Sex-biased difference in autoimmune diseases (1)

Systemic lupus erythematosus (SLE) is a highly polymorphic systemic autoimmune disease that affects multiple organs including kidneys and heart. The incidence is estimated at 2 -5 cases per 10,000 individuals. SLE is called “women’s disease” because the incidence rate is 8:1 – 15:1 (Women: Men). With this regard, estrogen receptor antagonist treatments have been effective in SLE patients. In males, SLE has a late onset and different clinical features. These results suggest that male may have specific pathogenetic factors.

Rheumatoid arthritis (RA) affects approximately 1% (1 in 100 people) of the population and is characterized by chronic joint inflammation, functional impairment, disability, and premature mortality. It is suggested that RA involves various environmental factors in its pathogenesis. In RA, sex-bias shows very impressive manner. In between age 55-65, the female to male prevalence ratio is 2:1, but older than 75 years, men have higher prevalence than women. Since, the onset and severity of RA are inversely correlated with androgen levels, a male sex hormone, this results explain increased incidence rate in men after 55 years and and less severe disease in man than in women. Active RA is found by a peak in the morning correlated with prolactin plasma levels. The onset and severity of RA inversely associated with androgen levels. It may explain older men have higher incidence.

Multiple sclerosis (MS) affects 1 case per 1,000 individuals in Western countries and is the most common chronic inflammatory disease of the central nervous system causing neurological disability. MS affects women two times to three times as often as men. Interestingly, while males tend to display primary progressive disease and accumulate disability faster than females in relapse-onset MS. Earlier puberty and obesity during childhood are significant risk factors for MS. Female MS patients experience clinical improvements during pregnancy, particularly in the last trimester, with a re-bound in relapses occurring in the first trimester postpartum. In addition, lower testosterone levels associated with higher disability in men with MS. Vitamin D deficiency and smoking are known as risk factors of MS.

1. E. Ortona, M. Pierdominici, A. Maselli, C. Veroni, F. Aloisi, Y. Shoenfeld, Sex-based differences in autoimmune diseases. Ann. Ist. Super. Sanita. 52, 205–212 (2016).