Impaired primary in-vitro antibody response in progressive systemic sclerosis patients: rôle of suppressor monocytes

The primary in-vitro antibody response developed by peripheral blood mononuclear cells (PBM) towards trinitrophenyl coupled to polyacrylamide beads (TNP-PAA) was evaluated in 17 untreated patients with progressive systemic sclerosis (PSS). This response was markedly depressed as compared with that of 19 control patients and 28 normal subjects. In eight PSS patients and eight normal controls the anti-TNP response was measured before, and after, a PBM filtration on nylon wool columns. This procedure dramatically reduced the proportion of monocytes identified as mononuclear cells staining positively for peroxidases, and restored the response of PSS PBM to the level observed in normal PBM. In four experiments, plastic-adherent cells from either normal subjects of PSS patients were added to autologous nylon-passed PBM. This did not modify the response from normal PBM but inhibited the response of PSS PBM. The inhibitory effect of PSS plastic-adherent cells was insensitive to a 2,000 R X-ray irradiation. These results strongly suggest that the impaired in-vitro antibody response observed in PSS can be attributed to a suppressor monocyte. The concanavalin-A-induced suppressor cells of the antibody response were assayed in PSS. They exerted a suppressive effect to the same extent as in controls.