Biomedical subjects

W Borkowsky

Publications and source records attributed to W Borkowsky.

At least 19 recordsLinked to original sources

PubMed1999

Measuring recent thymic emigrants in blood of normal and HIV-1-infected individuals before and after effective therapy.

The role of the thymus in HIV-1 pathogenesis remains unclear. We developed an assay to quantify the number of recent thymic emigrants in blood based on the detection of a major excisional DNA byproduct (termed alpha1 circle) of T cell receptor rearrangement. By studying 532 normal individuals, we found that alpha1 circle numbers in blood remain high for the first 10-15 yr of life, a sharp drop is seen in the late teen years, and a gradual decline occurs thereafter. Compared with age-matched uninfected control individuals, alpha1 circle numbers in HIV-1-infected adults were significantly reduced; however, there were many individuals with normal alpha1 circle numbers. In 74 individuals receiving highly active antiretroviral therapy, we found no appreciable effect on alpha1 circle numbers in those whose baseline values were already within the normal range, but significant increases were observed in those with a preexisting impairment. The increases in alpha1 circle numbers were, however, numerically insufficient to account for the rise in levels of naive T lymphocytes. Overall, it is difficult to invoke thymic regenerative failure as a generalized mechanism for CD4 lymphocyte depletion in HIV-1 infection, as alpha1 circle numbers are normal in a substantial subset of HIV-1-infected individuals.

Adolescent↗

PubMed1999

Changes in frequency of HIV-1-specific cytotoxic T cell precursors and circulating effectors after combination antiretroviral therapy in children.

Combination antiretroviral therapy has had a major role in reducing human immunodeficiency virus type 1 (HIV-1) plasma viral loads in HIV-1-infected adults but a variable effect in infants, in whom complete viral suppression appears to be less readily achieved. In adults, after the reduction in plasma viremia, there is a decrease in the numbers of circulating cytotoxic T cell (CTL) effectors and precursors in the majority of patients. This longitudinal study assessed the effect of combination drug therapy on the frequency of HIV-1-specific CTL responses in 8 HIV-1-infected children. Following treatment, the frequency of HIV-1-specific CTL responses initially increased, especially in children with incomplete viral suppression but with increasing CD4+ cell counts. In children with complete viral suppression, the frequency of HIV-1-specific CTL responses decreased, suggesting that viral replication is required to maintain CTL responses in the systemic circulation.

Anti-HIV Agents↗

PubMed1999

Dynamics of human immunodeficiency virus type 1 replication in vertically infected infants.

Plasma human immunodeficiency virus type 1 (HIV-1) turnover and kinetics were studied in children aged 15 days to 2 years following the initiation of a triple antiretroviral drug regimen consisting of zidovudine, lamivudine, and nevirapine. HIV-1 turnover was at least as rapid as that previously described in adults; turnover rates were more rapid in infants and children aged 3 months to 2 years than in infants less than 3 months of age. These data confirm the central role of HIV-1 replication in the pathogenesis of vertical HIV-1 infection and reinforce the importance of early, potent combination therapies for the long-term control of HIV-1 replication.

Acquired Immunodeficiency Syndrome↗

PubMed1999

A polymorphism in the regulatory region of the CC-chemokine receptor 5 gene influences perinatal transmission of human immunodeficiency virus type 1 to African-American infants.

There are natural mutations in the coding and noncoding regions of the human immunodeficiency virus type 1 (HIV-1) CC-chemokine coreceptor 5 (CCR5) and in the related CCR2 protein (the CCR2-64I mutation). Individuals homozygous for the CCR5-Delta32 allele, which prevents CCR5 expression, strongly resist HIV-1 infection. Several genetic polymorphisms have been identified within the CCR5 5' regulatory region, some of which influence the rate of disease progression in adult AIDS study cohorts. We genotyped 1,442 infants (1,235 uninfected and 207 HIV-1 infected) for five CCR5 and CCR2 polymorphisms: CCR5-59353-T/C, CCR5-59356-C/T CCR5-59402-A/G, CCR5-Delta32, and CCR2-64I. The clinical significance of each genotype was assessed by measuring whether it influenced the rate of perinatal HIV-1 transmission among 667 AZT-untreated mother-infant pairs (554 uninfected and 113 HIV-1 infected). We found that the mutant CCR5-59356-T allele is relatively common in African-Americans (20.6% allele frequency among 552 infants) and rare in Caucasians and Hispanics (3.4 and 5.6% of 174 and 458 infants, respectively; P < 0.001). There were 38 infants homozygous for CCR5-59356-T, of whom 35 were African-Americans. Among the African-American infants in the AZT-untreated group, there was a highly significant increase in HIV-1 transmission to infants with two mutant CCR5-59356-T alleles (47.6% of 21), compared to those with no or one mutant allele (13.4 to 14.1% of 187 and 71, respectively; P < 0.001). The increased relative risk was 5.9 (95% confidence interval, 2.3 to 15.3; P < 0.001). The frequency of the CCR5-59356-T mutation varies between population groups in the United States, a low frequency occurring in Caucasians and a higher frequency occurring in African-Americans. Homozygosity for CCR5-59356-T is strongly associated with an increased rate of perinatal HIV-1 transmission.

5' Untranslated Regions↗

PubMed1998

Safety and immunogenicity of HIV recombinant envelope vaccines in HIV-infected infants and children. National Institutes of Health-sponsored Pediatric AIDS Clinical Trials Group (ACTG-218).

Study objectives were to evaluate the safety and immunogenicity of three HIV recombinant glycoproteins in HIV-infected infants and children between 1 month and 18 years of age with asymptomatic (P-1) infection. Using Chiron rgp 120 (SF-2) 15 or 50 microg; MicroGeneSys rgp 160 (IIIB) 40 or 320 microg; Genentech rgp120 (MN) 75 or 300 microg; or adjuvant control (Alum or MF-59), children were randomized to a double-blind, placebo-controlled, dose-escalating study of vaccine administered intramuscularly at entry and 1, 2, 3, 4, and 6 months later. No adverse events were attributed to study vaccines. Between 30% and 56% of volunteers exhibited a lymphoproliferative response as defined in terms of stimulation index (SI) to vaccine antigens; 65% of vaccinees but none of placebo recipients exhibited moderate or strong responses after enzyme immunoassay to HIV specific antigens. CD4 cell counts and quantitative HIV culture did not differ significantly among vaccine and control groups, nor were differences found among groups in HIV disease progression. The rgp160 and gp120 subunit vaccines were safe and immunogenic in this population.

AIDS Vaccines↗

PubMed1998

Expression patterns of the HIV type 1 coreceptors CCR5 and CXCR4 on CD4+ T cells and monocytes from cord and adult blood.

We have measured the surface expression of the HIV-1 coreceptors CCR5 and CXCR4 on CD4+ T cells and monocytes from cord and adult blood. The expression of CCR5 was largely restricted to the memory (CD45RAlow) subset, whereas CXCR4 was expressed on both memory and naive (CD45RAhigh) T cells. The paucity of memory CD4+ T cells in cord blood means that CCR5-positive cells are relatively uncommon, so the overall extent of CCR5 expression was reduced in cord blood, compared with adult blood. IL-2 activation of CD4+ T cells from both cord and adult bloods caused a substantial increase in CCR5 expression, but moderately decreased CXCR4 expression. PHA stimulation increased CCR5 expression slightly, but only on naive cells. Monocytes expressed both CCR5 and CXCR4 at levels that differed little between cord and adult blood.

Adult↗

PubMed1998

Increased transmission of vertical hepatitis C virus (HCV) infection to human immunodeficiency virus (HIV)-infected infants of HIV- and HCV-coinfected women.

The transmission of perinatal hepatitis C virus (HCV) infection was studied retrospectively in 62 infants born to 54 HCV- and human immunodeficiency virus (HIV)-coinfected women enrolled in a prospective natural history study of HIV transmission. Infant HCV infection was assessed by nested RNA polymerase chain reaction. The overall rate of vertical HCV transmission was 16.4% (9/62). Most HCV-infected children did not develop antibodies to HCV. The rate of HCV infection was higher among HIV-infected infants (40%) than among HIV-uninfected infants (7.5%; odds ratio, 8.2; P = .009). This difference in transmission was not related to differences in maternal HCV load, as measured by branched DNA assay, or mode of delivery. Why HIV-infected infants of HCV- and HIV-coinfected women have significantly higher rates of perinatal HCV transmission remains to be elucidated. The rate of HCV transmission in HIV-uninfected infants of HCV- and HIV-coinfected women is similar to that reported for infants born to HIV-seronegative mothers.

Causality↗

PubMed1997

Two newly identified mutations (Thr233Ile and Leu152Met) in partially adenosine deaminase-deficient (ADA-) individuals that result in differing biochemical and metabolic phenotypes.

Deficiency of adenosine deaminase (ADA-) results in autosomal recessive immunodeficiency disease of varying severity. Partial ADA- [ADA deficiency in erythrocytes (RBCs) but substantial ADA in non-RBCs] has also been identified, primarily by population screening of healthy adults in Africa and newborns in New York State. Normal immune function and/or minimal elevations of toxic metabolites in childhood suggested that partial ADA deficiency was benign and therefore that six mutations identified in partially ADA-deficient newborns and expressing 8-80% of normal ADA in non-RBCs were not pathogenic. However, the lowest activity mutation (Arg211Cys) has now been reported in patients with adult-onset immunodeficiency. We have now molecularly and biochemically studied two additional individuals whom we found to represent opposite ends of the spectrum of partial ADA deficiency as to biochemical abnormalities and age of ascertainment. Homozygosity for a newly identified Leu152Met mutation expressing considerably less activity than the pathogenic Arg211Cys mutation was found in a currently healthy 10-year-old Afghanistani child (ascertained at birth). He had the highest accumulation of the metabolite dATP among 13 partially ADA-deficient patients studied, but considerably lower than in those with immunodeficiency. Homozygosity for a newly identified Thr233Ile mutation expressing somewhat greater ADA activity than Arg211Cys was found in a healthy young adult Kung individual, associated with very low metabolite concentrations. Biochemical findings and a family history suggestive of immunodeficiency in prior offspring support the idea that the Leu152Met mutation could result in disease in homozygous individuals challenged by severe environmental insult or in heterozygosity with a null mutation. The pathogenicity of the Thr233Ile mutation, as well as a previously described Ala215Thr mutation with relatively lower activity is less likely but will only be determined by long-term observation of individuals carrying these mutations. Although, in contrast to other partial mutations, neither of these two mutations are at CpG hot spots, the frequency of CpG mutations remains high for partial mutations but is also similarly high in ADA- immunodeficient patients (5/8 vs 12/21).

Adenosine↗

PubMed1997

Impaired early growth of infants perinatally infected with human immunodeficiency virus: correlation with viral load.

OBJECTIVE: To evaluate the effect of viral load on the early growth of infants infected with human immunodeficiency virus (HIV). METHODS: Plasma concentrations of p24-antigen and HIV ribonucleic acid were measured retrospectively and correlated with growth parameters for the first 18 months of life in a cohort of 47 term infants born to HIV-infected mothers prospectively enrolled in a study of perinatal HIV transmission. Comparisons of the mean weight and length of the 18 HIV-infected and 29 uninfected infants for each interval and across intervals were made. Viral load was correlated with standard deviation scores. Infants were stratified by high and low viral load during the first 6 months of life. RESULTS: At birth, no difference in weight and length was observed between HIV-infected and uninfected infants. Between birth and 6 months of age, the infected infants grew less rapidly than the uninfected infants, a finding temporally associated with an exponential increase in HIV viremia. The linear growth of infected infants remained consistently less than that of the uninfected infants after 6 months of life, although the differences were no longer statistically significant and tended to decrease with age in parallel with declines in viral load. The median plasma concentration of HIV ribonucleic acid was significantly higher at 3, 6, 12, and 18 months in infected infants in whom growth failure developed. Infants who had a high viral load in the first 6 months of life were significantly more likely to have severe growth failure. Though the mean SD for weight of the infected infants was always less than that of the uninfected infants, the differences were small and not significant. CONCLUSIONS: Our results confirm the observation that stunting is an early frequent finding in perinatal HIV infection. The deleterious effect of HIV on linear growth appears to be correlated with the level of postnatal HIV viremia, although the exact mechanism of this association remains to be elucidated.

Birth Weight↗

PubMed1997

CD8+ T-cell-mediated suppression of HIV replication in the first year of life: association with lower viral load and favorable early survival.

OBJECTIVE AND DESIGN: To study the role and development of non-cytotoxic CD8+ T-cell-mediated suppression of HIV replication in early perinatal HIV infection in a prospective study of vertically infected infants. CD8 T-cell-mediated HIV suppression was measured several times during the first year of life and correlated with viral load, cytotoxic T-cell (CTL) activity, in vitro antibody production (IVAP) and clinical outcome. METHODS: CD8+ T-cell-mediated HIV suppression was measured by comparing the amount of p24 antigen produced by endogenously infected lymphocytes with cultures of the same number of autologous CD4+ T cells from which CD8+ cells were removed immunomagnetically. CD8 viral suppressive activity (VSA) was defined as a > or = 50% reduction in p24 antigen in the cultures containing CD8+ cells. RESULTS: CD8+ T-cell-mediated HIV VSA was detected in 11/16 infants in the first year of life, including six/nine infants studied before 6 months and as early as 3 weeks of age. Infants who demonstrated CD8 VSA had a lower early peak and 6-month 'setpoint' plasma HIV RNA concentration than infants who lacked CD8 VSA [1.51 versus 4.94 and 0.094 versus 0.639 x 10(6) copies/ml, respectively, and higher CD4 percentage at 1 year of age. Survival of infants lacking CD8 VSA (four/six were rapid progressors) was shorter than for infants who demonstrated CD8 VSA (none out of 10 were rapid progressors). CD8 VSA was present before CTL and before or at the same time as IVAP in two of two and 11 of 14 infants studied, respectively. CONCLUSIONS: CD8+ T-cell-mediated VSA can be demonstrated in a large proportion of HIV-infected infants early in the course of infection. This non-cytolytic HIV-suppressive immune response appears to play an important protective role in the early control of perinatal HIV infection at a time when other immune responses are either absent or deficient.

CD4-Positive T-Lymphocytes↗

PubMed1996

Neurodevelopment, growth, and viral load in HIV-infected infants.

The relation of HIV-1 infection to infant growth and neurodevelopment was studied prospectively in a cohort of 65 infants born to women at risk for HIV infection. No differences were observed at birth between infected infants (INF) and uninfected infants (SR) of HIV-infected women, and infants of uninfected women (SN) with similar socioeconomic background and exposure to drugs. However, postnatal linear growth and cognitive-motor development of INF infants were impaired when compared to SR and SN infants. Declines in linear growth were observed within the first 6 months of life, whereas delays in neurodevelopment were first appreciated at 12 months. In INF infants, decreased linear growth was positively correlated with developmental delay. Moreover, growth and development were both correlated with HIV viral load. INF infants with high plasma HIV RNA copies (> 5 x 10(5)/ ml) at 6 months of life were more likely to exhibit severe growth and developmental delay than infants with a lower viral burden. The implications of these findings with respect to the mechanism of action of HIV-related growth and neurodevelopmental impairments are discussed.

Body Height↗

PubMed1996

Transfer factor--current status and future prospects.

We have detected new clues to the composition and function of "Transfer Factor" using the direct Leucocyte Migration Inhibition (LMI) test as an in vitro assay of Dialysates of Leucocyte Extracts (DLE). This approach has revealed two opposing antigen-specific activities to be present in the same > 3500 < 12,000 DA dialysis fraction - one activity is possessed of Inducer/Helper function (Inducer Factor). The opposing activity is possessed of Suppressor function (Suppressor Factor). When non-immune leucocyte populations are cultured with Inducer Factor they acquire the capacity to respond to specific antigen and inhibition of migration occurs. This conversion to reactivity is antigen-specific and dose-dependent. When immune leucocyte populations are cultured with Suppressor Factor their response to specific antigen is blocked and Inhibition of Migration is prevented.

Animals↗

PubMed1996

Dialyzable lymphoid extract (DLE) from mice resistant to STZ-induced diabetogenesis can interrupt the progress of diabetes in STZ-treated CD-1 mice.

DLE was prepared from the minority of euglycemic CD-1 mice, previously injected with STZ, and was administered to hyperglycemic CD-1 male mice 1, 2 and 3 weeks after completion of multidose STZ. Mice treated with DLE derived from 2 x 10(7) (IX) or 10(8) lymphocyte equivalents (lymph.equ) were significantly less hyperglycemic than the saline treated controls (P < 0.001). The effects of DLE remained evident for more than 10 weeks after the final DLE treatment. Mice treated with DLE prepared from diabetic mice (hg DLE) developed a somewhat more rapid onset of hyperglycemia than the STZ treated control animals, although this effect did not achieve statistical significance (P = 0.1). This DLE was absorbed on a rat insulinoma cell line (RIN), which contains interspecies cross-reacting islet antigens, and compared to the unabsorbed DLE. Mice treated with hg DLE preabsorbed on RIN cells, showed a slower onset of hyperglycemia. DLE prepared from euglycemia mice and the RIN-absorbed fraction were equally capable of preventing hyperglycemia (P < 0.05). In order to determine whether the DLE effects were genetically restricted, DLE was prepared from BALB/c mice, normally resistant to the diabetogenic effects of multidose STZ, both before and after STZ treatment. STZ primed CD-1 mice treated with 3 weekly doses of 2 x 10(7) lymph. equ. of untreated BALB/c derived DLE, STZ treated BALB/c derived DLE, and STZ treated CD-1 DLE were all less hyperglycemic than the control mice, who received saline (P < 0.001). However, mice treated with CD-1 DLE were less hyperglycemic than the mice given BALB/c derived DLE (P < 0.05). These effects were relatively long-lived. Mice that were given the > 3,500 Dalton fraction of CD-1 DLE were significantly less hyperglycemic than either the control mice or those treated with the < 3,500 Dalton fraction of CD-1 DLE (P < 0.05). Effects remained evident for more than 3 months after the last dose of DLE. Pancreatic tissue from the mice treated with the > 3,500 Dalton fraction of CD-1 derived DLE revealed slightly more islets of a slightly greater size with less surrounding inflammation than either control mice or mice treated with the < 3,500 Dalton fraction of DLE.

Animals↗

PubMed1996

The amount of early p24 antigenemia and not the time of first detection of virus predicts the clinical outcome of infants vertically infected with human immunodeficiency virus.

Twenty-three children vertically infected with human immunodeficiency virus type 1 (HIV-1) were studied for viremia during the first days of life. Nine had HIV-1 infection within the first week (early); 14 had HIV-1 first detected by day 11-90 (late). The groups had similar incidence and time of onset of symptomatic HIV-1 infection and survival. CD4 T cell percentages, rates of CD4 T cell attrition, quantitative cell-associated viremia, and p24 antigen concentrations were comparable. Children with peak antigen concentrations >100 pg/mL during the first 6 months (5 early, 6 late) fared worse than those with lower p24 levels. Thus, HIV-1-infected infants with detectable virus in the first few days of life do not have a worse prognosis than infants whose virus is detectable only later. Elevated p24 antigenemia during the first 6 months of life correlates strongly with poor clinical outcome and is independent of the time virus was first detected.

Age Factors↗

PubMed1996

Randomized study of the tolerance and efficacy of high- versus low-dose zidovudine in human immunodeficiency virus-infected children with mild to moderate symptoms (AIDS Clinical Trials Group 128). Pediatric AIDS Clinical Trials Group.

The current dosage of zidovudine for children is 180 mg/m2 every 6 h. To investigate whether a lower dosage was equally effective, human immunodeficiency virus (HIV)-infected children (3 months to 12 years) with mild to moderate symptoms were randomly assigned to receive either high-dose (180 mg/m2/dose) or low-dose (90 mg/m2/dose) zidovudine (double-blind). Treatments were compared with respect to neuropsychologic function, survival, clinical and laboratory evidence of disease progression, and safety and tolerance. Four hundred twenty-six HIV-infected children were enrolled; median time for receipt of study drug was 35 months. Zidovudine in either dose was well tolerated, with no difference in efficacy or tolerance by treatment group using any clinical or laboratory parameter. In children with mild to moderate disease, a reduction of zidovudine to 90 mg/m2/dose will result in substantial cost savings and should be the recommended dose.

AIDS Dementia Complex↗

PubMed1996

Cytomegalovirus infection in human immunodeficiency virus type 1-infected children.

BACKGROUND: Cytomegalovirus (CMV) is a frequent opportunistic infection in human immunodeficiency virus type 1 (HIV-1)-infected children. The interactions of CMV and HIV-1 in coinfected children are not well-characterized. OBJECTIVE: To evaluate the prevalence of asymptomatic CMV infection and symptomatic CMV disease and to assess the influence of CMV on clinical and laboratory markers of HIV disease progression in CMV-coinfected children. METHODS: Serial urine CMV cultures were performed on 500 children (131 HIV-1-infected (HIV+), 129 seroreverters born to HIV-infected mothers, and 240 HIV-uninfected (HIV-)). The clinical, immunologic and virologic data of 131 HIV+ children were analyzed. RESULTS: CMV was recovered in 40 of 131 HIV+ (31%), 22 of 129 seroreverters (17%) and 30 of 240 HIV- (13%) children. Of the 40 HIV+ children with CMV coinfection, 7 developed symptomatic CMV disease (17.5%) including chorioretinitis (3), colitis (2) and pneumonitis (2). The HIV+ children with symptomatic CMV disease had significantly lower mean CD4+ T lymphocyte proportions (17% vs. 26%; age-adjusted P = 0.013) and greater HIV p24 antigen concentrations (329 pg/ml vs. 57 pg/ml; age-adjusted P = 0.13) than HIV+ children with asymptomatic CMV infection. In a subset of children coinfected with CMV before 6 months of age (n = 11), 5 (45%) developed symptomatic CMV disease, and 4 of these 5 children died within 10 months of diagnosis of CMV disease. At the time of the first positive CMV culture in these children, mean CD4+ T lymphocyte proportions did not differ according to the presence or absence of CMV-related symptoms (symptomatic CMV+, 21% vs. asymptomatic CMV = 38%; P = 0.14). In HIV+ children with symptomatic CMV disease, p24 antigen concentrations were greater than in those with asymptomatic CMV infection (461 vs. 190 pg/ml, P = 0.06). CONCLUSIONS: Symptomatic CMV disease occurred in young CMV-coinfected children with low CD4+ lymphocytes and elevated HIV p24 antigen concentrations. Whether progressive immunodeficiency allows the emergence of CMV disease or CMV infection causes more rapidly progressive HIV-1 disease or whether there is a more complex relationship remains to be determined.

Age Factors↗

PubMed1995

Major histocompatibility complex class II DR alleles DRB1*1501 and those encoding HLA-DR13 are preferentially associated with a diminution in maternally transmitted human immunodeficiency virus 1 infection in different ethnic groups: determination by an automated sequence-based typing method.

Transmission of human immunodeficiency virus 1 (HIV-1) from an infected women to her offspring during gestation and delivery was found to be influenced by the infant's major histocompatibility complex class II DRB1 alleles. Forty-six HIV-infected infants and 63 seroreverting infants, born with passively acquired anti-HIV antibodies but not becoming detectably infected, were typed by an automated nucleotide-sequence-based technique that uses low-resolution PCR to select either the simpler Taq or the more demanding T7 sequencing chemistry. One or more DR13 alleles, including DRB1*1301, 1302, and 1303, were found in 31.7% of seroreverting infants and 15.2% of those becoming HIV-infected [OR (odds ratio) = 2.6 (95% confidence interval 1.0-6.8); P = 0.048]. This association was influenced by ethnicity, being seen more strongly among the 80 Black and Hispanic children [OR = 4.3 (1.2-16.4); P = 0.023], with the most pronounced effect among Black infants where 7 of 24 seroreverters inherited these alleles with none among 12 HIV-infected infants (Haldane OR = 12.3; P = 0.037). The previously recognized association of DR13 alleles with some situations of long-term nonprogression of HIV suggests that similar mechanisms may regulate both the occurrence of infection and disease progression after infection. Upon examining for residual associations, only only the DR2 allele DRB1*1501 was associated with seroreversion in Caucasoid infants (OR = 24; P = 0.004). Among Caucasoids the DRB1*03011 allele was positively associated with the occurrence of HIV infection (P = 0.03).

Acquired Immunodeficiency Syndrome↗

PubMed1995

Shortened survival in infants vertically infected with human immunodeficiency virus with elevated p24 antigenemia.

OBJECTIVE: To determine whether the amount of p24 antigenemia in the first 6 months of life is a predictor of survival in children infected vertically with human immunodeficiency virus type 1. METHODS: A retrospective study of vertically infected infants and children who were followed prospectively from early infancy and who had quantitation of plasma p24 antigen concentration in the first 6 months of life. Infants were first stratified by duration of survival as infants who died before 2 years of age (short-term survivors) and infants who survived to 2 years of age (intermediate-term survivors). The median p24 antigen concentration and the proportion of infants in each group with high concentrations of antigen were compared. Analyses with and excluding all p24 determinations made after the use of antiretroviral agents were compared Kaplan-Meier product limit analysis was used to compare survival in infants with low and high antigenemia during the first 6 months of life. RESULTS: The median p24 antigen concentration in 15 short-term survivors was 228 pg/ml, compared with 14 pg/ml in 26 intermediate-term survivors (p < 0.05). The proportion of children with > 100 pg/ml of p24 was higher in short-term than in intermediate-term survivors (p = 0.01). Survival to 2 years of age in infants in whom all p24 antigen values during the first 6 months of life were 100 pg/ml or less was 91%, in comparison with 39% in infants with values greater than 100 pg/ml (p = 0.0017). CONCLUSIONS: Elevated p24 antigenemia in the first 6 months of life is associated with shorter survival and may be a useful predictor of outcome.

Antigens, Viral↗