Pulmonary function indices in children with sickle cell anemia in Enugu, south-east Nigeria

Surfactant protein D as a marker for pulmonary complications in pediatric patients with sickle cell disease: Relation to lung function tests

BACKGROUND

Surfactant protein D (SP-D) is considered a candidate biomarker for lung integrity and for disease progression.

AIM

We determined the level of SP-D in children and adolescents with SCD and assessed its possible relation to pulmonary complications and lung function.

METHODS

Serum SP-D levels were assessed in 50 SCD patients compared with 30 healthy controls. High-resolution computerized tomography (HRCT) of the chest was done. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁ ), FEV₁ /FVC% and forced expiratory flow rate during 25-75% of expiration (FEF25-75%) were determined.

RESULTS

SP-D was significantly higher in SCD patients than controls, particularly patients with sickle cell anemia than those with sickle β-thalassemia. SP-D levels were significantly associated with increasing severity of interstitial lung disease. The highest SP-D levels were observed among patients with restrictive lung disease followed by mixed type then obstructive lung disease. SP-D was positively correlated to HbS and serum ferritin while negatively correlated to duration of hydroxyurea treatment and parameters of pulmonary functions. ROC curve analysis revealed that SP-D cutoff value 720 ng/mL could significantly detect the presence of abnormal pulmonary function among SCD patients with 82% sensitivity and 88% specificity. Logistic regression analysis showed that SP-D is an independent factor related to abnormal pulmonary function in SCD.

CONCLUSIONS

SP-D may be a promising biomarker for screening of SCD patients for risk of later pulmonary complications.

Acute chest syndrome in sickle cell anaemia: higher serum levels of interleukin-8 and highly sensitive C-reactive proteins are associated with impaired lung function

BACKGROUND

Sickle cell anaemia (SCA) is a chronic inflammatory disorder with multiple organ manifestations including acute and long-term pulmonary dysfunction.

AIMS/OBJECTIVES

To assess lung function of children with SCA and determine the possible role of acute chest syndrome (ACS), serum inflammatory cytokines, highly sensitive C-reactive protein (hs-CRP), leucocytes and 25-hydroxyvitamin D on the development of impaired lung function.

SUBJECTS AND METHODS

Lung function of 76 children with SCA was determined by spirometer and classified into normal or impaired. Sociodemographic, clinical, haematological, biochemical and immunological data of the two groups were compared by univariate and multivariate analyses.

RESULTS

Fifty (65.8%) patients had impaired lung function, comprising of 30.3%, 3.9% and 31.6% with restrictive, obstructive and mixed disease patterns, respectively. Children with previous ACS were 3.6 times more likely to have impaired lung function than those without ACS (82.1% vs 56.3%, p = 0.02, OR 3.6, 95% CI 1.2-10.8). Interleukin (IL)-8 and hs-CRP were significantly higher in patients with impaired lung function (p = 0.02 and <0.001, respectively). Using logistic regression, previous ACS (OR 5.8, 95% CI 1.1-5.8, p = 0.03) and higher serum IL-8 levels (OR 3.0, 95% CI 1.0-8.0, p = 0.02) independently predicted the presence of abnormal lung function.

CONCLUSIONS

Lung dysfunction, predominantly restrictive pattern, is common in SCA and is associated with previous ACS and alterations in immunological markers, especially serum IL-8 and hs-CRP.

ABBREVIATIONS

ACS: acute chest syndrome; CBT: chronic blood transfusion; ELISA: enzyme-linked immunosorbent assay; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; HPLC: high-density liquid chromatography; hs-CRP: highly sensitive C-reactive proteins; HU: hydroxyurea; IL: Interleukin; PEFR: peak expiratory flow rate; SEM: standard error of the mean; TLC: total lung capacity; 25-OHD: 25-hydroxyvitamin D; VOC: vaso-occlusive crisis; WGH: Wesley Guild Hospital.