JAK3 and pelvic inflammatory disease: Atypical JAK3-deficiency has been described previously.[4,7,8,12–14,16,18,19] Some studies suggested that specific JAK3 mutations may be hypomorphic or revertant mosaicism, thus allowing JAK3 mediated signal transduction.[12] Siblings with the same JAK3 mutations may have greatly different clinical manifestations, one with typical PID manifestations, while the other nearly normal.[8,15,16] Some patients with JAK3 heterozygous mutation or without a JAK3 mutation still developed the classical PID phenotype seen with JAK3 insufficiency.[15,16,18]