benefit ratio of breastfeeding newborn infants of seropositive mothers is today acceptable in a developed country when planning a specific study. Institute of Clinical Paediatrics, 10126 Turin, Italy; and Paediatnc Clinic III,
PIER-ANGELO TOVO MAURIZIO DE MARTINO,
Firenze, Italy
For the Italian Multicentre
Study
1. Centers for Disease Control. Classification system for human immunodeficiency virus (HIV) infection in children under 13 years of age. MMWR 1987; 36: 225-35. 2. Piot P, Plummer FA, Mhalu FS, et al. AIDS: an international perspective. Science
1988; 239: 573-79.
NEED TO CONFIRM HTLV-I SCREENING ASSAYS
SIR,-Dr Babona and Professor Nurse (Nov 12, p 1148) report a on antibodies to human T-lymphotropic virus type I (HTLV-I) among blood donors from Papua New Guinea. A screening test was used, without verification of antibody specificity by a confirmatory assay. We have used the same gelatin agglutination screening assay for HTLV-I (’Serodia’; Fujirebio, Tokyo) in a survey in Djibouti, but we confirmed all repeatedly positive sera by the more specific western blot (WE) (Diagnostic Biotechnology, Singapore). WB seropositivity was defmed by the presence of bands indicating antibodies to the p24 and the pig 19 gag viral proteins or to the p 19 protein plus antibodies to other relevant antigens, according to the manufacturer’s guidelines. All sera positive by WB were assayed twice, and results were reproducible. Of the 20 sera that were repeatedly reactive by agglutination testing, only 4 (20%) were confirmed by WB; 1 other serum gave an equivocal result. All 4 sera meeting the manufacturer’s requirements for HTLV-1 confirmed positivity also exhibited antibodies to gp46. Details of the epidemiological survey will appear survey
elsewhere.1