Human T-cell lymphotropic virus type I infection in Barbados: results of a 20-year follow-up study

Adult T-cell leukemia/lymphoma in South and Central America and the Caribbean: systematic search and review

Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South America. We performed a systematic search and review to identify publications on ATL in these countries to verify if this disease was getting recognition in these regions as well as the characteristics of the observed cases. The median age of 49.4 years was lower than that referred to in Japan. According to our findings in most Brazilian states and in some other countries, ATL is not being recognized and should be strongly considered in the differential diagnosis of T-cell leukemias/lymphomas. Failure to identify these cases may be due to the unsystematic realization of serology for HTLV-1 and phenotypic identification of non-Hodgkin lymphomas that may result from lack of resources. Detection of ATL cases has been more feasible with cooperation from foreign research centers. A huge effort should be made to improve the surveillance system for ATL diagnosis in most of the South- and Central-American and Caribbean countries, and this attitude should be embraced by public organs to support health professionals in this important task.

Reproducibility and correlations of multiplex cytokine levels in asymptomatic persons

RATIONALE

Cytokines are humoral regulatory molecules that act together in immunologic pathways underlying pathogenesis. Grossly elevated blood levels characterize certain diseases; variations within physiologic ranges could also have significance. We therefore evaluated the performance characteristics of a multiplex cytokine immunoassay.

METHODS

We used a fluorescent bead-based (Luminex) immunoassay kit to simultaneously measure interleukin (IL) 1beta, IL2, IL4, IL5, IL6, IL7, IL8, IL10, IL12p70, IL13, IFNgamma, granulocyte colony-stimulating factor, and tumor necrosis factor-alpha. We tested identical aliquots of serum from 38 asymptomatic individuals on three different days and matched sets of serum, heparinized plasma, and acid citrate dextrose plasma from an additional 38 healthy donors expected to have low cytokine concentrations. We applied multiple imputation to calculate unbiased reproducibility estimates for measurements below the limits of detection. Correlations among the cytokines were assessed by Spearman rank order coefficients and principal components analyses.

RESULTS

Of the 13 cytokines, 3 were undetectable (IL1beta, IL2, IL5) in more than half of the serum samples. Coefficients of variation for replicate serum measurements ranged from 18% to 44%, with intraclass correlation coefficients ranging from 55% to 98%. Only IL4, IL6, and IL8 had statistically significant correlations (Spearman rho, 0.42-0.94) between serum and acid citrate dextrose or heparin plasma levels.

CONCLUSIONS

Interindividual differences outweigh substantial laboratory variation for these assays, yielding high intraclass correlation coefficients despite unimpressive coefficients of variation. Plasma measurements generally are not reflective of serum levels and hence are not interchangeable. With their small volume, low cost per test, and multiplex capacity, Luminex-based cytokine assays have potential utility for epidemiologic studies.

Gender difference in skin reactivity to purified protein derivative among carriers of HTLV-I in Japan

The incidence of malignancies due to oncogenic virus infections tends to be higher in men than in women. Gender-related differences in cell-mediated immunity, which plays a role in viral pathogenesis, may explain this observation. To explore this possibility in the context of HTLV-I infection, we examined skin reactivity to purified protein derivative (PPD) among 128 residents of an HTLV-I endemic area in Japan, who were born before 1921 and are assumed to have been exposed to M. tuberculosis bacilli. The odds ratio (OR) for reduced PPD reactivity (erythema <10 mm in diameter) was calculated by multiple logistic regression analysis. Men were significantly less likely than women to have reduced PPD reactivity among HTLV-I-negative individuals (26% versus 59%; p < .01); whereas this gender difference was not apparent among HTLV-I carriers (63% versus 62%; p = .87). HTLV-I positivity was strongly associated with reduced PPD reactivity in men, but not in women (odds ratio [OR], 7.3 versus 1.2; p = .05). Although this observation may be due, in part, to a longer average duration of HTLV-I infection in men compared with women, the finding also raises the possibility that men may be inherently more susceptible to loss of PPD reactivity by HTLV-I infection.

Retesting of bone donors 2 months after donation guarantees sufficient safety of bone allografts

Both allogeneic bone grafting and blood transfusion may transmit infections from the donor to the recipient. The most effective means to reduce the risk of infection is careful donor selection and screening of donors for markers of infection. The risk of blood transfusion-transmitted HIV infection in Finland, calculated with the incidence/window period model, is approximately 1:3,300,000. The calculated risk for hepatitis B (HBV) and C (HCV) is 1:217,000 and 1:147,000 donations, respectively. In bone banking we can further reduce the risks by retesting the living donors. Retesting 2 months after donation seems to be sufficient, at least in countries with a low incidence of transplantation-transmitted infections.