Publications

BACKGROUND

Cystatin C has been proposed as an alternative marker of kidney function among HIV-infected persons in whom serum creatinine is affected by extrarenal factors.

METHODS

In this cross-sectional study, we compared estimated glomerular filtration rates (eGFR) using serum creatinine versus cystatin C between 150 HIV-uninfected and 783 HIV-infected men. We evaluated the prevalence of chronic kidney disease (CKD; eGFR less than 60 mL/min/1.73 m) and examined the influence of extrarenal factors on GFR estimates among HIV-infected men.

RESULTS

Estimated GFRSCR was similar by HIV serostatus, but eGFRCYSC was lower in HIV-infected men. A higher proportion of HIV-infected men were classified as having CKD when using eGFRCYSC versus eGFRSCR (7% vs 5%, P < 0.01). In HIV-infected individuals without CKD, eGFRSCR was higher than eGFRCYSC, whereas it was lower than eGFRCYSC in persons with CKD. In HIV-infected men, older age, proteinuria, and prior clinical AIDS were inversely associated with both GFR estimates. Higher serum albumin levels and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were associated with lower eGFRSCR. HIV viral load, hepatitis C coinfection, and serum alkaline phosphatase were inversely associated with eGFRCYSC.

CONCLUSION

Among HIV-uninfected and HIV-infected men of similar social risk behaviors, GFR estimates differed by biomarker and kidney function level. Estimated GFRCYSC classified a larger proportion of HIV-infected men with CKD compared with eGFRSCR. Differences between these GFR-estimating methods may be the result of the effects of extrarenal factors on serum creatinine and cystatin C. Until GFR-estimating equations are validated among HIV-infected individuals, current GFR estimates based on these biomarkers should be interpreted with care in this patient population.

Humanized Bone marrow/Liver/Thymus (BLT) mice recapitulate the mucosal transmission of HIV, permitting study of early events in HIV pathogenesis and evaluation of preexposure prophylaxis methods to inhibit HIV transmission. Human hematopoiesis is reconstituted in NOD-scid mice by implantation of human fetal liver and thymus tissue to generate human T cells plus intravenous injection of autologous liver-derived CD34(+) hematopoietic stem cells to engraft the mouse bone marrow. In side-by-side comparisons, we show that NOD-scid mice homozygous for a deletion of the IL-2Rγ-chain (NOD-scid IL-2Rγ(-/-)) are far superior to NOD-scid mice in both their peripheral blood reconstitution with multiple classes of human leukocytes (e.g., a mean of 182 versus 14 CD4(+) T cells per μl 12 weeks after CD34(+) injection) and their susceptibility to intravaginal HIV exposure (84% versus 11% viremic mice at 4 weeks). These results should speed efforts to obtain preclinical animal efficacy data for new HIV drugs and microbicides.

RATIONALE

Several predictors of mortality in patients with idiopathic pulmonary fibrosis have been described; however, there is a need for a practical and accurate method of quantifying the prognosis of individual patients.

OBJECTIVES

Develop a practical mortality risk scoring system for patients with idiopathic pulmonary fibrosis.

METHODS

We used a Cox proportional hazards model and data from two clinical trials (n = 1,099) to identify independent predictors of 1-year mortality among patients with idiopathic pulmonary fibrosis. From the comprehensive model, an abbreviated clinical model comprised of only those predictors that are readily and reliably ascertained by clinicians was derived. Beta coefficients for each predictor were then used to develop a practical mortality risk scoring system.

MEASUREMENTS AND MAIN RESULTS

Independent predictors of mortality included age, respiratory hospitalization, percent predicted FVC, 24-week change in FVC, percent predicted carbon monoxide diffusing capacity, 24-week change in percent predicted carbon monoxide diffusing capacity, and 24-week change in health-related quality of life. An abbreviated clinical model comprising only four predictors (age, respiratory hospitalization, percent predicted FVC, and 24-wk change in FVC), and the corresponding risk scoring system produced estimates of 1-year mortality risk consistent with observed data (9.9% vs. 9.7%; C statistic = 0.75; 95% confidence interval, 0.71–0.79).

CONCLUSIONS

The prognosis for patients with idiopathic pulmonary fibrosis may be accurately determined using four readily ascertainable predictors. Our simplified scoring system may be a valuable tool for determining prognosis and guiding clinical management. Additional research is needed to validate the applicability and accuracy of the scoring system.

BACKGROUND

HIV-infected women have lower HIV RNA levels and higher CD4-cell counts than do men. This observation has been attributed to the immunomodulatory effects of sex steroid hormones, such as estrogen and progesterone. Limited data exist regarding potential sex differences in HIV RNA level and CD4 parameters among prepubertal children with untreated HIV infection.

METHODS

We examined the relationship of sex to HIV RNA level and CD4 parameters among 670 perinatally HIV-infected, antiretroviral therapy-naive African children aged <18 years (median age, 4.8 years) using multivariate linear regression. In a subset of 188 children, we used longitudinal data to compare changes in HIV RNA levels and CD4 percentage over time. Levels of CD4 and CD8 T-cell activation (CD38+HLA-DR+) were also compared between boys and girls.

RESULTS

Female children had lower HIV RNA levels (P = .0004) and higher CD4 percentages (P < .0001), compared to male children. Multivariate linear regression demonstrated an independent association of sex with both HIV RNA level and CD4 percentages after controlling for other covariates. Multilevel mixed-effects linear regression analysis of longitudinal HIV RNA level and CD4 parameter data showed that sex differences persisted across all observed ages. Levels of T-cell activation did not differ between the sexes.

CONCLUSIONS

Significant sex differences in HIV RNA levels and CD4 parameters are present in HIV-infected children before the onset of puberty. These data suggest that intrinsic genetic differences between male and female individuals, unrelated to sex steroid hormone levels, influence HIV RNA level and CD4 parameters in HIV-infected individuals.