Despite high coverage of vaccinations, incidence of pertussis (whooping cough) has been increasing throughout the world and large outbreaks were reported in several countries.Adolescents and adults with atypical pertussis symptoms have become the main sources of infants′ pertussis.Since clinicians are lack of experience in making diagnosis based on atypical symptoms, laboratory methods are needed.The currently recommended laboratory methods include bacterial culture, PCR and serology ELISA.It is well known that sensitivity and specificity of the above-mentioned methods may vary depending on many factors such as status of vaccination, timing of specimen collection and onset of symptoms.Serology ELISA to measure specific anti-pertussis toxin IgG antibodies in serum has been proven to be one suitable method for the diagnosis of pertussis infection in adolescents and adults.In this review, we summarize the current status of methods used in China and other countries for the laboratory diagnosis of pertussis and discuss the clinical relevance of serology ELISA for pertussis diagnosis.

Toll-like receptor 5 (TLR5) is one of the pattern recognition receptors and recognizes the flagellin protein of bacteria.It activates innate immune responses and induces production of a series of cytokines.TLR5 functions as a bridge linking innate and adaptive immunities.It is known that TLR5 plays an important role in the occurrence and development of certain infectious diseases.This review summarizes the relationships of TLR5 polymorphisms with the development of infectious diseases and discusses the possible pathogenesis.

Interleukin-17A (IL-17A) is one of the proinflammatory cytokines produced by a subset of CD4+T cells named Th17 cells. It plays a crucial role in both host innate and adaptive immune responses against colonization and infection of respiratory tract bacteria. Studies in animal models have demonstrated that IL-17A can induce the expressions of various chemokines, inflammatory factors and adhesion molecules via multiple intracellular signaling pathways and recruit neutrophils to infection sites. Moreover, recent stud-ies have shown that single nucleotide polymorphisms (SNPs) of IL-17A coding gene can regulate the produc-tion of IL-17A in serum, resulting in individual difference in colonization rate by Streptococcus pneumoniae. This review presents recent data related to the structure, functions and signaling pathways of IL-17A, sum-marizes its roles in host defense based on studies in animal models and discusses the effects of genetic varia-tion of IL-17A on colonization, susceptibility, clinical characteristics and disease prognosis of human respira-tory tract bacteria.

The pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains unclear. Many studies have shown that Toll-like receptors are involved in the development and progression of NAFLD, especially nonalcoholic steatohepatitis. This article reviews the role of Toll-like receptors in the pathogenesis of NAFLD from three aspects: interactions between Toll-like receptors and inflammatory factors, interactions between Toll-like receptors and free fatty acids, and Toll-like receptor gene polymorphism.