Sir,I read with interest the case report by Gupta et al. published in the July–August 2017 issue of Lung India.[1] Till date, two hypotheses are present that could explain the simultaneous occurrence of tuberculosis (TB) and leprosy in the same individual, namely, coinfection and cross-immunity. The authors mentioned that the studied patient questions the cross-immunity theory, as the patient, with active TB developed leprosy.[1] I presume that the following point might be helpful in solving the mystery of development of TB and leprosy in the case in question. It is obvious that immunodeficient individuals are more vulnerable to wide spectrum, serious infections due to low immunity. Published data obviously appointed out to the contribution of human immunodeficiency virus (HIV) infection to the development of TB[2] and leprosy.[3] To the best of my knowledge, HIV infection is still a substantial health threat in India. The current national HIV prevalence is 0.26% compared with a global average of 0.2%.[4] Accordingly, I presume that underlying HIV infection ought to be considered in the case in question. Hence, the diagnostic algorithm of CD4 count and viral overload measurements was envisaged. If that diagnostic algorithm was achieved and it revealed underlying HIV infection, the case in question could be truly considered a novel case report as the co-occurrence of HIV, TB, and leprosy in a patient has never been reported in the literature so far.