the circadian rhythm has a lot to do with night sweats in Sjogren's syndrome. Redundant because it's common knowledge that melatonin, ACTH, cortisol and the circadian rhythm are intrinsically related to basically the fundamentals of our well-being from a number of perspectives. If anything consider that proper sleep, quality sleep, represents wellness in all its capacity, for anyone (be it a sick or healthy individual, young or elder, etc etc etc).
Late, disturbed and irregular sleep impacts tremendously on fatigue, on nausea states, and on incidence of dizziness, all so unfortunately typical of Sjogren's. But what I have observed as the most typical result of an externally disturbed sleep pattern are the night sweats. As stated in this incredible article by Papagerakis et al (2014) the circadian system is a complex network that communicates and determines the functioning of peripheral organs and tissues. Do not forget the relevant link between primary Sjogren's and the adrenal glands  and the cascading unwellness that can emerge from their disturbance.
An affected circadian rhythm will result in an affected genetic expression that controls and maintains different human homeostatic patterns. Most importantly, as the author so well describes, an affected circadian rhythm will negatively impact and condition the functioning of the salivary glands, teeth development and other oral processes/structures . Don't forget there is an adrenal glands - night sweats link taking place in menopause, so there is probably an exertion to the adrenal glands that is responsible for the night sweats in primary Sjogren's syndrome. I am inclined to believe that the cortex part of the adrenal glands, the part that is in fact responsible for the secretion of corticosteroids involved in (among numerous other things) the immune system's functioning, is the agent that we all need to lay our eyes on.
I recently found a website that teaches how to determine whether one is going through adrenal exhaustion, however, I am not a doctor, so all I can do is state that if you want to be positive of the quality of such test you definitely should seek advice from a HCP. The test is fairly simple to perform as the picture below describes:
That's it for now, I'll most definitely be posting soon on yet another recent discovery I made whilst reading a few articles on incidence of candidiasis in Sjogren's patients. This is a terrible issue for most of the patients as roughly Sjogren's patient's are affected with this problem up to four-fold in comparison to the controls. The article is a great read and I will try and bring in a summary for the blog's audience. That and a temporary relieve-treatment based on onions that can alleviate athlete's foot. You must not miss it.
 Mavragani, C. P., Schini, M., Kaltsas, G., Moutsopoulos, H. M. (2012). "Brief report: adrenal autoimmunity in primary Sjogren's syndrome". Arthiritis and Rheumatism, 64(12), pp. 4066-4071.
 Papagerakis, S., Zheg, L., Schnell, S., Sartor, M. A., Somers, E., Marder, W., McAlpin, B., Kim, D., McHugh, J., Papagerakis, P. (2014). "The circadian clock and the oral health and diseases". Journal of Dental Research, 93(1), pp. 27-35.
 Adrenal exhaustion, Lorna Vanderhaeghe Health Solutions - Women helping women, [http://www.healthyimmunity.com/books/An-A-Z-Woman-s-Guide-to-Vibrant-Health/Adrenal-Exhaustion.asp], last visited on the 25-Jul-2017, last update unknown.
Image kindly taken from menopause and your disturbed sleep, MyMT, [https://www.mymenopausetransformation.com/mymt/why-your-bodys-natural-circadian-rhythm-is-so-important-during-menopause/].