Novel CD4 and CD8 T-cell subsets

Relationship between Vitamin D, Inflammation and Lung Function In Patients with Severe Uncontrolled Asthma

BACKGROUND

Recently epidemiological studies showed that low vitamin D is linked to airway hyperresponsiveness, decreased lung function, poor asthma control, and steroid-resistant asthma.

AIM

We investigated the relationship between Vitamin D, inflammation with circulating IL-33 and lung function in 30 patients with severe uncontrolled asthma.

MATERIALS AND METHODS

The study included 30 patients with severe uncontrolled asthma. In each of them were measured serum levels of IL-33 and Vitamin D by the ELISA method. The pulmonary function is measured by basic spirometry parameters, FEV1. The results were statistically elaborated according to the Pearson's Correlation Tests.

RESULTS

The results showed statistically insignificant correlation between Vitamin D and IL-33, and Vitamin D with FEV1 (Vit.D/IL-33; r = 0.11323, p = 0.551); (Vit.D/FEV1; r = -0.1005; p = 0.597) Correlation between IL-33 and FEV1 is negative but statistically significant (IL-33/FEV1; r = -0.5248; p = 0.003).

CONCLUSION

Because there are little studies about the link between vitamin D and asthma, further research to clarify the mechanism how vitamin D control the activity of CD4+ T cells and the related Th2-type cytokines in the parthenogenesis of asthma.

CD8(+) T cells producing IL-3 and IL-5 in non-IgE-mediated eosinophilic diseases

The cytokines IL-5, IL-3, and GM-CSF are crucial for eosinophil development, survival, and function. To better understand their role in non-IgE-mediated eosinophilic diseases, we investigated plasma levels of these cytokines as well as cytokine expression in peripheral blood T cells. While we did not find any evidence for an involvement of T-cell-derived GM-CSF, some of these patients did show an increased proportion of IL-5- or IL-3-producing CD4(+) T cells. However, in a significant proportion of patients, IL-5-producing CD8(+) T cells, so-called Tc2 cells, which in healthy donors can only be detected at very low levels, were prominent. Furthermore, increased IL-3 production by CD8(+) T cells was also observed, strongly supporting the notion that CD8(+) T cells, not just CD4(+) T cells, must also be considered as a potential source of the cytokines promoting eosinophilia.

Acute generalized exanthematous pustulosis, a clue to neutrophil-mediated inflammatory processes orchestrated by T cells

PURPOSE OF REVIEW

Circumstantial evidence exists that certain neutrophilic inflammatory processes are regulated by T cells, but how this occurs is not well understood. The present review presents data on how T cells may directly orchestrate a neutrophilic inflammation by specific release of the neutrophil-attracting chemokine CXCL8 (formerly known as interleukin-8).

RECENT FINDINGS

Acute generalized exanthematous pustulosis (AGEP) is an uncommon cutaneous eruption that is most often provoked by drugs, by acute infections with enteroviruses, or by mercury. It is characterized by acute, extensive formation of nonfollicular sterile pustules on an erythematous background, fever and elevated numbers of blood neutrophils. Involvement of T cells in drug-induced AGEP was suggested by positive patch tests and lymphocyte transformation tests. Moreover, drug-specific CD4+ and CD8+ T cells could be isolated and propagated in vitro from patch test sites and blood from AGEP patients. Their main characteristic is a high level of CXCL8 production.

SUMMARY

T cells are involved even in some neutrophil-rich inflammatory responses, and they may orchestrate the immune reaction directly by high CXCL8 production or indirectly via interleukin-17 production, which induces CXCL8 production in various cell types. AGEP serves as a valuable model for characterizing T cells with a particular function--namely production of CXCL8--leading to neutrophilic inflammation. It is tempting to speculate that elucidation of this pathomechanism will help to improve our understanding of similar neutrophilic eruptions (e.g. pustular psoriasis) and may reveal new targets for pharmacotherapeutic interventions in such diseases.

Modulation of CD4 T cell function by soluble MHC II-peptide chimeras

Peptides antigens of 8 to 24 amino acid residues in length that are derived from processing of foreign proteins by antigen presenting cells (APC), and then presented to T cells in the context of major histocompatibility complex molecules (MHC) expressed by APC, are the only physiological ligands for T cell receptor (TCR). Co-ligation of TCR and CD4 co-receptor on T cells by MHC II-peptide complexes (signal 1) leads to various T cell functions depending on the nature of TCR and CD4 co-ligation, and whether costimulatory receptors (signal 2) such as CD28, CTLA-4, CD40L are involved in this interaction. Recently, the advance of genetic engineering led to the generation of a new class of antigen-specific ligands for TCR, i.e., soluble MHC class I-, and MHC class II-peptide chimeras. In principle, these chimeric molecules consist of an antigenic peptide which is covalently linked to the amino terminus of alpha-chain in the case of MHC I, or beta-chains in the case of MHC II molecules. Conceptually, such TCR/CD4 ligands shall provide the signal 1 to T cells. Since soluble MHC-peptide chimeras showed remarkable regulatory effects on peptide-specific T cells in vitro and in vivo, they may represent a new generation of immunospecific T cell modulators with potential therapeutic applicability in autoimmune and infectious diseases. This review is focused on the immunomodulatory effects of soluble, MHC class II-peptide chimeras, and discuss these effects in the context of the most accepted theories on T cell regulation.