Detection of HIV-1 RNA in two consecutive blood donations screened negative for HIV antibodies

BACKGROUND AND OBJECTIVES

An unusual serological pattern of HIV-1 seroconversion in a blood donor is described. The seroconversion panel was used to investigate the sensitivity of existing screening assays.

MATERIALS AND METHODS

A volunteer blood donor who had given blood 79 times was diagnosed anti-HIV-1-antibody-positive. The heteroduplex mobility assay identified a subtype B HIV-1 strain. The frozen plasmas from the last four blood donations had been kept at -30 degrees C. They were thawed and aliquoted for subsequent testing.

RESULTS

The last two blood donations contained HIV-1 RNA, 2,800 copies/ml (October 26) and 170 copies/ml (November 23). Weak anti-p24 antibodies were detected by Western blot in the October 26 sample, and a clear p24 reactivity along with a faint gp160 reactivity was observed on November 23. HIV p24 antigen was undetectable in both samples. Out of 13 screening assays, only 6 gave positive results on the November sample and 7 negative results which were obtained by 1 competitive enzyme immunoassay (EIA) and 6 of the 9 sandwich EIAs.

CONCLUSION

Most sandwich EIAs gave prolonged false-negative results in the present case. p24 antigen testing was negative and would not have reduced the risk of HIV transmission.

Standardisation of muscular biopsy of gluteus medius in French trotters

Morphometric measurements were taken from 41 French trotters of various ages and both sexes. Biopsy location was determined for the dorsal compartment as being one-third of the distance from the tuber sacrale to the tuber coxae and for the ventral compartment as being one-third of the distance from the tuber coxae to the caudal Cd1-Cd2 intervertebral joint. Ten horses were biopsied at these 2 sites at a sampling depth equal to half the total depth of the compartment as measured by ultrasonography. The percentage of slow and fast myosin heavy chain fibres was measured by using an immunoenzymatic method. The depth of the dorsal and ventral compartments of the gluteus medius was significantly greater in males than in females. The depth of the ventral compartment was greater in the case of a straight hip than of a wide hip and was greater in young horses than in older horses. The ventral and the dorsal compartments were composed in the mid-portion of 81.3 and 75.6% of fast myosin heavy chains, respectively. It was concluded that the locations and sampling depths in the gluteus medius could be standardised in French trotters by taking into account anatomical references, sex, age and width of the hip.