One year follow-up study of T-cell subsets and incidence of seropositivity for HTLV-I and HTLV-III antibodies in patients treated "on demand" or sporadically with clotting concentrates.

A 1-year follow-up study of the T-cell subset abnormalities was carried out in 16 severe haemophilia A patients, treated "on demand" with an average amount of 500 U/kg/yr of factor VIII concentrate (group A) and in 15 mild haemophiliacs or von Willebrand patients treated only sporadically with less than 3000 U of factor VIII and no longer exposed to any other blood component in the 2 years preceding the beginning of the study (group B). In group A, 50% and 70% of patients showed a reduced or inverted T 4/T 8 ratio, respectively, at the beginning and at the end of follow-up. These values were of 30% and 20% in patients of group B, suggesting a long-lasting effect of concentrate therapy on T-cell subsets. The low T 4/T 8 ratio was mainly due to an increase of suppressor cells. None of the patients was found positive for anti HTLV-I, whereas 3 patients, all belonging to the group A, showed antibodies against HTLV-III. Thus, in these patients, HTLV-III seems not to be the only cause of low T 4/T 8 ratio.

Epidemiological survey of HIV infection in the Veneto region of Italy.

A seroepidemiological survey of the Veneto region was undertaken to determine the prevalence of HIV antibodies in the sera of subjects belonging to known risk groups for AIDS and related conditions. The sera were tested by ELISA and confirmed by radioimmunoassay (Western blot). Of the AIDS patients sero-positive for HIV antibodies, 55% (6/11) were from the intravenous drug abuser group and 18% (2/11) from the homosexual group. A similar trend was seen in seropositive LAS patients, 85% (88/104) belonged to the drug abuser group and 6% (6/104) to the homosexual group. In seropositive asymptomatic subjects 83.7% (426/509) came from the drug abuser group and 4.9% (25/509) from the homosexual group. Thus drug abusers appear to be the major risk group in the Veneto region. They give rise to another risk group namely children born to seropositive drug abuser women. The seropositivity for HIV antibodies was low (0.02%) in subjects not in any risk group. Antibodies to HIV can be detected in amniotic, vitreous and cerebrospinal fluids as well as in sera.

LAV/HTLV-III neutralizing antibodies in the sera of patients with AIDS, lymphadenopathy syndrome and asymptomatic seropositive individuals.

Serum samples which had previously been found positive for LAV/HTLV-III antibodies by the ELISA test and then confirmed by radioimmunoassay (Western blot) were tested for the presence of neutralizing antibodies. No neutralizing activity was found in the sera of a group of patients with the clinical diagnosis of AIDS. However in patients with LAS and other related pathologic conditions the percentage of sera positive for neutralizing antibodies was 27% and 55% respectively. At least 50% of the sera from seropositive asymptomatic individuals had neutralizing activity but with the exception of the haemophiliac group the mean titre was much lower than that of LAS patients. No relationship was found between the neutralizing titre and the antibody specificity detected by Western blot analysis for p41 and p120.