Role of CD4:CD8 ratio in predicting HIV co-infection in patients with newly diagnosed tuberculosis

Sensitivity and specificity of the mean corpuscular volume and CD4/CD8 ratio in discriminating between rifampicin resistant and rifampicin sensitive tuberculosis

Background

There is need for simple, cost effective and widely available point of care tests for low level health facilities in developing countries to screen for drug resistant tuberculosis (TB) after bacteriological confirmation of TB by smear microscopy. We evaluated the sensitivity and specificity of the mean corpuscular volume (MCV) and CD4/CD8 ratio in discriminating between rifampicin resistant (RR-TB) and rifampicin sensitive (RS-TB) tuberculosis.

Methods

We performed a secondary analysis of data from a cross sectional study that enrolled adult participants with bacteriologically confirmed pulmonary TB at a national tuberculosis treatment center in Uganda. Blood samples were tested for CD4 and CD8 cell counts, HIV serology and a full hemogram. Rifampicin sensitivity and the bacillary load grade were determined by Xpert MTB/RIF®. Fifty-five participants that had RR-TB (cases) were matched with 110 participants that had RS-TB (controls) for age, sex and HIV status in a ratio of 1:2 respectively. Sensitivity (Se), specificity (Sp), area under curve (AUC) analysis and determination of optimal cut-offs were performed using receiver operating characteristic curves.

Results

Cases differed from controls with respect to residence (p = 0.031), bacillary load grade (p < 0.010) and MCV (p = 0.021). The Se, Sp and AUC of the MCV (cut-off of > 74.6 femtolitres (fl)) were 88.9%, 34% and 0.607 (p = 0.021) respectively for RR-TB. Among HIV positive participants, the respective Se, Sp and AUC of the MCV for RR-TB (cut-off of > 72.5 fl) were 97.2%, 22.2% and 0.608 (p = 0.061). The respective Se, Sp and AUC of the CD4/CD8 ratio (cut-off of > 0.40) were 67.3%, 50.0% and 0.559 (p = 0.199) on the overall and 54.1%, 71.6% and 0.628 (p = 0.024) among the HIV positive participants for RR-TB.

Conclusion

The MCV had a high sensitivity but very low specificity for RR-TB. The CD4/CD8 ratio had a low sensitivity and specificity for RR-TB among HIV positive individuals. The utility of either test is low due to low diagnostic accuracy.

Mapping quantitative trait loci for T lymphocyte subpopulations in peripheral blood in swine

Background

Increased disease resistance through improved general immune capacity would be beneficial for the welfare and productivity of farm animals. T lymphocyte subpopulations in peripheral blood play an important role in immune capacity and disease resistance in animals. However, very little research to date has focused on quantitative trait loci (QTL) for T lymphocyte subpopulations in peripheral blood in swine.

Results

In the study, experimental animals consist of 446 piglets from three different breed populations. To identify QTL for T lymphocyte subpopulations in peripheral blood in swine, the proportions of CD4+, CD8+, CD4+CD8+, CD4+CD8-, CD4-CD8+, and CD4-CD8- T cells and the ratio of CD4+:CD8+ T cells were measured for all individuals before and after challenge with modified live CSF (classical swine fever) vaccine. Based on the combined data of individuals from three breed populations, genome-wide scanning of QTL for these traits was performed based on a variance component model, and the genome wide significance level for declaring QTL was determined via permutation tests as well as FDR (false discovery rate) correction. A total of 27 QTL (two for CD4+CD8+, one for CD4+CD8-, three for CD4-CD8+, two for CD4-CD8-, nine for CD4+, two for CD8+, and eight for CD4+:CD8+ ratio) were identified with significance level of FDR < 0.10, of which 11 were significant at the level of FDR < 0.05, including the five significant at FDR < 0.01.

Conclusions

Within these QTL regions, a number of known genes having potential relationships with the studied traits may serve as candidate genes for these traits. Our findings herein are helpful for identification of the causal genes underlying these immune-related trait and selection for immune capacity of individuals in swine breeding in the future.

Concomitant pleural and disseminated tuberculosis in AIDS: immune response or HIV infection compartmentalization?

Although, pleural (PT) and disseminated tuberculosis (DT) have been considered as extreme endpoints of the Th1-Th2 immunological spectrum of the Mycobacterium tuberculosis infection, these conditions can occur together. The presence of PT and DT could be explained by (1) PT as primary condition, with progression of HIV infection possibly leading to dissemination of bacilli located in the pleura; (2) preexisting PT, with reinfection at lower LTCD4+ count explaining the DT form; (3) simultaneous acute PT and DT, considering immune compartmentalization phenomena in pleura. There are several important aspects of the immune response and its compartmentalization in co-infected patients with tuberculosis and HIV. PT and DT should not be always considered as extremes of the immunological response against M. tuberculosis, both diseases together may be explained after the understanding of compartmentalization of immune response. Associations between these entities are not so rare, while they remain incompletely explained. This brief review discusses several points of this contradictory association.

Drug–drug interactions and tolerance in combining antituberculosis and antiretroviral therapy

Worldwide, tuberculosis (TB) is one of the most important infectious diseases in subjects with HIV infection. Although effective therapy is available for both conditions, there are major problems in the concurrent treatment of HIV and TB co-infection. In this article the knowledge available on drug-drug interactions between anti-HIV and anti-TB compounds is analysed, particularly with regard to pharmacological interactions secondary to interference with cytochrome P450 enzymes. Within the same setting, facts and possible interpretations of the problems encountered in terms of tolerance and safety of the concurrent treatment of TB and HIV are also reviewed. Current guidelines, as well as additional possible strategies to be adopted in this particular co-morbidity setting are discussed.

Comparison of CD4 and CD8 lymphocyte counts in HIV-negative pulmonary TB patients with those in normal blood donors and the effect of antitubercular treatment: hospital-based flow cytometric study

BACKGROUND

This study was designed to flow cytometrically determine baseline and sequential values of CD4 and CD8 lymphocyte subsets in patients without the human immunodeficiency virus and with pulmonary tuberculosis (TB) and to correlate these values with those obtained from normal male blood donors and with the radiologic extent of disease and response to therapy.

METHODS

We studied 39 male patients without the human immunodeficiency virus and with sputum positive for pulmonary TB who had been admitted to Military Hospital (Cardiothoracic Center) in Pune, India. Clinical, laboratory, and radiologic evaluations of these patients were done. Hematologic parameters were assessed by an automated hematology cell counter (AcT*Diff, Coulter), and T-cell subsets (CD4 and CD8) were determined flow cytometrically (EPICS-XL, Coulter).

RESULTS

CD4 counts and percentages of CD4 were significantly lower, but CD8 values were normal, in patients with pulmonary TB when compared with values obtained in normal blood donors. The CD4/CD8 ratio was significantly lower in patients with TB. The CD4 counts normalized with antitubercular treatment. The radiologic extent of disease did not correlate well with the immune parameters studied.

CONCLUSIONS

TB is a reversible cause of CD4 lymphocytopenia and is associated with normal numbers of CD8 cells. The radiologic extent of disease does not seem to determine the immune response.