Anti-Serotonin polyclonal antibody

The association between selective serotonin reuptake inhibitor (SSRI) exposure and cancer incidence has been investigated; however, no epidemiological study has investigated the association between exposure to individual SSRIs and kidney cancer incidence. The aim of this study is to examine whether SSRI use affected the risk of kidney cancer. We conducted a population-based retrospective cohort study using data from Taiwan's National Health Insurance Research Database. After adjusting for sex, age, urbanization level, comorbidity and medication use through propensity score matching, we identified 222 024 SSRI users and 221 361 SSRI nonusers. A robust Cox proportional hazards model was used to examine the associations between use of individual SSRIs and the risk of kidney cancer with 1- and 2-year induction periods. The result showed that SSRI users tended to be associated with a lower risk of kidney cancer with a 2-year induction period than nonusers; however, the association was not statistically significant (adjusted hazards ratio [aHR] = 0.88, 95% confidence interval [CI] = 0.77-1.01). We further examined the effects of individual SSRIs and observed a significantly lower risk of kidney cancer associated with the use of citalopram (aHR = 0.67, 95% CI = 0.47-0.96) and paroxetine (aHR = 0.75, 95% CI = 0.58-0.97) with the 2-year induction period. These findings support that SSRIs are associated with decreased kidney cancer risk and indicate that citalopram and paroxetine have protective effects in depressed patients with kidney cancer.

Background Heparin-induced thrombocytopenia (HIT) is typically caused by platelet-activating immunoglobulin G (IgG) antibodies (Abs) against platelet factor 4 (PF4) complexed with heparin (H). Much less frequent "autoimmune" HIT is distinguished from typical HIT by platelet activation without heparin and the presence of both anti-PF4/H and anti-PF4 IgG. We developed three murine monoclonal anti-PF4 Abs with a human Fc-part, 1E12, 1C12, and 2E1, resembling autoimmune HIT Abs. Objectives To characterize 1E12, 1C12, and 2E1 in comparison to the heparin-dependent monoclonal anti-PF4/H Abs 5B9 and KKO, and polyclonal Abs from patients with typical HIT (group-2) and autoimmune HIT (group-3). Methods Interactions of Abs with PF4 and PF4/H were studied by enzyme-linked-immunosorbent assay, single-molecule force spectroscopy, isothermal titration calorimetry, and dynamic light scattering. Serotonin release assay and heparin-induced platelet activation assay were used to assess platelet activation. The binding sites of monoclonal Abs on PF4 were predicted in silico (MAbTope method). Results 1C12, 1E12, and 2E1 displayed higher affinity for PF4/H complexes than 5B9 and KKO, comparable to human group-3 Abs. Only 1C12, 1E12, 2E1, and group-3 Abs formed large complexes with native PF4, and activated platelets without heparin. The predicted binding sites of 1C12, 1E12, and 2E1 on PF4 differed from those of KKO and 5B9, but were close to each other. 2E1 exhibited unique bivalent binding, involving its antigen recognition site to PF4 and charge-dependent interactions with heparin. Conclusion 1C12, 1E12, and 2E1 are tools for studying the pathophysiology of autoimmune HIT. 2E1 provides evidence for a new binding mechanism of HIT Abs.