B cell modulation in rheumatology

Stress-related suppression of peripheral cytokines predicts future relapse in alcohol-dependent individuals with and without subclinical depression

Chronic alcohol abuse and depressive symptoms are both associated with peripheral cytokine changes. Despite this, cytokine adaptations have not been assessed in co-morbid populations or prospectively as predictors of relapse. We examine cytokine responses to stress in alcohol-dependent individuals and social drinkers, both with and without subclinical depression. We also examine the potential link between cytokine adaptations in response to stress and prospective alcohol relapse risk. Thirty-three, alcohol-dependent individuals (21 with and 12 without high depressive symptoms) and 37 controls (16 with and 21 without high depressive symptoms) were exposed to two 5-minute personalized guided imagery conditions (stress and neutral) across consecutive days in a randomized and counterbalanced order. Alcohol craving and serum measures of tumor necrosis factor alpha (TNFα), tumor necrosis factor receptor 1 (TNFR1), interleukin-6 (IL-6), and interleukin-1 receptor antagonist (IL-1ra) were collected prior to and following imagery exposure. Following treatment discharge, follow-up interviews were conducted over 90 days to assess relapse. Dampened IL-1ra and IL-6 in response to stress was observed as a function of alcohol dependence and not moderated by depressive symptoms. Lower levels of IL-6 following stress also predicted greater drinking days following treatment. Conversely, high depressive symptomatology was associated solely with pro-inflammatory adaptations. Stress-related suppression of TNFα predicted drinking severity only in alcohol-dependent individuals with subclinical depression, and suppressed TNFR1 following stress was only seen in individuals with subclinical depression. Stress-induced suppression of pro-inflammatory TNF markers may indicate a risk factor for alcohol-dependent individuals with co-occurring depressive symptoms.

ER stress-inducible protein MANF selectively expresses in human spleen

Mesencephalic astrocyte-derived neurotrophic factor (MANF; also known as arginine-rich, mutated in early tumors; ARMET), is an ER stress-inducible protein, and widely expressed in mammalian tissues. In this study, we are interested in the profile of MANF expression in human splenocytes. Three patients with spleen trauma were enrolled in this study. Immunohistochemistry and immunofluorescence were used to detect MANF expression in the four types of cells, including T cells, B cells, plasma cells, and macrophages in spleens by using the specific antibodies of anti-CD3, anti-CD20, anti-CD138, and anti-CD68, respectively. We found that MANF-positive cells extensively distributed in the red pulp and marginal-zone of spleen, and MANF was almost localized in the cytoplasm of splenocytes. Double immunofluorescent staining results showed that MANF localized mainly in the plasma cells and macrophages, but not in T and B cells. Meanwhile, we found that some MANF-positive cells expressed ER stress-related proteins, including ATF6, XBP1s, BiP, and CHOP. These results suggest that the selective expression of MANF in splenocytes may be involved in plasma cell differentiation and immune regulation.

Pharmacokinetics and pharmacodynamics of anti-BR3 monoclonal antibody in mice

PURPOSE

To characterize the pharmacokinetic (PK) and pharmacodynamic (PD) properties of a monoclonal antibody directed against the B-cell activating factor (BAFF) receptor 3 (BR3), following intravenous (IV) and subcutaneous (SC) administration in mice.

METHODS

Single IV doses of 0.2, 2.0 and 20 mg/kg and a single SC injection of 20 mg/kg of anti-BR3 antibody was administered to mice. Serum drug and BAFF concentrations and splenic B-cell concentrations were measured at various time points. Pooled PK profiles were described by a two-compartmental model with time-dependent nonlinear elimination, and BAFF profiles were defined by an indirect response model. Fractional receptor occupancy served as the driving function for a competitive reversible antagonism model to characterize B-cell dynamics.

RESULTS

Noncompartmental analysis revealed a decrease in drug clearance (31.3 to 7.93 mL/day/kg) with increasing IV doses. The SC dose exhibited slow absorption (T(max) = 2 days) and complete bioavailability. All doses resulted in a dose-dependent increase in BAFF concentrations and decrease in B-cell counts. The proposed model reasonably captured complex PK/PD profiles of anti-BR3 antibody after IV and SC administration.

CONCLUSIONS

A mechanistic model was developed that describes the reversible competition between anti-BR3 antibody and BAFF for BR3 receptors and its influence on B-cell pharmacodynamics.