Israel Medical Association Journal

Background: Abatacept acts as a co-stimulation modulator preventing activation of T cells. Although it is approved for the treatment of rheumatoid arthritis (RA), its effects on adaptive immune response have not been fully elucidated. 

Objectives: To observe, in a cohort study, based on a clinical practice setting, the variation of peripheral blood T cells, immunoglobulin levels, and autoantibodies in the serum of RA patients during abatacept therapy. 

Methods: Our study comprised 48 RA patients treated with abatacept. All clinical data were collected at baseline and after 3 months of treatment. Clinical and laboratory tests included erythrocyte sedimentation rate, C-reactive protein, 28-joint disease activity score, RF, anti-citrullinated protein antibody, total immunoglobulins, immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), and lymphocyte sub-population. 

Results: Total immunoglobulin serum levels significantly decreased after 3 months of treatment and correlated positively with disease activity both at baseline and after 3 months of abatacept treatment. A reduction of serum IgM, IgG, IgA and RF was also demonstrated. The absolute number and percentage of cytotoxic (CD8+) T cells significantly decreased after 3 months of abatacept treatment, in particular the percentage of cytotoxic (CD8+) T cells significantly decreased only in patients responding to the treatment.

Conclusions: Our results highlight a different role of abatacept in the modulation of the adaptive immune response in RA by the reduction of polyclonal B-cell activation and cytotoxic T cells. 

 

Objectives: To explore IL-17A-producing CD3+CD4+T cells in peripheral blood of patients with persistent AR and assess the degree of atopy, eosinophil count (Eo count), and bronchial hyper-responsiveness (BHR) to methacholine.

Methods: The study involved 61 patients and 30 controls. The percentage of CD3+CD4+IL-17A+T cells in peripheral blood was measured by flow cytometry, bronchial challenges with Mch were performed, as was skin prick tests with standard inhalant allergens, and Eo count was measured. Atopic status was determined by the number of positive SPT results and wheal mean diameter.

Results: A statistically significant difference in Th17 cell percentage was found in the AR and control groups (2.59 ± 1.32% and 1.24 ± 0.22% respectively, P = 0.001). Forty-one patients (67.2%) were polysensitized to indoor and outdoor allergens, while 20 (32.8%) had positive skin prick tests to indoor allergens. CD4+T cells were significantly higher in the patient group compared to the control group (2.91 ± 1.5% versus 1.91 ± 0.62%, P = 0.005), as was Eo count (4.48 ± 2.13 vs. 2.32 ± 1.83) (P = 0.0001). Forty-one in the AR group (67%) and 7 (23%) in the control group were Mch-positive (P = 0.001). The percentage of IL-17A-producing CD4+T cells was significantly higher in males compared to females (3.15 ± 1.8% versus 2.31 ± 0.9%, P = 0.02)

Conclusions: Polysensitized AR patients exhibited higher IL-17A-producing CD4+T cell levels and eosinophil counts. Male patients displayed a higher frequency of IL-17A-producing T cells. 

Background: Epidemiological data show significant associations of vitamin D deficiency and autoimmune diseases. Vitamin D may prevent autoimmunity by stimulating naturally occurring regulatory T cells.

Objectives: To elucidate whether vitamin D supplementation increases Tregs[1] frequency (%Tregs) of circulating CD4+ T cells.

Methods: We performed an uncontrolled vitamin D supplementation trial among 50 apparently healthy subjects including supplementation of 140,000 IU at baseline and after 4 weeks (visit 1). The final follow-up visit was performed 8 weeks after the baseline examination (visit 2). Blood was drawn at each study visit to determine 25-hydroxyvitamin D levels and %Tregs. Tregs were characterized as CD4+CD25++ T cells with expression of the transcription factor forkhead box P3 and low or absent expression of CD127.

Results: Forty-six study participants (65% females, mean age ± SD 31 ± 8 years) completed the trial. 25(OH)D[2] levels increased from 23.9 ± 12.9 ng/ml at baseline to 45.9 ± 14.0 ng/ml at visit 1 and 58.0 ± 15.1 ng/ml at visit 2. %Tregs at baseline were 4.8 ± 1.4. Compared to baseline levels we noticed a significant increase of %Tregs at study visit 1 (5.9 ± 1.7, P < 0.001) and 2 (5.6 ± 1.6, P < 0.001).

Conclusions: Vitamin D supplementation was associated with significantly increased %Tregs in apparently healthy individuals. This immunomodulatory effect of vitamin D might underlie the associations of vitamin D deficiency and autoimmune diseases. Hence, our finding provides a rationale for further studies to investigate vitamin D effects on autoimmunological processes.

Background: Multiple drug allergy syndrome is a rarely reported clinical condition characterized by an adverse reaction to more than one different class of pharmacologically and structurally unrelated drugs. The pathogenesis may involve immediate-type or delayed-type hypersensitivity.

Objectives: To further characterize patients with MDA[1] in terms of the type of CADR, drug intake and clinical drug suspicion.

Methods: The study group comprised 12 patients (6 males, 6 females) with CADRs[2] showing in vitro drug-induced IFNγ[3] release for multiple drugs, suggesting the presence of MDA. The diagnostic role of in vitro IFNγ release in identifying the culprit drugs was evaluated in terms of clinical data and the results of in vivo tests (withdrawal and/or challenge tests) with the offending drugs.

Results: Clinical relevance was attributed to in vitro drug-induced IFNγ release towards multiple drugs in this series of 12 patients with a variety of CADRs, implying MDA. The results of in vivo tests for the offending drugs confirmed the diagnosis. The main causative agents responsible were antibiotics and non-steroidal anti-inflammatory drugs.

Conclusions: The study further supports the role of a T cell-mediated mechanism in the pathogenesis of MDA. The in vitro drug-induced IFNγ release test may serve as a laboratory tool to identify the culprit drugs associated with this allergy.  

Background: The global spread of tuberculosis necessitates the development of an effective vaccine and new treatment modalities. That requires a better understanding of the differences in regulation of the immune responses to Mycobacterium tuberculosis between individuals who are susceptible or resistant to the infection. Previous immune studies in young Ethiopian immigrants to Israel did not demonstrate anergy to purified protein derivative or a Th2-like cytokine profile.

Objectives: To evaluate the profile of Th1 and Th2 cytokine production in immigrant TB patients, in comparison with asymptomatic control subjects.

Methods: The present study included (part 1): 39 patients with acute TB[1] (group 1), 34 patients with chronic relapsing TB (group 2), 39 Mantoux-positive asymptomatic TB contacts (group 3), and 21 Mantoux-negative asymptomatic controls (group 4). Patients were mainly immigrants from Eastern Europe and Ethiopia. Levels of interferon gamma, interleukin 2 receptor, IL-6[2] and IL-10 were measured in serum and in non-stimulated and PPD[3]-stimulated peripheral blood mononuclear cell culture supernatants, using commercial ELISA kits. In addition (part 2), levels of IFNg[4] and IL-12p40 were evaluated in 31 immigrant Ethiopian patients and 58 contact family members.

Results: Patients with acute disease tended to secrete more cytokines than contacts, and contacts more than chronic patients and controls, without a specific bias. None of the patients showed in vitro anergy. Discriminant probability analysis showed that from the total of 12 available parameters, a cluster of 6 (IFNg-SER[5], IFNg-PPD, IL-2R[6]-SER, IL-10-SER, IL-10-NS[7] and IL-6-PPD) predicted an 84% probability to become a TB contact upon exposure, 71% a chronic TB patient and 61% an acute TB patient. Family-specific patterns of IFNg were demonstrated in the second part of the study.

Conclusions: Firstly, no deficiency in cytokine production was demonstrated in TB patients. Secondly, acute TB patients secreted more cytokines than contacts, and contacts more than unexposed controls. Thus, neither anergy nor a cytokine dysregulation explains susceptibility to acute TB disease in our cohort, although chronic TB patients produced less cytokines than did acute patients and less than asymptomatic contacts. Thirdly, a certain cytokine configuration may predict a trend of susceptibility to acquire, or not acquire, clinical TB. It is presently unclear whether this finding may explain the disease spread in large populations. Finally, the familial association of IFNg secretion levels probably points towards a genetic regulation of the immune response to Mycobacterium tuberculosis. 

Tumor necrosis factor-associated fever syndrome is an autosomal dominant disorder caused by mutations of the TNFRSF 1A gene encoding the 55 kD TNF receptor (p55 TNF-RI).

Background: Cell-mediated immunity is impaired in uremia. Cell-matrix interactions of immune cells such as CD4+T lymphocytes with extracellular matrix are an important requirement for an intact immune response. The adherence of CD4+T cells of healthy subjects (normal T cells) to ECM components is inhibited in the presence of uremic serum. Such decreased adhesive capacity is also found in T cells of dialysis patients. Various chemokines and cytokines affect the attachment of CD4+T cells to ECM.

Objective: To evaluate chemokine (MIP-1β and RANTES) and tumor necrosis factor α-induced adhesion of CD4+T cells to ECM in a uremic milieu.

Methods: We examined adhesion of normal CD4+T cells (resting and activated) to intact ECM in response to soluble or bound chemokines (MIP-1β and RANTES) and to TNF-α following incubation in uremic versus normal serum. Thereafter, we evaluated the adhesion of resting CD4+T cells from dialysis patients in a similar fashion and compared it to that obtained from a healthy control group.

Results: Addition of uremic serum diminished soluble and anchored chemokine-induced attachment of normal resting and activated CD4+T cells to ECM compared to a normal milieu (a peak response of 10–11% vs. 24–29% for soluble chemokines, P<0.001; 12–13% vs. 37–39% for bound chemokines on resting cells, P<0.01; and 18–20% vs. 45–47% for bound chemokines on activated cells, P<0.02). The same pattern of response was noted following stimulation with immobilized TNF-α (7 vs. 12% for resting cells, P<0.05; 17 vs. 51% for activated cells, P<0.01).  Adherence of dialysis patients’ cells to ECM following stimulation with both bound chemokines was reduced compared to control T cells (15–17% vs. 25–32%, P<0.0000). In contrast, adherence following stimulation by TNF-α was of equal magnitude.

Conclusions: Abnormal adhesive capacity of T lymphocytes to ECM in uremia may, in part, be related to a diminished response to MIP-1β, RANTES and TNF-α. However, whereas reduced adhesion to chemokines was present in both normal CD4+T cells in a uremic environment and in dialysis patients’ T cells, TNF-α-induced adhesion was found to be inhibited only in normal cells in a uremic milieu.

____________________________

ECM = extracellular matrix

TNF-α = tumor necrosis factor-a