Pulmonary artery systolic hypertension is common and associated with increased mortality among adult sickle cell disease (SCD) patients in the United States. Although the prevalence of SCD is highest in subSaharan Africa, the frequency of pulmonary artery systolic hypertension and the risk factors for the development of pulmonary hypertension have not been reported from Africa. We studied 208 hydroxyurea naïve Nigerian SCD patients at steady state and 94 healthy controls. Pulmonary artery systolic hypertension was defined prospectively as tricuspid regurgitant jet velocity ≥2.5 m/sec. Results were compared with a previously published US prospective SCD cohort. Only 7% of Nigerians compared with 46% of US adults with SCD were >35 years. Tricuspid regurgitant jet velocity was ≥2.5 m/sec in 25% of Nigerian SCD patients. Higher jet velocity was associated with greater serum globulin (P 5 0.002), blood urea nitrogen (P 5 0.019) and lactate dehydrogenase concentrations (P 5 0.026) and with inability to walk >300 m in 6 min (P 5 0.042). Compared with the US cohort, Nigerian patients had more hemolysis as indicated by lower hemoglobin and higher lactate dehydrogenase concentrations (P ≤ 0.003). Pulmonary hypertension is common among Nigerian SCD patients. The public health implication of this finding is significant considering the potential number of individuals at risk for this complication. Better understanding of the long term outcome of pulmonary hypertension and causes of death in SCD and the institution of preventive measures are major public health challenges for Africa. The inclusion of African sites in sickle cell pulmonary hypertension clinical trials should be encouraged. Am. J. Hematol. 83:485-490, 2008. V

Background HIV-associated neurocognitive disorder (HAND) is a great source of morbidity in sub-Saharan African region. However, the magnitude of this problem remains largely uninvestigated despite having the largest number of population with HIV/AIDS. The aim of this study is to determine the prevalence of HAND among patients attending a tertiary health facility in Nigeria. Method We conducted a cross-sectional study among HIV-positive patients on antiretroviral therapy (ART) for at least 1 year. They were assessed using the International HIV Dementia Scale, Word Recall Test, Stick Design Test, Subjective Cognitive Complaint Questionnaire, Alcohol Use Disorder Identification Test, Drug Abuse Screening Test, Center for Epidemiological Study–Depression Scale, Instrumental Activity of Daily Living, and neurological examination. The CD4 count and viral load were determined for all the participants. A consensus diagnosis was made on each case based on the Frascati criteria. Data obtained were analyzed using “SPSS” for Windows version 15. Results A total of 418 HIV-positive patients participated in the study, of which 325 (77.8%) are females. The mean age (standard deviation) of the participants was 37.2 (9.3) years. The prevalence of HAND was 21.5% (95% confidence interval [CI] = 17.6%-25.4%), of which 9.6% were asymptomatic. The significant predictors of HAND in this study are duration of illness (odds ratio [OR] = 1.33 P < .001), detectable viral load (OR = 0.19, P < .001), CD4 count (OR = 0.99, P < .001), education (OR = 0.94, P = .011), stopping medication (OR = 3.55 P = .01), and severity of illness (OR = 1.24, P = .005). Conclusion One-fifth of the HIV-positive patients in this study had HAND. Various sociodemographic and clinical features were related to the prevalence of HAND.

Secondary pulmonary hypertension (PAH) has been shown to have a prevalence of 30% in patients with sickle cell disease (SCD) with mortality rates of 40% at 40 months after diagnosis in the United States. The burden of SCD is highest in sub-Saharan Africa, especially in Nigeria (West Africa), where approximately 6 million people are afflicted. The true global incidence, prevalence, and burden of SCD and its associated end organ complications however remain unknown. Chronic hemolysis represents a prominent mechanistic pathway in the pathogenesis of SCD-associated pulmonary hypertension via a nitric oxide (NO) scavenging and abrogation of NO salutatory effects on vascular function, including smooth muscle relaxation, downregulation of endothelial adhesion molecules and inhibition of platelet activation. Many known infectious risk factors for PAH are also hyperendemic in Africa, including Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS), chronic hepatitis B and C, and possibly malaria. Interactions between these infectious complications and SCD-related hemolysis could yield an even higher prevalence of pulmonary hypertension and compound the existing global health systems challenges in managing SCD. Indeed, our preliminary analysis of African immigrants currently in the United States suggests that pulmonary hypertension represents a significant complication of SCD in the African subcontinent. There is clearly a need to include Africa and other parts of the world with high SCD prevalence in future comprehensive studies on the epidemiology and treatment of end organ complications of an aging SCD population world-wide. Am.

The pathogenesis of sickle vaso-occlusive crisis (VOC) in sickle cell disease (SCD) patients involves the accumulation of rigid sickle cells and the stimulation of an ongoing inflammatory response, as well as the stress of infections. The immune response, via cytokine imbalances and deregulated T-cell subsets, also has been proposed to contribute to the development of VOC. In this study, a panel of high-sensitivity cytokine kits was used to investigate cytokines in the sera of SCD patients in VOC. The results were compared primarily with those for stable SCD patients and secondarily with those for normal healthy people who served as controls. The cytokines studied included interleukin-2 (IL-2), IL-4, and IL-10. Lymphocyte subsets of patients with VOC were also studied and were compared with those of both control groups (20 stable patients without crisis [SCD group] and 20 normal healthy controls [NHC]). The VOC group was notable for remarkably elevated levels of IL-4, among the three cytokines tested, compared with those for the SCD and NHC groups. Patients with VOC also differed from stable SCD patients and NHC by having notably lower IL-10 levels, as well as the lowest ratio of CD4 ؉ to CD8 ؉ T cells (0.7). The patterns of the proinflammatory cytokine IL-2 did not differ between VOC and stable SCD patients, but NHC had significantly lower IL-2 levels than both the VOC and SCD groups. Our results demonstrate coexisting levels, both high and low, of TH1-and TH2-type cytokines, as well as diminished levels of T-cell subsets in VOC. These results are discussed in an effort to better understand the importance of the immune system profile in the pathogenesis of sickle cell VOC. Since the possibility that a cytokine imbalance is implicated in the pathogenesis of sickle cell crisis has been raised, our results should prompt further investigation of the host immune response in terms of TH1 and TH2 balance in sickle cell crisis.

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