[Evaluation of a new rapid ELISA technique for detecting human cytomegalovirus antibodies (CMV). Applications in emergency blood transfusion and in organ transplantation]. / Evaluation d'une nouvelle technique rapide par Elisa de dépistage des anticorps anticytomégalovirus humain (CMV). Applications pour les transfusions sanguines en urgence et dans un contexte de transplantation d'organes.

Immunocubes can detect very low HCMV IgG levels with at least the same sensitivity as the reference technique: ELISA. Samples containing bacteria showed no particular interference on the test, and results for non-infected material were in agreement with those of ELISA. The rapid test did not give any false positive reactions even with samples from patients with very high antiherpes immunoglobulins levels. Samples from transplant patients at the beginning of seroconversion or diluted to IgG titers corresponding to ELISA cut-off values were always detected as positive by immunocubes. In view of the rapidity of the test, its high specificity, its ability to detect levels corresponding to extremely low IgG signals in ELISA, and the possibility of conserving objective proof of the test, we conclude that this rapid immunocube technique is of great interest for current serologic screening in an emergency context, especially for transfusion and organ transplantation.

[Serological confirmation of HIV infections in hospital practice: analysis of indeterminate western blot results]. / Sérologie de confirmation de l'infection par le VIH en pratique hospitalière: analyse des western blots indéterminés.

Among 770 Western blots for HIV-1 confirmation on sera from subjects at high risk for HIV infection, 4.3% (33 cases) were indeterminate. Isolated, stable, reproducible anti-gp 160 reactivity, highly suggestive of a nonspecific reaction, was found in 16% of cases. There were three other probably nonspecific patterns with anti-gp 160 and either anti-gp 41 or anti-gp 120 reactivities and thin, atypical bands. Two patterns with anti-p24 and either anti-gp 160 or anti-gp 120 reactivities were consistent with HIV-1 seroconversion. Reactivity directed solely against gag products was seen in 18% of cases. The repeat test, performed in 16 cases, showed an identical pattern in 3 cases, a modified pattern in 3 cases, negative results in 9 cases, and seroconversion in 1 case. No case of HIV-2 infection was detected. Indeterminate Western blot results reflect nonspecific reactivity in most instances but should nevertheless lead to the exclusion of technical artefacts, seroconversion, and HIV-2 infection.

[Estimated biological markers of progression in human immunodeficiency virus infection]. / Marqueurs biologiques prévisionnels d'évolution au cours de l'infection par le virus de l'immunodéficience humaine.

The biological markers for determining as early as possible the progression in the infection by the human immunodeficiency virus (HIV) are very important for the health care of patients, and to adapt their anti-retroviral treatment. Among those, four independent biological markers for predicting a pejorative evolution in the following 36 months are used in medical practice: two specific for HIV, p24 antigenemia and serum titre of antibodies to the p24 core antigen, and two non-HIV specific surrogate markers, the beta 2-microglobulinemia and the absolute number of CD4 T cell in blood. P24 antigenemia corresponds to an active retroviral in vivo replication. The cut off for detection is about 10 pg/ml. It is difficult to detect in black people, and in the asymptomatic or pauci-symptomatic stages of the disease. The apparition or the increase of the serum p24 antigen levels suggest the occurrence of opportunistic infections. P24 antigenemia decreases or disappears during the treatment by zidovudine. The diminution or the disappearance of serum antibodies directed to the p24 core protein are secondary to the deficiency of the humoral immunity, and to an increase of the viral replication, which occur at the late stage of the disease. The diminution or the disappearance of serum antibodies to p24 precede the occurrence of AIDS by several months. The increase of the serum beta 2-microglobulin level is associated with the severity of the disease. In the San Francisco prospective cohort, the progression to AIDS in 36 months was 69% when beta 2-microglobulinemia was more than 5 mg/l, 33% when it was between 3.1 to 5 mg/l, and 12% when it was less than 3 mg/l. The beta 2-microglobulin intra-thecal synthesis level could serve as a marker for the specific HIV encephalitis. The CD4 lymphocyte count constitutes an independent provisional marker for progression to AIDS, probably the most important, but mainly of statistical value. A lymphocyte count of 200 CD4/mm3 is considered as the threshold of full blown AIDS. Beside these classic biological markers, numerous other parameters have been evaluated, without knowing their practical interest. Although the predictive markers for AIDS have a real statistical significance, their interpretation could be difficult or hazardous when applied to a sole individual. In a relatively short delay, the actual biological markers will probably be completed or changed, in the routine medical practice, by the use of direct virological markers evaluating the viral load (plasmatic or cellular viremia).