Prevalence of G6PD deficiency in a large cohort of HIV-infected patients

Heme-Induced Macrophage Phenotype Switching and Impaired Endogenous Opioid Homeostasis Correlate with Chronic Widespread Pain in HIV

Chronic widespread pain (CWP) is associated with a high rate of disability and decreased quality of life in people with HIV-1 (PWH). We previously showed that PWH with CWP have increased hemolysis and elevated plasma levels of cell-free heme, which correlate with low endogenous opioid levels in leukocytes. Further, we demonstrated that cell-free heme impairs β-endorphin synthesis/release from leukocytes. However, the cellular mechanisms by which heme dampens β-endorphin production are inconclusive. The current hypothesis is that heme-dependent TLR4 activation and macrophage polarization to the M1 phenotype mediate this phenomenon. Our novel findings showed that PWH with CWP have elevated M1-specific macrophage chemokines (ENA-78, GRO-α, and IP-10) in plasma. In vitro, hemin-induced polarization of M0 and M2 macrophages to the M1 phenotype with low β-endorphins was mitigated by treating cells with the TLR4 inhibitor, TAK-242. Similarly, in vivo phenylhydrazine hydrochloride (PHZ), an inducer of hemolysis, injected into C57Bl/6 mice increased the M1/M2 cell ratio and reduced β-endorphin levels. However, treating these animals with the heme-scavenging protein hemopexin (Hx) or TAK-242 reduced the M1/M2 ratio and increased β-endorphins. Furthermore, Hx attenuated heme-induced mechanical, heat, and cold hypersensitivity, while TAK-242 abrogated hypersensitivity to mechanical and heat stimuli. Overall, these results suggest that heme-mediated TLR4 activation and M1 polarization of macrophages correlate with impaired endogenous opioid homeostasis and hypersensitivity in people with HIV.

Review article: Emerging issues in pediatric skin of color, Part 2

Dermatology for pediatric skin of color is the application of dermatology to the genetically diverse and distinctive segment of the pediatric population that includes children of non-White racial and ethnic groups with increased pigmentation including individuals of Asian, Hispanic/LatinX, African, Native American, Pacific Island descent, indigenous people among others with overlap in particular individuals, and mixtures thereof. The discipline of pediatric skin of color can be challenging with difficulty in diagnosis of common conditions due to underlying pigmentation, variations in common hair styling practices, and differences in demographics of cutaneous disease. Whereas some conditions are more common in children of color, other conditions have nuances in clinical appearance and therapeutics with regard to skin color. This article, the second of the series, focuses on inflammatory skin disease nuances, melanocytic disorders, and hypopigmented mycosis fungoides.

Heme attenuates beta-endorphin levels in leukocytes of HIV positive individuals with chronic widespread pain

The prevalence of chronic widespread pain (CWP) in people with HIV is high, yet the underlying mechanisms are elusive. Leukocytes synthesize the endogenous opioid, β-endorphin, within their endoplasmic reticulum (ER). When released into plasma, β-endorphin dampens nociception by binding to opioid receptors on sensory neurons. We hypothesized that the heme-dependent redox signaling induces ER stress, which attenuates leukocyte β-endorphins levels/release, thereby increasing pain sensitivity in people with HIV. Results demonstrated that HIV positive individuals with CWP had increased plasma methemoglobin, erythrocytes membrane oxidation, hemolysis, and low plasma heme scavenging enzyme, hemopexin, compared to people with HIV without CWP and HIV-negative individuals with or without pain. In addition, the leukocytes from people with HIV with CWP had attenuated levels of the heme metabolizing enzyme, heme oxygenase-1, which metabolizes free heme to carbon-monoxide and biliverdin. These individuals also had elevated ER stress, and low β-endorphin in leukocytes. In vitro, heme exposure or heme oxygenase-1 deletion, decreased β-endorphins in murine monocytes/macrophages. Treating cells with a carbon-monoxide donor or an ER stress inhibitor, increased β-endorphins. To mimic hemolytic effects in a preclinical model, C57BL/6 mice were injected with phenylhydrazine hydrochloride (PHZ). PHZ increased cell-free heme and ER stress, decreased leukocyte β-endorphin levels and hindpaw mechanical sensitivity thresholds. Treatment of PHZ-injected mice with hemopexin blocked these effects, suggesting that heme-induced ER stress and a subsequent decrease in leukocyte β-endorphin is responsible for hypersensitivity in people with HIV.

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase: Do Single Nucleotide Polymorphisms Affect Hematological Parameters in HIV-Positive Patients?

This descriptive, cross-sectional study aimed at evaluating the prevalence of G6PD deficiency and the 376A ⟶ G, 202G ⟶ A single nucleotide polymorphisms (SNPs) among HIV patients attending care at a teaching hospital in Ghana and determine how the SNPs affect haematological profile in HIV. A total of 200 HIV-positive Ghanaians were recruited. Venous blood samples were obtained and complete blood count, and G6PD screening and genotyping for the 376A ⟶ G, 202G ⟶ A SNPs were performed. Out of the 200 participants, 13.0% (26/200) were G6PD-deficient based on the methemoglobin reductase technique, with 1.5% (3/200) and 11.5% (23/200) presenting with partial and full enzyme defect, respectively. Among the 13.0% participants with G6PD deficiency, 19.2% (5/26), 30.8% (8/26), and 19.2% (5/26) presented with 376A ⟶ G only (enzyme activity (EA): 1.19 U/g Hb), 202G ⟶A only (EA: 1.41 U/g Hb), and G202/A376 SNPs (EA: 1.14 U/g Hb), respectively. Having the 376A ⟶ G mutation was associated not only with lower red blood cell (RBC) count (3.38 × 106/µL (3.16-3.46) vs 3.95 × 106/µL (3.53-4.41), p = 0.010) but also with higher mean cell volume (MCV) (102.90 (99.40-113.0) vs 91.10 fL (84.65-98.98), p = 0.041) and mean cell haemoglobin (MCH) (33.70 pg (32.70-38.50) vs 30.75 pg (28.50-33.35), p = 0.038), whereas possessing the 202G ⟶ A mutation was associated with higher MCV only (98.90 fL (90.95-102.35) vs 91.10 fL (84.65-98.98), p = 0.041) compared to G6PD nondeficient participants. The prevalence of G6PD deficiency among HIV patients in Kumasi, Ghana, is 13.0% prevalence, comprising 1.5% and 11.5% partial and full enzyme defect, respectively, based on the methemoglobin reductase technique among HIV patients in Ghana. Among G6PD-deficient HIV patients, the prevalence of G202/A376 SNPs is 19.2%. The 376A ⟶ G mutation is associated not only with lower RBC count but also with higher MCV and MCH, whereas the 202G ⟶ A mutation is associated with higher MCV compared to the normal G6PD population.

[Glucose-6-phosphate-dehydrogenase deficiency management in western countries. A literature review]

Glucose-6-phosphate-dehydrogenase (G6PD) deficiency is the most prevalent abnormal enzyme condition in the general population, but most patients are asymptomatic (crises are triggered by certain drugs or foods). The clinical consequences are greater in patients coming from endemic areas of malaria (antimalarial medication can trigger a crisis). The increase in migratory flows has led to an increase in the number of people affected by the deficiency in our practice, which makes it interesting to carry out a literature review of this condition. Some authors have communicated that patients with G6PD deficiency have an increase in prevalence of cardiovascular diseases, which requires the strict control of cardiovascular risk factors. However, these patients show a decrease in colorectal cancer prevalence. In addition, donations of bone marrow and haematopoietic derivatives could be performed safely.

Acute Retroviral Syndrome Presenting with Hemolytic Anemia Induced by G6PD Deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme defect described in humans. Hemolysis in affected patients is usually triggered by circumstances involving free radical damage. While acute HIV infection is known to be a state of overwhelming oxidative stress, virus-induced hemolytic events in G6PD-deficient patients has rarely been reported. Despite an estimated overall prevalence of 6.8%⁻13% of this disorder in the HIV population, clinically significant hemolysis has been largely attributed to the use of offending medications rather than HIV infection itself. Here, we present a patient whose first episode of G6PD deficiency-associated hemolysis occurred as the main presentation of acute HIV infection.

Haematological manifestations of human immune deficiency virus infection

Early in the human immunodeficiency virus (HIV) epidemic, infected patients presented to medical attention with striking abnormalities in each of the major blood cell lineages. The reasons for these derangements remain complex and multifactorial. HIV infects multipotent haematopoietic progenitor cells and establish latent cellular reservoirs, disturbs the bone marrow microenvironment and also causes immune dysregulation. These events lead to cytokine imbalances and disruption of other factors required for normal haematopoiesis. Activation of the reticulo-endothelial system can also result in increased blood cell destruction. The deleterious effects of medications, including first and second generation anti-retroviral agents, on haematopoiesis were well documented in the early years of HIV care; in the current era of HIV-care, the advent of newer and less toxic anti-retroviral drugs have had a more beneficial impact on haematopoiesis. Due to impaired regulation of the immune system and potential side effects of one or more anti-retroviral agents, there is also an increase in coagulation abnormalities such as thromboembolism, and less frequently, acquired disorders of coagulation including thrombotic thrombocytopenic purpura, immune thrombocytopenic purpura and acquired inhibitors of coagulation. In this article we review the epidemiology and aetiology of select non-oncological haematological disorders commonly seen in people living with HIV-acquired immune deficiency syndrome.

G6PD Deficiency in an HIV Clinic Setting in the Dominican Republic

Because human immunodeficiency virus (HIV)-infected patients receive prophylaxis with oxidative drugs, those with glucose-6-phosphate dehydrogenase (G6PD) deficiency may experience hemolysis. However, G6PD deficiency has not been studied in the Dominican Republic, where many individuals have African ancestry. Our objective was to determine the prevalence of G6PD deficiency in Dominican HIV-infected patients and to attempt to develop a cost-effective algorithm for identifying such individuals. To this end, histories, chart reviews, and G6PD testing were performed for 238 consecutive HIV-infected adult clinic patients. The overall prevalence of G6PD deficiency (8.8%) was similar in males (9.3%) and females (8.5%), and higher in Haitians (18%) than Dominicans (6.4%; P = 0.01). By logistic regression, three clinical variables predicted G6PD status: maternal country of birth (P = 0.01) and a history of hemolysis (P = 0.01) or severe anemia (P = 0.03). Using these criteria, an algorithm was developed, in which a patient subset was identified that would benefit most from G6PD screening, yielding a sensitivity of 94.7% and a specificity of 97.2%, increasing the pretest probability (8.8-15.1%), and halving the number of patients needing testing. This algorithm may provide a cost-effective strategy for improving care in resource-limited settings.

Case Report: Paroxysmal nocturnal hemoglobinuria in a woman heterozygous for G6PD A-

We describe a case of paroxysmal nocturnal hemoglobinuria (PNH) in a woman who is heterozygous for the glucose-6-phosphate dehydrogenase A-   ( G6PDA-) allele. PNH is associated with one or more clones of cells that lack complement inhibition due to loss of function somatic mutations in the PIGA gene.  PIGA encodes the enzyme phosphatidylinositol glycan anchor biosynthesis, class A, which catalyses the first step of glycosylphosphatidylinisotol ( GPI)  anchor synthesis. Two GPI anchored red cell surface antigens regulate complement lysis. G6PD catalyses the first step of the pentose phosphate pathway and enzyme variants, frequent in some populations have been selected because they confer resistance to malaria, are associated with hemolysis in the presence of oxidizing agents including several drugs. The patient had suffered a hemolytic attack after taking co-trimoxazole, a drug that precipitates hemolysis in G6PD deficient individuals. Since both G6PD and PIGA are X-linked we hypothesized that the PIGA mutation was on the X-chromosome carrying the G6PDA- allele. Investigations showed that in fact the PIGA mutation was on the X-chromosome carrying the normal G6PD B allele. We speculate that complement activation on G6PD A- red cells exposed to Bactrim might have triggered complement activation inducing the lysis of G6PD B PNH Type II red blood cells or that the patient may have had a PNH clone expressing G6PDA- at the time of the hemolytic episode.

Dengue virus type 2 (DENV2)-induced oxidative responses in monocytes from glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD normal subjects

BACKGROUND

Dengue virus is endemic in peninsular Malaysia. The clinical manifestations vary depending on the incubation period of the virus as well as the immunity of the patients. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent in Malaysia where the incidence is 3.2%. It has been noted that some G6PD-deficient individuals suffer from more severe clinical presentation of dengue infection. In this study, we aim to investigate the oxidative responses of DENV2-infected monocytes from G6PD-deficient individuals.

METHODOLOGY

Monocytes from G6PD-deficient individuals were infected with DENV2 and infection rate, levels of oxidative species, nitric oxide (NO), superoxide anions (O2-), and oxidative stress were determined and compared with normal controls.

PRINCIPAL FINDINGS

Monocytes from G6PD-deficient individuals exhibited significantly higher infection rates compared to normal controls. In an effort to explain the reason for this enhanced susceptibility, we investigated the production of NO and O2- in the monocytes of individuals with G6PD deficiency compared with normal controls. We found that levels of NO and O2- were significantly lower in the DENV-infected monocytes from G6PD-deficient individuals compared with normal controls. Furthermore, the overall oxidative stress in DENV-infected monocytes from G6PD-deficient individuals was significantly higher when compared to normal controls. Correlation studies between DENV-infected cells and oxidative state of monocytes further confirmed these findings.

CONCLUSIONS/SIGNIFICANCE

Altered redox state of DENV-infected monocytes from G6PD-deficient individuals appears to augment viral replication in these cells. DENV-infected G6PD-deficient individuals may contain higher viral titers, which may be significant in enhanced virus transmission. Furthermore, granulocyte dysfunction and higher viral loads in G6PD-deificient individuals may result in severe form of dengue infection.

Atopic dermatitis in African American children: addressing unmet needs of a common disease

Recent published data suggest that the prevalence of atopic dermatitis (AD) in African American children is significantly higher than in Caucasians. There are certain characteristics in the presentation of AD in African Americans that seem to differ from those in other racial groups, but there is a paucity of information on this topic. In this review, we highlight the differences in pathophysiology, clinical presentation, and treatment of AD between African Americans and Caucasians. It is important for dermatologists to understand these differences in order to provide better care for African American children with AD.