Immune restoration syndrome refers to acute worsening of disease symptoms in an HIV positive person infected with another infectious pathogen (such as tuberculosis) when effective antiretroviral therapy begins to restore immune function.

In a prospective, multicenter study, French researchers analyzed antibody responses and Mycobacterium tuberculosis clinical isolate genotypes in 24 consecutive HIV positive tuberculosis patients treated with HAART who either went on to develop a tuberculosis immune restoration syndrome (TB-IRS) or did not.

Circulating antibodies against ManLAM, ESAT-6/CFP10, and phenolic glycolipid TB (PGL-TB-1, a Mycobacterium tuberculosis-specific antigen) in HIV-TB coinfected patients were measured by ELISA at the initiation of anti-TB treatment, at initiation of HAART, and periodically thereafter.

The presence of circulating B-cells was also monitored by in vitro antibody production against ESAT-6/CFP10 and PGL-TB1. Finally, 16 out of 24 Mycobacterium tuberculosis clinical isolates from patients with TB-IRS were genotyped using spoligotyping and MIRUs-VNTR typing.

Results

• 11 of 24 patients (45.8%) experienced TB-IRS.

• TB-IRS patients had significantly lower anti-PGL-TB1 antibody compared to those without TB-IRS prior to development of TB-IRS.

• These very low levels were neither related to CD4 counts or complexed antibodies.

• No differences in antibody levels were observed with the other tested antigens.

• In addition, no specific TB strain genotype was associated with TB-IRS.

Conclusion

In conclusion, the study authors wrote, "The presence of specific anti-PGL-TB1 antibodies only in TB-IRS negative patients represents for the first time [emphasis added-Ed] an indicator of a potential protective response or a diagnostic biomarker for the detection of non-progression to TB-IRS in HIV-TB coinfected patients starting HAART."

Université Paris VII et Service de Microbiologie, Hôpital Saint-Louis, Assistance Publique--Hôpitaux de Paris, Paris, France.

6/06/08

Reference
N Simonney, G Dewulf, JL Herrmannn, and others. Anti-PGL-TB1 responses as an indicator of the immune restoration syndrome in HIV-TB patients. Tuberculosis (Edinb). May 19, 2008 [Epub ahead of print].

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