Results of different strategies for reducing cytomegalovirus-associated mortality in allogeneic stem cell transplant recipients.

BACKGROUND: Several preventive strategies against cytomegalovirus (CMV) disease have been developed during the last decade. These have frequently been used in combination, and it has been difficult to identify each strategy's contribution. METHODS: Risk factors for CMV disease, death in CMV disease and transplant-related mortality were analyzed in 584 patients, who underwent a total of 594 allogeneic bone marrow transplants. RESULTS: The overall probability of CMV disease was 8.9%. No seronegative patient who had a seronegative marrow donor developed CMV disease. The corresponding probabilities for seronegative patients with seropositive donors, seropositive patients with seronegative donors, and seropositive patients with seropositive donors were 5.4%, 13.7%, and 11.7%, respectively. In multivariate Cox models, the use of preemptive antiviral therapy and being CMV-seronegative reduced the risk for CMV disease, CMV-associated death, and transplant-related mortality (TRM). Patients who received unrelated or mismatched family donor transplants had increased risks for CMV disease, CMV-associated death, and TRM. Older age was a significant risk factor for CMV disease and TRM. A total of 258 patients who were monitored by polymerase chain reaction for CMV DNA were analyzed separately to assess whether addition of another CMV preventive strategy could give benefit. Patients who received mismatched or unrelated donor transplants had increased risk for CMV disease, death in CMV disease, and TRM. High-dose acyclovir prophylaxis or addition of intravenous immune globulin had no influence. CONCLUSIONS: Preemptive therapy based on polymerase chain reaction for CMV DNA was associated with reduced risks for CMV disease, CMV-associated death, and TRM, whereas other prophylactic modalities did not give additional benefit.

Intravenous immune globulin affects cytokine production in T lymphocytes and monocytes/macrophages.

Immune globulin for intravenous use (IVIG) has been used in many inflammatory conditions due to its immunomodulatory potential. The effector mechanisms are incompletely understood. This study dealt with the effects of IVIG on cytokine production in vitro. Cytokine synthesis was identified at the single-cell level using cytokine-specific MAb and indirect immunocytochemical techniques. Peripheral blood mononuclear cells (PBMC) were stimulated for 96 h by immobilized anti-CD3 MAb or by a combination of a protein kinase C activator (PMA) and a calcium ionophore (ionomycin). The addition of IVIG (6 mg/ml) caused a marked inhibition of proliferation and blast transformation despite unaffected cell survival. Anti-CD3-stimulated cultures containing IVIG exhibited a significant inhibition of production of T-cell derived lymphokines IL-2, IL-10, TNF-beta, IFN-gamma and TNF-alpha (made by both monocytes and T cells), while synthesis of the monokine IL-8 was significantly increased. The expression of IL-2 receptors was significantly suppressed. Similar but transient inhibition of most T-cell products (IL-2, IL-3, IL-4, IL-5, IL-10, TNF-beta and GM-CSF) was noted in the PMA/ionomycin-containing cultures. In contrast, no effects were found on IFN-gamma or TNF-alpha production. The superantigen streptococcal pyrogenic exotoxin-A (SPE-A) induced vigorous cell activation and extensive cytokine synthesis. IVIG was added either at the beginning or 24 h after the initiation of cultures in order to elucidate the importance of direct toxin-neutralization. Addition of IVIG from the beginning of cultures induced a strong reduction of blast transformation and an almost complete inhibition of lymphokine production, in particular of IFN-gamma and TNF-beta. Supplementation with IVIG 24 h after initiation of cultures also led to a significant decrease in lymphokine synthesis. Monokine production (IL-1 alpha, IL-1 beta, IL-1ra, IL-6 and IL-8) was either unaffected or even increased. These two facts argue against direct antigen-neutralization as being the only mechanism at work. However, in IVIG-exposed PBMC stimulated with LPS, IL-6 production was significantly reduced. A significant upregulation of IL-1ra was noticed in unstimulated PBMC cultured with IVIG. The results in all the experiments did not indicate a cytotoxic effect by IVIG on cell survival and the production of certain cytokines were unaffected. Instead, the authors believe that the results suggest a previously little examined functional link where the humoral immune response may have direct immunoregulatory effects on the cellular immune system.