Salivary immunoglobulins in recipients of bone marrow grafts. I. A longitudinal follow-up

Patients receiving bone marrow transplantation (BMT) are prone to a variety of bacterial, viral and fungal infections in their oral cavity. We have therefore followed alterations in salivary Ig levels associated with BMT. Most of the patients were transplanted with allogeneic, MHC-matched BM after T cells were depleted by ex vivo treatment with an anti-lymphocytic monoclonal antibody (Campath-1) and autologous complement. Parotid saliva was collected at various time internals before and after BMT, and IgM, IgG and IgA concentrations were determined by an enzyme linked immunosorbent assay (ELISA). A gradual fall in Ig levels was detected following patient's conditioning with a combination of chemo- and radiation therapy beginning 10 days prior to BMT. A rise in the titer of salivary Ig could be detected as early as 4 days post-BMT, which increased continuously and reached plateau levels within 2-3 weeks. However, about 3 weeks later the Ig titers decreased again and persisted at low levels for variable periods of time. A second increase in salivary Ig was detected approximately 2 months post-BMT, which persisted for prolonged periods of time. These results suggest that Ig secreted by donor B-lymphocytes and plasma cells passively transferred with the BM can rapidly reconstitute the salivary IgM, IgG and IgA of the immunocompromised recipient. However, when these cells cease to produce Ig the patients are still immunoincompetent and therefore enter a second phase of salivary Ig deficiency which may render them highly susceptible to opportunistic oral infections. A second and persistent increase in salivary Ig levels appears several months post-BMT, along with the overall reconstitution of hemopoiesis in the patient.