Significance of serum lactate dehydrogenase and its isoenzymes during post-burn follow-up

Abstract

The present study aims to evaluate the role of lactate dehydrogenase (LDH) isoenzymes in thermal burns. A total of 18 patients of both genders with 20 to 50% total burn surface area (TBSA), admitted to the Burn Ward of JN Medical College and Hospital was assessed. These patients were subjected to general and systemic examinations. The sera collected at day 1, 2, 5 and 10 during follow-up of burn patients were used for LDH quantitation. PAGE profiles showed significant differences in the levels of LDH isoenzymes in all the burn subjects (P=0.05). Software analysis of gel-scans showed the presence of five isoenzyme bands of which LDH-1 and -2 are the least contributors. During follow-up, it was observed that the ranking of LDH isoenzymes approaches control values at day 2 in 20% TBSA patients, while in the remaining cases it occurs at day 5. 3Ddensitograms indicated high activity of LDH in 50% of TBSA patients even at day 10; however, the relative ranking of these isoenzymes was similar to control values (LDH-4>- 5>-3>-1>-2). We were of the opinion that the high activity of LDH enzyme is due to the enzyme-immunoglobulin-G (LDH-IgG) complex, but surprisingly we did not observe this complex in 50% of burn patients at any of the durations. Therefore, it is suggested that LDH isoenzymes play a role in the pathophysiology of the disease and can be an asset to ascertain the invisible tissue damage. Moreover, the high activity of LDH in 50% of burns is due to some unknown mechanism and not due to the binding of LDH with IgG.

Keywords

• enzyme-immunoglobulin complex
• lactate dehydrogenase isoenzymes
• polyacrylamide gel electrophoretic profiles
• thermal burns