The effect of various forms of treatment of vasculitis on C₃, C₄ and C_5a complement levels in infants and children attending Assiut University Children Hospital (AUCH)

Department of Medical Laboratory Technique, AlNoor University College, Nineveh, Iraq

^* Corresponding Author: researcherstaff06@alnoor.edu.iq

Abstract

Vasculitis is an umbrella term for various and heterogeneous disorders sharing the presence of inflammation of blood vessel walls (Geetha & Jefferson, 2020). Immune cell infiltrates involve the presence of leukocytes in the vessel with immune-complex deposition, which implies the activation of the complement system and then the swelling and destruction of vessel mural structures. The lumen is narrowed or occluded leading to ischemia and necrosis (Chimenti et al., 2015). It produces local symptoms resulting in hypoperfusion, infarction and hemorrhage and systemic symptoms with an increase in acute phase reactants (Salvador, 2020).

According to the size of the blood vessel affected and the distribution of vascular injury, pediatric vasculitis is classified into small vessel vasculitis as in Henochonlein Purpura (HSP), medium-sized vessel vasculitis as in Kawasaki disease and large vessel vasculitides affecting the aorta and its proximal branches. Some forms of small vessel vasculitis are characterized by the presence of antineutrophil cytoplasmic antibodies (ANCAs), whereas others are associated with immune complex deposition in affected tissues. Clinical presentation supported by specific laboratory test, imaging, and confirmatory histology are necessary in order to perform vasculitides’ diagnosis (Sivaraman et al., 2020). To assess the severity of vasculitis and response to treatment, urinary biomarkers such as albumin/creatinine ratio (A/C ratio) in urine have been proved to be easily done and correlated well with both clinical and serological results (Zhang, 2020).

Aim of Work: The aim of this study is to assess the effect of various forms of drugs, used in treatment of vasculitis, on the serum levels of complements (C3, C4, and C5a) and Antineutrophil cytoplasmic antibodies (ANCA), in infants and children attending Assiut University Children Hospital (AUCH).

Conclusion: In conclusion, cases on combined Methotrexate and Steroid therapy scored best regarding the lowering of C5a level in serum, however, in our cases as a whole, the level of C5a didn’t differ significantly from its level in control.

Although the 3 arms of therapy used in this study had good effect on C3 & C4 levels, yet their effect on C5a level was not significant from control. This finding could be explained by the fact that most of our studied cases were of the immune-complex deposition diseases type (which have no effect on C5a) and were ANCA negative. Therefore, C5a inhibitor drugs probably will not be suitable in treatment of most common causes of pediatric vasculitis encountered in this series. Perhaps, this type of therapy might be used in ANCA-Positive associated vasculitides, e.g. Wegener’s Granulomatosis.

Further research with bigger number of ANCA positive cases is needed to decide whether such cases could benefit from the use of C5a inhibitors or not.