Researchers ID potential biomarker in sarcoidosis for recurrent disease
ACE/lymphocyte ratio may help predict systemic involvement, recurrence
A new study from researchers in Turkey suggests that a ratio taking into account the amount of angiotensin-converting enzyme (ACE) and of lymphocytes, a type of white blood cell — a ratio elevated in patients with recurrent disease after stopping treatment — is a potential biomarker for people with sarcoidosis with systemic, or body-wide, involvement.
Results from the study supported the ACE/lymphocyte ratio as a biomarker to predict disease recurrence, the team noted.
The study, “The ACE/lymphocyte ratio and CONUT score: Key predictors of extrapulmonary involvement and recurrence in sarcoidosis,” was published in the journal Sarcoidosis, Vasculitis and Diffuse Lung Diseases.
Ratio’s use found to have accuracy of over 60%
Sarcoidosis is caused by the excessive activation of the immune system, which leads to the formation of small clumps of inflammatory cells, called granulomas, in different organs. The disease commonly affects the lungs and lymph nodes, but other organs may also be impacted.
Here, researchers from institutions in Istanbul analyzed whether the ACE/lymphocyte ratio and the CONUT score — fully, the Controlling Nutritional Status score, a marker of nutritional status — are associated with systemic involvement and recurrence in sarcoidosis. ACE levels are a known indicator of granuloma burden and disease activity in sarcoidosis. Lymphocytes, meanwhile, are often reduced in people with sarcoidosis.
A total of 156 adults were involved in the analysis. About one-third, or 50 patients, had systemic disease, defined as having skin, eye, heart, and/or neurological involvement, and high levels of calcium in the urine. Participants with or without systemic involvement had a similar age (44.9 vs. 45.5 years), but those with systemic disease were most commonly women (70% vs. 54.7%).
Additionally, patients with systemic involvement had significantly higher blood ACE levels (75.7 vs. 59.1) and an ACE/lymphocyte ratio (54 vs. 35.2), as well as lower lymphocyte levels (1.76 vs. 1.88), compared with those without systemic disease.
Further analysis indicated that the ACE/lymphocyte ratio could predict systemic involvement at a cutoff value of 19.55, meaning that people with levels below the threshold were less likely to have systemic disease.
Researchers noted the measure had an accuracy of 64.4%, a sensitivity of 78%, and a specificity of 39.8%. Sensitivity refers to the ability of a test to correctly identify individuals who have the disease, while specificity is the test’s ability to correctly identify individuals who do not have the condition.
The ACE/lymphocyte ratio, which was evaluated for the first time in the literature, can be used to predict … recurrence in post-treatment follow-up.
Overall, 24 patients (15.4%) experienced disease recurrence requiring a new course of treatment with steroids, most commonly those with systemic involvement (24% vs. 11.3%). The mean time to relapse after steroid withdrawal was 13 months.
Participants with recurrent disease most commonly had systemic involvement (50% vs. 28.1%), and had significantly higher ACE levels (99.3 vs. 58.6) and ACE/lymphocyte ratio (76.9 vs 34.8). Also, all patients experiencing recurrence underwent treatment, compared with 45.7% of those in whom the disease did not recur.
Further analysis indicated that a cutoff value of 22.4 for the ACE/lymphocyte ratio could predict sarcoidosis recurrence with an accuracy of 71.4%, a sensitivity of 79.2%, and a specificity of 44.8%. People with levels below the threshold were less likely to have a disease recurrence.
Regarding the CONUT score, no significant associations with systemic involvement and recurrent sarcoidosis were found.
“The ACE/lymphocyte ratio, which was evaluated for the first time in the literature, can be used to predict extrapulmonary involvement, which can have high mortality … as well as recurrence in post-treatment follow-up,” the researchers concluded.
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