Interstitial pneumonitis associated with human herpesvirus-6 infection after marrow transplantation.

Severe interstitial pneumonitis in 2 marrow-transplant recipients was associated with human herpesvirus-6 (HHV-6) infection. The virus was repeatedly detected in respiratory specimens from 1 patient, and HHV-6-infected cells were shown in lung tissue from both patients by immunohistochemical staining. The infected cells were primarily intra-alveolar macrophages, although infected lymphocytes were seen. HHV-6 should be considered as a cause of unexplained lung disease in marrow-transplant recipients and other immunocompromised patients.

Pneumonitis associated with coinfection by human herpesvirus 6 and Legionella in an immunocompetent adult.

The authors report a case of pneumonitis in a young healthy man caused by coinfection with human herpesvirus 6 (HHV-6) and Legionella pneumophila. The patient's course was complicated by severe respiratory, renal, hepatic, and central nervous system dysfunctions, which were believed to be primarily the results of his Legionella infection. Aggressive antibiotic treatment produced no response, and Legionella remained isolatable from lung tissue throughout several weeks of antimicrobial therapy. Human herpesvirus 6 was isolated from a sample of peripheral blood during the acute stage of the patient's illness, and numerous HHV-6--infected macrophages and lymphocytes were detected by immunohistochemical staining of biopsy-derived lung tissue. Paradoxically treatment of the patient with high-dose corticosteroids resulted in dramatic improvement of his condition, including clearance of the Legionella infection. The demonstration that corticosteroids efficiently inhibit HHV-6 replication in vitro suggests that the virus may have contributed to the patient's pneumonitis by enhancing tissue inflammation, by compromising the function of pulmonary macrophages, and, perhaps, by destroying the patient's CD4+ T lymphocytes. Human herpesvirus 6 may be able to function as a synergistic cofactor in lung infections by Legionella and other pathogens.

Duration of response to intramuscular versus low dose intradermal hepatitis B booster immunization.

OBJECTIVE: To determine the duration of the immune response to plasma-derived hepatitis B vaccine among healthcare workers responding to booster doses of intradermal (ID) or intramuscular (IM) vaccine in 1986 and those with protective levels of antibody to hepatitis B surface antigen (anti-HBs) in 1986 without booster vaccine. Both groups received a primary hepatitis B vaccine series 24 to 36 months earlier. DESIGN: Cross-sectional follow-up study two years later of an inception cohort defined in 1986. SETTING: An academically affiliated metropolitan county hospital. PARTICIPANTS: Group 1: Hospital employees responding to booster doses of hepatitis B vaccine given ID or IM in 1986 due to low anti-HBs levels. Forty-one (82%) of 50 eligible persons were evaluated. Group 2: Persons not receiving booster vaccine in 1986 due to protective levels of anti-HBs. A random sample of 95 persons was drawn from a pool of 152 participants with protective levels in 1986. Sixty-five (68%) of 95 contacted persons were restudied. RESULTS: In 1988, 14 (64%) of 22 previous ID responders had anti-HBs levels greater than or equal to 10 milli-international units (mIU)/mL, compared with 17 (89%) of 19 IM responders (p = .055). The 1988 geometric mean titer of IM recipients was 66.4 +/- 4.5 mIU/mL and of ID recipients was 20.7 +/- 7.4 (p = .04). None of 65 Group 2 subjects' anti-HBs titers dropped below 10 mIU/mL by 1988. CONCLUSIONS: Plasma-derived hepatitis B vaccine recipients with anti-HBs levels greater than or equal to 10 mIU/mL at 24 to 36 months after primary immunization are likely to maintain these levels two years later. The diminished durability of the antibody response together with the increased rate of local side effects associated with the ID injection route may limit its applicability as an alternative to using IM booster doses of hepatitis B vaccine.