Polyclonal Antibody Secretion during Acute Graft‐versus‐Host Disease

Spontaneous plaque‐forming cells (S‐PFC) were followed in 67 bone marrow transplantation (BMT) recipients and 41 controls. Patients with no acute graft‐versus‐host disease (GVHD) had decreased IgA and IgM S‐PFC up to 7 weeks after BMT compared with controls. Patients with acute GVHD had increased lgG, IgA, and IgM PFC compared with controls and patients without GVHD during the first 4 weeks after BMT. The maximum number of S‐PFC increased with increasing severity of acute GVHD. However, at diagnosis of GVHD there was no difference in S‐PFC in patients who resolved their GVHD or in those who developed more severe GVHD. After 6 weeks, patients with acute GVHD had significantly decreased IgA and IgM S‐PFC compared with normal. No major changes in S‐PFC were induced during various infections. However, a patient who developed urticaria had a dramatic increase in S‐PFC. Patients studied more than a year after BMT had reduced IgM S‐PFC compared with controls. It is concluded that S‐PFC are redueed after BMT. but markedly enhaneed during acute GVHD.