RESUMO
Clinical, biochemical and molecular evidence for the sickle cell anemia (SCA) crisis in Nigerian patients arising from parvovirus b19 infection remains inadequate. This study determined the prevalence and correlates of anti-parvovirus b19 antibodies in a population of SCA patients and non-SCA healthy controls in Lagos, Nigeria. In this prospective cross-sectional study, we enrolled 73 confirmed SCA patients from 5 district hospitals in Lagos and 81 sex and age-matched non-SCA healthy controls. Serum sample from each study participant was screened for anti-parvovirus b19 by ELISA and PCR techniques. Standard biomedical assays were also done. Anti-parvovirus b19 IgM and IgG antibodies were detected in 22 (14.3%) and 97 (62.9%) of the 154 sera screened, 13 (17.8%) and 45 (61.6%) in SCA patients; 9 (11.1%) and 52 (64.2%) in non-SCA controls. The overall seronegativity rate was 19.5%. Parvovirus B19 DNA was found in 2 (11.1%) of the 18 IgM seropositive SCA serum samples screened. On the whole, parvovirus b19 infection was more commonly asymptomatic in non-SCA controls but caused significant elevation in liver enzymes in infected SCA patients (P < 0.05). The risk of acute parvovirus b19 infection increased 65 times during unsteady state among the SCA patients. Although no deaths of infected patients were recorded during the study, age below 12 years, hospitalization and overcrowded environment were risk factors for infection. We conclude that parvovirus b19 is common in SCA patients, incurring greater susceptibility to infections.
RESUMO
INTRODUCTION: Microbial burden involving parvovirus B19 infection has been recognised as a major cause of morbidity and mortality in sickle cell anaemia (SCA) patients. Given the recent reports of parvovirus B19 infection in Nigeria and the role of inflammation in sickle cell crisis, knowledge of the relationship between the two may be essential for deploying appropriate interventions in infected patients. This study determined the serum levels of tumour necrosis factor alpha (TNF-α) and C-reactive protein (CRP) as inflammatory markers in Nigerian SCA patients with and without parvovirus B19 infections. METHODS: A total of 64 SCA patients aged 5-25 years and 41 age-matched apparently healthy volunteers with haemoglobin genotypes AA or AS were enrolled with consent into the study. Parvovirus B19 infection and serum levels of TNF-α and CRP were determined by the ELISA method. RESULTS: The overall prevalence rate of parvovirus B19 infection in the study subjects was 13.3%. This rate further showed gender variation and negative correlation with age. Significant (p < 0.05) increases in serum CRP and TNF-α levels, with further elevation in unsteady state SCA patients, were observed in comparison with the control. Unlike the control, 29.6% and 21.9% of the SCA patients elicited TNF-α and CRP above threshold levels, respectively. Parvovirus B19 infection was found to elicit greater increases in these inflammatory markers than in infected non-SCA controls. CONCLUSION: We conclude that parvovirus B19 infection is common in this environment, and that serum TNF-α and CRP are predictors of clinical inflammatory episodes in infected SCA patients.
