Complex sentence: Immunology explains pathogenesis and the characteristics of rheumatological disorders, and most of the new treatment modalities are based on immunology, better understanding of genetic basis of rheumatological disorders makes rheumatology a specialty rapidly developing as a medical specialty based on new scientific discoveries.
Split into simpler sentences: Immunology explains pathogenesis and the characteristics of rheumatological disorders, and most of the new treatment modalities are based on immunology. Better understanding of genetic bases of rheumatological disorders makes rheumatology a specialty rapidly developing as a medical specialty based on new scientific discoveries.