We stimulated the referral of patients under the age of 35 years, with clinical features suggestive of immune deficiency to the single immunology clinic in the country, where these patients were investigated for the presence of PIDD. Stool samples from patients with PIDD were cultured for the presence of poliovirus (PV). Poliovirus isolates were tested for intratypic differentiation (ITD). The VP1 region of all poliovirus isolates was sequenced.
Of 942 patients investigated, 51 (5.4 % ) were diagnosed with PIDD. Five (10.2 % ) patients excreted poliovirus. A patient with X linked agammaglobulinemia (XLA) excreted a mixture of all three Sabin like (SL) poliovirus serotypes. One patient with severe combined immune deficiency (SCID) excreted SL type 2, and another with SCID excreted SL type 3. One patient with SCID excreted a P2 vaccine-derived poliovirus (VDPV 2), and another with common variable immune deficiency (CVID) excreted a VDPV 3. The 3 patients with SCID died before scheduled collection of subsequent samples one month later, while the patient with XLA had cleared the virus in stool sample collected after 3 and 11 months. The CVID patient with VDPV 3 excreted for 7 months, and has developed a 23 nucleotide divergence in VP1 (¡«900 nucleotides) from the parental Sabin virus.
In our study, several patients with SCID, XLA and CVID excreted poliovirus. With improving health care quality patients with CVID and XLA may survive longer especially with provision of intravenous immune globulin. Regular screening of patients with PIDD for excretion of poliovirus is necessary to identify chronic excretors and make available specific therapies.