CT and MR imaging findings of ocular adnexal mucosa-associated lymphoid tissue lymphoma associated with IgG4-related disease: multi-institutional case series

AIM:To report CT and MR imaging findings of ocular adnexal mucosa-associated lymphoid tissue lymphoma associated with IgG4-related disease(IgG4-MALT lymphoma),a rare but clinically important complication of ocular adnexal IgG4-related disease.METHODS:We retrospectively reviewed all cases of histologically confirmed ocular adnexal IgG4-related disease at three ter tiary and one secondary referral centers,between February 2003 and December 2016.Seven cases of histopathologically diagnosed IgG4-MALT lymphoma were identified.CT and MR images were analyzed by consensus of two experienced head and neck radiologists.RESULTS:Lacrimal glands were the main site of involvement in all seven patients.The lesions typically showed well-demarcated margins,iso-to hyperattenuation on precontrast CT,T2 hypo-to isointensity,T1 isointensity,and homogenous internal architecture with homogenous enhancement pattern.Lesions were mostly hyperdense and isointense to normal extraocular muscles on postcontrast CT and MR images,respectively.CONCLUSION:Unlike in typical ocular adnexal IgG4-related disease,T2 isointensity and hyperattenuation on precontrast CT images were noted in some IgG4-MALT lymphoma cases.Although the findings may be nonspecific,the possibility of accompanying MALT lymphoma may need to be considered,when ocular adnexal lesions in patients clinically suspected of having IgG4-related disease are refractory to glucocorticoids and show T2 isointensity and hyperattenuation on precontrast CT for the optimal management of the patients.However,this is a case series of a very rare complication of ocular adnexal IgG4-related disease,and thus caution is warranted to generalize the conclusion.

Polymyxin B Alleviates Angiotensin II-Induced Stress Fiber Formation and Cellular Hypertrophy

Polymyxin B is widely used antibiotic in the clinic for resistant Gram-negative infections. In addition, polymyxin B-immobilized hemoperfusion cartridge has been used for endotoxin removal therapy in patients with septic shock. The aim of this study was to investigate the anti-fibrotic and anti-cellular hypertrophic effects of polymyxin B, and further to explore its possible mechanism. Polymyxin B (3, 10 μM) significantly inhibited stress fiber formation induced by angiotensin II (Ang II) in rat heart-derived H9c2 cells. Furthermore, polymyxin B (1 - 10 μM) showed a potent inhibitory effect on Ang II-induced cellular hypertrophy in H9c2 cells. Under the mechanism study, the inhibitory activities of polymyxin B against kinases involved in cellular hypertrophy such as AKT1, CAMK, GRK5, GSK3β, MLCK, PKC, PKD2, AMPK, ROCK2, p70S6K, SGK1were evaluated. Polymyxin B possesses a potent G protein related kinase 5 (GKR5) inhibitory activity with IC50 value of 1.1 μM, and has an ATP non-competitive inhibitory mode. Taken together, these results indicate that polymyxin B alleviates Ang II-induced stress fiber formation and cellular hypertrophy, and propose that one mechanism underlying these effects involves inhibition of the GRK5 pathway.

Long-primed germinal centres with enduring affinity maturation and clonal migration

Germinal centres are the engines of antibody evolution. Here, using human immunodeficiency virus (HIV) Env protein immunogen priming in rhesus monkeys followed by a long period without further immunization, we demonstrate germinal centre B (BGC) cells that last for at least 6 months. A 186-fold increase in BGC cells was present by week 10 compared with conventional immunization. Single-cell transcriptional profiling showed that both light- and dark-zone germinal centre states were sustained. Antibody somatic hypermutation of BGC cells continued to accumulate throughout the 29-week priming period, with evidence of selective pressure. Env-binding BGC cells were still 49-fold above baseline at 29 weeks, which suggests that they could remain active for even longer periods of time. High titres of HIV-neutralizing antibodies were generated after a single booster immunization. Fully glycosylated HIV trimer protein is a complex antigen, posing considerable immunodominance challenges for B cells1,2. Memory B cells generated under these long priming conditions had higher levels of antibody somatic hypermutation, and both memory B cells and antibodies were more likely to recognize non-immunodominant epitopes. Numerous BGC cell lineage phylogenies spanning more than the 6-month germinal centre period were identified, demonstrating continuous germinal centre activity and selection for at least 191 days with no further antigen exposure. A long-prime, slow-delivery (12 days) immunization approach holds promise for difficult vaccine targets and suggests that patience can have great value for tuning of germinal centres to maximize antibody responses.