A seroepidemiological study of human immunodeficiency virus infection in northeast Zaire.

To evaluate the incidence of human immunodeficiency virus type 2 infections in an endemic African area, we have studied 134 patients from Northeast Zaire. Sera were tested for HIV-1 and HIV-2 antibodies to asses cross-reactivity or a possible double infection. Sixty five (48.5%) serum samples were reactive for HIV-1 and six (4.5%) for HIV-2 using specific Western blots. The enzyme immunoassays used to detect HIV-2 showed cross-reactivity with HIV-1 in 17 samples (16.5%). Tests based upon synthetic peptides corresponding to specific from human immunodeficiency viruses confirm their ability to discriminate antibodies directed against both viruses in 42/47 samples (89.4%); in 5/47 (10.6%) this test could not distinguish double infection from cross-reactivity. We suggest that the high number of sexual partners may be responsible for HIV transmission in our study group.

PIP: To evaluate the incidence of human immunodeficiency virus type 2 infections in an endemic African area, the authors have studied 134 patients from Northeast Zaire. Sera were tested for HIV-1 and HIV-2 antibodies to assess cross-reactivity or a possible double infection. 65 (48.5%) serum samples were reactive for HIV-1 and 6 (4.5%) for HIV-2 using specific Western blots. The enzyme immunoassay used to detect HIV-2 showed cross-reactivity with HIV-1 in 17 samples (16.5%). Tests based upon synthetic peptides corresponding to specific glycopeptides from human immunodeficiency viruses confirm their ability to discriminate antibodies directed against both viruses in 42/47 samples (89.4%); in 5/47 (10.6%) this test could not distinguish double infection from cross-reactivity. The authors suggest that the high number of sexual partners may be responsible for HIV transmission in this study group. (author's)

A study of different parameters of cell-mediated immunity in patients with active and chronic tuberculosis.

A study was carried out on cell-mediated immunity in healthy persons and patients with tuberculosis in order to extend the diagnostic capacity in tuberculosis. We studied the relation between baciloscopy and the state of specific cell-mediated immunity in vivo (Mantoux) and in vitro (leukocyte migration inhibition assay with PPD-RT 23 to evaluate specific cell-mediated immunity and PHA to evaluate nonspecific immunity) in 131 patients with active tuberculosis, in 63 patients with chronic tuberculosis, in 62 healthy persons and 10 individuals living with tuberculosis patients. The results demonstrate that the percentage of reaction was very low in both tests, being of no statistical significance the difference between patients with active or with chronic tuberculosis, although it was significant in the control group. In about half of the patients with active tuberculosis a positive baciloscopy could be observed; the percentage was much lower in patients suffering from chronic tuberculosis, the difference between the two groups significant from a statistical point of view. At the same time when we carried out an evolutionary study in 10 patients with positive baciloscopy, we observed a slight capacity of conversion of immunity when the baciloscopy was negative.

Evaluation of the pre-S (pre-S(1)Ag/pre-S(2)Ab) system in hepatitis B virus infection.

The diagnostic and prognostic value of pre-S(1)Ag and pre-S(2)Ab was investigated in 69 HBsAg surface antigen positive patients--14 with acute hepatitis B, 30 with chronic liver disease (six chronic persistent hepatitis, 14 chronic active hepatitis, 10 with cirrhosis) and in 25 asymptomatic carriers. Pre-S(1)Ag was found in all patients with chronic hepatitis B virus (HBV) infection regardless of viral replication. In contrast, pre-S(2)Ab was not detected in any patients. Acute hepatitis was studied sequentially with periodic controls at 20 day intervals. Pre-S(1)Ag cleared before HBsAg in six of 14 (43%) patients who progressed favourably, and the two antigens cleared simultaneously in eight of 14 (57%) cases. Patients with early clearance of pre-S(1)Ag progressed favourably, thus indicating the prognostic value of this test, which, however, is still of limited practical application given the small temporal difference between the moment of clearance of the two antigens. The first markers to clear, however, were HBeAg and DNA-HBV, which showed significant differences with respect to the clearance of HBsAg. Moreover, pre-S(2)Ab appeared before HBsAb in 57.1% of our patients and was found in some patients before pre-S(1)Ag and HBsAg had cleared (42.8%), thus allowing complete viral clearance and acute HBV infection to be predicted earlier.