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Rheumatologic manifestations in patients with selected primary immunodeficiencies evaluated at the University Hospital.

OBJECTIVE
To characterize an IgA deficient and common variable immunodeficiency (CVI) group of patients in terms of the presence of rheumatologic manifestations.


BACKGROUND
Although the molecular basis of some of the primary immunodeficiencies has been elucidated, it has not been possible to explain why in most cases these conditions are often associated with autoimmune manifestations, besides infections. The concomitant inability to fight infections adequately (immunodeficiency) and an inordinate reaction of the immune system to self components (autoimmunity) has been a perplexing situation.


METHODS
The clinical and immunological profile of 71 patients fulfilling the diagnostic criteria of selective IgA deficiency (n=38) and common variable immunodeficiency (n=33) were evaluated for concurrent rheumatologic manifestations after a thorough medical history, physical examination and pertinent immunological parameters.


RESULTS
The most common autoimmune conditions identified in patients with selective IgA deficiency were Crohn's disease and systemic lupus erythematosus (SLE); while immune thrombocytopenic purpura and Crohn's disease were the most common disorders associated to CVI. Anti-IgA antibodies were only found in 26.6% (95% C.I. 10.1-51.4) of patients with selective IgA deficiency but were present in all patients with that condition and SLE. Fifty per cent patients with CVI and ITP exhibited ANA positivity.


CONCLUSIONS
The IgA-deficient group of patients in this study showed a higher prevalence of autoimmune conditions and greater positivity for ANA as compared to patients with CVI. In contrast to other reports with around 44% positivity of anti-IgA antibodies in selective IgA patients these were only present in 263% of patients with that disorder in this study. The high prevalence of antinuclear antibodies not associated with any clinical autoimmune condition in the IgA-deficient patients in this study will need to be further explored to ascertain why IgA-deficient patients may be at an increased risk of autoimmunity. Inflammatory bowel disease (Crohn's disease and ulcerative colitis) constituted the most common clinical autoimmune manifestations in both groups of patients studied. ITP was the commonest organ-specific autoimmune condition identified in the CVI group, as reported in previous publications. The limited number of patients studied does not allow a reliable estimate of the prevalence of SLE in the IgA-deficient population analyzed. The observed differences in frequency of positive antibodies and clinical autoimmune conditions in our patients cannot be taken as typical due to the limited number examined and the exclusion of pediatric cases in the IgA deficient group. A continued surveillance of these patients might help to establish more definite tendencies regarding rheumatologic manifestations in primary immunodeficiencies.