SUMMARYT helper cell type 1 (Th1) and type 2 (Th2) immune responses are characterized by a different pattern of cytokine expression following T-cell activation. Alterations of the ratio of Th1 to Th2 cells are important determinants of susceptibility to viral and parasitic infections, allergies, antitumour responses, and autoimmunity. In this work we bring new evidence for an effect of haptoglobin (Hp), a positive acute-phase protein, on T-lymphocyte functions. We show that Hp specifically interacts with both resting and activated CD4 þ and CD8 þ T cells. This specific binding results in a strong suppression of induced T-cell proliferation. In addition, Hp exhibits a strong in vitro inhibitory effect on Th2 cytokine release, while the production of interferon-g (IFN-g) and interleukin-2 (IL-2) is only slightly inhibited at high Hp doses. As a result, the presence of Hp promotes Th1 activation over Th2 activation in vivo as evidenced in Hp-deficient mice. Anti-CD3 monoclonal antibody injection indeed resulted in predominant IL-4 production in Hp À/À mice, in contrast to predominant IFN-g production in Hp þ/þ mice. We conclude that Hp plays a modulating role on the Th1/Th2 balance by promoting a dominant Th1 cellular response. This points to a role of acute-phase proteins in balancing immune responses.

We have shown that the risk in HV allergic patients for misdiagnosis of multivalent pollen sensitization is 16%, and we have confirmed that sting induced anti-pollen sIgE are directed to similar CD in venoms and pollen. We found evidence that the recognition of CCD might be related to the 'atopic' trait. Importantly, a positive bromelain CAP test does not exclude clinical reactivity to both venoms in 'CCD positive' HV allergic patients.

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Our data provide evidence for systemic activation of the cellular immune system in patients with purely cutaneous DLE. Similarities in the lymphocyte immunophenotypic profiles in patients with DLE compared with SLE suggest that there are common immunopathological processes in these two conditions.

Reactivity toward soluble recall antigens (Candida albicans, cytomegalovirus, herpes simplex, streptokinase-streptodornase, and influenza) was determined in cultures of peripheral blood mononuclear cells from 41 rheumatoid arthritis patients (with clinically active as well as inactive disease) and from 28 controls. In the group with clinically active rheumatoid arthritis we found an increased incidence of "anergy," defined as nonreactivity to three or more antigens. In an attempt to explain this decreased antigen reactivity, the latter was correlated with peripheral blood lymphocyte subsets, as defined by two-color immunofluorescence with a panel of eight monoclonal antibodies. We found a significantly lower number of memory T4 cells (CD4+CD45RA-) and a significantly higher number of the CD3-CD57+ (nonspecific suppressor) cells and of CD3-CD56+/CD16+ (natural killer) cells in anergic RA patients. In the total group of rheumatoid arthritis patients, the antigen reactivity correlated positively with the percentage of memory T4 cells. Antigen reactivity was negatively correlated with the percentage of CD3-CD57+ cells and of the CD3- natural killer cells in peripheral blood. Our data suggest that a decrease in memory T4 cells and an increase in nonspecific suppressor cells may contribute to the impaired cellular immune function in peripheral blood of rheumatoid arthritis patients.