Martha A. Redus

Factors influencing HIV-1 banding patterns in miniaturized Western blot testing of dried blood spot specimens

In the HIV Seroprevalence Survey among Childbearing Women (SCBW), antibodies to human immunodeficiency virus type 1 are detected using enzyme immunoassays (EIA) and Western blot (WB) methods modified to accommodate samples of blood dried on special collection paper. Dried blood spot (DBS) eluates positive by EIA are tested by one of two WB methods, the miniblot technique using equipment from Immunetics Corporation and the PBS Integra assay (pageblot) from Genetic Systems. In this report we compared the performance of the two WB methods. The identity and position of the viral proteins on the WB were identified using monoclonal antibodies and monospecific antisera. The blots differed substantially in their composition and concentration of viral glycoproteins. Performance of the WB assays with DBS elution buffers from different EIA kits was equivalent except for samples eluted in the Abbott buffer, which reduced detection of antibodies to the p31, p51, p55, and p66 viral proteins. Case classification of DBS, positive sera, dilution curve samples, and seroconversion panels was equivalent by both tests in the presence of all elution buffers. Proficiency evaluation panels sent to SCBW participating laboratories over a 3-year period were used to note the differences between the two WB methods in detection of antibodies to the viral glycoproteins.

Diagnosis of Human Ehrlichiosis with the Indirect Fluorescent Antibody Test: Kinetics and Specificity

Human ehrlichiosis, an acute febrile illness caused by Ehrlichia canis or a closely related rickettsial organism, was first recognized in 1986. Previously, the only Ehrlichia species known to infect humans was E. sennetsu, the agent responsible for sennetsu rickettsiosis, a disease that has been reported only in Japan and Malaysia. Laboratory diagnosis of rickettsial diseases, including human ehrlichiosis, is based primarily on serologic testing. The indirect fluorescent antibody test for detection of antibodies to E. canis in dogs was developed in 1972 and adapted for human use in 1986. From 1986 through 1988, sera from 85 patients demonstrated a fourfold rise in antibody titer to E. canis. Dates of onset of illness were available for 65 (76.5%) of these patients. A total of 160 sera were tested from these patients. The geometric mean titer rose sharply during the first 3 weeks of illness and slowly thereafter, peaking at 1280 (reciprocal titer) six weeks after onset. Titers were 280 in 7 (22%) of the 32 patients initially tested during the first week of illness, in 17 (68%) of 25 patients tested initially during the second week, in 100% of 18 patients tested initially during the third week, and in 11 (92%) of 12 patients tested initially during the fourth week. All the patients tested after the fourth week of illness had seroconverted. Of the 85 patients confirmed to have ehrlichiosis, 54 (63.5%) did not have diagnostic titers to any other rickettsial antigen. The remaining 31 (36.5%) patients with ehrlichiosis also had titers considered diagnostic of infection with Rickettsia rickettsii, R . typhi, or Coxiella burnetii; but in most of these patients, these diagnoses were not supported by epidemiologic or clinical evidence. Our results emphasize that patients who are suspected of having a tick-borne infection should be tested against E. canis as well as against the other rickettsiae.

Comparison of B1912 and Clofazimine (B663) in Mycobacterium leprae Infections

Summary The effect of clofazimine was compared with another, more newly developed rimino-compound, B1912, in M. leprae infections in mice. The two drugs were found to have very similar activity.

Discontinuous Administration of Clofazimine (B663) in Mycobacterium leprae Infections

Summary The prophylactic and spaced administration of clofazimine was studied. The drug had an effect when given orally for 2 days immediately after infection, but had no effect when given 5 weeks before infection. When given once every 4 weeks from Day 70 to Day 140 after infection, the drug had a distinct effect. It was also active when injected intraperitoneally on the day of infection.