Antibody Sirukumab Improves Depression and Anhedonia in Patients with Rheumatoid Arthritis
Patients with rheumatoid arthritis have high levels of the inflammatory proteins known as interleukin-6 (IL-6), which have been implicated in depression and stress. Rheumatoid arthritis is sometimes characterized by depressive symptoms as well. New research by Dai Wang and colleagues presented at the 2015 meeting of the Society of Biological Psychiatry suggests that treating the high levels of IL-6 in rheumatoid arthritis with the human anti–interleukin-6 antibody sirukumab can reduce symptoms of depression and anhedonia (loss of capacity to experience pleasure).
In the study, patients with rheumatoid arthritis and symptoms of depression or anhedonia were randomized to receive either placebo or sirukumab. After 12 weeks, those who received sirukumab had significantly reduced depression.
Editor’s Note: These data are consistent with meta-analyses showing that IL-6 is elevated in depression and with a study by Scott Russo showing that in animals, interfering with IL-6 blocks the development of depression-like behaviors that typically occur after repeated defeat stress (when an animal is subjected to attacks from a larger, more dominant animal).
In Veterans, PTSD Is Associated With Autoimmune Illnesses
At a recent scientific meeting, Thomas Neylan and colleagues reported that post-traumatic stress disorder (PTSD) may be connected to autoimmune illnesses. In this study, 673,277 veterans of the US military who had served in Iraq and Afghanistan were screened for the development of PTSD. The illness was diagnosed in 31% of the veterans, and those individuals had a higher incidence of autoimmune-related disorders including thyroiditis, rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and systemic lupus erythematosus. Neylan’s research group specifically examined those whose disorders developed after the onset of the PTSD, and found that the statistical relationship between their illnesses and PTSD was strong. However, the researchers also found that there was evidence of a similarly strong relationship in the other direction: veterans who were first diagnosed with some of these same autoimmune difficulties also went on to develop PTSD.
Many previous clinical and preclinical studies have linked altered immune and autoimmune mechanisms to severe stressors such as those that are involved in PTSD. This is the first study to unequivocally demonstrate the relationship in an extraordinarily large number of patients.
Editor’s Note: These findings resemble those that suggest that among the general population, childhood adversity is associated with an increased incidence of a variety of medical disorders in adulthood. Similarly, in the Bipolar Collaborative Network in which this editor (Post) is an investigator, we found that a history of childhood adversity in patients with bipolar disorder was associated with an increased incidence of a variety of medical illnesses in adulthood, including some related to immune and autoimmune function.
More research that would measure inflammatory markers in PTSD and mood disorders is needed. It would also be important to ascertain whether treatment of mood disorders and PTSD reduces the risk of autoimmune disorders.
