From the Guidelines
Elevated Lactate Dehydrogenase (LDH) levels are a significant indicator of disease activity and tissue damage in various autoimmune diseases, and should be monitored in conjunction with other laboratory markers and clinical symptoms to assess disease severity and progression. In autoimmune diseases, LDH elevation is often seen as a non-specific marker of inflammation and tissue damage. For instance, in systemic lupus erythematosus (SLE), LDH elevation correlates with disease activity, particularly during flares affecting major organs like the kidneys or lungs 1. Rheumatoid arthritis patients may show increased LDH levels during active disease phases, reflecting joint inflammation and tissue destruction. Autoimmune myositis conditions like dermatomyositis and polymyositis typically present with significantly elevated LDH due to muscle tissue breakdown, with levels often exceeding 500 U/L. Autoimmune hemolytic anemia causes LDH elevation through red blood cell destruction. The significance of LDH elevation is also highlighted in other studies, where it is used as a prognostic factor for disease severity and progression 2. For example, in cutaneous melanoma, elevated LDH levels are associated with worse survival and may predict response to therapy in stage IV patients. When monitoring autoimmune disease patients with elevated LDH, it is crucial to track trends rather than isolated values, as changes often reflect disease activity. While LDH elevation isn't diagnostic for any specific autoimmune condition, it provides valuable information when interpreted alongside clinical symptoms and other laboratory markers like CRP, ESR, and specific autoantibodies. The elevation occurs because LDH is released when cell membranes are damaged during the inflammatory processes characteristic of autoimmune diseases. Key points to consider when evaluating LDH elevation in autoimmune diseases include:
- LDH is a non-specific marker of inflammation and tissue damage
- LDH elevation correlates with disease activity in various autoimmune diseases
- Tracking trends in LDH levels is crucial for assessing disease severity and progression
- LDH elevation should be interpreted alongside other laboratory markers and clinical symptoms
- Elevated LDH levels are associated with worse survival and may predict response to therapy in certain diseases, such as cutaneous melanoma 2.
From the Research
Significance of Elevated Lactate Dehydrogenase (LDH) in Autoimmune Diseases
- Elevated LDH levels are associated with various diseases, including cancer, liver metastases, hematologic malignancies, and infection 3.
- In the context of autoimmune diseases, elevated LDH levels may reflect tissue damage and are an adverse prognostic marker in patients not eligible for stem cell transplantation 4.
- An increase in LDH level after treatment is indicative of a poor outcome and is significantly negatively correlated with treatment response and overall survival 5.
- Elevated LDH levels are also associated with features of advanced disease, add prognostic value to the international staging system, and predict inferior survival in patients with multiple myeloma 6.
Prognostic Value of LDH
- Very high isolated LDH is a distinguishing biomarker for the presence of cancer, liver metastases, hematologic malignancies, and infection 3.
- Elevated LDH levels are an independent predictor of mortality in admitted medical patients 3.
- LDH level normalization is attributable to effective treatment, while LDH level elevations are associated with therapeutic failure 7.
LDH and Autoimmune Side Effects
- The occurrence of autoimmune toxicity clearly correlates with clinical benefit in patients treated with ipilimumab 5.
- Changes in LDH level and side effects correlate with response to therapy and survival 5.
- Elevated LDH levels may be used to predict response to treatment and survival in patients with autoimmune diseases 5, 4.