Hemolysis scavenger proteins and renal function marker in children with sickle cell disease at steady state: A cross-sectional study

Abstract

Background and aims: Hemolysis is a fundamental feature of sickle cell disease (SCD) contributing to the vaso-occlusive crisis of patients. The objectives of the study were to assess the link between hemolysis proteins and hematological parameters, and to validate cystatin C (CYS C) as a potent renal marker in diagnoising SCD.

Method: Here, a cross-sectional study carried out at the pediatric SCD clinic of the Komfo Anokye Teaching Hospital comprised 90 SCD children (HbSC, HbSF, and HbSS). ANOVA, t-test, and Spearman's rank correlation analysis were done. Elevated proteins levels were compared to standard values; alpha-1 microglobulin (A1M) (1.8-65 µg/L), CYS C (0.1-4.5 µmol/L), and haemopexin (HPX) (500-1500 µg/mL).

Results: The mean (standard deviation) age of participants was 9.830 (±0.3217) years, and 46% of them were males. From simple descriptive analysis, we observed that all but one patient had their HPX level below the reference range (<500 µg/mL). Here, A1M levels were shown to be within the appropriate reference range for all the patients except few patients. CYS C levels were also all within the required reference values. A Spearman's rank correlation test between full blood count and HPX generally suggested a weak but positive correlation; RBC (coef. = 0.2448; p = 0.0248), HGB (coef. = 0.2310; p = 0.030), hematocrit (coef. = 0.2509; p = 0.020), and platelet (coef. = 0.1545; p = 0.160). Mean corpuscular volume (coef. = -0.5645; p = 0.610) had a stronger but negative correlation with HPX. This study depicts a positive and stronger association between CYS C and HPX levels (coef. = 0.9996; p < 0.0001), validating the use of CYS C as a useful marker of renal function in persons with SCDs.

Conclusion: In the present study, we show that A1M levels were normal for most of the patients, hence CYS C levels are not alarming in this study. Further, there exists a correlation between hemolysis scavenger proteins and hematological parameters.

Keywords: crisis; hematolgy; hemolysis; proteins; renal/kidney; scavenger; sickle cell.

Figure 1

(A) Variations of RBC count among the variants of SCD. (B) Variations of HGB levels among the variants of SCD. (C) Levels of HCT count among variants of SCD. (D) Levels of MCV among SCD patients. (E) Levels of PLT count among variants of SCD. (F) Levels of WBC count among variants of SCD, where p < 0.01*, p < 0.001,** and p < 0.0001*** generated by Kruskal−Wallis test. HCT, hematocrit; MCV, mean corpuscular volume; PLT, platelet; SCD, sickle cell disease; WBC, white blood count.

Figure 2

(A) Comparison of A1M levels to standard reference values. (B) Comparison of HPX levels to standard reference values. (C) Comparing Cystatin C levels to standard reference points. A1M, alpha‐1 microglobulin; HPX, haemopexin.

Figure 3

(A) Correlation of CYS C levels and A1M levels could be an indicator of renal dysfuncton. (B) Correlation test of A1M and HPX denoting the scavenging ability of A1M after HPX is depleted/overwhelmed, where *r = 1 indicates perfect association between CYS C and A1M; A1M and HPX and *p < 0.0001 denotes statistical significance. A1M, alpha‐1 microglobulin; CYS C, cystatin C; HPX, haemopexin.