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Biomedical subjects

J Pitt

Publications and source records attributed to J Pitt.

At least 55 records · Page 3Linked to original sources
PubMed1997

Maternal immunologic and virologic risk factors for infant human immunodeficiency virus type 1 infection: findings from the Women and Infants Transmission Study.

Maternal virus load of human immunodeficiency virus 1 (HIV-1) and maternal immunity are both associated with risk of an infected infant. The interrelationship of these two variables in describing that risk was assessed in a multisite study of 475 mother-infant pairs. Infant infection was associated with low CD4 cell percentage, high CD8, CD8/CD38, and CD8/DR cell percentages, persistently positive HIV-1 cultures, and high HIV-1 titer (P < .001, .001, .005, .006, .001, and .013, respectively). The association of CD4 cell percentage and increased CD8, CD8/CD38, and CD8/DR cell percentages with transmission was restricted to the 42% of women whose HIV-1 cultures were not persistently positive (all P < .001). Women with at least 1 negative culture and high CD4 cell percentage or low CD8 cell percentage were at very low risk (0-4%) of transmitting HIV-1, while those with always positive cultures transmitted at a high rate (18%-27%), regardless of immune status.

Adolescent↗
PubMed1997

Defining the time of fetal or perinatal acquisition of human immunodeficiency virus type 1 infection on the basis of age at first positive culture. Women and Infants Transmission Study (WITS).

It has been suggested that a positive diagnostic test for human immunodeficiency virus type 1 (HIV-1) during the first 48 h of life is indicative of intrauterine transmission, whereas negative tests during the first week with positive tests later indicate intrapartum transmission. On the basis of data from all 140 infected infants in the Women and Infants Transmission Study (WITS), the probability was estimated that an HIV-1 culture would be positive for the first time at each day of life if cultures were performed daily. The estimated probabilities (+/-SE) by days 0, 2, 4, 7, 9, 16, and 30 of life are 27.4% (+/-6.4%), 27.4% (+/-13.0%), 45.3% (+/-20.5%), 45.3% (+/-22.5%), 65.3% (+/-20.0%), 88.4% (+/-7.8%), and 89.3% (+/-7.0%), respectively. The initial 27% probability is consistent with the hypothesis that transmission usually occurs during the intrapartum period. However, the distribution of age at first positive culture does not separate clearly into two distinct intervals. More definitive methods for determining the timing of transmission are needed.

Age Factors↗
PubMed1996

The utility of IgA antibody to human immunodeficiency virus type 1 in early diagnosis of vertically transmitted infection. National Institute of Allergy and Infectious Diseases and National Institute of Child Health and Human Development Women and Infants Transmission Study Group.

OBJECTIVE: To determine the sensitivity and specificity of anti-human immunodeficiency virus (HIV) IgA in identifying infected infants at or before 6 months of age among the offspring of HIV-infected mothers. DESIGN: Prospective comparison of anti-HIV IgA measurement performed in 2 different laboratories by 2 different methods with the criterion standard of blood culture. SETTING: Five centers in the United States and Puerto Rico. PATIENTS: Population-based sample of 156 infants of HIV-infected mothers in the Women and Infants Transmission Study. MAIN OUTCOME MEASURES: Results of anti-HIV IgA test in relation to the infection status of the infants as measured by blood culture. RESULTS: Six-month plasma or serum samples were first tested in the 2 laboratories. The sensitivity and specificity of anti-HIV IgA in detecting infected infants at this age by laboratories 1 and 2 were 69% and 63% and 100% and 99%, respectively. A look-back study of samples obtained at birth, 1, 2, and 4 months was then performed on all infected children and a matched set of uninfected children. The performance of the test at birth was unsatisfactory in both laboratories (sensitivity 44% and 33%, specificity 43% and 60%), whether peripheral or cord blood was examined. At 1, 2, and 4 months, the sensitivity of the test was lower than at 6 months, but specificity was high. A modest correlation of absent anti-HIV IgA antibody and low percentage of CD4 cells in peripheral blood was seen at 6 months of age. CONCLUSIONS: The anti-HIV IgA test has moderate sensitivity and high specificity for the diagnosis of HIV infection at 6 months of age in the offspring of infected mothers.

Female↗
PubMed1996

Early detection of human immunodeficiency virus on dried blood spot specimens: sensitivity across serial specimens. Women and Infants Transmission Study Group.

OBJECTIVE: To evaluate the use of dried blood spot (DBS) specimens and the early diagnostic value of the polymerase chain reaction (PCR) for detection of the human immunodeficiency virus (HIV) in DBS specimens collected at predefined age intervals from a large cohort of U.S. infants at risk of congenital or perinatal HIV infection. DESIGN: We assayed available DBS specimens (n = 272) obtained during the first 4 months of life from 144 infants (41 infected, 103 uninfected) born to HIV-infected mothers enrolled in the Women and Infants Transmission Study. The DBS PCR results were compared with infant HIV infection status, PCR on liquid blood, and viral culture results. Analyses also included sensitivity and specificity of assay as related to the age of the infant when the specimen was obtained. RESULTS: The DBS specimen PCR results were concordant with results from liquid blood specimens and with results from viral culture. The DBS PCR was highly specific for all age groups. Sensitivity in detecting HIV infection status rapidly increased during the first month of life, from 19% (5/26) by 1 week to 96% (25/26) by 1 month of age. Specimens obtained on the day of birth or the next day were the least likely to have detectable HIV DNA. CONCLUSIONS: The PCR assay of DBS specimens is a reliable tool for the early diagnosis of HIV infection and has important advantage over that of liquid blood DNA PCR and viral culture. These advantages include a lower volume of blood required for testing, increased safety, and ease of storage or transport of specimens. Thus DBS PCR is a useful test for clinical and epidemiologic tracking of infants at risk of HIV infection.

Blood Preservation↗
PubMed1996

Diagnosis of infection with human immunodeficiency virus type 1 by a DNA polymerase chain reaction assay among infants enrolled in the Women and Infants' Transmission Study.

Early diagnosis of infection with human immunodeficiency virus type 1 (HIV- 1) in young infants is essential to decisions on their medical and social care. Whereas studies have suggested that polymerase chain reaction (PCR) is a sensitive and timely method of diagnosing HIV infection in children, these evaluations have been limited by the number of specimens studied. Recently, Roche Molecular Systems developed a complete HIV-1 DNA PCR testing kit (from specimen preparation to detection). In this study, use of this PCR test kit was evaluated for the detection of HIV infection in infants of seropositive mothers who were enrolled in the longitudinal, multicenter Women and Infants' Transmission Study. A total of 1209 blood specimens from 483 infants were tested and analyzed. The overall sensitivity and specificity of a single PCR test in determining HIV infection status in infants more than 1 but less than 36 months of age were 95% and 97%, respectively. For infected infants 1 to 6 months of age the sensitivity of the DNA-PCR test was 90% to 100%. In a direct comparison with coculture, the Roche DNA-PCR test was significantly more sensitive than coculture in the detection of HIV-1 in infected infants and was equivalent to coculture for the diagnosis of HIV in infants when a standardized algorithm was used to define infection status.

Algorithms↗
PubMed1996

Natural history of somatic growth in infants born to women infected by human immunodeficiency virus. Women and Infants Transmission Study Group.

OBJECTIVE: To evaluate the nature and magnitude of the effect of congenitally or perinatally acquired human immunodeficiency virus (HIV) infection on somatic growth from birth through 18 months of age. STUDY DESIGN: Anthropometry was performed serially in 282 term infants born to HIV-infected women in a multicenter prospective natural history cohort study. Repeated measures analysis was used to compare z-score anthropometric indexes of weight-for-age, length-for-age, weight-for-length, and head circumference-for-age between infected and uninfected infants, with adjustment for covariates including infant gender; maternal education; prenatal alcohol, tobacco, and/or illicit drug exposure; and mean prenatal CD4+ T-lymphocyte count. A separate repeated measures model was used to assess the effect of infant zidovudine treatment on growth. RESULTS: Infants infected with HIV were an estimated average 0.28 kg lighter and 1.64 cm shorter than uninfected infants at birth, were 0.71 kg lighter and 2.25 cm shorter by 18 months of age, and had a sustained estimated average decrement of 0.70 to 0.75 cm in head circumference. Patterns of growth were similar in male and female infants. Infected infants had a progressive decrement in body mass index from birth through 6 months of age. Infection with HIV was associated with significant decrements across all standardized growth outcome measures after adjustment for covariates. Mean z scores were lower for weight by 0.612 (p < 0.001), for length by 0.735 (p < 0.001), for weight-for-length by 0.255 (p = 0.02), and for head circumference by 0.563 (p < 0.001) SD units compared with uninfected infants. Zidovudine treatment was not associated with improved growth. CONCLUSION: The effect of congenitally or perinatally acquired HIV infection on infant growth is one of early and progressive decrements in attained linear growth and growth in mass, early and sustained decrements in head growth, and marked early decrements in body mass index.

Body Height↗
PubMed1996

After AIDS clinical trial 076: the changing pattern of zidovudine use during pregnancy, and the subsequent reduction in the vertical transmission of human immunodeficiency virus in a cohort of infected women and their infants. Women and Infants Transmission Study Group.

To determine the impact of the AIDS Clinical Trials Group (ACTG) Protocol 076 results on the subsequent use of zidovudine during pregnancy and the transmission rate of human immunodeficiency virus (HIV) in a cohort of mother-infant pairs (Women and Infants Transmission Study), a retrospective analysis was done. Transmission rates were calculated by simple proportion for infants with at least 6 months of follow-up, stratified by date of birth (n = 453 born on or before 1 March 1994; n = 103 born after 1 March 1994). Transmission rates decreased from 19% to 8% (P = .005, Fisher's exact test). Zidovudine use increased during pregnancy (22% vs. 89%) and in newborns (1% vs. 79%). Both cohorts were similar with respect to maternal immunosuppression, mode of delivery, and demographics. In summary, in a perinatal HIV observational study, the release of results of ACTG Protocol 076 was associated with an increase in zidovudine use during pregnancy and a concomitant decline in HIV transmission from mothers to infants.

Adult↗
PubMed1995

Interlaboratory variability of CD8 subset measurements by flow cytometry and its applications to multicenter clinical trials. NAID/NICHD Women and Infants Transmission Study Group.

Recent studies have demonstrated the utility of measuring subsets of CD8+ T cells as prognostic markers in epidemiology cohort studies of human immunodeficiency virus (HIV)-infected patients. Most of these studies evaluating the value of CD8+ T-cell subsets have been performed at single centers, and few data are available on variability in the measurement of the CD8+ cell populations in multicenter trials. In the current study, we addressed this question by evaluating interlaboratory variability from the five laboratories enrolled in the Women and Infants Transmission Study sponsored by the National Institutes of Health. This study evaluated 35 HIV-positive and 28 HIV-negative proficiency testing samples sent to the laboratories for evaluation. The study focused on the robust coefficient of variation (RCV) for CD38 (11%), HLA-DR (21%), and CD57 (15%) expression on the CD8+ population. Data from the current study indicated that the variability in these measurements is greater than that for CD3+ CD4+ (RCV, 5%) and CD3+ CD8+ (RCV, 5%) cells. Knowledge of the variability of the CD8+ subset measurements should guide investigators in the design and analysis of clinical trials and epidemiology studies. Ability to obtain improved interlaboratory agreement on CD8+ subset measurements will facilitate further evaluation of these markers in HIV studies.

CD3 Complex↗
PubMed1994

Blood culture in the first 6 months of life for the diagnosis of vertically transmitted human immunodeficiency virus infection. The Women and Infants Transmission Study Group.

Serial blood cultures over the first 6 months of life in 310 infants with vertical exposure to human immunodeficiency virus (HIV) in the Women and Infants Transmission Study were analyzed to determine their value for early diagnosis of HIV infection. Cultures were done at 0-7 days and 1, 2, 4, and 6 months of age: 55 infants were infected. Blood culture sensitivity in infected children was 24% (7/29) during the first week of life and 85%, 91%, 82%, and 88%, respectively, at 1, 2, 4, and 6 months. The sensitivity, specificity, and positive and negative predictive values of a single culture between 1 and 6 months of age were, respectively, 86.9%, 99.6%, 97.9%, and 97.5%. Two negative cultures between 1 and 6 months of age defined an uninfected infant with a specificity of 99.2%-100.0%. Blood culture done between 1 and 6 months of age in children of HIV-positive mothers is a sensitive and specific test for HIV infection, with high positive and negative predictive values.

Blood↗
PubMed1991

Lymphocytic interstitial pneumonia.

Lymphocytic interstitial pneumonia is at present a pathologic diagnosis. In the setting of a chronic interstitial pneumonia in a child with lymphocytosis, hyperglobulinemia, and lymphadenopathy or parotid enlargement, the diagnosis is often clinically presumed. At present the diagnosis can be established firmly only by lung biopsy. Models of pathogenesis include nonspecific stimulation of the immune system, HIV-specific stimulation, or synergy between EBV and HIV. Treatment includes oxygen and bronchodilators as needed. The role of zidovudine and of steroids in the management of LIP remains to be determined.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Perinatal human immunodeficiency virus infection.

Infection with HIV is rarely clinically apparent in the newborn period. At present, there is no satisfactorily sensitive and specific test to diagnose infection in the newborn nursery. Identification of women at risk for transmission of HIV to their infants and of infants at risk for vertically transmitted HIV infection, so that early diagnosis and treatment can be instituted, is the currently recommended approach.

Acquired Immunodeficiency Syndrome↗