Pathophysiology and treatment of aplastic anemia

Diagnosing and treating severe aplastic anemia

Severe aplastic anemia is a disorder of stem cell failure, leading to pancytopenia. The condition is characterized by an impairment of the function of hematopoietic stem cells. Patients typically have fatigue, infections, and increased or unusual bleeding. A bone marrow biopsy establishes the diagnosis. Treatment includes hematopoietic stem cell transplant or immunosuppressive therapy.

TNF-α -308 G>A polymorphism and risk of bone marrow failure syndrome: A meta-analysis

The influence of the TNF-α -308 G>A polymorphism on bone marrow failure syndrome susceptibility is unclear. We have conducted a meta-analysis of all relevant published studies. We searched PubMed, Chinese Biomedical Literature and China National Knowledge Infrastructure databases up to February 2015. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of associations. Eleven case-control studies with a total sample size of 909 cases and 1803 controls were eligible to assess the association between the TNF-α -308 G>A polymorphism and susceptibility to bone marrow failure syndrome. Overall, the TNF-α -308 G>A polymorphism was significantly associated with an increased risk of bone marrow failure syndrome in any genetic model. In stratified analysis by disease type, there was a significant association between the TNF-α -308 G>A polymorphism and increased risk of aplastic anemia but no significant association with myelodysplastic syndrome (AA vs. GG: OR=2.23, 95% CI=1.23-4.05, P=0.006; recessive model: OR=3.52, 95% CI=1.30-9.53, P=0.010). In subgroup analysis by ethnicity, there were significant associations between the TNF-α -308 G>A polymorphism and increased risk of bone marrow failure syndrome for Caucasians in two models, but not in Asian populations (AA vs. GG: OR=2.66, 95% CI=1.36-5.21, P=0.003; recessive model: OR=2.68, 95% CI=1.37-5.24, P=0.002). In conclusion, our meta-analysis suggests that the TNF-α -308 G>A polymorphism may contribute to the risk of bone marrow failure syndrome, particularly among Caucasian and aplastic anemia patients. Further investigations are needed to clarify the role of the TNF-α -308 G>A polymorphism in bone marrow failure syndrome.

The risk of infections in HIV-HCV coinfected patients during antiviral therapy with pegIFN+RBV

OBJECTIVES

Antiviral treatment with pegIFN/RBV decreases ANC and CD4+ cell count. An association between neutropenia, a low CD4+ cell count and infections has not been demonstrated so far in HIV-HCV coinfected patients.

METHODS

The incidence, type, and severity of infections were recorded in 85 HIV-HCV coinfected and 164 monoinfected patients receiving pegIFN/RBV for 48 weeks. ANC and CD4+ cell count were assessed every 4 weeks during therapy.

RESULTS

The incidence of infections was significantly higher in HIV-HCV than HCV-Mono (38% vs. 15%; p = 0.001). Types of infections: pneumonia (n = 16/n = 24), bacteraemia/sepsis (n = 5/n = 2), skin infections (n = 15/n = 12), urinary tract infections (n = 4/n = 1), OIs (n = 10/n = 1). The incidence of neutropenia grade 1, 2 3 or 4 was similar in HIV-HCV and HCV-Mono, respectively. The incidence of infections was not associated with neutropenia (HCV-Mono: p = 0.584; HIV-HCV: p = 0.23) or with CD4+ cell counts <200/μL (HIV-HCV: p = 0.29). OIs occurred more often in HIV-HCV patients with CD4+ cell count <200/μL (p = 0.024).

CONCLUSIONS

Up to 38% and 15% of HIV-HCV coinfected and HCV-monoinfected patients develop infections during pegIFN+RBV therapy but without any correlation to neutropenia. Antibacterial prophylaxis/treatment should be considered early in HIV-HCV coinfected patients developing CD4+ cell counts <200/μL during antiviral therapy as these patients have an increased risk of OIs.

Complete hematopoietic recovery after continuous iron chelation therapy in a patient with severe aplastic anemia with secondary hemochromatosis

A 16-yr-old male patient with hemochromatosis due to multiple packed red blood cell transfusions was referred to our emergency center for the treatment of severe aplastic anemia and dyspnea. He was diagnosed with aplastic anemia at 11-yr of age. He had received continuous transfusions because an HLA-matched marrow donor was unavailable. Following a continuous, approximately 5-yr transfusion, he was noted to develop hemochromatosis. He had a dilated cardiomyopathy and required diuretics and digitalis, multiple endocrine and liver dysfunction, generalized bleeding, and skin pigmentation. A total volume of red blood cell transfusion before deferoxamine therapy was about 96,000 mL. He received a regular iron chelation therapy (continuous intravenous infusion of deferoxamine, 50 mg/kg/day for 5 days q 3-4 weeks) for approximately seven years after the onset of multiple organ failures. His cytopenia and organ dysfunctions began to be gradually recovered since about 2002, following a 4-yr deferoxamine treatment. He showed completely normal ranges of peripheral blood cell counts, heart size, and liver function two years ago. He has not received any transfusions for the last four years. This finding suggests that a continuous deferoxamine infusion may play a role in the immune regulation in addition to iron chelation effect.

Oral manifestations of aplastic anemia in children

BACKGROUND

Few studies concerning oral manifestations of aplastic anemia (AA) in children have been reported. The purpose of the authors' study was to describe oral lesions in children with AA.

METHODS

The authors conducted a retrospective review using medical records of children diagnosed with AA who were treated at the Pediatric Service of the Regional Hospital of Concepción, Chile, between March 1996 and May 2001. They recorded episodes of oral mucosal lesions and assessed platelet and neutrophil counts at the time the oral lesions appeared.

RESULTS

Twelve children (nine boys and three girls) were diagnosed with AA. Their age range was 3 to 12 years (median age, 7 years). Nine subjects were receiving immunosuppressive therapy, and three received only supportive care. The most common oral manifestation of the disease was hemorrhage, which developed most often in patients with platelet counts less than 25 x 10(9) cells/liter. The second and third most common oral manifestations were candidiasis and viral infection, respectively.

CONCLUSIONS

Children with AA frequently exhibit oral manifestations of the condition. Prevention, early diagnosis and proper treatment of oral complications are essential to diminish morbidity and avoid a possible fatal outcome.

CLINICAL IMPLICATIONS

Oral lesions can be the first manifestation of AA; consequently, dentists should be aware of these manifestations so that an early diagnosis of the disease can be made.