Evaluation of Dynabeads and Cytospheres compared with flow cytometry to enumerate CD4+ T cells in HIV-infected Ugandans on antiretroviral therapy

BACKGROUND: Laboratory-based monitoring of antiretroviral therapy is essential but adds a significant cost to HIV care. The World Health Organization 2006 guidelines support the use of CD4 lymphocyte count (CD4) to define treatment failure in resource-limited settings. METHODS: We compared CD4 obtained on replicate samples from 497 HIV-positive Ugandans (before and during ART) followed for 18 months by 2 manual bead-based assays, Dynabeads (Dynal Biotech), and Cytospheres (Beckman Coulter) with those generated by flow cytometry at the Infectious Diseases Institute in Kampala, Uganda. RESULTS: We tested 1671 samples (123 before ART) with Dynabeads and 1444 samples (91 before ART) with Cytospheres. Mean CD4 was 231 cells/mm (SD, 139) and 239 cells/mm (SD, 140) by Dynabeads and flow cytometry, respectively. Mean CD4 was 186 cells/mm (SD, 101) and 242 cells/mm (SD, 136) by Cytospheres and flow cytometry, respectively. The mean difference in CD4 count by flow cytometry versus Dynabeads were 8.8 cells/mm (SD, 76.0) and versus Cytospheres were 56.8 cells/mm (SD, 85.8). The limits of agreement were -140.9 to 158.4 cells/mm for Dynabeads and -112.2 to 225.8 cells/mm for Cytospheres. Linear regression analysis showed higher correlation between flow cytometry and Dynabeads (r=0.85, r=0.73, slope=0.85, intercept=28) compared with the correlation between flow cytometry and Cytospheres (r=0.78, r=0.60, slope=0.58, intercept=45). Area under the receiver operating characteristics curve to predict CD4<200 cells/mm was 0.928 for Dynabeads and 0.886 for Cytospheres. CONCLUSION: Although Dynabeads and Cytospheres both underestimated CD4 lymphocyte count compared with flow cytometry, in resource-limited settings with low daily throughput, manual bead-based assays may provide a less expensive alternative to flow cytometry.     

The long-term effectiveness of generic adult fixed-dose combination antiretroviral therapy for HIV-infected Ugandan children

Background

Access to pediatric antiretroviral formulations is increasing in resource-limited countries, however adult FDCs are still commonly used by antiretroviral therapy (ART) programs.

Objective

To describe long-term effectiveness of using adult FDC of d4T+3TC+NVP (Triomune) in children for HIV treatment.

Methods

Clinical, immunologic, and virologic outcomes of HIV-infected ART-naïve children aged six months to 12 years, were evaluated up to 96 weeks post-ART initiation.

Results

From March 2004 to June 2006, 104 children were followed with a median age of 5.4 years, median CD4 cell percent and HIV-1 RNA were 11.0% (IQR 6.7–13.9) and 348,846copies/mL (IQR 160,941–681,313) respectively at baseline. Using Kaplan-Meir estimates, 75% of children had undetectable viral loads (<400copies/mL) at 96weeks of ART. Children with a baseline CD4 cell percent >15% were 3 times more likely to achieve viral load <400copies/mL than those with baseline CD4 cell percent <5% after adjusting for baseline age {aHR = 3.03 (1.10–8.32), p=0.03}; no difference was found among those with CD4 cell percent >5–14.9% and <5%.

Conclusion

Treatment with generic adult FDC for HIV-infected Ugandan children led to sustained clinical, immunologic and virologic response during 96 weeks of ART. Early initiation of ART is key to achieving virological success.     

Efficacy and Safety of Everolimus Plus Low‐Dose Tacrolimus Versus Mycophenolate Mofetil Plus Standard‐Dose Tacrolimus in De Novo Renal Transplant Recipients: 12‐Month Data

In this 12‐month, multicenter, randomized, open‐label, noninferiority study, de novo renal transplant recipients (RTxRs) were randomized (1:1) to receive everolimus plus low‐dose tacrolimus (EVR+LTac) or mycophenolate mofetil plus standard‐dose Tac (MMF+STac) with induction therapy (basiliximab or rabbit anti‐thymocyte globulin). Noninferiority of composite efficacy failure rate (treated biopsy‐proven acute rejection [tBPAR]/graft loss/death/loss to follow‐up) in EVR+LTac versus MMF+STac was missed by 1.4%, considering the noninferiority margin of 10% (24.6% vs. 20.4%; 4.2% [?3.0, 11.4]). Incidence of tBPAR (19.1% vs. 11.2%; p < 0.05) was significantly higher, while graft loss (1.3% vs. 3.9%; p < 0.05) and composite of graft loss/death/lost to follow‐up (6.1% vs. 10.5%, p = 0.05) were significantly lower in EVR+LTac versus MMF+STac groups, respectively. Mean estimated glomerular filtration rate was similar between EVR+LTac and MMF+STac groups (63.1 [22.0] vs. 63.1 [19.5] mL/min/1.73 m²) and safety was comparable. In conclusion, EVR+LTac missed noninferiority versus MMF+STac based on the 10% noninferiority margin. Further studies evaluating optimal immunosuppression for improved efficacy will guide appropriate dosing and target levels of EVR and LTac in RTxRs.     

Optimizing everolimus exposure when combined with calcineurin inhibitors in solid organ transplantation

The mammalian target of rapamycin (mTOR) inhibitor everolimus is a narrow therapeutic index drug for which optimal exposure levels are essential. The consistent pharmacokinetic profile of everolimus allows trough concentration (C₀) measurement to be an appropriate and reliable index for therapeutic drug monitoring (TDM). Exposure-response analyses of data from early fixed-dose trials demonstrated that rates of biopsy-proven acute rejection (BPAR) are significantly higher if everolimus C₀ declines below 3 ng/mL, an observation confirmed in subsequent concentration-controlled trials. Evidence for the most favorable upper limit is less clear but with reduced-exposure calcineurin inhibitor (CNI) therapy, an upper limit of 8 ng/mL appears to balance efficacy and safety outcomes. The recommended C₀ range is 3–8 ng/mL in kidney, liver and heart transplantation patients, based on LC–MS/MS monitoring in whole blood. Randomized clinical trials based on this target range have demonstrated rates of BPAR comparable to a regimen of mycophenolic acid with standard-exposure CNI. Everolimus exhibits moderate intrapatient pharmacokinetic variability, and it can be challenging to maintain stable concentrations within target range in some individuals. Many factors can influence everolimus exposure for a given dose, including hepatic function, activity of the drug efflux pump P-glycoprotein, the rate of everolimus metabolism, drug–drug interactions (predominantly with CYP3A4 and P-glycoprotein inhibitors, including cyclosporine), intake of fatty food, and patient adherence to the prescribed regimen. Trough concentration levels should be monitored 4–5 days after the first dose and after any change in everolimus dose, with additional monitoring in response to any change in concomitant medication or other clinical circumstances which could alter everolimus exposure. Although LC–MS/MS is the gold standard for everolimus monitoring, various immunoassays are widely used due to their relative simplicity and lower cost, and results can show considerable discrepancies with reference methods due to issues such as interassay variability and cross-reactivity. Method standardization will be important in the future to improve the consistency and reproducibility of results between centers. In conclusion, based on an extensive program of clinical trials, the optimal exposure range for everolimus in combination with reduced-exposure CNI therapy has been established and can be achieved in most transplant recipients through careful, planned TDM.     

Awake Craniotomy for Tumour Excision

Background

Craniotomy and excision of tumours can produce neurological deficits if the tumour is located close to eloquent areas of the brain. One technique of overcoming this problem is to keep the patient ‘awake’ during surgery.

Methods

Eight patients with intra cranial space occupying lesions (ICSOL) were operated ‘awake’, using a combination of skull block with sedation and analgesia. A mixture of 0.125% bupivacaine and 0.5% lignocaine was used for various nerve and field blocks. Midazolam, fentanyl and propofol in titrated doses were used to achieve conscious sedation.

Result

The procedure was successful in all the patients. They tolerated the procedure well and were able to follow the commands intraoperatively as desired. There were no significant complications.

Conclusion

Awake craniotomy with skull blocks with sedation and analgesia is a well established procedure. It requires a good rapport between surgeon, anaesthesiologist and the patient.Key Words: Awake craniotomy, Skull block, Sedation, Analgesia