Compared to stable period, exacerbation period serum periostin levels found significantly lower [5853 (2309–8427) pg/mL vs. 4479 (2766–6495) pg/mL; p = 0.05] and periostin levels were much lower in viral infection-induced exacerbations [2913 (893–4770) pg/mL vs. 7094 (4782–9596) pg/mL; p = 0.022]. Here, POSTN is linked to viral infectious disease.