Expression of CS-1 fibronectin precedes monocyte chemoattractant protein-1 production during elicitation of allergic contact dermatitis.

BACKGROUND: Leucocyte migration within inflammatory skin compartments in allergic contact dermatitis (ACD) is the result of a sophisticated multi-step event where multiple molecules are involved. OBJECTIVE: Since non-antigen-specific mechanisms have been described as an early participant in elicitation of ACD, we investigated the kinetics of the expression of monocyte chemoattractant protein-1 (MCP-1/CCL2) and the type of infiltrating cells. We compared the time course production of MCP-1/CCL2 with connecting segment-1 (CS-1) fibronectin and thymus and activation-regulated chemokine (TARC/ CCL17) expression. METHODS: Biopsies from 10 individuals challenged in their back with the antigen responsible for their contact dermatitis and an irrelevant antigen were taken at different times and histology, immunohistochemistry for CS-1 fibronectin, TARC/CCL17, CD3, CD68, CXCR3, CCR4 and in situ hybridization for MCP-1/CCL2 were performed. RESULTS: At positive antigen stimulated sites expression of MCP-1/CCL2 by basal keratinocytes and isolated cells in dermis started at 10 h. CS-1 fibronectin and TARC/CCL17 expression by blood endothelial cells was found at 2 and 10 h, respectively. This was followed by dermal accumulation of mononuclear cells with a significant increase of CD3+ and CD68+cells. At 48 h, approximately 58% of infiltrating cells were CXCR3+, and 35% CCR4+. CONCLUSIONS: We showed evidence of the fact that CS-1 fibronectin expression precedes the production of MCP-1/CCL2 and TARC/CCL17 in the skin of patients with ACD, suggesting that these molecules participate in the early complex process of migrating mononuclear cells during elicitation of ACD.

Clinical signs and symptoms are not enough for the correct diagnosis of allergic conjunctivitis.

BACKGROUND: Allergic Conjunctivitis (AC) has a high incidence in the general population and sometimes it is difficult to make a correct diagnosis, distinguish among the different subtypes of AC, and therefore, to indicate the suitable therapy. OBJECTIVE: To determine the best way to carry out an appropriate diagnosis of AC. METHODS: Thirty-one patients with clinical manifestations of AC and eleven controls were studied by measuring allergic and immunologic parameters. Only those patients confirmed as having AC were treated with ketotifen fumarate and further evaluated. RESULTS: According to allergic and immunological parameters, patients were divided into two groups. Group I patients had positive prick test toward at least one allergen, 60% exhibited high levels of tear-IgE, and only 36% conjunctival eosinophils. By contrast, patients from Group II had negative prick tests and laboratory findings similar to the control group. In group I there was a good correlation between levels of tear-IgE and eosinophils (r = 0.55; p = 0.009); key symptoms and signs and prick test (r = 0.52; p = 0.015), and prick test and eosinophils (r = 0.50 p = 0.022). The cardinal signs and symptoms scores dropped significantly in Group I as a consequence of the treatment (p < 0.0001). CONCLUSION: In order to have a reliable AC diagnosis, allergen-skin prick test, IgE in tears, and conjunctival eosinophils must be studied. Serum IgE is less important.

Interleukin 2 induction of proliferation in resting T lymphocytes requires contact with monocytes.

Resting human T cells are known to express significant numbers of intermediate but none or barely detectable low and high affinity IL-2 receptors (IL-2R). IL-2 alone failed to induce proliferation in these cells. However, in presence of small proportion of autologous monocytes, as low as 22 pM, IL-2 induced high levels of proliferation in resting T cells. Introduction of a semi permeable membrane between the two cell types or addition of an anti-CD11b mAb inhibited such induction of proliferation by IL-2. Neither recombinant IL-1 nor IL-1-containing cell-free extracts from activated monocytes substituted for intact monocytes. Autologous B cells failed to replace monocytes. Using antigen-specific cloned human T cells we have shown a lack of requirement for antigen. The proliferation was inhibited by anti-IL-2R alpha mAb. IL-2 appears to be unique since neither IL-4 nor IL-6, alone or in presence of monocytes, led to induction of proliferation in resting T cells. Combination of IL-2 and monocytes induced proliferation in all T cell subpopulations (CD4+, CD8+, CD45RA+ and CD45RO+) and antigen-specific clones examined. It also induces mRNA and surface expression of IL-2R alpha, appearance of high affinity IL-2R and induction of proliferation in large proportions of T cells. As in humans, the IL-2 induction of proliferation in murine resting T cells required contact with syngeneic monocytes, suggesting that such a mechanism of T cells activation is highly conserved.

Interleukin 2 induction of proliferation in resting T lymphocytes requires contact with monocytes.

Resting human T cells are known to express significant numbers of intermediate but none or barely detectable low and high affinity IL-2 receptors (IL-2R). IL-2 alone failed to induce proliferation in these cells. However, in presence of small proportion of autologous monocytes, as low as 22 pM, IL-2 induced high levels of proliferation in resting T cells. Introduction of a semi permeable membrane between the two cell types or addition of an anti-CD11b mAb inhibited such induction of proliferation by IL-2. Neither recombinant IL-1 nor IL-1-containing cell-free extracts from activated monocytes substituted for intact monocytes. Autologous B cells failed to replace monocytes. Using antigen-specific cloned human T cells we have shown a lack of requirement for antigen. The proliferation was inhibited by anti-IL-2R alpha mAb. IL-2 appears to be unique since neither IL-4 nor IL-6, alone or in presence of monocytes, led to induction of proliferation in resting T cells. Combination of IL-2 and monocytes induced proliferation in all T cell subpopulations (CD4+, CD8+, CD45RA+ and CD45RO+) and antigen-specific clones examined. It also induces mRNA and surface expression of IL-2R alpha, appearance of high affinity IL-2R and induction of proliferation in large proportions of T cells. As in humans, the IL-2 induction of proliferation in murine resting T cells required contact with syngeneic monocytes, suggesting that such a mechanism of T cells activation is highly conserved.

Cytokines in adenoviral disease in children: association of interleukin-6, interleukin-8, and tumor necrosis factor alpha levels with clinical outcome.

To explore the pathogenic mechanisms involved in adenovirus infection, we evaluated total levels of immunoglobulins, antiadenovirus antibodies, adenovirus-specific circulating immune complexes, and cytokines in serum samples obtained from 38 hospitalized children with adenovirus infection. According to their clinical findings and outcome, the infections were classified as follows: (1) moderate (group I, n = 10), (2) severe (group II, n = 12), and (3) fatal (group III, n = 16). About 60% of the children had elevated IgM levels. IgG-containing adenovirus-specific circulating immune complexes were initially detected in 7 of 16 group III patients, 4 of whom had low serum levels of the third component of complement. A decrease in initial antiadenovirus IgG antibodies was observed in 3 of 10 patients in group III. Serum interleukin-6 was not detected in group I (none of 10), but was present in group II (7 of 12, p = 0.016) and group III (13 of 16, p < 0.001). Interleukin-8 was detected in all groups; values in fatal cases were significantly higher than in surviving children. Tumor necrosis factor alpha was not observed in group I (none of 10) and was uncommon in group II (2 of 12) but was frequently detected in group III (9 of 15, p = 0.01). Interleukin-1 and interleukin-4 were rarely detected in serum samples. Increased concentrations of interleukin-6, interleukin-8, and tumor necrosis factor alpha were associated with hypoperfusion, febrile peaks, tonic-clonic seizures, and septic shock. In 5 of 10 patients in groups II and III, autoantibodies specific for smooth muscle were found. Our findings indicate that high serum values for interleukin-6, interleukin-8, and tumor necrosis factor alpha are associated with severity of adenovirus infection.

Defect of NK regulation in HIV-infected patients.

PIP: In Buenos Aires, Argentina, health workers obtained peripheral blood samples from 22 HIV-infected people with either no symptoms or persistent lymphadenopathy to examine natural killer cytotoxicity (NKC) of asymptomatic HIV-infected (HIV+AS) cases and the effect of factors that regulate normal NKC. Researchers compared these results with those of 10 healthy heterosexual controls. Even though NK cells of the HIV+AS cases were present in the same numbers and functioned as well as those in the controls, an inducer of interferon (Concanavalin A or ConA) could not force the cell system in vitro which demonstrated NK defectiveness. NK response to ConA of HIV+AS cases was lower than that of the healthy controls (p.05). On the other hand, the NK response to a prostaglandin antagonist (Indomethacin or IM) matched that of the healthy controls. Cell supernatants from normal peripheral blood mononuclear cells increased normal NK cell function (p.001), but those from HIV+AS cases did not do so. Thus it appeared that the HIV+AS cases were unable to produce sufficient NK enhancer factors. Cell supernatants from HIV+AS reduced normal NKC below baseline (p.05) indicating the presence of NK suppressor factors. The researchers believed products of the arachidonic acid metabolism by the cyclooexgenase pathway, maybe PGE2, may have contributed to NK suppression since IM negated suppressor activity of cell supernatants from HIV+AS subjects on normal NK function. They concluded that reduced production of enhancing factors, additional release of inhibitory factors, and deficiency at the NK effector system are likely to be the underlying causes for NK deficient function in AIDS. They noted that these effects function synergistically.^ieng

Cryostat sections with tissue amastigotes of Trypanosoma cruzi as a substrate for Chagas' disease serology.

Sera from 30 chronic chagasic patients together with 52 control samples (34 with other pathological conditions and 18 from normal individuals) were titrated by the indirect immunofluorescent technique (IFA) on Trypanosoma cruzi amastigotes. Acetone-fixed cryostat sections of skeletal muscle of Rockland mice 10 days post-infection with the RA isolate of T. cruzi were used as substrate. Results were compared with titres obtained by conventional IFA on epimastigotes. All 52 control sera had amastigote titres less than or equal to 2 double dilutions (dd) as compared with epimastigote values. Out of the 30 chagasic samples, differences were greater than or equal to 4 dd (less than or equal to 1 log) for 22, 3 dd for 5 and less than or equal to 2 dd for the remaining 3, when comparing amastigote and epimastigote titres. These results show that the use of amastigotes in cryostat sections of infected tissue for performing Chagas' serology in a simple, adequate and sensitive method.