What serum investigation result is likely to be elevated in a case of Henoch Schonlein Purpura?

In cases of Henoch-Schönlein purpura (HSP), which is a small-vessel vasculitis commonly seen in children, an elevation in serum IgA levels is frequently observed. This condition is characterized by inflammation of blood vessels, leading to skin purpura, arthralgia, abdominal pain, and sometimes renal involvement. The pathophysiology of HSP often involves an abnormal immune response, and IgA plays a crucial role in mucosal immunity.

The elevated IgA levels observed in HSP are thought to be related to the systemic activation of the immune system. Elevated levels of IgA can be indicative of ongoing immunological processes, which aligns with HSP's association with upper respiratory infections, where IgA is actively involved.

The other options do not typically show a consistent elevation in HSP. C-reactive protein is a marker of inflammation but is not specific to HSP. Platelet counts may remain normal, although thrombocytopenia can occur in some cases, it is not a hallmark of the disease. Liver enzymes are not directly related to HSP and are not expected to show elevation as part of the classical presentation of the condition. Thus, elevated IgA levels stand out as a relevant biomarker