Increases in CD4+ T lymphocytes occur without increases in thymic size in HIV-infected subjects receiving interleukin-2 therapy.

OBJECTIVE: To examine the potential contribution of the thymus to CD4+ T-lymphocyte increases in HIV-infected patients receiving intermittent interleukin-2 (IL-2) therapy. DESIGN: Fifteen HIV-infected patients treated with antiretroviral regimens who were enrolled in a study of intermittent IL-2 therapy and were willing to undergo serial thymic computed tomography (CT) were prospectively studied. METHODS: Thymic CT was performed before and approximately 6 and 12-17 months after intermittent IL-2 therapy was started. Scans were graded in a blinded manner. Changes in lymphocyte subpopulations were determined by flow cytometry. RESULTS: Statistically significant increases in CD4+ T lymphocytes occurred with IL-2 administration, with a preferential increase in naive relative to memory CD4+ T cells. Despite this increase in naive CD4+ T cells, overall there was a modest decrease in thymic volume observed during the study period. No correlation was found between changes in thymic volume indices and total, naive, or memory CD4+ T-lymphocyte counts. CONCLUSIONS: These findings demonstrate that the profound CD4+ T-lymphocyte increases seen with intermittent IL-2 administration are not associated with increases in thymic volume and more likely are due to peripheral expansion rather than increased thymic output.

High prevalence of osteonecrosis of the femoral head in HIV-infected adults.

BACKGROUND: Osteonecrosis has been reported to occur occasionally among HIV-infected patients. The diagnosis of symptomatic osteonecrosis of the hip in two of the authors' patients, together with reports from community physicians, raised a concern that the prevalence of osteonecrosis is increasing. OBJECTIVE: To determine the prevalence of osteonecrosis of the hip in asymptomatic HIV-infected patients and to identify potential risk factors associated with osteonecrosis. DESIGN: Survey and comparison study. SETTING: The Clinical Center of the U.S. National Institutes of Health. PARTICIPANTS: 339 asymptomatic HIV-infected adults (of 364 asked to participate) and 118 age- and sex-matched HIV-negative volunteers enrolled between 1 June and 15 December 1999. MEASUREMENTS: Osteonecrosis of the hip, as documented by magnetic resonance imaging. Data from clinic records and a patient questionnaire administered before magnetic resonance imaging were used in an analysis of risk factors. A subset of patients was evaluated for hypercoagulable state. RESULTS: Fifteen (4.4% [95% CI, 2.5% to 7.2%]) of 339 HIV-infected participants had osteonecrosis lesions on magnetic resonance imaging, and no HIV-negative participants had similar lesions. Among HIV-infected participants, osteonecrosis occurred more frequently in those who used systemic corticosteroids, lipid-lowering agents, or testosterone; those who exercised routinely by bodybuilding; and those who had detectable levels of anticardiolipin antibodies. CONCLUSIONS: Patients infected with HIV have an unexpectedly high occurrence of osteonecrosis of the hip. Although screening asymptomatic patients is not warranted, HIV-infected patients with persistent groin or hip pain should be evaluated for this debilitating complication.

Urinary cytology associated with human polyomavirus and indinavir therapy in HIV-infected patients.

We retrospectively analyzed 155 urine cytology samples (78 from patients treated with indinavir; 77, no indinavir) from 90 HIV+ patients to evaluate possible association between human polyomavirus and hematuria and to describe indinavir-associated urinary cytologic findings. The CD4 count also was recorded. Variables studied included the presence of cellular viral changes consistent with polyomavirus infection (PVCs), microscopic hematuria, multinucleated cells, indinavir crystals, neutrophils, and eosinophils. Twenty-two samples (15.8%) from patients with CD4 counts of more than 200/microL (>200 x 10(6)/L) showed PVCs. Multinucleated cells, of presumed histiocytic origin based on morphologic features and selective immunocytochemical findings, were present in a higher percentage of samples from indinavir-treated patients. Neutrophils were present in a higher percentage of indinavir-treated patients. Indinavir crystals were identified in 9 samples (12%) from patients receiving indinavir The lower percentage of PVCs in HIV+ patients with high CD4 counts likely represents an indirect antipolyomavirus indinavir effect by boosting immunity. Multinucleated cells (presumably histiocytic) and acute inflammation are associated with indinavir therapy. Indinavir crystals have a characteristic fan or circular lamellate appearance. Because indinavir crystals may be associated with genitourinary disease, recognizing and reporting them is clinically relevant in HIV+ patients.

Indinavir-associated interstitial nephritis and urothelial inflammation: clinical and cytologic findings.

The objective of the present study was to characterize the genitourinary syndromes that accompany indinavir-associated pyuria. Of 23 indinavir-treated patients with persistent pyuria, 4 had isolated interstitial nephritis, 10 had both interstitial nephritis and urothelial inflammation, 7 had isolated urothelial inflammation, and 2 had pyuria with nonspecific urinary tract inflammation. A total of 21 patients had multinucleated histiocytes identified by cytologic testing of urine specimens. Urine abnormalities resolved in all 20 patients who stopped receiving indinavir therapy. Pyuria continued in the 3 patients who continued receiving indinavir. Six patients had elevated serum creatinine levels, which returned to baseline levels when indinavir was discontinued. In conclusion, indinavir-associated pyuria was frequently associated with evidence of interstitial nephritis and/or urothelial inflammation, multinucleated histiocytes were commonly present in urine specimens, and cessation of indinavir therapy was associated with prompt resolution of urine abnormalities.

Diagnosis of avascular necrosis of the hip in asymptomatic HIV-infected patients: Clinical correlation of physical examination with magnetic resonance imaging.

OBJECTIVE: To determine if physical examination can identify avascular necrosis of the hip (AVN) in asymptomatic HIV-infected patients. DESIGN: Prospective, blinded population studyResults: Ten of the 176 patients were positive for AVN by MRI. Four subjects had unilateral disease and six had bilateral disease. Five hips (1.4%) in four patients were indeterminate. We evaluated physical examination maneuvers both singly and in combination. Tests done singly generally provided a higher degree of specificity (67-92%) but sensitivities were lower (0-50%) with all p-values ≥0.08. Positive predictive values based on physical exam, were <17% and negative predictive values were >90% for any single test. Combining all tests gave a high sensitivity (88%) and negative predictive value (98%), but low specificity (34%) and positive predictive value (6%) with p = 0.10. Only two of 16 hips with positive MRI findings showed no abnormalities when all tests were combinedConclusions: This study establishes the limited usefulness of a detailed physical examination of the hip early in the course of AVN. Patients who test negative on physical exam are unlikely to have AVN positive by MRI. Positive findings on physical examination of the hip may help identify patients who need further evaluation by MRI based on overall clinical suspicion.

Acute hepatitis caused by a novel strain of hepatitis E virus most closely related to United States strains.

A unique hepatitis E virus (HEV) strain was identified as the aetiological agent of acute hepatitis in a United States (US) patient who had recently returned from vacation in Thailand, a country in which HEV is endemic. Sequence comparison showed that this HEV strain was most similar, but not identical, to the swine and human HEV strains recovered in the US. Phylogenetic analysis revealed that this new HEV isolate was closer to genotype 3 strains than to the genotype 1 strains common in Asia. The fact that this HEV was closely related to strains recovered in countries where HEV is not endemic and was highly divergent from Asian HEV strains raises the questions of where the patient's infection was acquired and of whether strains are geographically as localized as once thought.