The high-burden regions of Sub-Saharan Africa, which accounted for greater than 70% of the HIV epidemic, are disproportionately affected by the high rates of TB coinfection. This might be explained by, the low immune tolerance of the population due to malnutrition and chronic infections aggravating immune suppression. In this review, we discuss the immunopathogenesis of this common co-infection that causes significant morbidity and mortality in people living with HIV globally.
We used 118 published studies using a two-step search strategy. Initial search of Pub Med Central and Google Scholar was undertaken followed by an analysis of the keywords. A second search using all the reference list of all identified reports and articles was searched for additional studies. Literature published as of January 1, 1981, that meets the inclusion criteria were considered. Qualitative data was extracted from papers included in the review.
Mortality occurs at both ends of the immunological spectrum of TB at one end HIV uninfected patient dies from asphyxiation from acute massive hemoptysis due to cavitary TB; at the other end, and far more frequently HIV-infected patient with disseminated TB dies from overwhelming infection with less evidence of focal pathology. There is no clear sign that the HIV-TB epidemic is slowing, especially considering the emergence of increasingly drug-resistant strains of MTB. A major challenge for the future is to discover immune correlates of TB protection and TB disease risk. Failure to define this conclusively has hindered TB prevention strategies, including the design of new TB vaccines to replace BCG, which provides only short-lived efficacy, prevents severe forms of the extra-pulmonary disease and is contraindicated in PLHIV.
The understanding of TB and HIV infection through immunological advances needs to be combined to describe the complex interactions between TB and HIV and the effects of ART. This shall occur in animal models and on human samples, to provide advances to rapidly translate into clinical solutions. Improved understanding of protective immunity could enhance vaccination strategies. Understanding the complex interactions between the individual components of innate and acquired immune responses to TB and HIV infection is likely to be the next step forward.
Mortality occurs at both ends of the immunological spectrum of TB at one end controls dies from asphyxiation from acute massive hemoptysis due to cavitary TB; at the other end, and far more frequently, a people living with HIV with disseminated TB dies from overwhelming infection with less evidence of focal pathology. There is no clear sign that the HIV-TB epidemic is slowing, especially considering the emergence of increasingly drug-resistant strains of MTB. A major challenge for the future is to discover immune correlates of TB protection and TB disease risk. Failure to define this conclusively has hindered TB prevention strategies, including the design of new TB vaccines to replace BCG, which provides only short-lived efficacy, prevents severe forms of the extra-pulmonary disease, and which is contraindicated in people living with HIV. New candidate vaccines are being developed and some are currently being assessed in clinical trials, including people living with HIV, recently reviewed by Rowland and McShane. Hopefully, these studies will help define protective immune responses and demonstrate whether poly-functional immune responses correlate with protection from TB disease. New immunodiagnostics appropriate for people living with HIV would have the potential to improve disease outcomes through early diagnosis and, if able to differentiate exposure, infection and disease, could improve the delivery of preventative measures such as isoniazid preventative therapy, to those in greatest need.
Author: Prof. Maria Inge Lusida, Dr., Ph.D., M.Kes., Sp.MK(K)
Detailed information from this research can be seen in our article at:
Getaneh Y, qamariyah Khairunisa S., Husada D., Kuntaman K., and Lusida M. I. 淚mpact TB co-infections on immune tolerance among people living with HIV: a systematic review, HIV Res. Clin. Pract., vol. 24, no. 1, p., 2023, doi: 10.1080/25787489.2023.2270822.
