Plasma virus load evaluation in relation to disease progression in HIV-infected children

Intravenous Bacillus Calmette-Guérin (BCG) Induces a More Potent Airway and Lung Immune Response than Intradermal BCG in Simian Immunodeficiency Virus-infected Macaques

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the leading causes of death due to an infectious agent. Coinfection with HIV exacerbates M. tuberculosis infection outcomes in people living with HIV. Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, is effective in infants, but its efficacy in adolescents and adults is limited. In this study, we investigated the immune responses elicited by BCG administered via i.v. or intradermal (i.d.) routes in SIV-infected Mauritian cynomolgus macaques (MCM) without the confounding effects of M. tuberculosis challenge. We assessed the impact of vaccination on T cell responses in the airway, blood, and tissues (lung, thoracic lymph nodes, and spleen), as well as the expression of cytokines, cytotoxic effectors, and key transcription factors. Our results showed that i.v. BCG induces a robust and sustained immune response, including tissue-resident memory T cells in lungs, polyfunctional CD4+ and CD8αβ+ T cells expressing multiple cytokines, and CD8αβ+ T cells and NK cells expressing cytotoxic effectors in airways. We also detected higher levels of mycobacteria-specific IgG and IgM in the airways of i.v. BCG-vaccinated MCM. Although i.v. BCG vaccination resulted in an influx of tissue-resident memory T cells in lungs of MCM with controlled SIV replication, MCM with high plasma SIV RNA (>105 copies/ml) typically displayed reduced T cell responses, suggesting that uncontrolled SIV or HIV replication would have a detrimental effect on i.v. BCG-induced protection against M. tuberculosis.

Intravenous BCG induces a more potent airway and lung immune response than intradermal BCG in SIV-infected macaques

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the leading causes of death due to an infectious agent. Coinfection with HIV exacerbates Mtb infection outcomes in people living with HIV (PLWH). Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, is effective in infants, but its efficacy in adolescents and adults is limited. Here, we investigated the immune responses elicited by BCG administered via intravenous (IV) or intradermal (ID) routes in Simian Immunodeficiency Virus (SIV)-infected Mauritian cynomolgus macaques (MCM) without the confounding effects of Mtb challenge. We assessed the impact of vaccination on T cell responses in the airway, blood, and tissues (lung, thoracic lymph nodes, and spleen), as well as the expression of cytokines, cytotoxic molecules, and key transcription factors. Our results showed that IV BCG induces a robust and sustained immune response, including tissue-resident memory T (TRM) cells in lungs, polyfunctional CD4+ and CD8αβ+ T cells expressing multiple cytokines, and CD8αβ+ T cells and NK cells expressing cytotoxic effectors in airways. We also detected higher levels of mycobacteria-specific IgG and IgM in the airways of IV BCG-vaccinated MCM. Although IV BCG vaccination resulted in an influx of TRM cells in lungs of MCM with controlled SIV replication, MCM with high plasma SIV RNA (>105 copies/mL) typically displayed reduced T cell responses, suggesting that uncontrolled SIV or HIV replication would have a detrimental effect on IV BCG-induced protection against Mtb.

APOBEC3G genotypes and proviral DNA hypermutations on HIV/AIDS disease progression in Thai and Cambodian children

Aim: To evaluate the effect of APOBEC3G host factor on HIV/AIDS progression in perinatally HIV-infected Thai and Cambodian children with distinct clinical patterns; rapid progressors (RPs) and long-term nonprogressors (LTNPs). Materials & methods: APOBEC3G genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in DNA samples. APOBEC3G-mediated G-to-A hypermutations were analyzed by sequencing of the vif/vpu genes from proviral DNA. Results: Frequency of APOBEC3G 186H/R genotypes, AA:AG:GG, in the RPs was 100:0:0% and 83:17:0% (p = 0.3) in LTNPs. Hypermutation of the vif-coding region was observed in none of the RPs and 8.3% of LTNPs (p = 0.5). Hypermutations at the vpu genes were not detected in either groups’ proviral DNA. Conclusion: We observed no significant association of APOBEC3G genotypes and hypermutation rates between children with different profiles of HIV/AIDS disease progression.

Human serum protein enhances HIV-1 replication and up-regulates the transcription factor AP-1

In vitro studies on HIV (HIV-1) replication and neutralization are usually performed in human cell cultures supplemented with FBS instead of human serum (HS). Here we show that in contrast to FBS, addition of increasing amounts of human serum from noninfected donors to the cell culture directly correlates with an increase in HIV-1 replication in vitro. This effect is independent of cell line, virus strain, or batch of pooled human serum used. We found that human serum affects viral transcription in a dose-dependent manner by activating the activator protein-1 (AP-1) member proteins c-FOS, JunD, and JunB in TZM-bl cells. Analysis of the human serum component responsible for this effect indicates that it is a protein having a molecular mass between 250 and 300 kDa. This serum protein, HIV-1 enhancing serum protein (HESP), might promote viral transcription in vivo and consequently play a role in disease progression.

Gender and race do not alter early-life determinants of clinical disease progression in HIV-1 vertically infected children

OBJECTIVE

To identify early life predictors of clinical progression before and beyond age 1 year.

DESIGN

Prospective follow-up of 161 vertically HIV infected children in the ongoing European Collaborative Study provided data from birth over 16 years.

METHODS

Kaplan-Meier and Cox regression procedures were used to assess the predictive value of first available laboratory and clinical markers for progression defined as serious disease or death. We investigate gender and race effects on associations and the optimal threshold for longitudinal CD4+ percentage measurements after age 6 months for predicting disease progression.

RESULTS

Earliest (during the first 6 months) measurements of CD4+ percentage below 20% [three-fold increased risk (P = 0.041)] and absolute lymphocytes (AL) (reduction of risk of three-quarters for a one log increase (P =0.014)) were independently associated with overall and rapid disease progression during the first year. Persistent lymphadenopathy (or hepatomegaly) in early life was also additionally associated with overall disease progression, and after age 1 year [greater than doubling of risk, (P = 0.040)], but not with rapid progression. Associations were not significantly dependent on gender or race. CD4+ percentage of 10% was the best prognostic cut-off.

CONCLUSIONS

Early clinical markers are strongly predictive of disease progression after 1 year of age into adolescence. However, rapid progression is less straightforward to predict, probably due largely to early progression during the first few months in such individuals. The independently predictive value of AL measurements suggest they could be used alone in the management of children in resource-poor settings.

Kinetics of early FIV infection in cats exposed via the vaginal versus intravenous route

To determine the influence of route of virus exposure on early pathogenesis of feline immunodeficiency virus (FIV) infection, cats were exposed to either of two FIV isolates (FIV-B-2542 or FIV-A-PPR) by vaginal or intravenous (IV) inoculation. Exposure to either virus clade by either route of inoculation resulted in vaginal and systemic infection. Peak plasma viremia and tissue proviral burden were 1-3 log(10) greater in cats infected with FIV-B-2542 vs. FIV-A-PPR, irrespective of inoculation route. Plasma RNA levels paralleled provirus titers in FIV-B-2542-infected cats and were highest in those exposed IV. In contrast, plasma RNA titers were higher in cats infected vaginally with FIV-A-PPR than in those infected IV. Despite early differences, PBMC provirus titers were similar in all groups by 9 weeks postinfection. In cats infected IV, but not vaginally, CD4(+) lymphocyte counts declined significantly independent of the magnitude of viremia. Mitogen-induced lymphoproliferation was decreased in all infected cats regardless of CD4(+) cell counts; this decline correlated with the magnitude of peak plasma viremia in FIV-B-2542, but not FIV-A-PPR, infected cats. These results establish that the kinetics of early FIV infection differ with route of exposure as well as virus isolate and that properties extrapolated from one virus isolate may not be universal.

The effect of plasma human immunodeficiency virus RNA and CD4(+) T lymphocytes on growth measurements of hemophilic boys and adolescents

OBJECTIVE

The investigation examined the associations of plasma human immunodeficiency virus (HIV) RNA and CD4(+) T lymphocytes with height, weight, skeletal maturation, testosterone levels, and height velocity for hemophilic children and adolescents with HIV infection in the Hemophilia Growth and Development Study.

STUDY DESIGN

Two hundred seven participants were evaluated over 7 years.

RESULTS

A threefold increment in baseline plasma HIV RNA was associated with a 0.98-cm decrease in height and a 1.67-kg decrease in weight; 100-cells/microL decrements in baseline CD4(+) were associated with a 2.51-cm decrease in height and a 3.83-kg decrease in weight. Participants with high plasma HIV RNA (>3125 copies/mL) experienced significant delay in achieving maximum height velocity and lower maximum velocity compared with those with low viral load. The high CD4(+) (>243)/low plasma HIV RNA group had earlier age at maximum height velocity compared with the other 3 groups and higher maximum height velocity compared with the low CD4(+)/high plasma HIV RNA and low CD4(+)/low plasma HIV RNA groups. Decrements in CD4(+) were associated with decreases in bone age and testosterone level.

CONCLUSIONS

CD4(+) and HIV RNA were important in predicting growth outcomes.

Enhanced interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha production by LPS stimulated human monocytes isolated from HIV+ patients

Periodontal disease and tooth loss is a common finding among advanced HIV+ patients. In addition to local oral lipopolysaccharide (LPS) stimulation, systemic up-regulation of monocyte pro-inflammatory cytokine secretion may also be involved in the pathogenesis of HIV disease. A study was undertaken to investigate IL-1beta, IL-6 and TNF-alpha production by resting and LPS stimulated monocytes isolated from HIV+ patients and also to investigate the relationship of the patient's HIV viral load status to the cytokine production. Whole blood samples in EDTA were collected from 39 HIV-1 infected patients and 20 age and sex matched uninfected controls. Plasma was separated by centrifugation. Viral load was determined using a quantitative RT-PCR. Monocytes were isolated by Ficoll-hypaque gradient separation followed by overnight plastic adherence. Cultured monocytes (1x10(6)/ml) were stimulated with LPS (1 microg/ml) of either P. gingivalis or F. nucleatum for 2, 8, 24 and 48 h and supernatant fluids were collected. IL-1beta, IL-6, and TNF-alpha levels in supernatant fluids were estimated by ELISA. Increased overall production of IL-1beta, IL-6 and TNF-alpha by LPS stimulated monocytes isolated from HIV-1 infected patients was observed when compared to HIV-1 uninfected controls. LPS stimulated monocytes from HIV-1 infected patients with high viral load (HVL) produced significant (p<0.05) elevations in these pro-inflammatory cytokines when compared to HIV-1 uninfected controls. Both LPS of P. gingivalis and F. nucleatum produced a comparable cytokine production by monocytes after 8 h of stimulation. These data suggest that enhanced IL-1beta, IL-6 and TNF-alpha is produced by monocytes/macrophages isolated from HVL HIV+ patients and may be involved in the overall pathogenesis of HIV-1 infection.

Feline immunodeficiency virus clade C mucosal transmission and disease courses

The transmissibility and pathogenicity of a clade C feline immunodeficiency virus (FIV-C) was examined via the oral-nasal, vaginal, or rectal mucosa. FIV-C was transmissible by all three mucosal routes. Vaginal transmission was most efficient (100%), oral exposure resulted in a 80% infection rate, and rectal transmission was least effective (44%). In contrast to previous intravenous passage studies, a broader range of host-virus relationships was observed after mucosal exposure. Three categories of FIV-C infection were defined: (1) rapidly progressive infection marked by high virus burdens and rapid CD4+ cell depletion (43% of vaginally exposed animals); (2) conventional (typical) infection featuring slowly progressive CD4+ cell decline (61% of all exposed animals); and (3) regressive (transient) infection marked by low and then barely detectable virus burdens and no CD4+ cell alterations (22% of rectally inoculated cats). These disease courses appear to have parallels in mucosal HIV and SIV infections, emphasizing the importance of the virus-mucosa interface in lentiviral pathogenesis.

Enhanced interleukin 1 beta, interleukin 6 and tumor necrosis factor alpha in gingival crevicular fluid from periodontal pockets of patients infected with human immunodeficiency virus 1

Loss of periodontal support and eventually tooth loss is a common finding among acquired immunodeficiency syndrome (AIDS) patients. The cause of this destruction may be an increase in periodontal disease activity at sites within the same individual and also may be related to an increase in the pro-inflammatory cytokines, diffused through the gingival crevicular sulcus in AIDS patients. A study was undertaken to determine the relative levels of the pro-inflammatory cytokines, interleukin 1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF-alpha), in gingival crevicular fluid collected from the deep (> 5 mm periodontal pocket depth) and shallow (< or = 3 mm periodontal pocket depth) periodontal pockets of 39 HIV-1-infected patients and 20 age-, race- and sex-matched uninfected controls. Complete medical history including risk factors such as intravenous drug abuse was taken. Gingival crevicular fluid samples were collected on periopaper strips. Cytokines were estimated by solid-phase enzyme-linked immunosorbent assay. To assess the degree of HIV activity, the viral load of these patients was determined by an Amplicor HIV-1 monitor kit using reverse transcriptase polymerase chain reaction. Gingival crevicular fluid from HIV-1-infected patients showed a two-fold increase in both IL-1 beta and TNF-alpha in deep periodontal pockets in comparison to shallow pockets, whereas IL-6 increased 1.8-fold. There was a significant (P < 0.05) increase in IL-1 beta, IL-6 and TNF-alpha in gingival crevicular fluid (both shallow and deep pockets) from HIV-1-infected patients in comparison to uninfected controls and also significantly elevated in deep versus shallow pockets in these patients. Although IL-1 beta, L-6 and TNF-alpha levels among HIV-1-infected patients with a high viral load (> 10,000 copies/ml) were higher than those from patients with a low viral load (< 400 copies/ml), only the increase in IL-1 beta level associated with deep pockets was significant (P < 0.05). There was also a trend of an increase in all the three cytokines among intravenous drug-abusing HIV-1-infected patients in comparison to non-intravenous drug abusers, but only the difference in IL-1 beta levels from deep pockets reached significance (P < 0.05). These enhanced pro-inflammatory cytokine levels in the gingival crevicular fluid of HIV-positive patients may be an important factor in causing the advanced periodontal lesions sometimes observed in HIV-positive patients.

Quantification of fungal DNA by using fluorescence resonance energy transfer and the light cycler system

The Light Cycler technique combines rapid in vitro amplification of DNA in glass capillaries with real-time species determination and quantification of DNA load. We have established a quantitative PCR protocol for two clinically important pathogens, Candida albicans and Aspergillus fumigatus. The sensitivity of the assay was comparable to those of previously described PCR protocols (5 CFU/ml). Specific detection of C. albicans and A. fumigatus could be achieved. The assay showed a high reproducibility of 96 to 99%. The assay was linear in a range between 10(1) and 10(4) Aspergillus conidia. As capillaries do not have to be reopened for post-PCR analysis, the risk of carryover contaminations could be minimized. The Light Cycler allowed quantification of the fungal loads in a limited number of clinical specimens from patients with hematological malignancies and histologically proven invasive fungal infections. Five of nine positive samples had fungal loads between 5 and 10 CFU/ml of blood, two of nine positive samples had fungal loads between 10 and 100 CFU/ml of blood, and two of nine samples had fungal loads of more than 100 CFU/ml of blood. All samples were also found to be PCR positive by PCR-enzyme-linked immunosorbent assay analysis.

Viral Load Monitoring in HIV Infection

Measurement of HIV-1 viral load is now an accepted part of clinical practice for the determination of clinical prognosis and antiretroviral effectiveness in HIV infection. Consensus guidelines have been published on the appropriate use of this testing. Furthermore, recent advances in molecular technology have improved the sensitivity and reproducibility of viral load assays, and these improved assays have provided new insight into the pathogenesis of HIV disease. This article reviews new issues affecting viral load quantification, including viral subtypes, sex, compartmental differences, and other covariables.

Oral Candida dubliniensis as a clinically important species in HIV-seropositive patients in the United States

OBJECTIVE

Interest in Candida dubliniensis has led to renewed clinical investigations regarding incidence, drug resistance, pathogenesis, and epidemiology of fungal infections in patients with HIV. C dubliniensis phenotypically resembles Candida albicans in many respects, yet it can be identified and differentiated as a unique Candida species by its phenotypic and genetic profiles. The purpose of this study was to prospectively evaluate the prevalence of C dubliniensis in clinical isolates and determine the clinical and demographic characteristics of patients harboring C dubliniensis.

STUDY DESIGN

Over a 6-week period, 24 yeast-positive isolates from HIV-positive dental patients were screened for C dubliniensis through use of phenotypic criteria. HIV viral load, CD4 count, and complete oral health evaluations were performed on each patient at the same visit during which the oral fungal surveillance culture was taken.

RESULTS

Six isolates from 24 HIV-seropositive and yeast-positive patients were shown to be consistent phenotypically and by electrophoretic karyotyping with the European reference strain of C dubliniensis. Dose-dependent susceptibility to fluconazole was shown in one of the C dubliniensis isolates. Five of the 6 patients demonstrated moderate to high viral loads. General oral health, as evidenced by the presence of advanced periodontal lesions and a high decayed, missing, and filled teeth index (>20), was poor in 3 of the 6 patients with C dubliniensis and 7 of the 18 patients with C albicans. A history of intravenous drug abuse was present in 50% of the C dubliniensis -positive patients, which is representative of the HIV-positive population at the hospital.

CONCLUSIONS

In this small sample, C dubliniensis represented 25% of the yeast-positive cultures. The clinical significance of this interesting species in the United States may be related to high viral load, rapid AIDS progression, and/or concomitant oral disease, such as a high caries index or periodontal disease.

Association of HIV viral load with oral diseases

OBJECTIVE

The measurement of HIV viral load as a predictor of disease progression has revolutionized the medical management of HIV patients. In this study, oral diseases as measured by DMFT (decayed, missing and filled teeth), periodontal assessment and oral Candidacolonization, were related to HIV viral load. Also correlated was HIV status assessments, including CD4+ count, a history of intravenous drug abuse (IVDA) and the use of protease inhibitor drugs.

MATERIALS AND METHODS

Oral and periodontal examination, dental radiographs, and tongue swab for fungal culture was accomplished over a 2-month period on 39 HIV positive patients attending the University of Maryland Dental School. Twenty-eight (71. 8%) of these patients had a history of IVDA. Viral load was measured by a quantitative RT-PCR.

RESULTS

Among the patients with high viral load (>10 000 copies ml-1), 92.3% were found to have a history of IVDA. Also, patients with high viral load demonstrated average CD4+ counts of 136 mm-3 while moderate viral load (400-10 000 copies ml-1) corresponded to average counts of 271 mm-3. Periodontal pocket depths (PPD) of >5 mm at a minimum of two oral sites were found in 76.9% of the patients with high viral load. Among the high viral load patients, 69.2% had DMFT >20, 69.2% were culture positive for Candida and 81.5% of patients on protease inhibitors demonstrated moderate or low viral loads.

CONCLUSION

These data demonstrated that elevated viral load levels correlate well with oral disease prevalence in this predominantly IVDA population of HIV-infected dental patients.

Characterization of the quantitative HCV NASBA assay

A quantitative nucleic acid sequence-based amplification assay (NASBA-QT) for detection of hepatitis C virus RNA (HCV-RNA) was evaluated and compared with the HCV branched-DNA (bDNA) assay (Chiron Corporation) and the HCV MONITOR assay (Roche Diagnostic Systems). For this evaluation five panels were designed: (1) serial dilutions of genotype 1b in-vitro HCV-RNA; (2) standards of in-vitro HCV-RNA genotypes 1a, 1b, 2, 3, 4, and 5; (3) a proficiency panel consisting of 12 HCV-RNA positive plasma samples of different genotypes and HCV-RNA concentrations and a genotype 1a and 1b 3-fold dilution series; (4) a panel of 67 HCV-RNA positive plasma samples obtained from patients with HCV infection and (5) an HCV-RNA positive control sample, diluted 50-fold in 25 different HCV-RNA negative plasma samples. The quantitative detection limit was found to be 10(3) copies per 100 microl and the qualitative detection limit 10(2.3) per 100 microl. The amplification efficiency was independent of the plasma matrix, but dependent on the HCV genotype. The HCV NASBA-QT assay was more than 10 times as sensitive as the bDNA assay while the quantitative results of both assays were highly concordant. The HCV NASBA-QT assay was comparable in sensitivity with the HCV MONITOR assay, but the HCV MONITOR assay yielded consistently lower values. It is concluded that the HCV NASBA-QT assay is a reliable assay for quantitative HCV-RNA detection in various settings.

Efficacy of and adherence to highly active antiretroviral therapy in children infected with human immunodeficiency virus type 1

BACKGROUND

Clinical trials in adults have demonstrated the efficacy of highly active antiretroviral therapy (HAART) to suppress replication of HIV-1 to nondetectable levels, but lower success rates have been observed in practice. We sought to determine the efficacy of HAART in our population of HIV-1-infected children and to identify determinants of efficacy, especially the role of adherence to prescribed antiretrovirals.

METHODS

The viral load and CD4+ T cell responses of 72 children with perinatally acquired HIV-1 treated with HAART including a protease inhibitor for at least 90 days were examined retrospectively in relation to adherence, as measured by pharmacy records for the first 180 days of HAART.

RESULTS

Patients were defined as adherent if > or =75% of protease inhibitors and > or =75% of all antiretroviral prescriptions were filled. Of the 42 patients (58%) who were adherent, nondetectable viral loads were achieved and maintained in 22 (52%). A Kaplan-Meier plot showed a drop-off in patients maintaining a nondetectable viral load after 200 days. Higher initial viral load was the only pretreatment factor that identified adherent patients at risk for treatment failure. Only 3 (10%) nonadherent patients maintained a viral load of <400 copies/ml. The adherent group had a prompt and sustained increase in CD4+ T cell counts.

CONCLUSIONS

HAART can achieve control of viral replication in HIV-1-infected children who adhere to therapy. However, treatment failure is likely unless there is a high level of adherence. Nonadherence to therapy is common and might be the major impediment to successful treatment of children infected with HIV-1.

The effects of HIV viral load on the phagocytic activity of monocytes activated with lipopolysaccharide from oral microorganisms

A study was undertaken to determine whether viral load status in HIV+ patients has any potential effect on monocyte phagocytic function both before and after challenge of the monocytes with lipopolysaccharide (LPS) isolated from oral microorganisms. LPS of two putative periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) was prepared. Whole blood samples in EDTA were collected from 30 HIV+ patients presenting for dental care at the University of Maryland. Control samples were prepared from appropriate uninfected individuals. Viral load was determined using quantitative RT-PCR (Amplicor, Roche Diagnostics). Phagocytic function was determined using FITC labeled Saccharomyces species in resting isolated monocytes and in cells after 24 h stimulation with 1 microgram/ml of LPS of P. gingivalis or F. nucleatum. Immunohistochemical staining was performed for complement receptor CR-1 (CD-35) on phagocyte cells. In HIV+ patients with high viral load (> 10,000 copies/ml), 13.5% of isolated resting monocytes demonstrated phagocytic activity, while 23% of the resting control monocytes from non-infected individuals showed phagocytic function. When the monocytes were stimulated with 1 microgram/ml of LPS of F. nucleatum, phagocytic activity was observed in 18.5% of monocytes in patients with high viral load, 33.5% with moderate viral load (400-10,00 copies/ml) and 51% with low viral load (<400 copies/ml), while 62% of the control monocytes demonstrated phagocytic activity. Stimulation of monocytes with LPS of P. gingivalis showed similar results. Complement receptor CD-35 showed a 50% decrease in expression in HIV+ patients with high viral load. A progressive decrease in monocyte/macrophage phagocytic function and CD-35 expression with and without oral LPS activation occurs after HIV infection and this trend appears to be accentuated in patients with high viral load. This relationship may contribute to increased susceptibility to oral opportunistic infections in advanced HIV+ patients.

Correlation of clinical parameters and immunological function with human immunodeficiency virus plasma viremia in children

Studies of immune function in human immunodeficiency virus (HIV)-infected children are important, because functional abnormalities can precede CD4+ T-cell loss and are associated with the development of opportunistic and bacterial infections. We sought to correlate clinical parameters and immunological function with HIV RNA plasma levels in 20 children. HIV RNA levels were measured by a polymerase chain reaction assay. We analyzed T-cell responses to mitogens (phytohemagglutinin, concanavalin A, and pokeweed [PWM]) and antigens (tetanus toxoid and Candida albicans); T-cell suppressor activity; and humoral immunity to Haemophilus influenzae, hepatitis B, tetanus, and diphtheria vaccines. The median age of the children was 6 years. Eight children had HIV RNA levels less than 200 to 9621 copies per milliliter (group I). Four children had 37,970 to 82,630 copies per milliliter (group II). Eight children had 102,100 to 191,200 copies per milliliter (group III). There were no differences in the HIV-related complications between group I and II children. Group I/II children had significantly higher CD4+ T-cell counts (P = 0.02), less symptomatic HIV disease (P = 0.005), and more detectable protective vaccine immunity (P = 0.014) compared with group III children. Responses to mitogens were conserved in most children. Group I children tended to have higher responses to tetanus toxoid than group II children and significantly higher responses than group III children (P = 0.01). Group I had significantly higher responses to C. albicans than groups II (P = 0.016) and III (P = 0.001). Group I/II children tended to have lower suppressor activity compared with group III children (median, 0 vs 64%). We demonstrated that humoral and cellular immune dysfunction exists at all stages of disease in HIV-infected children but was most severe in children with greater than or equal to 100,000 HIV RNA copies per milliliter. Function was the most intact in children with less than 10,000 copies per milliliter.