T helper cell (Th) subsets producing interleukin 4 (IL-4) or gamma interferon (IFN) play a reciprocal role in the regulation of human IgE synthesis. Though necessary, IL-4 alone was insufficient. Patients with hyper-IgE had significantly lower proportions of T-cells that produce IFN and TNF, but not IL-2 or IL-4. In patients with helminth infections or atopy production of IgE and eosinophilia may result from expansion of Th-2-like cells. T cell clones (TCC) specific for allergens and Toxocara canis (TES) showed dichotomy in cytokine secretion. Non-atopic donors gave insufficient TCC for comparison. Activation of the fibroblasts of the respiratory mucosae induces production of interstitial proteins such as collagen III, V, fibronectin.