Toll like receptor 4: an important molecule in recognition and induction of appropriate immune responses against Chlamydia infection.

Chlamydia species are obligate intracellular pathogens causing different infectious diseases particularly asymptomatic genital infections and are also responsible for a wide range of complications. Previous studies showed that there are different immune responses to Chlamydia species and their infections are limited to some cases. Moreover, Chlamydia species are able to alter immune responses through modulating the expression of some immune system related molecules including cytokines. Toll like receptors (TLRs) belonge to pathogen recognition receptors (PRRs) and play vital roles in recognition of microbes and stimulation of appropriate immune responses. Therefore, it appears that TLRs may be considered as important sensors for recognition of Chlamydia and promotion of immune responses against these bacterial infections. Accordingly, TLR4 detects several microbial PAMPs such as bacterial lipopolysacharide (LPS) and subsequently activates transcription from pro-inflammatory cytokines in both MYD88 and TRIF pathways dependent manner. The purpose of this review is to provide the recent data about the status and major roles played by TLR4 in Chlamydia species recognition and promotion of immune responses against these infections and also the relationship between TLR4 activities and pathogenesis of Chlamydia infections.

Anxiety leads to up-regulation of CD36 on the monocytes of chronic hepatitis B-infected patients.

Introduction It has been hypothesized that mental disorders including depression and anxiety can affect immune responses. The study was done to evaluate the relation between depression and anxiety and expression levels of CD36, CD68, and CD9 on peripheral blood monocytes of chronic hepatitis B (CHB) patients. Methods Sixty CHB patients were selected with various ranges of depression and anxiety. Depression and anxiety were evaluated using a standard questionnaire by an expert psychiatrist according to BECK's Depression Inventory II and Hamilton Anxiety Rating Scale, respectively. The levels of CD36, CD68, and CD9 on the peripheral blood monocytes have been performed using flow cytometry technique. Results The results demonstrated that levels of CD36 were significantly increased on the peripheral blood monocytes of CHB patients when compared with CHB patients with no anxiety. Expression levels of CD68 and CD9 were not significantly altered on the CHB patients with various ranges of anxiety. Expression levels of CD36, CD68, and CD9 were also not significantly altered on the CHB patients with various ranges of depression. Discussion It seems that anxiety induces inflammation in the CHB patients by induction of alteration in several molecules including up-regulation of CD36. CD36 plays important roles in the induction of tissue damage; hence, it may be hypothesized that anxiety may participate in the induction of some hepatitis B complications.