Helper inducer T cells in the lungs of sarcoidosis patients. Analysis of their pathogenic and clinical significance.

Phenotypic analysis of helper CD4+TQ1- cell population, the major helper T-cell subset for B-cell responses, was carried out in BAL fluid of sarcoidosis patients. Most of the BAL CD4+ cells lacked TQ1 membrane antigen. A correlation between the number of helper CD4+TQ1- cells and IgM and IgA levels was observed in 27 sarcoidosis patients' BAL. A role of CD4+TQ1- cells in modulating lung B-cell immunoglobulin secretion in sarcoidosis was confirmed by the fact that BAL IgG level and helper T-cell number correlated well in patients with low-intensity alveolitis. Results showed an inverse correlation between symptom duration and BAL IgM levels and CD4+TQ1- cell number. The number of helper cells was above normal in patients who had symptoms for less than 12 months and within normal range in those who had symptoms for more than that. The pathogenic and clinical relevance of these data is discussed.