Background: Common variable immunodeficiency (CVID) is a heterogeneous group of disorders with a wide range of clinical manifestations and immunological findings, which could possibly form the basis for classification into different phenotypes.

Objectives: This study was performed to distinguish between different clinical phenotypes in Iranian patients with CVID and compare complications and prognosis between these subgroups.

Methods: Ninety-three CVID patients were classified according to 5 clinical phenotypes: infections only (n=42), polyclonal lymphocytic infiltration (n=35), autoimmunity (n=10), malignancy (n=10), and enteropathy (n=9). The patients were further categorized into 4 groups based on age of diagnosis (cutoff, 13 years) and parental consanguinity.

Results: Grouping of patients showed that CVID children with parental consanguinity was the most frequent group (51%), followed by CVID children without parental consanguinity (21%), CVID adults without parental consanguinity (21%), and CVID adults with parental
consanguinity (7%). There were significant associations between the group of CVID children with parental consanguinity and the polyclonal lymphocytic infiltration (P=.011) and enteropathy (P=.048) phenotypes. This group also had a higher mortality rate than other groups (P=.014). High serum levels of immunoglobulin M (IgM) at the time of diagnosis were associated with the eventual development of autoimmunity (P=.023). The adjusted odds ratio (OR) for mortality in all phenotypes showed that mortality was significantly increased in patients with the polyclonal lymphocytic infiltration phenotype (Mantel-Haenszel OR=5.3, CI=3.42-6.2).

Conclusions: Parameters such as parental consanguinity and early onset of disease could describe a subgroup of CVID patients characterized by more complications, poorer prognosis, and a need for greater medical care and attention.

Key words: Common variable Immunodeficiency. Phenotyping. Consanguinity.