An autoimmune disease is a condition where the body's immune system mistakenly attacks its own healthy tissues. - Rheumatoid arthritis The immune system attacks the lining of the joints, causing inflammation and pain. - Hepatitis-B Primarily a viral infection that affects the liver. While the immune response plays a role in clearing the virus, it's not considered primarily an autoimmune disease. - Type 2 diabetes A metabolic disorder characterized by insulin resistance and high blood sugar. While there can be an autoimmune component in some forms of diabetes (like Type 1), Type 2 is largely due to lifestyle and genetic factors. - Filiariasis A parasitic disease transmitted by mosquitoes.